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Hematopoietic stem cell transplantation

When primary immunodeficiency is likely to cause significant harm or death, an allogeneic hematopoietic stem cell transplant (HSCT), more commonly known as a bone marrow transplant (BMT), may be the best treatment option.

Primary immunodeficiency (PI) causes a wide spectrum of symptoms with varying severity. Some forms of PI are mild and don't cause significant harm, or may be effectively treated with agents like immunoglobulin (Ig) replacement therapy. Other forms of PI are so severe that individuals have a very poor quality of life or can die as a result of their disease. When PI is likely to cause significant harm or death to someone, an allogeneic hematopoietic stem cell transplant (HSCT), more commonly known as a bone marrow transplant (BMT), may be the best treatment option.

Some common indications for allogeneic HSCT include severe combined immunodeficiency (SCID), Wiskott-Aldrich syndrome (WAS), chronic granulomatous disease (CGD), leukocyte adhesion deficiency (LAD), immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome, X-linked lymphoproliferative disease (XLP), hyper IgM syndrome, combined immune deficiency (CID), and hemophagocytic lymphohistiocytosis (HLH). Allogeneic HSCT can also be considered for other forms of PI.

How hematopoietic stem cell transplantation works

Illustration of Hematopoietic stem cell production.

Immune system cells develop from special cells that live in the bone marrow called hematopoietic stem cells. Hematopoietic stem cells produce all blood cells including red blood cells, platelet-producing cells, and immune system cells such as neutrophils, T cells, B cells, and natural killer (NK) cells. People with PI essentially have broken pieces in their immune systems. Immune system cells may be missing or just not work properly. An allogeneic HSCT can replace an individual’s own hematopoietic stem cells with stem cells that will produce functioning immune system cells. In this way, a person's immune system can be fixed.

Hematopoietic stem cells can be transferred from one person to another person. The person who receives the stem cells is called a recipient of HSCT. The term, allogeneic, indicates that the stem cells given to the recipient came from someone else, the hematopoietic stem cell donor. If an allogeneic HSCT is successful, the donor's hematopoietic stem cells will replace the recipient's own cells. The donor cells will live in the recipient’s bone marrow and make blood and immune system cells.

Illustration of Hematopoietic stem cell transplantation.

Allogeneic HSCT also fixes any problems with other blood cells. For example, platelets will be fixed in those with WAS who have a successful allogeneic HSCT. Unfortunately, problems outside of the blood or immune system will not be fixed. For instance, if an individual with IPEX has diabetes before transplant, they will still have diabetes after transplant, because the cells in the pancreas that make insulin have been destroyed by this disease, and HSCT cannot replace pancreatic cells.

Hematopoietic stem cells may be collected from the bone marrow, the peripheral blood, or from umbilical cord blood, so HSCT procedures may be called bone marrow transplants (BMT), peripheral blood stem cell transplants, or cord blood transplants depending on the source of the stem cells. The transplant itself does not require surgery for the recipient, as the hematopoietic stem cells are typically infused into a large vein in the same way that a patient receives a blood transfusion.

Finding a stem cell donor

The first step in HSCT is finding a suitable donor. Finding a donor can take several weeks or months. Donors can be family members or unrelated to the person undergoing HSCT. Unrelated donors are usually found through bone marrow registries or umbilical cord blood banks.

Whether related or not, the donor has to have the same or almost the same human leukocyte antigen (HLA) typing results, which are obtained from a blood test, as the HSCT recipient. The immune system uses HLA proteins on cells to help determine which cells belong to the body and which don't. HLA-matched donors are the best donors because when HLA proteins are the same between a donor and recipient, the chances of complications, such as graft rejection and graft versus host disease (GVHD), are low.

Everyone has two sets of HLA genes. One set is inherited from a person's mother, and the other set is inherited from a person's father. Transplant doctors typically look at 8-12 HLA genes when trying to find a matched donor. A fully matched donor would be an 8/8, 10/10, or 12/12 (depending on the testing lab) HLA-matched donor.

Types of donors

Illustration of Human Leukocyte Antigen (HLA) Typing in a family.

The best stem cell donor for an individual with PI is an HLA-matched sibling. The sibling must have the same mother and father as the recipient. Full biological siblings of the individual with PI have a 25% chance of being a perfect match, so families may need to look elsewhere for a donor. Note that it is important that potential sibling donors are evaluated for PI before being used as donors.

If there are no sibling donors available, the search for stem cells will move on to look for an HLA- matched, unrelated donor. These are individuals who volunteer to provide their stem cells and have no family connection to the HSCT recipient.

People who are willing to donate their stem cells are placed on an anonymous list called a registry. There are several registries worldwide. Doctors examine the registry and look for donor types that match the recipient's HLA. If the donor stem cells match the recipient's in HLA, then those cells can be requested for use in the HSCT.

Another source of stem cells is umbilical cord blood. Umbilical cord blood is sometimes donated by a mother after she has a child. The blood comes from the umbilical cord of her child and contains hematopoietic stem cells. The blood is frozen and kept in repositories for donation. The cord blood, which typically comes from an unrelated individual, could be a match for an HSCT recipient.

Because HLA genes are inherited, recipients are most likely to find HLA-matched, unrelated donors among people from a similar ethnic background. Unfortunately, because of a lack of representation in registries and cord blood banks, this means some ethnic groups and those of multi-ethnic heritage may have difficulty finding an HLA-matched, unrelated donor.

If there are no matched donors, a mismatched donor may be considered. If only one HLA allele is different between the person with PI and the donor, that would be noted as a 7/8, 9/10, or 11/12 HLA match. However, having an HLA mismatch increases the risks of graft rejection and GVHD—the greater the mismatch, the greater the risks of rejection or GVHD.

When a sibling HLA-matched donor or an unrelated HLA-matched donor cannot be found, then another option for stem cells is a haploidentical family match. This is a half-matched donor who is usually a parent but can be a sibling or even an aunt, uncle, or cousin.

Sometimes, a parent may be used as a donor. Parents are typically only a half-match to their children, so this type of transplant is called a haploidentical transplant. This type of transplant must be done in a special way because there is a high risk of graft rejection or acute GVHD. Donor T cells must be removed from the graft or otherwise destroyed to decrease the risk of severe GVHD.

Donation procedures

Hematopoietic stem cells can come from three sources: bone marrow, peripheral blood stem cells, or umbilical cord blood donations. Cord blood donations are collected from the umbilical cord at the time of a baby’s birth and processed in a special way to allow the cord blood to be frozen and stored until it is used.

One way hematopoietic stem cells are obtained is by taking them from the marrow in a person’s bones, which is why the HSCT is sometimes called a bone marrow transplant. The bone marrow is a soft, spongy substance found in the middle of the bones. There are many hematopoietic stem cells in the bone marrow.

During this procedure, hematopoietic stem cells are obtained from the donor while they are under general anesthesia. Doctors insert long needles into the donor’s hip multiple times to extract bone marrow cells. The bone marrow cells, which contain a lot of hematopoietic stem cells, are then put into a sterile bag.

Typically, the stem cells are separated from the collected bone marrow material, and then those separated stem cells are given to the HSCT recipient. This is called a bone marrow donation.

Some hospitals may choose to leave certain other cell types mixed in with the hematopoietic stem cells, as these cells may aid in engraftment. However, when other cells are left in, doctors will still remove T cells to reduce the chances and severity of GVHD, unless the donor is a matched sibling donor. With a matched sibling donor, removal of T cells is not necessary, and, in fact, leaving the T cells in may speed up recovery.

Another way hematopoietic stem cells are obtained from a donor is by collecting blood straight from their arm through an intravenous, or IV, line, which is a needle that goes into a vein in the arm.

The donor begins the process by receiving, over a period of several days, injections of a medication called filgrastim that causes their hematopoietic stem cells to leave the bone marrow and circulate in the blood. After the injections, during an hours-long procedure, the donor’s blood is collected through an IV. The blood passes through an apheresis machine (similar to a platelet or plasma donation machine) that removes stem cells. The rest of the donor’s blood components are returned to the donor. The stem cells are stored in a sterile bag for transfer to the HSCT recipient. This process is called peripheral blood stem cell donation. Sometimes more than one peripheral blood stem cell collection is performed in order to get enough stem cells.

Find hematopoietic stem cell transplant clinical trials

See if you are eligible for clinical trials evaluating new approaches and protocols for treating PI with a hematopoietic stem cell transplant (HSCT).

Preparing for allogeneic HSCT

Choosing a transplant center

Some individuals with PI may be fortunate enough to have a transplant center at their nearby hospital, but many will have to travel to specialized centers for transplantation. This can be difficult for families and can be emotionally and financially challenging. Individuals with PI and their families may or may not have options when it comes to choosing a transplant center. Sometimes insurance requires individuals to use certain specialists or certain facilities. Under other insurances, individuals can research facilities and doctors and choose what they think is best. Two resources for finding transplant specialists include the Primary Immune Deficiency Treatment Consortium (PIDTC) and The National Marrow Donor Program.

Individuals with PI and their families usually meet members of the transplant team, which can include physicians, nurse practitioners, social workers, psychologists, nurses, and financial counselors. These team members help prepare recipients and their families for the impact the transplant will have on family life, and they provide support and assistance with all aspects of the transplant.

Regardless, individuals and their families should ask key questions of the transplantation specialists. Points to keep in mind include the length of time the center has provided HSCTs, the number of HSCTs the center has performed on persons with the individual's specific PI, and the number of HSCT specialists on staff.

Here is a list of questions to ask a healthcare team before choosing them to perform the HSCT.

  • How many cases of the specific PI has the hospital treated with HSCT?
  • How many years has the hospital used HSCT to treat that PI?
  • How many HSCT doctors are on staff?
  • How much conditioning will be required before the HSCT?
  • Which doctor or group of doctors will be in charge of the individual's care after discharge?

Individuals with PI and their families should learn as much as they can about the HSCT procedure before it occurs. The following questions can be used to both educate caregivers and evaluate the hospital's experience.

  • What precautions should be taken prior to admission for transplant?
  • How long will the individual be in isolation?
  • What isolation precautions are required before, during, and after transplant?
  • What are the responsibilities of caregivers to keep isolation precautions in place?
  • What are the isolation guidelines and expectations of members of the medical team, and visitors when entering the individual's hospital room?
  • Describe the complications related to a person with this specific PI undergoing HSCT.
  • If things go well during transplant, what is the average amount of time in the hospital and the average recovery time?
  • What is expected of a caregiver while the individual is in the hospital and after the individual goes home?
  • Can the recipient receive live vaccines after the HSCT?

Staff at the hospital, in collaboration with the family, will often work with insurance companies to get approval for the transplant. The time spent at a transplant center can vary from center to center, and it also varies from person to person. However, recipients and families can generally expect to stay at or near the transplant center for at least 3-6 months before returning home. Allogeneic HSCTs are generally performed in the hospital, but once recipients are healthy enough, they are discharged from the hospital and return to the transplant clinic several times a week.

Pre-transplant evaluations

HSCT recipients typically have a large battery of tests and procedures done before transplant to make sure they are healthy enough to have a transplant. Healthcare providers may find hidden problems that need to be addressed prior to transplant, such as infections or organ function problems. Immunologists and transplant providers typically order many blood tests, as well as imaging studies, such as computerized tomography (CT) scans, ultrasounds, and/or magnetic resonance imaging (MRI). Special tests of kidney function are also done. The heart is evaluated with an echocardiogram (ECG, EKG), which is an ultrasound of the heart. If recipients are old enough, pulmonary function testing will be done. Some may need procedures such as a bone marrow biopsy, lumbar puncture, bronchoalveolar lavage, or gastrointestinal endoscopy prior to allogeneic HSCT. All of these tests usually take a few weeks to complete.

Consent for transplant

Before having a transplant, a recipient and/or family must give consent to proceed with the transplant. Members of the transplant team will meet with the recipient and/or family to go over the process and the risks and benefits in detail. Recipients and families should ask questions and be sure that they understand the proposed treatment before proceeding.

Hospital stay and the transplant

HSCT is different than organ transplants (e.g., liver, lung, or kidney) in several ways. The transplant itself is not a surgery, because the stem cells are given in a vein similar to a transfusion. Also, HSCT recipients need special preparation to receive the stem cells that solid organ patients don’t need. The process of replacing the stem cells in the bone marrow requires an inpatient stay of about six to eight weeks. This inpatient stay is what most people think of as 'the transplant.'

After discharge, full recovery of the immune system to a functioning immune system occurs as an outpatient and is a process that takes many months, up to a year. Unlike solid organ transplant recipients, HSCT recipients are able to wean off of immune suppressive medications if all goes well because the new immune system becomes accustomed or tolerant to the patient's body.

Central line

If the HSCT recipient is healthy enough to proceed with the transplant, they will receive a long-term (but ultimately temporary) IV line in a large vein in the chest or neck. This line is called a central line. The recipient will go under general anesthesia in order for the central line to be put in.

The central line helps doctors take blood from the recipient to monitor the progress of the new immune system. Doctors also use the line throughout the transplant process to administer chemotherapy, the donor cell infusion, antibiotic, antiviral, and antifungal medications to prevent infection, and IV fluids. It avoids the need for repeated IV placement and venipuncture. The recipient or a caregiver will need to learn to take care of the central line.


What happens during conditioning is similar to what happens before replanting a garden. If the HSCT recipient's immune system is a garden filled with weeds, the weeds may need to be cleared out before healthy plants can grow. For stem cell transplant, the conditioning regimen acts as weed killer. It is a combination of medications that destroy the recipient's own immune and stem cells to prepare for receiving the donor stem cells.

The goal of conditioning is to increase the chances of complete replacement of the recipient's immune system with donor cells and reduce the chance of treatment complications, such as failure to engraft and GVHD. On the other hand, the use of conditioning comes with side effects and the potential for serious risks of its own. Together, the recipient, their family, and their doctors should review the options available and decide whether to use conditioning based on the balance of benefits and risks.

In general, conditioning may be recommended when the recipient has some immune function or when the stem cell donor is not related to the recipient. In general, conditioning may not be recommended when the donor is a fully matched sibling or the recipient has an active infection, is very young (under 2 months of age), or is small (e.g., was born prematurely). Conditioning is also not recommended when treating certain types of SCID that amplify the toxicity of conditioning drugs. However, when conditioning is not used, the chances of the recipient achieving a fully functioning immune system are generally lower. The recipient may need additional treatment, have more infections post-transplant, or even need another HSCT later in life.

A doctor may strongly recommend that conditioning be used or not used based on his or her best judgment and current research guidelines, the recipient’s specific situation, and sometimes the hospital’s standard practice. If conditioning is recommended, questions to ask the doctor include:

  • What side effects may be most problematic?
  • What are the risks of the specific conditioning regimen?
  • Long term, do the potential benefits of conditioning outweigh the potential risks?
  • For the recipient, is conditioning the best choice?

If conditioning is not recommended, questions to ask the doctor include:

  • How likely is it that HSCT will lead to a fully functioning immune system?
  • What are the chances that the recipient will need another transplant later in life or lifelong immunoglobulin replacement therapy?
  • How likely is it that the recipient’s body will reject the transplant?

Types of conditioning regimens

There are two major categories of conditioning, drugs that target stem cells and drugs that target immune cells. They have different goals. HSCT recipients may have one or both types of conditioning before treatment.

Conditioning targeting stem cells uses chemotherapy drugs to reduce the number of stem cells in the recipient's bone marrow. Doctors call this myelosuppression. The goal is to make space in the recipient's bone marrow for the donor stem cells to engraft. There are several intensities of myelosuppressive conditioning. They use the same drugs, such as busulfan or melphalan, but vary in the dose and number of drugs used. The three categories of myelosuppressive conditioning include:

  • Myeloablative conditioning (MAC): This type of conditioning uses a higher dose of chemotherapy drugs aimed at completely getting rid of the recipient’s stem cells. Successful MAC makes plenty of empty space in the recipient's bone marrow for new stem cells to land and grow. In general, MAC has the best chance to fully replace the bone marrow with new stem cells to achieve a fully functioning immune system that can fight off infections. However, this approach does not always work in every patient and comes with more severe side effects and higher risk.
  • Reduced-intensity conditioning (RIC): This type of conditioning uses lower doses of chemotherapy drugs to achieve full replacement of the recipient's stem cells but with less toxicity. Successful RIC makes enough empty space for donor stem cells to land and grow. Use of RIC means less severe side effects and lower risk. But because RIC uses lower doses, there is a greater chance that replacement of the recipient's stem cells will be incomplete when compared with MAC. This means the recipient’s immune system might not be fully functioning after the transplant. For example, the recipient might still need lifelong immunoglobulin replacement treatment.
  • Low-dose conditioning: This type of conditioning uses very low doses of chemotherapy drugs and is more commonly used in gene therapy.

Conditioning targeting immune cells uses drugs to reduce the T and B cells in the recipient’s immune system. Doctors call this immunosuppression. The goal is to protect the donor stem cells from being attacked by the recipient’s immune cells. There are two categories of immunosuppressive drugs:

  • Antibody-based drugs: Antibody-based drugs, also called serotherapy, use antibodies to target the recipient’s immune cells with the goal of decreasing the risk of graft rejection. Examples include alemtuzumab and ATG (anti-thymocyte globulin).
  • Chemotherapy drugs: Some chemotherapy drugs kill immune cells, but not stem cells. Examples include cyclophosphamide and fludarabine.

Conditioning side effects

Conditioning can have short-term side effects and long-term risks. Short-term side effects are temporary and usually subside when the treatment starts working. Long-term side effects may appear months or years after conditioning. In addition, some short-term side effects may become chronic and last a long time.

Short-term side effects may be mild to severe:

  • Mucositis and nausea, vomiting, diarrhea: Chemotherapy can damage the lining of the mouth, throat, stomach, and intestines. This can be very mild or more problematic depending on the intensity of the conditioning regimen. Recipients may have sores, drooling, nausea, pain, vomiting, diarrhea, and sometimes bleeding. These side effects can be treated with pain medications, anti-nausea medications, and nutrition and fluid support such as a feeding tube.
  • Anemia, bleeding, and infection: Conditioning will reduce the number of all of the recipient’s blood cells, including immune cells, red blood cells, and platelets, for several weeks. During this time, the recipient is at an increased risk for infection, may have blood clotting problems, or may feel tired and weak because they have fewer red blood cells.
  • Vital organs, such as the brain, lungs, kidneys, and liver, may be harmed. Sometimes these complications can be treated with medication.

Any one of these long-term complications is infrequent, but recipients and their families should know that they do sometimes occur:

  • Chronic problems from harm to vital organs, such as the brain, lungs, kidney, and liver. Sometimes these complications can be treated with medication.
  • Bone growth suppression, which may result in shortened stature as an adult.
  • Endocrine abnormalities, such as growth hormone deficiency, hypothyroidism (underactive thyroid), and ovarian and testicular dysfunction.
  • Reduced fertility.
  • Increased risk of cancer.
  • Developmental delay or problems with learning.
  • Issues with the development and arrangement of teeth.

Stem cell infusion

Once a donor is found, the timing of the transplant must be arranged so that the donor cells are ready when the recipient has completed conditioning and is ready to receive them. The planned day of stem cell infusion is called Day 0. Stem cells are given through the central line like a blood transfusion. Similar to a blood transfusion, the stem cell transplant is a minor procedure that can take as short as 30 minutes or as long as a few hours. General anesthesia is not necessary and caregivers may be present during the procedure.

After Day 0, recipients typically remain in the hospital for several weeks while doctors wait for the new stem cells to grow. In the garden analogy, once the weeds are gone and the seeds are planted, there is a period of time when the garden is empty because it takes time for the healthy plants to grow. During this time, there are no blood cells being produced by the bone marrow, so it is common for the recipient to need blood and/or platelet transfusions.

Recipients are watched closely for any signs of infection, and they may need pain medicines, medicines for nausea, and fluid and nutrition support. Frequent blood tests are performed to monitor for any signs of organ dysfunction. Most recipients also receive medications that suppress the immune system in order to help prevent GVHD. Common examples include cyclosporine or tacrolimus.


After an HSCT, doctors expect engraftment to occur. Engraftment is when the donor's hematopoietic stem cells grow in the recipient and start making healthy blood cells. Transplant teams monitor the recipient with a blood test called a complete blood count (CBC). When the stem cells start to work, the numbers of particular blood cells will start to rise.

The anticipated time it takes for different cell types to recover to a safe level varies. Until doctors are sure that there is good engraftment, the recipient will be monitored very closely. Sometimes the recipient is given medication to jumpstart white blood cell production specifically.

Once there are signs of engraftment, a special blood test will be done to determine what percentage of blood cells are from the donor, called an engraftment or chimerism study. Chimerism refers to having cells in the body with different genes, in this case, hematopoietic stem cells and blood cells with the donor's genes and all other cells with the recipient’s genes. The higher the percentage of blood cells with the donor’s genes, the better the HSCT has worked.

Once the blood counts recover to a safe level, recipients may be able to transition to outpatient care at the transplant center. Recipients will have a lot of oral medications, and many need some IV medications, IV fluids, or IV nutrition during the early outpatient treatment phase. Home healthcare services, depending upon an individual's insurance coverage, may help with these needs.

Early transplant complications

Allogeneic HSCT can have many complications and it is difficult to estimate the risks for each individual.

The donor stem cells may not find a place to land in the recipient’s bone marrow and, therefore, may not give rise to all the different types of immune cells. If donor stem cells don’t grow (primary graft failure) or don't last (secondary graft failure), a recipient is said to have graft failure. An individual will often have a second transplant if this occurs.

Sometimes graft failure occurs because a recipient’s immune system, even if it doesn't work very well, attacks the graft. This is called graft rejection. An individual will often have a second transplant if this occurs.

The donor stem cells may engraft and start working to make T cells with the help of the thymus, but fail to engraft in the bones, where B cells are made. If this happens, the recipient may still need lifelong immunoglobulin replacement therapy, antibiotics, or other ongoing therapy to help the immune system.

If a donor's stem cells grow, but the recipient's stem cells also grow after transplant, an individual is said to have mixed chimerism. This will be evident in the engraftment study. Mixed chimerism is more likely to happen with lower-intensity conditioning regimens. In general, mixed chimerism is okay for many individuals with many types of PI, as long as there are enough donor cells to keep the individual healthy. The level and type of donor cells needed depend on the PI for which that individual was treated.

Recipients usually require blood transfusions early after transplant. After successful engraftment, the recipient changes blood type from their own blood type to the blood type of the donor. Once the donor marrow is producing a good amount of red blood cells, the recipient will generally no longer need transfusions.

Recipients have low platelet counts and are prone to bleeding after transplant. They often receive platelet transfusions for several weeks after transplant to prevent bleeding. After successful engraftment, they generally no longer need transfusions.

In the first few months after transplant, a donor’s immune system may recognize a recipient’s cells as being foreign, and mount an attack against the recipient’s own tissues, just as it would fight an infection. HSCT recipients take immunosuppressive medicines for approximately six months after transplant to prevent GVHD. Sometimes, despite the preventative medications, GVHD still occurs. The most common signs of acute GVHD are rash or diarrhea. It can also affect the liver or other organs. Acute GVHD can be mild or severe. It is usually treated with steroids and other immunosuppressive medications.

Chronic GVHD typically occurs later than acute GVHD and can last a long time. It can affect several organs including the skin, mouth, gastrointestinal tract, eyes, lungs, and genitourinary tract. It is usually treated with steroids and other immunosuppressive medications.

Individuals with PI are prone to infections prior to allogeneic HSCT, but the risk goes up further immediately after transplant. Recipients are monitored very closely for infections during and after transplant. Several antimicrobial medications are given to prevent infections, and Ig replacement therapy may be given regularly. Recipients are treated aggressively for any sign of infection. It is important that the recipient or caregivers call immediately if the recipient has a fever or other signs of infection after discharge from the hospital.

Chemotherapy used in conditioning can damage organs such as the liver and lungs. Certain transplant medications can damage the kidneys. Organ function is another thing that will be closely monitored after transplant.

TMA is characterized by injury to little blood vessels during or after transplant. This can lead to blood clotting in the little blood vessels and organ dysfunction.

Even though transplant outcomes are now very good for most individuals with PI, survival is not 100%. As a gross estimation, the chances of survival are approximately 80% for most individuals with PI. However, if a matched (HLA) sibling is available as a donor, survival is closer to almost 100%. Chances of survival may be higher or lower depending on several factors such as diagnosis, age, pre-existing complications, donor relation, and HLA match, as well as other variables.

Hospital discharge

The recovery process for a recipient after an HSCT takes at least several months, and will vary according to conditioning, the type of donor, any complications, and the individual hospital or transplant center’s criteria for discharge. Typically, once a recipient's donor cells are producing enough neutrophils and platelets to keep the patient safe, they are ready for discharge. Recipients must not have fevers or bleeding, and they need to be able to take their medications as prescribed. Recipients and/ or caregivers must be comfortable taking care of the central line, and they may also need to learn to give IV fluids, IV nutrition, and even some IV medications.

Once a recipient is discharged, they usually come back to the transplant clinic several times a week for lab work, examinations, and infusions. Often recipients are discharged to housing that is close to the transplant center, particularly if their own homes are some distance away. Recipients can still develop complications after discharge, including infections, organ toxicities from medications, and GVHD.

Once engraftment occurs, and the frequency of blood draws goes down, the central line may be taken out.

By Day +100, some recipients are ready to return to their own homes and can continue to follow up just with their local healthcare providers. Recipients often still need to take several medications for the first year after transplant, including immune-suppressive medications to prevent GVHD. Until they have a full recovery of immune cell numbers and are successfully weaned off of immune suppressive medications, recipients should remain isolated. In isolation at home, visitors should remain restricted, and the recipient will not be allowed outside, or in public places, for several months. Neutrophils recover just a few weeks after transplant, but T cells require many months and B cells may take 1-2 years.

Healthcare providers can do blood tests to see how an individual’s immune system is recovering and make recommendations about when it is safe to stop isolation. Once the immune system is fully recovered, recipients should receive routine re-vaccination following the transplant.

Preparing to return home

Once a family's time in the hospital or in a temporary apartment comes to an end, the family must consider how to prepare their home for the arrival of the newly transplanted individual.

The patient must stay at home, and should not go out into public places until the doctor gives permission. The recipient is still very vulnerable to infection, and germs must be controlled as much as possible.

Families must consider guidelines for travel, visitors, food preparation, home cleaning, and mold remediation. All families are different and suggested ideas on visitors and cleaning will vary with doctor recommendations and family lifestyle.

Travel: When the recipient rides in the car, keep the vehicle windows up and set the heat or air conditioning to recirculate the inside air instead of pulling in outside air. This is particularly important when driving past construction sites, which can throw fungal spores into the air.

Visitors: Limit visitors to those who live in the house and any regular caretakers of the patient, such as nurses.

  • Visitors must not have been sick for at least seven days prior to visiting, as they could still be contagious.
  • No visitors beyond caretakers should be allowed in the home, especially children, as they are often exposed to illness at school, and may be contagious.
  • Any people, including visitors and family, who enter the home must wash their hands before touching objects in the home, and handwashing should occur just before touching the recipient.
  • When household members arrive home each day from activities like school, work, or shopping, they should put on fresh clothes.
  • Visitors, as well as household members, must be careful not to cough or sneeze near the recipient.
  • If household members get sick, they should avoid direct care of the recipient, touching the recipient (unless they've washed their hands immediately), being within six feet (coughing distance) of the baby, and should wear a mask.

Food preparation: Keep these food-related recommendations in mind.

  • The recipient should only consume jarred foods or foods that have been fully cooked. They should not eat raw vegetables or fruit.
  • Avoid keeping fruits and vegetables on the counter, as they may give rise to fungal spores, even if they do not look spoiled. Refrigerate fruits and vegetables instead.
  • The recipient should not eat honey, yogurt or other products with live cultures, or probiotics.

For infants on formula, consider following these recommendations:

  • Powdered formula is less safe because it is not sterile. However, if a ready-to-feed liquid alternative cannot be used and you must use powder, then:
    • Option 1: Prepare formula with boiled water. Bottled water is not acceptable. After boiling, cool the water in a refrigerator so that it can be used as soon as possible. Any that isn't consumed should be discarded within an hour of turning off the heat on the boiling water.
    • Option 2: Prepare formula with bottled water that is filtered (not spring water) and process the filtered water further through a reverse osmosis filter before mixing it with the powder.

Home cleaning

  • Steam clean carpets.
  • Regularly mop all hard surface floors.
  • Put a HEPA filter in the vacuum.
  • Make home a shoeless house.
  • Install HEPA filters in the HVAC unit and change them monthly.
  • Consider purchasing a free-standing HEPA air filter unit for the main room where the recipient stays.
  • Keep windows and doors closed to minimize entry of mold or fungus.
  • Routinely clean all touchable items and surfaces.
  • Routinely clean places that are often touched by others in the home, such as faucets, countertops, doorknobs, window blind rods, and light switches.
  • Remove house plants and cut flowers from the home, these are sources of mold.
  • Consult your doctor about pets in the home. If pets remain in the house, they should not come in contact with the recipient.

Mold remediation: If mold is discovered in walls or carpets before the recipient comes home, have it professionally removed and complete all other cleaning several weeks before the recipient arrives home. If mold is discovered after the recipient is home, it is best not to disturb it. Have the severity of the mold problem evaluated by a professional. Consult with your immunologist. Relocation may be necessary.

Long-term follow-up

By 1-2 years post-transplant, most recipients have good immune system recovery and do not need frequent follow-up. It is generally recommended that an individual return for follow-up yearly or every other year, as this long-term follow-up is important to monitor them for late complications of transplant. These late complications are mostly related to the conditioning medications given to prepare the recipient for transplant, but they may also be related to organ damage caused by infection or immune dysregulation before the transplant.

The severity and likelihood of late complications related to allogeneic HSCT is variable. Possible long-term complications from chemotherapy drugs include harm to vital organs such as the brain, lungs, kidneys, and liver. Sometimes, these complications are reversible with medication.

Other complications include endocrine problems such as thyroid function, growth, or puberty issues, reduced fertility, and increased risk of cancer.

Individuals who develop chronic GVHD need special long-term follow-up. The transplant team can tell recipients and caregivers more about what long-term monitoring may be needed.

This page contains general medical and/or legal information that cannot be applied safely to any individual case. Medical and/or legal knowledge and practice can change rapidly. Therefore, this page should not be used as a substitute for professional medical and/or legal advice.

Adapted from the IDF Patient & Family Handbook for Primary Immunodeficiency Diseases, Sixth Edition 
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