If a child is diagnosed and treated within the first few months of life before the child has a serious infection, then the long-term survival rate is more than 90%. With early treatment, most children with SCID should be able to develop their own working immune system. The best course of treatment for a child with SCID depends on several factors including the type of SCID, the child’s health, and doctor recommendations.
Most infants with SCID are treated with HSCT, or bone marrow transplant, which results in a new immune system that is able to fight infection. In HSCT, doctors take healthy blood-forming cells that can develop into a healthy immune system from a donor and put them into a child. The donor cells provide the child with an immune system.
Another less common but promising treatment option is gene therapy, which is currently in clinical trials. In gene therapy, doctors extract a child’s defective blood-forming cells, correct the defect, and put the corrected cells back into the child. The repaired cells provide the child with a working immune system.
A third treatment, enzyme replacement therapy, can only be used for children with ADA-SCID. In enzyme replacement therapy, the missing enzyme is regularly injected into the child with SCID to boost the ADA enzyme. The results are temporary and do not permanently repair the immune system. Eventually children with ADA-SCID will require either HSCT or gene therapy for long-term results.
Prior to these treatments, a child with SCID will begin the treatment process by taking antibiotics, antivirals and antifungals to ward off infection. The child will also receive immunoglobulin therapy, or Ig, an infusion of antibodies designed to boost the child’s immune system. The Ig is obtained through human plasma donors.
Most children with SCID are treated with hematopoietic stem cell transplantation, or HSCT, also known as a bone marrow transplantation. In this treatment, hematopoietic stem cells are taken from a donor. The hematopoietic stem cells that are taken from the donor are infused into a child with SCID. Those cells multiply over time and develop an immune system for the child.
Gene therapy is an experimental treatment currently available for children with ADA-SCID, X-linked SCID, and Artemis SCID. Families of children who choose this therapy must enroll in a clinical trial.
For children who have ADA-SCID, a treatment called PEG-ADA is available. Children with ADA-SCID lack an important enzyme which helps their immune system function.