Published in PEDIATRICS Volume 143, number 2, February 2019
Earlier publications have shown that newborn screening can be highly effective for the early detection of severe combined immunodeficiency (SCID). Screening 3.25 million California infants of diverse ethnicity with the T-cell receptor excision circle test substantiates the value of newborn screening for the diagnosis of SCID and non-SCID T-cell lymphopenia. Both are more common and more genetically heterogeneous than previously thought.
Testing of T cell receptor excision circles (TRECs) in dried blood spots followed, if indicated, by a standard flow cytometry test within the screening program was highly sensitive and specific. SCID diagnosed early by newborn screening has had a very high rate of survival (94%) with excellent immune reconstitution after both allogeneic hematopoietic cell transplantation and gene therapy. Diverse causes for non-SCID neonatal T lymphopenia were found, many of which resolved during follow-up.