Long-Term Clinical Outcomes of Severe Combined Immunodeficiency Patients Given Nonablative Marrow Transplants

Severe combined immunodeficiency (SCID) is a syndrome characterized by profound T-cell deficiency that is universally fatal in infancy unless immune reconstitution is achieved by hematopoietic stem cell transplantation, gene therapy, or enzyme replacement. Published long-term clinical follow-up is limited for transplanted patients with SCID.

To characterize the long-term outcomes of patients with SCID treated at a single center.

We examined the clinical outcomes of 177 successive SCID infants given allogeneic bone marrow over 38 years without pretransplant chemotherapy or post-transplant graft-versus-host disease prophylaxis. A total of 90% received T-cell-depleted haploidentical parental marrow. Clinical status was assessed by questionnaires delivered by mail or electronically. Molecular type of SCID, demographics, and type, date and age of transplant were obtained from a database.

Eighty-eight questionnaires were completed for survivors ranging in age from 2 to 38 years. Survival remained higher in those transplanted before 3.5 months of age. Half of the cohort remained on immunoglobulin replacement. Health conditions reported included rashes, anxiety, depression, warts, and mouth ulcers. Most reported that these were transient, self-resolving issues. Attention-deficit/hyperactivity disorder, warts, and learning disabilities were reportedly more prevalent than in the general population. Most reported having no active concerns about their health. We found substantial scholastic achievement, with half of adult patients reporting college attendance. Most patients had a healthy body mass index.

Overall, our findings are consistent with those in the last update in 2009 in this population. Age at transplant remains a key variable in survival.