Immunologic recovery in thalassemic marrow graft recipients following high-dose busulfan and cyclophosphamide.

T lymphocyte subsets, mitogenic response, and immunoglobulin levels were studied in peripheral blood from 95 thalassemic patients before and at different times after bone marrow transplantation. With the exception of patients receiving more than 100 transfusion units before transplant, who showed an increased percentage of CD8-positive cells, thalassemic patients were essentially immunologically normal. Depressed lymphocyte proliferative response to phytohemagglutinin, concanavalin-A, and pokeweed mitogen; decreased IgG, IgM and IgA levels; and abnormal T subpopulation distribution were observed early after transplant. Long-term transplanted patients showed complete recovery of the immunological profile with the exception of the IgA levels, which were significantly decreased up to 2 years after transplant.