Development of immunologic functions after bone marrow transplantation in 33 patients with severe combined immunodeficiency.

We retrospectively analyzed the development of lymphocytes and of the main immunological functions in 33 patients with severe combined immunodeficiency who survived at least 6 months after bone marrow transplantation (BMT). Eighteen patients received HLA-identical BM and 15 received HLA-nonidentical BM. Development of immune functions occurred faster after HLA-identical BMT as full T- and B-lymphocyte-mediated responses were present at day 186 versus 505, respectively (P = .05). In addition, antibody responses remain completely or partially absent in 8 of 15 patients of the second group. Detection of antibody response after HLA-incompatible BMT correlated with engraftment of donor B cells in informative cases. In patients who received an HLA-nonidentical BMT after chemotherapy (6 of 15), development of immune functions occurred more rapidly and 6 of 6 had B-cell functions, including normal antibody production. Autoimmunity was not uncommon and was found after HLA-incompatible BMT (4 of 15) or after HLA-partially phenotypically identical BMT (2 of 3). Antibodies were in most cases specific for blood cells. Occurrence of autoimmunity correlates with poor B-cell functions and to a lesser extent with defective T-cell responses. This type of study may lead to definition of a more accurate strategy for performing BMT in patients with severe combined immunodeficiency.