Immune recovery following bone marrow transplantation.

83 patients undergoing allogeneic or autologous BMT because of haematologic malignancies have been studied before and after transplantation at different intervals. The determinations consisted of lymphocyte counts, E-rosetting, lymphoblastic response, evaluation of serum immunoglobulin levels, skin testing, and in a smaller part of the patients surface marker studies using monoclonal antibodies of the BL-series. At first after BMT the lymphocyte and T cell counts went to normal between 4-18 weeks post transplant, about 4 weeks earlier in autologous than in allogeneic BMT. T suppressor cells showed an early increase compared to T helper cells which normalized much slower about 6 months after BMT. Lymphoblastic responses, however, tended to normal not before the second half of the first year both in autologous and allogeneic transplantation. Skin test reactivity became normal during the 2nd and 3rd year posttransplant, which was more complete in autologous than in allogeneic BMT. The IgG and IgM levels were depressed for half a year and IgA levels for 2 years. The most striking aspect was the multiphase course of lymphoblastic response in every individual patient. We suggest this to be the expression of sequential differentiation of donor lymphocytes.