LYMPHOCYTE RECONSTITUTION AFTER ALLOGENEIC BLOOD STEM-CELL TRANSPLANTATION FOR HEMATOLOGIC MALIGNANCIES

Forty-one patients were studied at set times after allogeneic blood st em cell transplantation (alloBSCT) for recovery of lymphocyte numbers and function, Cells were mobilized with G-CSF from HLA-matched related donors and cryopreserved, Graft-versus-host disease (GVHD) prophylaxi s consisted of cyclosporine and methotrexate; G-CSF was administered p ost-transplant. Median time to absolute lymphocyte count (ALC) greater than or equal to 500/mu l was 17 days vs 41 and 49 days in historical alloBMT patients with G-CSF (n = 23) or no cytokine (n = 29) post-tra nsplant, respectively (P < 0.0001), CD4/CD8(+) ratio was 1.9 on day 28 after alloBSCT, then gradually declined to 0.8 at 1 year due to more rapid CD8(+) cell recovery, Mean phytohemagglutinin-induced T cell res ponses were lower than normal on day +28 (P < 0.05), then tended to re cover towards normal values, Natural-killer cytotoxicity remained low from day +28 to 1 year post-alloBSCT, but considerable lymphokine-acti vated killer cytotoxicity was induced from cells already obtained on d ay +28, Faster lymphocyte recovery correlated with better survival in alloBSCT patients (median follow-up 287 days, P = 0.002), ALC recovery was not affected by acute GVHD, CMV infections or doses of infused ce lls, ALC recovery did not correlate with survival in either historical alloBMT group, These data suggest that after alloBSCT lymphocyte reco nstitution is faster than after alloBMT, and that quicker lymphocyte r ecovery predicts better survival in the alloBSCT setting.