CIRCULATING ENDOGENOUS THROMBOPOIETIN, INTERLEUKIN-3, INTERLEUKIN-6 AND INTERLEUKIN-11 LEVELS IN PATIENTS UNDERGOING ALLOGENEIC BONE-MARROWTRANSPLANTATION

To elucidate the physiologic role of thrombopoietin (TPO) for hematolo gic reconstitution following alogeneic bone marrow transplantation (BM T), serum TPO levels as well as interleukin-3 (IL-3), IL-6 and IL-11 w ere serially measured in 55 samples from 3 patients who underwent allo geneic BMT using an enzyme-linked immunosorbent assay (ELISA). The TPO level was higher in the serum taken during marrow aplasia than in the pretransplant serum. The serum TPO levels and platelet counts showed a strong inverse relationship in all patients examined. We also sequen tially measured endogenous serum TPO levels before and within 36 h aft er platelet transfusions. Endogenous serum TPO levels were inversely c orrelated with platelet mass following platelet transfusions. Serum le vels of IL-3 had no apparent correlation with platelet counts and seru m levels of IL-11 remained below the detection levels (31.3 pg/ml) in all samples. Serum levers of IL-6 were high during myeloaplasia and mo re upregulated in the febrile period. These findings support the view that TPO is the central regulator for megakaryopoiesis in vivo and the rationale for its clinical use after allogeneic BMT.