INTERLEUKIN-1 PRODUCTION FOLLOWING T-CELL-DEPLETED AND UNMODIFIED MARROW CRAFTS

Interleukin-1 (IL-1) production by endotoxin-stimulated cultured monoc ytes from 31 participants in grafts of marrow depleted of mature cellu lar elements by treatment with soybean agglutinin and sheep red blood cells (SBA(-)E(-)) and 12 recipients of unfractionated bone marrow wer e studied and compared with normal controls. Patients were studied pri or to marrow transplant (BMT) and at 1 month, 2 to 4 months, and 5 to 6 months post-transplant. Deficiencies in IL-1 production (<50 units) were detected in both transplant groups prior to and at 1 month post-B MT. From 2 to 4 months post-transplant, 67% of the recipients of unmod ified marrow and 45% of the recipients of SBA(-)E(-) marrow grafts pro duced a normal level of IL-1. By 5 to 6 months post-transplant and the reafter, the proportions of patients exhibiting deficiencies in IL-1 p roduction in each group were equally low. We also evaluated the impact of early deficiencies of IL-1 on engraftment, hematopoietic function, and immunological reconstitution. Deficiencies in IL-1 production per sisting to 2 to 4 months post-BMT did not significantly affect the deg ree of chimerism or the time to recovery of neutrophil counts to 500/m u l in recipients of either unmodified or T-cell-depleted marrow. Plat elet recovery during the first 50 days posttransplant was significantl y slower in the IL-1-deficient group, but thereafter rebounded, so tha t by 4 months post-BMT patients nts with initial deficiencies in IL-1 production achieved levels comparable with those attained by patients with normal production of IL-1. When we looked at the lymphocyte respo nse to phytohemagglutinin (PHA), there was no difference detected amon g patients with or without IL-1 deficiency receiving unmodified transp lants. In contrast, recipients of T-cell-depleted grafts exhibiting a prolonged deficiency of IL-1 experienced a slower rate of recovery of PHA responses. Our results suggest that IL-1 may play an important rol e in the early expansion of megakaryocytic precursors following an all ogeneic marrow transplant and may facilitate the functional developmen t of allogeneic lymphoid progenitors following a T-cell-depleted marro w graft.