Interleukin-1 (IL-1) production by endotoxin-stimulated cultured monocytes from 31 participants in grafts of marrow depleted of mature cellular elements by treatment with soybean agglutinin and sheep red blood cells (SBA-E-) and 12 recipients of unfractionated bone marrow were studied and compared with normal controls. Patients were studied prior 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-BMT. From 2 to 4 months post-transplant, 67% of the recipients of unmodified marrow and 45% of the recipients of SBA-E- marrow grafts produced a normal level of IL-1. By 5 to 6 months post-transplant and thereafter, the proportions of patients exhibiting deficiencies in IL-1 production 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 persisting to 2 to 4 months post-BMT did not significantly affect the degree of chimerism or the time to recovery of neutrophil counts to 500/mu l in recipients of either unmodified or T-cell-depleted marrow. Platelet recovery during the first 50 days post-transplant was significantly slower in the IL-1-deficient group, but thereafter rebounded, so that by 4 months post-BMT patients 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 response to phytohemagglutinin (PHA), there was no difference detected among patients with or without IL-1 deficiency receiving unmodified transplants. 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 role in the early expansion of megakaryocytic precursors following an allogeneic marrow transplant and may facilitate the functional development of allogeneic lymphoid progenitors following a T-cell-depleted marrow graft.

Adolescent↗

PubMedDate not supplied

Interactions between metal ions and poly(ethylene glycol) in the fusion of human erythrocytes.

Diffusion of the fluorescent membrane probe, Dil-C16 (3), from labelled to unlabelled human erythrocytes has been employed to monitor hemi-fusion (membrane fusion) in monolayers of cells exposed to poly(ethylene glycol) (PEG). Diffusion of the cytoplasmic probe, 6-carboxyfluorescein, was used similarly to monitor cell fusion (cytoplasmic mixing). Hemi-fusion, which is normally seen when erythrocytes are exposed to dehydrating concentrations of commercial PEG 6000, did not occur when the PEG was pretreated with Chelex 100 resin to remove metal ions. Cytoplasmic mixing, which is normally observed when the dehydrated erythrocytes are substantially rehydrated, also failed to occur when both PEG 6000 and the rehydrating buffer had been treated with Chelex 100. The re-addition to Chelex-treated PEG of components removed by the resin, and the addition of 10 mu mM concentrations of La3+ or Al3+, restored its ability to induce hemi-fusion and cell fusion. Higher concentrations of several other metals, including Ca2+, were also effective. These observations show that metal ions are required for hemi-fusion with erythrocytes in the presence of PEG, and that dehydration alone is insufficient to induce hemi-fusion. Phosphatidylserine was apparently not accessible in erythrocytes treated with PEG 6000 until the cells were rehydrated. This indicates that metal ions do not assist the hemi-fusion of erythrocytes by forming trans complexes with surface phosphatidylserine when the cells are dehydrated by PEG.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗