Soluble CD23 increases IL-3 induction of histamine synthesis by human bone marrow cells

Interleukin 3 (IL-3) and soluble CD23 (sCD23/IgERII) have similar capacities to induce basophil development from human bone marrow (BM) precursors. IL-3 also has the capacity to induce de novo histamine synthesis from human BM cells. In the present study, we examined the effect of sCD23 on histamine synthesis by human BM cells and its relationship with IL-3. Our data showed that recombinant 25 KDa sCD23, although on its own failed to induce histamine release, significantly enhanced IL-3-stimulated histamine synthesis by BM cells. These data provide further support for the cytokine-like role of sCD23 on hematopoietic cells.