ENHANCED EXPRESSION OF CD14 ANTIGEN ON MYELOID LINEAGE CELLS DERIVED FROM THE BONE-MARROW OF PATIENTS WITH SEVERE RHEUMATOID-ARTHRITIS

Objective. We previously reported the accumulation of abnormal myeloid cell populations reacting with CD14 (MY4) monoclonal antibody in the iliac and epiphyseal bone marrow of patients with severe rheumatoid ar thritis (RA). Therefore, we investigated in vitro production and modul ation of CD14+ myeloid cells from iliac bone marrow cells. Methods. Mo nonuclear cells were prepared from iliac bone marrow aspirates from pa tients with RA. The presence of unusual myeloid cells was assessed by 2 color flow cytometry of cells cultured under various conditions. Res ults. Cultured iliac bone marrow cells of patients with severe RA prod uced 14.7% of CD14+CD15+ cells on average. Cultures derived from healt hy donors and from patients with a milder form of RA produced fewer CD 14+CD15+ cells (<10%). The production of CD14+CD15+ cells was enhanced by granulocyte macrophage colony stimulating factor and interleukin 1 beta, but inhibited by T lymphocytes. Conclusion. Production and modu lation of CD14+ myeloid cells were observed in iliac bone marrow of pa tients with severe RA.