Flowcytometric analysis of bone marrow cells from patients with rheumatoid arthritis

Abstract

We have reported that the presence of a specific type of myeloid cell was found in the epiphyseal bone marrow of affected joints from patients with active severe rheumatoid arthritis (RA) .
In the bone marrow of 38 patients with RA involving three kinds of disease subset 10 least erosive (LES), 18 more erosive (MES), 10 mutilating disease (MUD), the absolute number of iliac pan-myelocytes (CD15⁺CD16^-cells) was 288/mm³, 528/mm³and 801/mm³ (median), respectively. These values were significantly increased as compared with 7 healthy subjects in whom CD15⁺CD16^-cells were 153/mm³ (P<0.01 for MES and MUD) but LES was not. And there was a marked correlation (γ_s=0.476 P < 0.05) between percentage of CD15⁺CD16^-cells in the affected tibial bone marrow and iliac bone marrow of RA. Furthermore, a higher percentage of iliac CD8-positive T-lymphocytes expressed HLA-DR (30.5%) from patients with RA than did those from normal subjects (14.4%) .
This novel findings of coordinate elevated levels of myelocytes and activated T-lymphocytes in bone marrow of RA suggests an immunological imbalance that may have implication in the disease.