Abstract
Recently human B lymphocytes expressing the T cell antigen-CD5 (Leu1, OKT1), the 67kd surface protein, have been found in normal blood and lymphoid organs. These circulating CD5+ B cells coexpress B cell differentiation antigens CD20, CD21, CD19, surface IgM, IgD and HLA-DR. We researched these CD5+ B cells using two-color immuno-fluorescence analyses. In 39 RA patients (7 males, 32 females), the CD5+ antigen was detected on an average in 13.8% (±13.6 SEM) of the B cells of peripheral blood in comparison with an average of (5.8±2.5% SEM) in healthy controls. The CD5+ B cell/total B cell ratio did not have a statistically significant relation with any clinical parameters such as ESR, duration of disease, rheumatoid factor, number of affected joints, stage of drug treatment, except for age. On the other hand, the increase in CD5+ B cell subpopulation appeared in the patients with rheumatoid factor and who had a relatively short duration of disease. This study suggests that the CD5+ B cell subpopulation plays some role in the spectrum of the disease.
