Abstract
We have established a human B cell line (TKS-1) from the peripheral blood of a patient with rheumatoid arthritis (RA) stimulated with phorbol myristate acetate (PMA). TKS-1 was a monoclonal B cell line, because it expressed surface κ light chain and other surface B cell markers, and had gene rearrangement of κ light chain in its DNA. Furthermore TKS-1 expressed CD 15 antigen, which was known to define human monocytes, granurocytes and Hodgkin's disease. So we investigated whether Leu M1 (CD 15)+B cell subset existed in the peripheral blood without any stimulation. CD 15+B cells existed in the peripheral blood from three patients with active RA who had complications such as the interstitial pneumonitis and the phlegmone. CD 15+B cells disappeared in association with the improvement of clinical symptoms while patients were treated with high or moderate doses of methylprednisolone or prednisolone, however, these cells reappeared at the time of relapsing. CD 15+B cells could not be observed in the peripheral blood with other collagen diseases, infectious diseases and interstitial pneumonitis. These findings indicated that CD 15+B cells existed in the peripheral blood of some patients with RA.
