Studies of surface immunoglobulins on human B lymphocytes. II. Characterization of a population of lymphocytes lacking surface immunoglobulins but carrying Fc receptor (SIg-Fc+ cell).

Surface markers and organ distributions of B lymphocytes bearing surface immunoglobulins (SIg B) and lymphocytes lacking SIg but carrying Fc receptors (SIg-Fc+), and the variations of both the cell populations in the autoimmune diseases were studied. Peripheral blood lymphocytes contained approximately 9% SIg B and 22% SIg-Fc+ cells. Both the populations of SIg B and SIg-Fc+ cells were included in the cells that formed no E-rosettes. When previously treated with neuraminidase, however, the SIg-Fc+ cells formed E-rosettes, whereas SIg B showed no ability to form rosettes. C receptors as detected by human complement were found in the large portions of SIg B but in a minority of the SIg-Fc+ cell population. The tissues that contained the highest concentrations of SIg B and SIg-Fc+ cells were the spleen and peripheral blood, respectively. In the patients with an autoimmune disease in active stages SIg B cells in the peripheral blood markedly increased and, reversed, SIg-Fc+ cells decreased; in contrast, in remission of the diseases SIg B cells dropped down and SIg-Fc+ increased up to their normal levels. A possible relationship between the SIg B and SIg-Fc+ cells in regard to the differentiation of B lymphocytes was presemed.