Spontaneously enhanced in vitro immunoglobulin synthesis by B cells in systemic lupus erythematosus

Abstract

In vitro immunoglobulin (Ig) synthesis was studied in peripheral blood lymphocytes (PBL) from patients with systemic lupus erythematosus (SLE) (SLE-PBL) in the presence or absence of pokeweed mitogen (PWM). In the presence of PWM, IgM and IgG syntheses were reduced in SLE-PBL, while in the absence of PWM, IgG synthesis was enhanced when compared with normal PBL although IgM synthesis was not significantly augmented. Preincubation and time course studies suggested that the enhancement of IgG synthesis in SLE is not due to the serum factors. The coculture experiments using separated T- and B-rich fractions indicated that reduced Ig synthesis in the presence of PWM may be the result of impaired T- and B-cell functions in SLE, and that raised Ig synthesis in the absence of PWM will be the result of primary B-cell activation. These results suggested that B cells in SLE-PBL are primarily activated and produce Ig without the aid of T cells.