To study antibody (Ab) biosynthesis in rheumatoid arthritis (RA), the immunoglobulin (Ig)M anti-Fc, anti-Fab′, and antistreptokinase-streptodornase (SKSD) produced by peripheral blood lymphocytes (PBL) were measured at intervals from 1 to 19 d in culture. PBL from 17 seropositive patients with active RA and 30 age-matched controls were evaluated. Within the first 24 h, PBL from six of eight patients released >30 ng IgM anti-Fc, even in the absence of pokeweed mitogen (PWM). This early release of Ab was blocked by cycloheximide. With or without PWM, PBL from normal donors did not release IgM anti-Fc until after 3-5 d in vitro. By day 9, unstimulated PBL from seven patients made > 100 ng IgM anti-Fc. Un-stimulated PBL from normals never made >95 ng of this Ab.
Holly H. Birdsall, Roger D. Rossen