Abstract
The in vivo and in vitro synthesis of anti‐tetanus toxoid antibody (anti‐tet) was measured after booster immunization with tetanus toxoid in 9 patients with systemic lupus erythematosus (SLE) and 9 controls. In vitro culture of peripheral blood lymphocytes (PBL) from both patients and controls showed maximal antitet synthesis 7 days after booster immunization, and maximal serum titers occurred by day 14. The initial in vitro burst of anti‐tet synthesis was not dependent upon pokeweed mitogen (PWM) stimulation, whereas later synthesis was PWM dependent. Two differences between patients and controls were observed:1) patients with SLE had a lower mean pre‐boost serum titer of anti‐tet, and 2) one‐third of the patients showed a blunted serum anti‐tet response. To study whether these abnormalities were a result of altered immune regulation, anti‐tet synthesis was measured by the coculture of separated SLE‐B or control‐B cells and separated SLE‐T or control‐T or control‐T cell populations (± irradiation to remove suppressor T cell activity). These coculture studies showed that both abnormalities were due to a lack of SLE‐B cell response, not to abnormalities of SLE‐helper T or SLE‐ suppressor T cell function.