Cellular mechanism of DNA‐specific antibody synthesis by lymphocytes from systemic lupus erythematosus patients

The cellular mechanism of anti‐DNA antibody synthesis in patients with systemic lupus erythematosus (SLE) was studied by DNA‐specific solid‐phase radioimmunoassay. Anti‐DNA antibody synthesis in response to DNA was T‐dependent, and the experiments with reconstituted lymphocytes from identical twins discordant for SLE showed that B cells and T cells from SLE patients must cooperate to synthesize anti‐DNA antibody. Anti‐DNA antibody synthesis by lymphocytes from patients with inactive SLE was enhanced by T4 cells and suppressed by T8 cells in response to DNA. Although T4 cells from patients with active SLE could enhance anti‐DNA antibody synthesis by autologous B cells, their T8 cells could not suppress anti‐DNA antibody synthesis by autologous B cells. These results indicate that elevated anti‐DNA antibody synthesis in response to DNA in patients with active SLE is due to abnormalities of both SLE B cells and SLE T cells. They further indicate that dysfunction of T8 cells from patients with active SLE may, in part, be responsible for deficient regulation of anti‐DNA antibody synthesis.