The in vitro production of anti-nuclear antibodies by human peripheral blood mononuclear cells. Demonstration of T cell requirement and soluble inducing factor(s) for anti-nuclear antibodies triggering in patients with systemic lupus erythematosus.

Peripheral blood mononuclear cells (PBMC) of 29 patients with systemic lupus erythematosus (SLE) and 14 normal individuals were investigated for the in vitro production of anti-nuclear antibodies (ANA). Twenty-eight of 29 SLE patients but only one control spontaneously produced ANA in unstimulated PBMC. Pokeweed mitogen induced ANA synthesis in six controls. No detectable ANA was observed in B cell enriched fraction except in two cases of SLE. Recombination of B + T cell enriched fractions and PBMC supernatants from SLE patients could induce B cells to synthesize ANA. These results indicate that: (1) SLE patients spontaneously produced ANA in vitro whereas controls rarely did; (2) autoreactive clones exist in normal individuals but are kept under control and (3) T cell help is required for ANA triggering.