Effect of exogenous IL-4 and IL-6 on in vitro anti-β₂GPI antibody production.

Peripheral blood B cells from patient E.Y. were cultured with or without β₂GPI-specific CD4⁺ T-cell clone EY9 in the presence of GP-F (10 μg/mL) plus exogenous IL-4, IL-6, or both IL-4 and IL-6 (5 ng/mL unless indicated otherwise) for 10 days. In some experiments, anti-HLA-DR (1 μg/mL) or anti-CD40L (1 μg/mL) mAb was added to the cultures supplemented with IL-6 as indicated. Anti-β₂GPI antibody levels in undiluted culture supernatants were measured by ELISA. Significant anti-β₂GPI antibody production in culture with exogenous cytokine compared with the control culture without cytokine is shown as an asterisk. The results were similar in 2 independent experiments.