In order to assess whether HCQ had a dose-dependent inhibitory effect on CD154 expression in SLE patients, various doses of HCQ were used to treat purified CD4+ T cells from lupus patients in vitro for 24 hours, and then stimulated by 1 μg/ml ionomycin for 6 hours. The gene discussed is CD40LG; the disease is systemic lupus erythematosus.