Efficacy Analysis of Hydroxychloroquine Therapy in Systemic Lupus Erythematosus: a Study on Disease Activity and Immunological Biomarkers

Background: Hydroxychloroquine (HCQ) is a widely prescribed medication to patients with systemic lupus erythematosus (SLE), with potential anti-inflammatory effects. This study was performed to investigate the efficacy of HCQ therapy by serial assessment of disease activity and serum levels of proinflammatory cytokines in SLE patients.

Methods: In this prospective cohort study, 41 newly diagnosed SLE patients receiving 400 mg HCQ per day were included. Patients requiring statins and immunosuppressive drugs except prednisolone at doses lower than 10 mg/day were excluded. Outcome measures were assessed before commencement of HCQ therapy (baseline visit) as well as in two follow-up visits (1 and 2 months after beginning the HCQ therapy). Serum samples of 41 age-matched healthy donors were used as controls.

Results: Median levels of IL-1β (p < 0.001), IL-6 (p = 0.001), and TNF-α (p < 0.001) were significantly higher, whereas, median CH50 level was significantly lower (p < 0.001) in SLE patients compared with controls. Two-month treatment with HCQ resulted in significant decrease in SLEDAI-2K (p < 0.001), anti-dsDNA (p < 0.001), IL-1β (p = 0.003), IL-6 (p < 0.001) and TNF-α (p < 0.001) and a significant increase in CH50 levels (p = 0.012). The reductions in SLEDAI-2K and serum levels of IL-1β and TNF-α were significantly greater in the first month compared with the reductions in the second month.

Conclusion: HCQ therapy is effective on clinical improvement of SLE patients through interfering with inflammatory signaling pathways, reducing anti-DNA autoantibodies and normalizing the complement activity.