Background/Purpose: The guideline or recommendation for lupus nephritis (LN) has been recently established by both ACR and EULAR, and hydroxychloriquine (HCQ) is recommended for all patients unless there is a contraindication. Although HCQ improves outcomes by reducing renal flares and limiting the accrual of renal damage, its therapeutic effect on renal response has been rarely investigated. In this study, we evaluated its therapeutic effect by focusing on the renal response in Japanese patients with LN class III or IV.

Methods: Patients who were diagnosed as LN class III or IV and treated with mycophenolate mofetil (MMF) as induction therapy were retrospectively investigated. We divided them into two groups according to whether HCQ was received. In this study, we selected patients who were treated with HCQ from early phase of induction therapy, within 4-weeks from high-dose glucocorticoid initiation for HCQ users. Clinical features including renal pathological findings and cumulative complete renal response (CR) were compared.

Results: We identified 7 (38.9%) patients with HCQ and 11 (61.1%) patients without. Although a significantly higher percentage of LN class III was determined in HCQ users comparing to non-HCQ users, there was no other difference in two groups at baseline. A significantly higher cumulative CR rate was detected in HCQ users comparing to non-HCQ users for 1 year (p=0.02) (Figure 1). Multivariate analysis indicated that HCQ use was the independent factor correlated with CR achievement (OR 15.9, 95%CI 1.76-380.1, p=0.02).

Conclusion: HCQ use from early phase of induction therapy may have additional therapeutic effect on renal response in Japanese LN patients with MMF treatment.