Hydroxychloroquine as a Promising Therapy for Systemic IgG4-Related Disease: A Case Report

BACKGROUND IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory disease potentially affecting every part of the human body. Because of variability in clinical presentation, IgG4-RD can be challenging to diagnose. Untreated disease can lead to irreversible organ damage such as fibrosis. Early recognition and therapy are therefore essential. The first step in the treatment of IgG4-RD is glucocorticoid therapy, but the relapse rate after tapering is high. Other agents that are commonly used are disease-modifying antirheumatic drugs (DMARDs) and rituximab. Hydroxychloroquine is not common in the treatment of IgG4-RD, but can be promising. CASE REPORT We here describe a case of a patient with systemic IgG4-RD with manifestation in the pancreas, lung, and salivary glands. Initial treatment consisted of prednisone, with good response. Because of relapse after tapering, prednisone was restarted in combination with azathioprine. However, azathioprine had to be discontinued because of adverse effects. While tapering prednisone, new pulmonary manifestations emerged and hydroxychloroquine was started. This led to an excellent clinical response with no additional adverse effects. CONCLUSIONS This case report on IgG4-RD demonstrates a good response to treatment with hydroxychloroquine. Hydroxychloroquine is believed to have anti-inflammatory and anti-fibrotic effects, which may favorably influence the treatment of IgG4-RD. Therefore, hydroxychloroquine may be a good treatment option in IgG4-RD. Larger cohorts are required to study the efficacy of hydroxychloroquine in IgG4-RD.