Coexistence of Acute Crescent Glomerulonephritis and IgG4-Related Kidney Disease

Introduction: IgG4-related disease (IgG4-RD) is a fibroinflammatory disorder that may involve almost each organ or system. IgG4-related kidney disease (IgG4-RKD) refers to renal lesions associated with IgG4-RD. The most frequent morphological type of renal lesions is IgG4-related tubulointerstitial nephritis (IgG4-TIN) which is associated with increased IgG4-positive plasma cell infiltration and interstitial fibrosis. Case Report: Herein, we present a rare case with coexisting IgG4-RKD and acute crescent glomerulonephritis with concomitant severe tubulointerstitial lesions instead of classic IgG4-TIN. Conclusion: IgG4-RKD and acute crescent glomerulonephritis can occur in the same patient. This case may give us a clearer viewpoint of the disease.