Immunoglobulin G4-related Kidney Disease Associated With Autoimmune Hemolytic Anemia

Awareness of the uncommon associated clinical manifestations of immunoglobulin G4 (IgG4)-related kidney disease is essential for the early diagnosis and effective treatment of patients. To the best of our knowledge, there have been few reports of patients with IgG4-related kidney disease associated with autoimmune hemolytic anemia. We here report a rare case of IgG4-related kidney disease associated with autoimmune hemolytic anemia. A 70-year-old man with kidney dysfunction and severe anemia had been diagnosed with chronic kidney disease and treated without any improvement. On admission, he had a high serum creatinine level, low hemoglobin level, positive direct Coombs test, and mild proteinuria. Serum IgG and IgG4 were elevated. Kidney biopsy showed marked infiltration of IgG4-positive plasma cells and storiform fibrosis in the interstitial compartment, which confirmed the diagnosis of IgG4-related kidney disease. Corticosteroid therapy was initiated, and subsequently, the kidney dysfunction and anemia dramatically improved.