Glomerular galactose-deficient IgA1 and apoptosis inhibitor of macrophage staining in secondary IgA nephropathy associated with alcoholic cirrhosis

Immunoglobulin A nephropathy (IgAN) is associated with liver diseases, including alcoholic cirrhosis. When IgAN occurs in patients with liver disease, it is referred to as secondary IgAN; however, the mechanisms underlying secondary IgAN remain unclear. Herein, we present a case report of IgAN in a patient with a history of alcoholic liver cirrhosis, who presented with hematuria and proteinuria. A kidney biopsy revealed diffuse subendothelial deposition and mild mesangial proliferation. Immunofluorescence showed strong positive signals for IgA and IgM in the glomerular capillaries. There were no restrictions between the kappa and lambda staining. Electron microscopy revealed electron-dense deposits in the mesangial and subendothelial kidney regions. Histological diagnosis confirmed IgAN, typically associated with alcoholism. Further examination revealed that galactose-deficient IgA1 antibodies had merged with IgA, and a positive staining for the apoptosis inhibitor of macrophage antibodies along the glomerular capillaries was observed. These findings suggest that primary IgAN and alcoholic cirrhosis-related IgAN may share a common underlying mechanism.