Case Report: Two cases of IgG4-related kidney disease with monoclonal gammopathy

Case 1 was diagnosed with IgG4-TIN combined with MGRS, which showed significant renal and hematological improvement after corticosteroid therapy. Case 2 was diagnosed as secondary membranous nephropathy combined with MGUS, but IgG4-MN cannot be ruled out. His renal function improved with methylprednisolone and rituximab treatment, but the M-protein persisted. We review the related diagnosis and treatment to provide more information for clinical practice.