CD40LG and cryoglobulinemia: analyzed 57 cases of IgM‐producing B‐cell lymphoproliferative disorders (including WM and MGRS) with renal involvement, categorizing renal pathology into amyloid‐related glomerulonephritis (33%), non‐amyloid glomerulonephritis (including cryoglobulinemia and Monoclonal immunoglobulin deposition disease, 35%), tubulointerstitial nephritis (including lymphocytic infiltration and cast nephropathy, 14%), and unrelated renal diseases (18%) [11].