Kidney involvement of patients with Waldenström macroglobulinemia and other IgM-producing B cell lymphoproliferative disorders

Background and objectives Kidney involvement in Waldenström macroglobulinemia is less well described compared with kidney manifestations in multiple myeloma. Design, setting, participants, & measurements Of the 1363 patients seen with Waldenström macroglobulinemia and other IgM-secreting B cell lymphoproliferative disorders seen at the Mayo Clinic between 1996 and 2015, 57 kidney biopsies were retrospectively studied. The biopsy findings were correlated with clinical, kidney, and hematologic characteristics. Criteria for inclusion were evidence of a monoclonal IgM protein and availability of a kidney and a bone marrow biopsy for review. Glomerular and tubulointerstitial pathologies were categorized according to whether they were related to the monoclonal IgM. Results Of the 57 patients identified, monoclonal gammopathy–related kidney lesions were identified in 82% (47 of 57 biopsies), whereas nonmonoclonal gammopathy–related kidney lesions were seen in 18% (ten of 57). Monoclonal gammopathy–related kidney lesions included monoclonal Ig–related amyloidosis (n=19; 33%), nonamyloid glomerulopathy (n=20, 35%), and tubulointerstitial nephropathies (n=8; 14%). The most common monoclonal gammopathy–related kidney lesion was monoclonal Ig–related amyloidosis (n=19; 33%) followed by cryoglobulinemic GN (n=13; 28%). Lymphoma infiltration was the most common tubulointerstitial lesion (n=4; 9%). The hematologic diagnosis was Waldenström macroglobulinemia in 74% (n=42), monoclonal gammopathy of renal significance in 16% (n=9), and marginal zone lymphoma (n=2), chronic lymphocytic leukemia (n=2), and low-grade B cell lymphoma (n=2) in 4% each. Conclusions Our study confirms a diverse variety of kidney lesions in patients with monoclonal IgM gammopathy.