MO196KIDNEY INVOLVEMENT IN WALDENSTROM MACROGLOBULINEMIA AND IGM MONOCLONAL GAMMOPATHY

Abstract

Abstract Background and Aims Renal manifestations of IgM gammopathy are less common than those seen in patients with multiple myeloma. However, a wide spectrum of kidney diseases has been described in previous publications. We aim to characterize kidney involvement in patients with Waldenström Macroglobulinemia and IgM-secreting B cell lymphoproliferative disorders. Method We retrospectively studied 7 patients with a circulating monoclonal IgM and renal histology showing evidence of monoclonal immunoglobulin deposits or lymphomatous infiltration. Demographic, clinical and laboratory data were collected. Results Of the 7 patients studied, four (57%) were male and the median age was 68 years old (range 41-79). Among the 7 patients, 5 met criteria for Waldenström Macroglobulinemia after bone marrow biopsy; none of them had hyperviscosity syndrome. Four patients presented with nephrotic syndrome and all had impaired renal function and hypertension. Four patients had microscopic hematuria and only one patient showed no proteinuria. Mean serum creatinine levels were 2.9mg/dL. Renal biopsy showed different patterns of renal injury, including typical intracapillary monoclonal deposits disease (5 patients), membranoproliferative glomerulonephritis with cryoglobulinemia (1 patient), AL-amyloidosis (1 patient) and interstitial lymphoplasmacytic infiltration with CD20+ lymphocytes associated with minimal change disease. Follow-up data were obtained in 4 patients: 3 underwent chemotherapy but only one achieved complete remission and 2 progressed to end-stage renal disease. Conclusion Although rare, Waldenström Macroglobulinemia and IgM gammopathy are responsible for diverse manifestations of renal disease. A prompt diagnosis is of utmost importance in order to ensure early start of therapy, which should be directed at the underlying hematologic disorder, to improve renal survival.