Clinicopathologic Spectrum of Lysozyme-Associated Nephropathy

IntroductionLysozyme-associated nephropathy (LyN), a rare cause of kidney injury in patients with chronic myelomonocytic leukemia (CMML), has not been well described to date. We report the clinicopathologic spectrum LyN from multi-institutional series.MethodWe identified 37 native biopsies and retrospectively obtained data.ResultsThirty-seven had median age 74 years included 78% males. Their most common presentation was acute (AKI) or AKI on disease (CKD) (66%) estimated glomerular filtration rate (eGFR) 21.7 ml/min per 1.73 m2, proteinuria 1.7 g. A minority (15%) partial Fanconi syndrome. Serum lysozyme levels were elevated all tested. Hematologic disorder (n = 28, 76%) etiology, including CMML 15), myeloid 5), myelodysplastic syndrome (MDS) 5). Nonhematologic causes 5, 14%), metastatic neuroendocrine carcinoma 3), sarcoidosis, leprosy. Etiology unknown 4 (11%). Pathology showed proximal tubulopathy abundant hypereosinophilic intracytoplasmic inclusions, characteristic staining pattern by immunostain. Mortality high (8/30). However, among 22 alive, 85% treated, 7 improved function, 1 who discontinued dialysis 6 increase eGFR >15 m2 compared at time biopsy.ConclusionIncreased awareness full may lead prompt diagnosis, earlier treatment, potentially outcome this entity. Lysozyme-associated series. data. Thirty-seven biopsy. Increased