When leukemia harms the kidneys: a scoping review of lysozyme-induced nephropathy in chronic myeloid leukemia and chronic myelomonocytic leukemia.

Lysozyme-induced nephropathy (LyN) is a rare and underdiagnosed renal complication associated with hematologic malignancies, particularly chronic myelomonocytic leukemia (CMML), and less commonly, chronic myeloid leukemia (CML). This scoping review aims to consolidate current knowledge of the pathophysiology, diagnosis, clinical features, management, and epidemiology of LyN in these patient populations. Methods: In accordance with PRISMA-ScR guidelines, a comprehensive literature search was conducted through PubMed, Embase, and Scopus from inception to March 2025. Eligible studies included adult patients diagnosed with LyN in the setting of CMML or CML, confirmed either clinically or by renal biopsy. Extracted data included study design, lysozyme levels, hematologic and renal presentations, diagnostic modalities, treatment strategies, and outcomes. Results: A total of ten studies met the inclusion criteria: five case reports, three retrospective cohort studies, and two pathology-based reviews. The majority involved CMML patients with markedly elevated serum or urinary lysozyme levels. Renal biopsies consistently demonstrated proximal tubular injury, eosinophilic cytoplasmic granules, and positive lysozyme immunostaining, with occasional leukemic infiltration. Treatment focused on the underlying hematologic malignancy, using agents such as hypomethylating agents, hydroxyurea, or tyrosine kinase inhibitors. Renal outcomes varied, with four patients progressing to end-stage kidney disease and three requiring dialysis. Conclusion: Lysozyme-induced nephropathy is a clinically significant but frequently overlooked tubulointerstitial complication in patients with CMML and CML. Early recognition facilitated by lysozyme quantification and kidney biopsy may allow for timely therapeutic intervention and improved renal outcomes. Increased clinical awareness and further prospective studies are warranted to guide screening strategies and optimize management protocols.