Abstract: SA-PO249
Lysozyme-Associated Nephropathy Successfully Treated with Dasatinib in Chronic Myeloid Leukemia
Session Information
- Onconephrology: Immunological Cross-Talk
November 04, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Pal, Chaitanya A., University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Ravender, Raja, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Shaffi, Saeed Kamran, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Teixeira, J. Pedro, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Schmidt, Darren W., University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Caza, Tiffany, Arkansas Department of Education, Little Rock, Arkansas, United States
- Garcia, Pablo, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
Introduction
Lysozyme-associated nephropathy (LyN) is a rare and underrecognized entity causing acute tubular injury. Serum lysozyme levels are elevated in chronic myelomonocytic leukemia and other forms of leukemia with myelomonocytic differentiation. We present a case of acute kidney injury (AKI) treated with dasatinib in the setting of chronic myeloid leukemia (CML) secondary to LyN.
Case Description
A 45-year-old man with a recent diagnosis of BCR-ABL-positive CML was referred to our clinic for abnormal renal function. At the time of CML diagnosis, his serum creatinine was 1.94 mg/dl and white blood cell count (WBC) was 203,000/microliter. He was treated with the tyrosine kinase inhibitor dasatinib and after six months his WBC normalized and creatinine improved to 1.6. His exam in renal clinic was notable for no hypertension or edema. Labs were significant for urine protein-creatinine ratio (UPCR) 0.2 g/g, kappa-lambda ratio mildly elevated to 1.85, and no evidence of Fanconi syndrome. Kidney biopsy revealed tubular injury with positive lysozyme staining in the proximal tubules and 2+ mesangial IgA staining with minimal interstitial fibrosis with a MEST-C score of 0. Since his CML was adequately treated, we concluded his lysozyme levels were likely improving. He continued dasatinib, and three months later creatinine improved further to 1.43 and UPCR was undetectable.
Discussion
Lysozyme is a cationic protein mainly produced by monocytes and macrophages. It is freely filtered at the glomerulus and reabsorbed in the proximal tubule via endocytosis. Excessive lysozyme production causes proximal tubulopathy and can result in AKI, Fanconi syndrome, and proteinuria. LyN is an underdiagnosed entity that often resolves with cytoreductive therapy. Interestingly, our patient had minimal proteinuria and no evidence of Fanconi syndrome, and we concluded his LyN had already responded to dasatinib by the time he was seen in renal clinic.