Table 2.

Lysozyme-induced nephropathy (LyN): teaching points

•Lysozyme is a small cationic protein produced by monocytes that is freely filtered by the glomerulus and reabsorbed by proximal tubules.

•Overproduction of lysozyme in patients with chronic monocytic or myelomonocytic leukemia may lead to nephrotic-range proteinuria (lysozymuria).

•Lysozyme-induced nephropathy is a rare cause of acute kidney injury in patients with chronic monocytic or myelomonocytic leukemia.

•Lysozyme-induced nephropathy is characterized by acute tubular injury with abundant cytoplasmic granular inclusions that stain strongly for lysozyme and have an ultrastructural appearance consistent with that of autophagolysosomes.