Renal amyloidogenic leukocyte chemotactic factor 2 combined with IgA nephropathy: A case report.

Rationale: Amyloidogenic leukocyte chemotactic factor 2 (ALECT2) was recently considered as a new clinicopathologic type of amyloid, which frequently affects kidney in adults and results in different degrees of renal insufficiency and failure with or without proteinuria. Here, we present a case of combining LECT2-associated renal amyloidosis with immunoglobulin (Ig)A nephropathy.

Patient Concerns: A 71-year-old Chinese man presented with edema of both lower extremities.

Diagnoses: There was pale eosinophilic material strongly positive for the Congo red stain in interstitium with demonstrated apple green birefringence under polarized light. Immunofluorescent stain was positive for IgA deposits (4+), IgG deposits (2+), C3 deposits (3+) within the mesangium and capillary wall. Immunohistochemistry was positive for κ (+), λ (2+) in mesangial area, and LECT2 (2+) in the interstitium. On electron microscopy, there were electron-dense deposits within mesangial area and subendothelial and randomly orientated and nonbranching fibrils 10 nm in size found in the interstitium areas. Liquid chromatography tandem mass spectrometry was performed on peptides extracted from Congo red-positive, microdissected areas of the paraffin-embedded kidney specimen. LECT 2-associated renal amyloidosis with IgA nephropathy was pathologically confirmed by renal biopsy.

Interventions: Steroids (60 mg/d) were used to treat IgA nephropathy daily. Antihypertensive treatment was switched to an angiotensin-converting enzyme inhibitor.

Outcomes: One year after diagnosis, creatine remained stable in the normal range, and 24-hour proteinuria decreased to 2.9 g.

Lessons: To date, ALECT2 has still not been comprehensively investigated. The findings of this research provide insights for concurrent IgA nephropathy with ALECT2.