COVID-19 Infection Can be Associated With Pauci-Immune Type of Crescentic Glomerulonephritis: A Case Report
American Journal of Clinical Pathology
COVID-19 infection is known to cause various podocytopathies, but the pauci-immune type of crescentic glomerulonephritis (C-GN) following COVID-19 infection has only rarely been reported.
We report a case in which a positive proteinase-3 was correlated with a pauci-immune type of C-GN in a patient who contracted COVID-19 infection. Methods/Case Report
The patient was a 56-year-old woman who had a normal baseline serum creatinine (sCr) two years ago before she developed acute respiratory failure and acute kidney injury (sCr at 1.57 mg/dl) with significant proteinuria (urine protein/creatinine ratio [UPCR] at 1.02) and 2-3+ hematuria following a COVID-19 infection. The ANCA screening tests, including a recent one, were negative several times, but her protein-3 was low positive (14) and myeloperoxidase-3 was negative recently. Her current sCr increased to 2.93 mg/dl with UPCR at 3.1 and 2+ hematuria. A renal biopsy was performed, which showed one glomerulus for light microscopy and one glomerulus for immunofluorescent studies in the absence of proliferation, crescentic formation, or necrosis. Immunofluorescent stains were all negative in the glomerulus, but the methylene-blue stained sections for electron microscopy revealed three glomeruli with cellular crescents without necrosis. The ultrastructural examination did not show additional findings. The biopsy was consistent with proteinase-3 associated C-GN, pauci-immune type. She started cyclophosphamide treatment. Results (if a Case Study enter NA)
COVID-19 can be associated with the pauci-immune type of C-GN. Under this condition, the ANCA screening test can be deceiving (false negative) in ruling out C-GN, so more specific tests such as myeloperoxidase and proteinase-3 should be ordered to enhance the chances of detecting renal vasculitis.
Pokharel A, Metcalf BD, Li W, Kanaan HD, Zhang PL. COVID-19 infection can be associated with pauci-immune type of crescentic glomerulonephritis: a case report. Am J Clin Pathol. 2023 Nov;160(Suppl 1):S105-S106. doi:10.1093/ajcp/aqad150.232