Suspected immune-complex glomerulonephritis in FIV-infected cats: A clinical case series

Feline immunodeficiency virus (FIV) is a retroviral infection that causes progressive immunosuppression in cats and predisposes them to systemic complications, including renal disorders such as immune-complex glomerulonephritis (ICGN). ICGN may develop due to immune-complex deposition within the glomeruli. Early detection of renal involvement in FIV-positive cats is essential for clinical management and prognosis. This report presents two suspected cases of ICGN in FIV-infected domestic cats. Both were tested for retroviral infections using a commercial rapid test kit for FIV/FeLV. Clinical examination, serial complete blood count, and serum biochemical analysis were performed, including blood urea nitrogen (BUN), creatinine, and symmetric dimethylarginine (SDMA) to assess renal function. Both cats tested positive for FIV and negative for FeLV. The first cat showed normal BUN (33.8 to 29.9 mg/dL) but elevated creatinine (2.47 to 2.6 mg/dL) and increased SDMA (12.5 to 20.6 µg/dL), consistent with early renal dysfunction. The second cat showed progressive and severe deterioration with elevated BUN from 89.91 to 149.84 mg/dL, creatinine from 6.05 to 9.66 mg/dL, and SDMA from 29.9 to 43.3 µg/dL, indicating moderate renal impairment. Both cats also exhibited progressive anemia and leukocytosis, reflecting chronic inflammation and immunosuppression associated with FIV infection. The combination of retroviral infection, hematological changes, and renal biomarker elevation strongly suggests immune complex–mediated renal injury. This case series emphasizes the importance of integrating retroviral testing, hematology, and renal biomarkers, particularly SDMA, for early identification of kidney involvement in FIV-infected cats. Further histopathological confirmation is required to establish the ICGN diagnosis.