Anti-neutrophil Cytoplasmic Antibody (ANCA)-Negative Pauci-Immune Crescentic Glomerulonephritis: A Case Series From a Tertiary Care Hospital in South India.

BACKGROUND

Pauci-immune crescentic glomerulonephritis (PICGN) is a critical form of renal disease characterized by a swift deterioration in kidney function and crescent formation in glomeruli, usually in the absence of notable immune deposits. While commonly associated with anti-neutrophil cytoplasmic antibodies (ANCAs), a subset of patients presents without detectable ANCA, complicating both diagnosis and management.

OBJECTIVE

This case series presents an overview of the clinical manifestations, laboratory parameters, biopsy findings, and therapeutic outcomes observed in individuals diagnosed with ANCA-negative PICGN through histological confirmation.

METHODS

This series reviews seven retrospective cases of ANCA-negative PICGN managed at a tertiary hospital in South India, focusing on clinical presentation, investigations, renal biopsy findings, treatment strategies, and outcomes.

RESULTS

All seven patients exhibited acute kidney injury (AKI), significant proteinuria, and active urinary sediment. Inflammatory markers were elevated in all cases. Renal biopsies demonstrated 70-90% crescent formation with the absence of immune complex deposits. Serologic tests for ANCA, antinuclear antibody (ANA), and double-stranded DNA (dsDNA) were negative; complement levels remained within the normal limits. Three patients had identifiable urinary tract infections with Gram-negative organisms. Two patients developed pulmonary involvement. Each patient was treated with a combination of corticosteroids and cyclophosphamide, alongside supportive renal replacement therapy through dialysis. Four patients improved partially, one showed a slow response, while two succumbed during hospitalization.

CONCLUSION

ANCA-negative PICGN represents a severe crescentic glomerulonephritis with significant diagnostic and therapeutic implications. Prompt renal biopsy and early immunosuppressive therapy are essential for renal salvage. Despite treatment, outcomes remain variable, emphasizing the need for heightened clinical suspicion and timely intervention. ANCA-negative PICGN is an aggressive glomerular disease. Renal biopsy is indispensable in seronegative cases of rapid renal deterioration. Due to its aggressive nature, this form of glomerular disease requires timely histopathological evaluation and the immediate initiation of immunosuppressive therapy, especially when autoimmune serology is negative. Although partial recovery is possible, mortality remains a concern.