Immune-complex deposits in anti-neutrophil cytoplasmic antibody associated crescentic glomerulonephritis; a report of two cases

Abstract

Anti-neutrophil cytoplasmic antibody (ANCA)-associated crescentic glomerulonephritis is an important cause for rapidly progressing glomerulonephritis. It is generally classified under pauci-immune glomerulonephritis. However, 12%-18% of ANCA-associated crescentic glomerulonephritis show immune-complex deposits causing a diagnostic dilemma. We report 2 cases of ANCA-mediated glomerulonephritis with associated immune-complex deposits. First case is a 19-year-old female patient presented with fever and bilateral lower limb purpura since one day. Immunologic work-up was normal except positivity for cytoplasmic or c-ANCA by indirect immunofluorescence (IF). Kidney biopsy showed presence of segmental cellular crescent with fibrinoid necrosis. IF showed strong fine granular positivity for IgG, IgA, C3, C1q, kappa and lambda along the glomerular capillary walls. Second case is a 20-year-old male presented with low grade fever for last one month and vomiting for last two days. Immunologic work-up was unremarkable except positivity for cytoplasmic or c-ANCA by indirect IF. Kidney biopsy showed 14 glomeruli of which 8 glomeruli showed cellular crescents. IF for IgG, IgA, C3, kappa and lambda was done, which showed strong fine granular positivity along the glomerular capillary walls. Both the cases were treated with intravenous methylprednisolone and oral prednisone on a weaning regimen, and monthly therapy of intravenous cyclophosphamide. The maintenance phase consisted of mycophenolate mofetil and oral prednisone administrated in alternate-day low-dose regimen. Both the patients are on regular follow-up and are doing well.These immunecomplexes act synergistically with ANCA to cause more severe damage to the kidneys with a poorer outcome. Thus a prompt diagnosis and management of these patients is crucial.