Direct Immunofluorescence of Renal Biopsy: Perspective of an Immunopathologist

Abstract

ABSTRACT Aims This study was undertaken to analyze the strength of direct immunofluorescence microscopy in the diagnoses of renal diseases vis-á-vis histopathology. An attempt was also made to present advantages and pitfalls of this age old technique. Settings and design A total of 250 consecutive renal biopsies received over a period of 1 year were analyzed. The histopatholgy and direct immunofluorescence slides were reported by two separate pathologists and later compared to reach a final diagnosis. Results Two cores examined by histopatholgy and direct immunofluorescence microscopy yielded a final diagnosis in 98% cases. In 2% of renal biopsies (4 biopsies with a ‘descriptive’ label and 1 case of amyloid like nephropathy), additional diagnostic aids like electron microscopy were required to clinch a conclusive diagnosis. No case of anti-glomerular basement membrane glomerulonephritis or hereditary glomerular disease was observed over 1 year period under review. Conclusion Direct immunofluorescence helped to detect IgA nephropathy (5% cases), it incresed the sensitivity of detection of focal segmental glomeulosclerosis (23 more cases) and membranous glomerulopathy (2 more cases). It helped in detection as well as grading of glomerulonephritis in lupus nephritis. Crescentic glomerulonephritis could be further categorized into immune complex and pauci-immune subtypes. Immunofluorescent dye thioflavin T proved out to be a very sensitive dye for detection of amyloidosis. Membranoproliferative glomerulonephritis/ diffuse proliferative glomerulonephritis cases were less well discriminated by direct immunofluorescence than histopathology. Two percent of renal biopsies (2 cases of membranoproliferative glomerulonephritis, 1 case of membranous glomerulopathy, 1 case of mesangioproliferative glomerulonephritis) were false negative on direct immunofluorescence implying technical errors. Thus, correct diagnosis of glomerulonephritis requires direct immunofluorescence microscopy in parallel with light microscopic examination and also correlation with clinical features, serological as well as biochemical parameters. In less than 2% of patients, electron microscopy might be essential. How to cite this article Minz RW, Chhabra S, Joshi K, Khirwadkar N, Sakhuja V, Pasricha N, Bhardwaj R. Direct Immunofluorescence of Renal Biopsy: Perspective of an Immunopathologist. J Postgrad Med Edu Res 2015;49(1):10-17.