Role of Immunofluorescence in Adult Onset Nephrotic Syndrome-A Study in a Tertiary Care Centre of Western India

Abstract

Introduction: Study of renal Immunofluorescence (IF) is an ancillary but essential technique in evaluation of renal biopsies in glomerulopathies and also it enlightens on the pathogenesis of nephrotic syndrome. Aim: To determine the role of IF in evaluating definite subtyping and diagnosis of adult onset nephrotic syndrome and attempting clinicopathological correlation. Materials and Methods: A total of 52 patients of adult onset nephrotic syndrome were evaluated clinically and with pertinent investigations; and subjected to USG guided percutaneous renal biopsy which was processed and stained for light microscopy and for immunofluorescence by direct method (DIF) using antibodies against IgG, IgM, IgA and C3. Results: The predominant age group affected was 18-47 years (78.85%). Male:female ratio was 1:0.63. The most frequent glomerular lesion encountered was Focal Segmental Glomerulosclerosis (FSGS, 36.54%) followed by lupus nephritis (26.92%) and IgA nephropathy (9.62%). The most common glomerular lesion in males was FSGS and that in females was lupus nephritis. DIF was mainly coarsely granular whenever present. One case of lupus nephritis and diabetic nephropathy, showed non specific IF. It was negative in all cases of FSGS, Minimal Change Disease (MCD) and renal amyloidosis. The IF helped in differentiating eight cases that were normal on light microscopy as IgA nephropathy (n=5) and authentic MCD (n=3). It helped in endorsing 19 cases of FSGS to be a progression of MCD. It was also of help in sub-typing all cases of Membranoproliferative Glomerulonephritis (MPGN) (n=3) as MPGN-Type I. Conclusion: IF was of great help in diagnosing exact type of glomerulopathy in adult onset nephrotic syndrome and provided insight in its pathogenesis.

Keywords

• biopsy
• focal segmental glomerulosclerosis
• glomerulopathy
• lupus nephritis
• renal biopsy