Evaluation of cases of membranoproliferative glomerulonephritis according to newer classification: A retrospective record-based study.

Background: Membranoproliferative glomerulonephritis (MPGN) has traditionally been classified on electron microscopy (EM) into different types based on the location of the immune complexes. Sethi et al. subsequently suggested a more relevant etiology-based and clinically useful classification based on immunofluorescence.

Methods: In this retrospective study, 18 diagnosed cases of MPGN over a one-year period for which direct immunofluorescence (DIF) study results were available, were selected. Cases without archived records of immunofluorescence photographs/reports were excluded. Histological diagnosis of MPGN was confirmed and DIF results were analyzed with reference to antibodies to IgG, IgA, IgM, C3, C1q, kappa, and lambda light chains.

Results: Evaluation of cases revealed 8 males and 10 females with age range from 11 to 66 years. Fifteen cases presented with nephrotic syndrome. On evaluation, 88.89% cases (16/18) were immune complex mediated while two (11.11%) were of complement mediated type of MPGN. Among immune complex-mediated cases, a single case of monoclonal gammopathy associated or light chain mediated MPGN was present.

Conclusion: The classification described by Sethi et al. is easy to use since it relies on DIF instead of EM which is not readily available. Most of the cases were immune complex mediated whereas incidence of complement mediated MPGN, that is, C3 glomerulopathy was low (11.11%). Application of the new classification allows more relevant categorization of cases based on etiology and without the requirement of EM.