Study of Correlation between Renal CD68 with Oxford MEST-C Scores and C3 Immunoreactivity in IgA Nephropathy

Background IgA nephropathy (IgAN) is the most frequent primary glomerular disease worldwide. The prognostic role of CD68, a macrophage marker, is under debate. We investigated the prognostic value of CD68 macrophage count and its correlation with Oxford Scoring system (MEST-C scores) and C3 immunoreactivity in IgAN. Materials and Methods Kidney biopsies of all adult patients diagnosed with IgAN between 2011 and 2020 were evaluated using the Oxford MEST-C scoring system. Immuno-histochemical staining was performed using monoclonal antibodies against CD68. Glomerular macrophages were quantified & correlated with each component of the MEST-C score and the intensity of mesangial IgA and C3 immunostaining. Renal CD68 counts were also correlated with demographic and clinical features. Additionally, correlations were performed between glomerular & interstitial CD68, with the IgAN percent risk prediction score. Results Glomerular and interstitial CD68 were correlated with proteinuria ( p < 0.05). Hypertension, eGFR, and risk prediction scores correlated with the mean interstitial CD68. Correlation was observed between mesangial cellularity (M) and the mean glomerular or interstitial CD68. Correlation was also observed between interstitial fibrosis and tubular atrophy (IFTA) with mean interstitial CD68. The number of globally sclerosed & normal glomeruli and crescent (C) correlated with mean interstitial CD68. Conclusion We demonstrate a correlation of mesangial and interstitial CD68 macrophage count with a number of clinical parameters. Further studies with larger sample numbers and follow-up biopsies are required to validate it.