Association of Co-dominant Immunoglobulin G Deposit in Immunoglobulin A Nephropathy With Poor Clinicopathological and Laboratory Parameters

Introduction: Immunoglobulin A (IgA) nephropathy is the commonest primary glomerulonephritis with a wide range of clinical presentations and laboratory findings. There is a paucity of studies regarding the significance of co-dominant immunoglobulin G (IgG) deposition in IgA nephropathy. Methods: The study included retrospective and prospective biopsy-proven cases of IgA nephropathy from 2013-2020 with a minimum of eight glomeruli. Clinical and laboratory parameters were analysed for the IgA and IgG co-dominant cases as compared to those of the non-IgG group. Results: A total of 58 cases of IgA nephropathy were included in the study out of which 25 biopsies (43.1%) were categorized as IgA plus IgG, and the rest 33 biopsies (56.8%) as the non-IgG group. A significant correlation was noted amongst the IgA plus IgG group with respect to the elevated mean arterial pressure (MAP) (p=0.038) and proteinuria (p=0.002) as compared to the non-IgG group. Amongst the MEST-C (mesangial hypercellularity, endocapillary hypercellularity, segmental sclerosis, tubular atrophy/interstitial fibrosis, crescents) variables, endocapillary hypercellularity correlated with elevated MAP (p=0.04), raised serum creatinine (p=0.005), and decreased estimated glomerular filtration rate (eGFR) (p=0.002). Conclusion: Co-dominant IgG deposit serves as an adverse marker pointing towards a deranged renal function in IgA nephropathy.