The following is a summary of “Histological reappraisal of IgA nephropathy: the role of glomerular pattern of injury and mesangial complement deposition,” published in the April 2024 issue of Nephrology by Obrișcă et al.

Researchers conducted a retrospective study analyzing how the type of glomerular injury seen under light microscopy (LM) and the amount of C3 staining in the kidney’s mesangial area relate to IgAN’s clinical importance.

They reviewed patients with primary IgA nephropathy who had kidney biopsies and at least a year of follow-up. They reevaluated the LM pattern of glomerular injury based on a modified HAAS classification. Mesangial C3 deposition by immunofluorescence (IF) staining was scored semi-quantitatively. This study’s primary outcome was doubling serum creatinine or ESRD (dialysis, renal transplant, or eGFR<15 ml/min), along with secondary outcomes being eGFR decline per year. 

The results studied 214 patients with an average age of 41.4±12.6 years. The mean eGFR was 55.2±31.5 ml/min, and the median 24-h proteinuria of 1.5 g/day (IQR: 0.8-3.25). The main types of kidney injury seen were mesangioproliferative (37.4%), sclerotic (22.5%), and proliferative/necrotizing patterns (21.4%). Those with sclerosing and crescentic patterns had the worst kidney survival rates (5-year renal survival of 48.88% and 42.9%) and fastest decline in kidney function (-2.32 ml/min/year and -2.16 ml/min/y, respectively) compared to other glomerular patterns of injury. Intense C3 staining was also linked to worse kidney outcomes than those without intense C3 staining (35.5% vs. 21.4%, P=0.04). After adjusting for other factors, patients with crescentic and sclerosing patterns had significantly higher risks (3.6 fold and 2.1 fold) for kidney problems compared to those with mesangioproliferative pattern, and intense mesangial C3 deposition also predicted worse outcomes (HR, 3.33; 95%CI, 1.21-9.2). 

Investigators concluded that the LM pattern of glomerular injury and the amount of C3 deposits could better predict kidney outcomes in IgA patients with nephropathy.

Source: bmcnephrol.biomedcentral.com/articles/10.1186/s12882-024-03577-z