Microangiopathic lesions linked to poorer immunosuppression response in IgA nephropathy

A prospective cohort study published in Nephrology Dialysis Transplantation evaluated whether renal arteriolar microangiopathic lesions were associated with immunosuppressive treatment response in IgA nephropathy. It included 620 patients with biopsy-proven primary disease and persistent proteinuria ≥1 g/day despite at least three months of optimized supportive care with renin–angiotensin system inhibitors. All subsequently received immunosuppressive therapy for more than six months. Two pathologists independently reviewed the lesions.

Treatment response required a ≥50% reduction in proteinuria to <1 g/day, together with an eGFR decline of <25%. Microangiopathic lesions were present in 154 patients (24.8%), who had higher blood pressure, more severe proteinuria, and lower eGFR than patients without lesions. Non-response rates were 61.0% versus 26.2%, respectively. Lesions were independently associated with non-response in multivariable analysis (odds ratio 4.04; 95% CI 2.61–6.25), with consistent findings after propensity score matching and across prespecified subgroups.

These findings identify a biopsy feature associated with poorer treatment response, but do not establish that lesions cause resistance to immunosuppression or that withholding treatment improves outcomes. The observational design remains susceptible to residual confounding. Only the abstract was available; specific immunosuppressive regimens and longer-term kidney outcomes were not reported in the supplied text.