Renal relapse in ANCA-associated vasculitis can be predicted by the presence of CD4 + T cells in the urine

A recent study demonstrated that urinary CD4 + T-cell counts have the potential to identify individuals with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis who are at a significant risk of experiencing renal relapse within a 6-month period. This study’s findings were published in the Journal of the American Society of Nephrology.

The PRE-FLARED was a prospective multicenter biomarker study that enrolled 102 individuals with ANCA-associated vasculitis in remission. This study aimed to predict the occurrence of renal relapse by quantifying the levels of urinary CD4 + T-cell subsets through flow cytometry at the baseline, and then monitoring the clinical outcomes during a six-month follow-up period.

Out of the total participants, 2 had non-renal flares, 10 experienced renal relapses, and 90 remained in stable remission. Patients who relapsed had a significantly higher median baseline urinary CD4 + T-cell count compared to those in remission. The analysis of urinary CD4 + T-cell counts using receiver operating characteristic curve showed an area under the curve value of 0.88 for predicting renal flares, hematuria, proteinuria, and outperforming ANCA titers. With a cutoff of 490 CD4 + T cells per 100 ml urine, the sensitivity and specificity in identifying patients with future renal flares were 60% and 97.8%, respectively. Combining urinary CD4 + T-cell counts with proteinase-3 ANCA levels in a post hoc analysis suggested improved predictive performance in the PR3 + subgroup. Additionally, the number of urinary CD4 + T cells demonstrated a limited correlation with a decline in glomerular filtration rate (GFR) and an increase in proteinuria over the follow-up period.

According to the above study, urinary CD4+ T-cell counts could be used to detect individuals with ANCA-associated vasculitis who face a considerable risk of renal relapse within six months. The incorporation of these counts with ANCA levels has been shown to enhance the accuracy of relapse prediction.