Abstract: FR-PO0159
Urinary CD4+CD38+HLA-DR+EM T Cells as a Biomarker for Diagnosis of Acute Interstitial Nephritis
Session Information
- AKI: Mechanisms - 2
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Mirkheshti, Pouneh, Charite - Universitatsmedizin Berlin, Berlin, BE, Germany
- Metzke, Diana, Charite - Universitatsmedizin Berlin, Berlin, BE, Germany
- Goerlich, Nina, Charite - Universitatsmedizin Berlin, Berlin, BE, Germany
- Klocke, Jan, Charite - Universitatsmedizin Berlin, Berlin, BE, Germany
- Enghard, Philipp, Charite - Universitatsmedizin Berlin, Berlin, BE, Germany
Background
Acute Interstitial Nephritis (AIN) is a frequent differential diagnosis in cases of deteriorated kidney function. Confirming the diagnosis of AIN presently requires a kidney biopsy, which is an invasive procedure not free of risk. In previous studies, we established flow cytometry analysis of urine cells as biomarker to detect kidney inflammation. In the present study, we investigated urinary T cells, monocytes and eosinophils as potential biomarkers for AIN.
Methods
A total of 181 urine samples from patients undergoing biopsy at Charité for unexplained renal function decline were analyzed via flow cytometry, divided into an exploratory (n=81) and a validation cohort (n=100). Samples in the exploratory cohort were stained for T cell subsets, monocytes and eosinophils, samples in the validation cohort only for T cell subsets. T cells were stained for CD4+, CD8+ and subdivided into naive (NV), effector memory (EM), central memory (CM), and effector memory T cells re-expressing CD45RA (TEMRA). HLA-DR and CD38 expression were also assessed. Based on interstitial involvement, patients were classified into three groups: 9% had AIN (n=16), 42% had lymphocytic infiltrates in glomerular diseases (LI; n=77), and 49% had other diseases without interstitial involvement (OD; n=88).
Results
In our exploratory cohort, the subset with the highest discriminatory power for AIN diagnosis were urinary CD4+CD38+HLA-DR+EM T cells, showing significantly higher counts in AIN compared to LI (p<0.001) and OD (p<0.001). These results were confirmed in the validation cohort, were AIN patients had significantly higher counts than those with OD (p<0.02). Furthermore, pooled AIN patients with preceding corticosteroid therapy had lower counts than those without treatment. Combined ROC analysis of this cell population as a biomarker for AIN yielded an AUC of 0.82 (0.68-0.96; 16 AIN vs. 165 non-AIN). A cut-off of 137 cells per 100 ml urine resulted in a sensitivity of 81.3% and a specificity of 80.6% for predicting AIN. Incorporating a maximum urine albumin-creatinine ratio (uACR) of 1 mg/g as exclusion criterion for AIN and the condition of no prior steroid therapy further improved the AUC to 0.95 (0.9-1; 9 AIN vs. 65 non-AIN).
Conclusion
Urinary CD4+CD38+HLA-DR+EM T cells are a potential diagnostic biomarker for AIN.
Funding
- Government Support – Non-U.S.