Abstract: TH-PO1076
Thrombotic Microangiopathy in the Kidney Biopsy: Histology Is Similar in Patients with and Without Genetic Pathogenic Variants
Session Information
- Pathology and Lab Medicine
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1700 Pathology and Lab Medicine
Authors
- Brodsky, Sergey V., The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
- Satoskar, Anjali A., The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
- Dasgupta, Alana, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
- Alley, Tiffany Leigh, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
- Ibrahim, Dalia Y., The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
Background
Thrombotic microangiopathy (TMA) is a clinicopathologic syndrome that results from endothelial cell injury. Several genetic mutations are associated with TMA development. Histologic features of TMA on the kidney biopsy include the glomerular, arterial and arteriolar injury. Glomerular features include fibrin microthrombi in glomerular capillaries, acellular closure of glomerular capillaries, fragmented red blood cells (RBC). In arteries and arterioles, fibrin microthrombi, mucoid intimal thickening, fragmented RBC in the wall maybe seen. There are no specific histologic features described for any TMA etiology. The goals of this retrospective clinicopathologic study were to develop a weighted scoring system for the histologic features of TMA and correlate it with the results of genetic testing for complement mutations and disease outcomes.
Methods
This retrospective cohort study included patients who underwent genetic testing at the Iowa clinics between January 2010 and January 2024. From those, patients with a kidney biopsy were selected. Cases with advanced chronic kidney injury were excluded. The final cohort included 40 patients; renal recovery was assesed at 12 month after the biopsy. Patients were stratified into 3 groups: no mutation, clinically significant mutation, and mutation of unknown significance. A total of 13 histologic features were assessed, scored from 0-3 and divided into three categories – glomerular (Active Glomerular Score (AGS)), vascular (Active Vascular Score (AVS)), and Chronic Kidney Injury Score (CKIS).
Results
There was no significant difference among the three groups with regards to age, gender, or race. All patients with clinically significant mutation where treated with Eculizumab for the duration of follow-up (12 months), while median treatent was 2.5 months in patients with no mutations. Composite histologic scores (AVS, AGS, CKIS) did not show significant differences across renal recovery groups, while some individual markers: fragmented RBCs, intimal fibrin, EM endothelial swelling were associated with lower odds of renal recovery.
Conclusion
There was no association between histologic features and the presence of genetic mutations associated with TMA. The histologic features of fragmented RBCs, intimal fibrin, and endothelial cell swelling had prognostic value for renal recovery.