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Abstract: SA-PO848

C5b-9 Deposition on Cultured Endothelial Cells in Patients with Thrombotic Microangiopathy of Different Etiology

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Guillen, Elena, Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona,, Barcelona, Spain
  • Escudero-Saiz, Víctor Joaquín, Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona,, Barcelona, Spain
  • Martínez-Chillarón, Marta, Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona,, Barcelona, Spain
  • Quintana, Luis F., Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona,, Barcelona, Spain
  • Martinez-Sanchez, Julia, Hemostasis and Erythropathology Laboratory, Hematopathology, Pathology Department, Biomedical Diagnostic Center (CDB), Hospital Clínic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
  • López, Alex Ramos, Hemostasis and Erythropathology Laboratory, Hematopathology, Pathology Department, Biomedical Diagnostic Center (CDB), Hospital Clínic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
  • Moreno, Patricia Molina, Hemostasis and Erythropathology Laboratory, Hematopathology, Pathology Department, Biomedical Diagnostic Center (CDB), Hospital Clínic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
  • Diaz-Ricart, Maribel, Hemostasis and Erythropathology Laboratory, Hematopathology, Pathology Department, Biomedical Diagnostic Center (CDB), Hospital Clínic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
  • Palomo, Marta, Hematology External Quality Assessment Laboratory, Biomedical Diagnostic Center (CDB), Hospital Clinic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
  • Blasco Pelicano, Josep Miquel, Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona,, Barcelona, Spain
Background

Thrombotic microangiopathies (TMAs) are a group of diseases linked by endothelial injury for different mechanisms, one of which is deregulation of the complement system. The differential diagnosis of TMAs is challenging due to the etiological overlap and the absence of specific biomarkers, hence complement assessment may be a useful tool to improve the management of these patients.

Methods

Complement terminal pathway was assessed by analyzing deposition of C5b-9 (C5b-9d) on cultured endothelial cells (CEC), by immunofluorescence, after exposing them to the plasma of patients with TMA from different etiology, obtained between June-2021 and April-2023. C5b-9 deposits were calculated as percentage of labeled area over the total area analyzed. An increase ≥ 2x was considered significant.

Results

120 samples were included (95 patients, 51(53.7%) men, 49±15 years), of which 58(48.3%) had a positive result (C5b-9d ≥ 2x;Figure 1). Of these, 40(69.0%) presented renal function impairment at diagnosis: 6(10.3%) AKI-1, 7(12.1%) AKI-2, 17(29.3%) AKI-3 and 10(10.7%) required dialysis. Regarding the evolution of renal function, 33(56.9%) patients presented complete remission, 9(15.5%) partial remission, 2(3.4%) started long-term dialysis program and 6(10.3%) died.

Conclusion

Our series shows that TMA is a frequent condition, with high morbi-mortality. The analysis of C5b-9d on CEC could be a useful biomarker to differentiate those cases in which there is a complement overactivation, which may allow to individualize the treatment and follow-up of these patients. In addition to aHUS, C5b-9d was mainly observed in TMA associated with hematological diseases, drugs, and infections.

Figure 1. Etiology of TMA in patients with positive dC5b-9. The percentage expresses the positive cases of each etiology over the total number of positive cases. In parentheses, positive cases are shown over the total number of cases analyzed for each etiology.