Abstract: SA-PO661
Investigating the Role of the Complement System in Paediatric Sickle Cell Disease
Session Information
- Glomerular Diseases: IgA and Complement-Mediated GN
November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1302 Glomerular Diseases: Immunology and Inflammation
Authors
- Diatlov, Daniel, University of Toronto Institute of Medical Science, Toronto, Ontario, Canada
- Bohorquez, Arlette, The Hospital for Sick Children Research Institute Cell Biology Program, Toronto, Ontario, Canada
- Jackson, Melanie E., The Hospital for Sick Children Division of Haematology/Oncology, Toronto, Ontario, Canada
- Cheong, Melina, The Hospital for Sick Children Division of Haematology/Oncology, Toronto, Ontario, Canada
- Licht, Christoph, The Hospital for Sick Children Division of Nephrology, Toronto, Ontario, Canada
Background
Sickle cell disease (SCD) is one of the most common hereditary red blood cell (RBC) disorders in the world, with an estimated 300,000 infants born with the disease annually. In SCD, a mutation in the gene for β-globin results in rigid sickled RBCs that can form blockages in the micro-vessels within organs, such as the kidney, leading to RBC lysis, endothelial cell (EC) damage, ischemia/reperfusion injury, and extremely painful vaso-occlusive crises (VOC). SCD can give rise to a variety of renal manifestations such as hyperfiltration, microalbuminuria, and AKI. Approximately 16-18% of overall mortality in patients with SCD is ascribed to kidney disease. The complement system – a critical part of the innate immune system - is involved in a myriad of kidney and vascular disorders, and emerging research points to the involvement of complement in SCD, potentially contributing to sickle cell nephropathy (Fig. 1A).
Methods
Paediatric patients with SCD (HbSS or HbS/β0) were enrolled during hospital admission with diagnosed VOC or acute chest crisis (ACS) not caused by infection. Patient serum was collected during hospital admission (crisis) and during follow-up (steady state). Complement activity was measured using the WIESLAB Complement System Screen (Svar Life Science). Immunofluorescence (IF) imaging was used to measure the deposition of C3b and C5b-9 on the surface of ECs exposed to patient serum.
Results
There is equal classical and alternative pathway activity during disease steady state and crisis, with an interesting trend showing elevated MBL pathway activity during crisis compared to steady state (Fig. 1B). IF assay data shows significantly elevated deposition of C3b and C5b-9 proteins on ECs when comparing crisis samples and healthy controls, with a trend suggesting a potential difference in complement deposition between steady state and crisis patients (Fig. 1C).
Conclusion
Our preliminary data shows complement is active in SCD, resulting in elevated C3b and C5b-9 deposition on ECs during SCD crisis. Future work will focus on further quantifying complement activity, and assessing the functional consequences of this on the surface of ECs.
Funding
- Commercial Support –