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Methods for Quantitative Detection of Antibody-induced Complement Activation on Red Blood Cells
Published on: January 29, 2014
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Complement ratios C3bc/C3 and sC5b-9/C5 do not increase the sensitivity of detecting acute complement activation
Anub Mathew Thomas1, Viktoriia Chaban2, Søren E Pischke3
1Department of Immunology, Oslo University Hospital and University of Oslo, Norway; Department of Neurology, Drammen Hospital, Vestre Viken Hospital Trust, Norway.
Molecular Immunology
|December 15, 2021
Summary
The ratio of complement activation products to parent proteins did not improve detection of complement activation in acute heart failure or cardiac arrest patients. Complement activation markers C3bc and sC5b-9 alone were sensitive indicators.
Area of Science:
- Immunology
- Clinical Diagnostics
- Biochemistry
Background:
- Complement activation is implicated in various diseases.
- Ratios of complement activation products to parent proteins may offer enhanced sensitivity for detection.
- This study investigates the utility of C3bc/C3 and sC5b-9/C5 ratios in acute clinical settings.
Purpose of the Study:
- To evaluate if C3bc/C3 and sC5b-9/C5 ratios improve the detection of complement activation compared to activation products alone.
- To assess the diagnostic value of these ratios in patients with ST-elevated myocardial infarction (STEMI) and out-of-hospital cardiac arrest (OHCA).
Main Methods:
- Analysis of C3, C3bc, C5, and sC5b-9 in 629 STEMI and 672 OHCA patient samples.
- Healthy controls (n=20) were used to establish reference cut-off values.
- Calculation and comparison of activation product levels versus their respective ratios.
Main Results:
- Increased C3bc/C3 and sC5b-9/C5 ratios were primarily driven by elevated C3bc and sC5b-9 levels.
- Decreased C3 or C5 levels minimally impacted the ratios.
- Strong correlations were observed between activation products and their ratios in both patient groups.
- The terminal complement complex sC5b-9 alone was a better predictor of worse outcomes than the sC5b-9/C5 ratio.
Conclusions:
- C3bc and sC5b-9 are sensitive markers for systemic complement activation.
- The ratios C3bc/C3 and sC5b-9/C5 do not enhance the detection of complement activation in these acute clinical conditions.
