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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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Selective decrease in complement C2 hemolytic activity is a sensitive marker for cryoglobulinemia and active disease
Atila Granados Afonso de Faria1, Fernanda Correa Chaves2, Maria Lucia Gomes Ferraz2
1Rheumatology Division, Medicine Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
Summary
Selective low C2 hemolytic activity (C2h) in Hepatitis C Virus (HCV) patients indicates complement activation. This finding is linked to cryoglobulinemia, active disease, and specific HCV genotypes.
Area of Science:
- Immunology
- Virology
- Complement System
Background:
- Hepatitis C Virus (HCV) infection can lead to selective deficiencies in C2 hemolytic activity (C2h) without affecting other complement components.
- This phenomenon, termed selective low/non-detected C2h, requires further investigation into its underlying immunological and clinical basis.
Purpose of the Study:
- To characterize the immunologic and clinical factors associated with selective low or non-detected C2 hemolytic activity in Hepatitis C Virus (HCV) patients.
- To identify predictors and clinical implications of this complement deficiency in the context of HCV infection.
Main Methods:
- Quantified C2 hemolytic activity (C2h), HCV viral load, cryoglobulinemia, and complement components in 726 HCV patients.
- Performed sequential C2h measurements in 189 patients and analyzed associations with clinical and laboratory parameters.
Main Results:
- 15.9% of patients had non-detected C2h and 16.9% had low C2h; 30.7% showed temporal oscillations.
- Selective low/non-detected C2h correlated with higher AST, ALT, APRI, detectable HCV-RNA, cryoglobulinemia, and HCV genotype 3.
- Elevated ALT, HCV genotype 3, active disease, and viral load were independent predictors of low/non-detected C2h.
Conclusions:
- Selective C2h decrease serves as a sensitive indicator of complement activation in HCV patients.
- This deficiency is significantly associated with cryoglobulinemia, active disease, elevated liver enzymes, higher viral load, and HCV genotype 3.
