Effects of MASP2 haplotypes and MASP‐2 levels in hepatitis C‐infected patients

Mannan‐binding lectin (MBL) and MBL‐associated serine protease 2 (MASP‐2) are components of the lectin pathway, which activate the complement system after binding to the HCV structural proteins E1 and E2. We haplotyped 11 MASP2 polymorphisms in 103 HCV patients and 205 controls and measured MASP‐2 levels in 67 HCV patients and 77 controls to better understand the role of MASP‐2 in hepatitis C susceptibility and disease severity according to viral genotype and fibrosis levels. The haplotype block MASP2*ARDP was associated with protection against HCV infection (OR = 0.49, p = .044) and lower MASP‐2 levels in controls (p = .021), while haplotype block AGTDVRC was significantly increased in patients (OR = 7.58, p = .003). MASP‐2 levels were lower in patients than in controls (p < .001) and in patients with viral genotype 1 or 4 (poor responders to treatment) than genotype 3 (p = .022) and correlated inversely with the levels of alkaline phosphatase, especially in individuals with fibrosis 3 or 4 (R = ?.7, p = .005). MASP2 gene polymorphisms modulate basal gene expression, which may influence the quality of complement response against HCV. MASP‐2 levels decrease during chronic disease, independently of MASP2 genotypes, most probably due to consumption and attenuation mechanisms of viral origin and by the reduced liver function, the site of MASP‐2 production.