Associations of chemokine system polymorphisms with clinical outcomes and treatment responses of chronic hepatitis C

Abstract

Background & Aims: CCR5Δ32, a 32–base pair deletion of the CC chemokine receptor (CCR) 5 gene, is associated with slowed human immunodeficiency virus disease progression in heterozygotes and protection against infection in homozygotes. A recent study found a higher than expected frequency of CCR5Δ32/Δ32 in patients with hepatitis C virus infection. The roles of other disease-associated chemokine system polymorphisms have not been evaluated in hepatitis C virus infection. Methods: Six chemokine system polymorphisms (CCR5Δ32, CCR5 promoter 59029–G/A, CCR2 -64I, RANTES [regulated upon activation, normal T cells expressed and secreted] - 403 -G/A, and - 28 -C/G and stromal derived factor 1 -3'A) were studied in 417 patients with liver diseases (339 with hepatitis C) and 2380 blood donors. The clinical parameters of hepatitis C virus infection were compared between carriers and noncarriers of each genetic variant. Results: The frequency of CCR5Δ32 homozygosity was 0.8% in whites with hepatitis C virus and 1.1% in controls ( P = 0.75). The CCR5Δ32 allele was not associated with any of the clinical parameters of hepatitis C virus infection. Hepatitis C virus–seropositive whites with the RANTES - 403-A allele were less likely to have severe hepatic inflammation compared with those without (odds ratio, 0.34; P = 0.03). In multivariate analysis, the CCR5 promoter 59029 -A allele was marginally associated with a sustained response to interferon therapy (odds ratio, 3.07; P = 0.048). Conclusions: In this cohort, the frequency of CCR5Δ32 homozygosity in patients with hepatitis C was similar to controls. The high prevalence of CCR5Δ32 homozygosity in the hepatitis C virus patients of the earlier study likely reflects resistance to human immunodeficiency virus infection in hemophiliacs rather than a susceptibility to hepatitis C virus infection. Expression of CCR5 and RANTES may be important in the modulation of hepatic inflammation and response to interferon therapy in chronic hepatitis C.