IL28B polymorphism, blood interferon-alpha concentration, and disease stage of HCV mono-infected and HCV-HIV co-infected patients

Interferon (IFN) preactivation, interleukin-28B (IL28B) alleles, and liver fibrosis act as predictors of response to antiviral therapy against hepatitis C. We aimed to verify if blood IFN concentration, a putative biomarker of interferon preactivation, might depend on carriage of a given IL28B genotype and/or advanced hepatic fibrosis. The study population included 187 hepatitis C patients (75 of whom were HIV coinfected), who were genotyped for the rs12979860 polymorphism and staged non-invasively by transient elastography. Blood IFN, measured by an enzyme immunoassay, was detectable in 68/187 patients (36%). Seventy-three patients (39%) were C/C homozygotes, 25 (13%) were T/T homozygotes, and 89 (48%) were heterozygotes. The fibrosis stage was F0-F1 in 70 patients (37%), F2-F3 in 54 patients (29%), and F4 in 63 patients (34%). IFN levels were higher among patients with HIV coinfection (p=0.044) and patients with better renal function (p=0.041), without association with the IL28B genotype or the hepatitis C stage. From the multivariate analysis, the only independent predictor of higher level of IFN was the age of patients (p=0.019), whereas independent predictors of a fibrosis stage ≥F2 were age (p=0.007), belonging to the HIV/HCV group (p=0.048) and current alcohol consumption (p=0.008). In conclusion, a sizable proportion of HCV carriers have detectable IFN levels that do not indicate a greater severity of disease or display any relationships to specific rs12979860 variants.