Hepatitis C virus (HCV) genotypes and disease progression in HIV/ HCV–coinfected patients

Six major hepatitis C virus (HCV) geno-types have been described, and HCV ge-notypes 1–4 are the predominant circu-lating genotypes in Western countries [1]. These genotypes show a distinct geo-graphic distribution, as well as a different susceptibility to interferon (IFN)–based therapies [1]. Only recently have other dif-ferences between HCV genotypes been ap-preciated (table 1). For example, patients carrying HCV genotype 2 and with nor-mal levels of transaminases are at higher risk for experiencing alanine aminotrans-ferase (ALT) flares; however, they have the best response to IFN-based therapies [2]