Hepatitis C virus NS3 mutations in haemophiliacs

Haemophiliacs have high hepatitis C virus (HCV) exposure risk from blood products that did not undergo heat inactivation or disease-specific screening prior to 1987. Repeated exposure to infected factor concentrates predisposes haemophiliacs to higher likelihood of HCV from multiple sources. HIV coinfection could result in impaired clearance of less fit variants resulting in enrichment of quasispecies carrying resistance mutations. We postulated that haemophiliacs demonstrate increased prevalence of baseline signature mutations in the HCV NS3/4 serine protease coding domain. We examined the prevalence of putative HCV protease inhibitor mutations, mutations, subclassified into dominant mutations if changes conferred resistance, and minor variants not associated with drug resistance, in patients with haemophilia A or B, infected with HCV or HCV/HIV, prior to HCV PI exposure. A total of 151 subjects were evaluated, including 22 haemophiliacs and 129 non-haemophilic controls. Of the 58 mutations detected, 55 (95%) were resistance mutations and three (5%) were minor variants. Dominant mutations were detected in 10 (45.5%) haemophiliacs and in 43 (33.3%) controls (OR 1.67, 95% CI 0.67-4.16). There was no statistical difference in proportion of dominant mutations (P = 0.27) or minor variants (P = 0.47) between groups, despite adjustment for HIV status (P = 0.44). No significant differences in dominant or minor resistance mutations between haemophiliacs and non-haemophiliacs were observed. HIV presence or prior HAART exposure did not affect baseline distribution. We conclude that haemophiliacs are not at higher risk for pre-existing HCV PI mutations, and prospective studies of response to PI-based regimens with HCV activity are indicated.