Plasma IP-10 levels ≥150 pg/mL occurred more often in non-Aboriginals (51% versus 20%, P = 0.014), those with HCV RNA >6 log IU/mL (76% versus 41% in those <4 log IU/mL, P

= 0.002) and those with HIV infection (70% versus 42%, P = 0.002). No differences were observed in the proportions with plasma IP-10 level ≥150 pg/mL by sex, age, or estimated duration of HCV infection. In adjusted logistic regression CH5424802 molecular weight analyses (Table 2), HCV RNA >6 log IU/mL (versus <4 log adjusted odds ratio [AOR] 6.11; 95% CI: 2.11, 17.69) and HIV infection (AOR 2.11; 95% CI: 0.96, 4.61) were independently associated with plasma IP-10 levels ≥150 pg/mL, while individuals of Aboriginal ethnicity were less likely to have plasma IP-10 levels ≥150 pg/mL at the time of acute HCV detection (AOR 0.17; 95% CI: 0.05, 0.58). No difference was observed in the frequency of IL28B rs12979860 CC genotype among buy PLX3397 Aboriginals and non-Aboriginals (39% versus 53%, P = 0.254). Plasma IP-10 levels were monitored longitudinally in 20 untreated individuals with acute HCV (eight with clearance, Fig. 3; Supporting Fig. 2). Although

IP-10 levels generally mirrored HCV RNA levels, there was no clear pattern that could predict clearance or persistence. Among the 245 participants who were positive for HCV RNA at the time of acute HCV detection, 214 were either untreated (n = 137) or had chronic infection (persistent HCV RNA and estimated duration of infection ≥26 weeks) at the time of treatment initiation (n = 77) and formed the study population for assessment of spontaneous clearance (Fig. 1). In this group who were HCV RNA-positive at acute HCV detection (n = 214), spontaneous clearance occurred in 14% (29 of 214) of individuals. Among those with available plasma IP-10 levels at acute HCV

detection (n = 187), individuals who failed to clear HCV spontaneously had significantly higher mean plasma IP-10 levels at acute HCV detection than those with spontaneous viral clearance (248 ± 32 versus 142 ± 22 pg/mL, P = 0.008; Fig. 4A); however, the median plasma IP-10 levels did not differ (133 versus 103 pg/mL, P = 0.430). Although one individual had a very high IP-10 value (3,071 pg/mL), mean IP-10 levels remained significantly higher in those without clearance excluding this individual (230 ± 27 versus MCE 142 ± 21, P = 0.010). ROC curve analysis identified an IP-10 level of 380 pg/mL as the most useful threshold associated with spontaneous clearance. No patients with a baseline IP-10 ≥380 pg/mL (0 of 22) achieved spontaneous clearance, compared to 16% (27 of 165) of those with IP-10 levels <380 pg/mL (P = 0.048; Fig. 4B). There was no significant difference in the proportion with spontaneous clearance stratified by plasma IP-10 levels above and below 150 pg/mL (15%, <150 pg/mL, versus 13%, ≥150 pg/mL; P = 0.835). Other factors associated with spontaneous viral clearance were also examined (Table 3).