Background:  Central nervous system (CNS) manifestations of chronic hepatitis C (HCV) and chronic HIV-1 infections reported to date include neurocognitive impairment, altered CNS metabolites and evidence of HCV or HIV-1 replication in the CNS. No studies have assessed the effect of acute HCV infection on the CNS.

Methods:  Ten individuals with chronic stable HIV-1 infection with documented acute HCV infection (HCV RNA polymerase chain reaction-positive and HCV antibody-negative, group 1), underwent cerebral proton magnetic resonance spectroscopy (MRS) using acquisition parameters to quantify myo-inositol/creatine (mI/Cr) ratio in the right basal ganglia (RBG). Two matched control groups also underwent MRS:  group 2—10 with chronic HIV-1 infection and no evidence of HCV infection; and group 3—10 with no evidence of HIV or HCV. Subjects also underwent computerised neurocognitive assessments (CogState™).

Results:  RBG mI/Cr ratio in group 1 was significantly lower than groups 2 and 3 (2.90 (±0.7) vs 3.34 (±0.4) and 3.43 (±0.4), mean (SD) for group 1 versus 2 and 3 respectively, p = 0.049) with 50% of subjects in group 1 having a mI/Cr ratio below the lowest observed ratio in either other groups (see the figure). On neurocognitive testing, significant defects in the monitoring domain were observed in group 1, compared to matched controls (p = 0.021).

Conclusions:  Acute HCV infection in HIV-1-infected subjects is associated with CNS involvement. Reduced mI/Cr ratio is a marker of infection and immune activation of microglial cells. Clinicians should be aware of early CNS involvement when assessing subjects with acute HCV infection.