Kinetics of intrahepatic hepatitis C virus (HCV)-specific CD4⁺ T cell responses in HCV and Schistosoma mansoni coinfection: Relation to progression of liver fibrosis

The kinetics of intrahepatic hepatitis C virus (HCV)-specific CD4 ⁺ T cell responses and their role in progression of fibrosis have not previously been characterized. Subjects with HCV/Schistosoma mansoni coinfection have a more rapid progression of HCV liver fibrosis than do those with HCV infection alone. The present prospective longitudinal study compared the liver histology, HCV-specific intrahepatic and peripheral CD4⁺ T cell proliferative responses, and cytokines (enzyme-linked immunospot) in 48 subjects with unresolved acute HCV infection with or without S. mansoni coinfection, at 6-10 months after acute infection and at the end of follow-up (96 ± 8.7 months), and the findings were correlated to the rate of progression of fibrosis per year. Coinfected subjects had significant worsening of fibrosis, compared with subjects with HCV infection alone. At baseline, subjects with HCV infection alone had stronger multispecific intrahepatic HCV-specific CD4⁺ T helper 1 responses than did coinfected subjects, who had either no responses or weak, narrowly focused responses, and, over time, these T cell responses were maintained only in the liver. The rate of progression of fibrosis and virus load inversely correlated with intrahepatic HCV-specific CD4⁺ T cell response. The present prospective analysis indicates that enhancement of progression of liver fibrosis is associated with failure to develop early, multispecific, HCV-specific CD4⁺ Th1 responses, suggesting that novel therapeutic approaches inducing strong cellular immune responses might limit subsequent liver damage in individuals with chronic hepatitis C.