A specific CD4+ T cell proliferation rate was higher in OBI carriers (3.0%) and CHB carriers (3.2%) than in donors with resolved HBV infection (2%) or non-infected individuals (1.6%) (OBI vs. resolver or non-infection, P < 0.01; CHB vs. resolver or non-infection, P < 0.001; Figure 1A). Here, CD4 is linked to infection.