Consequently, if the change in the number of cytokine-producing and cytotoxic cells, non-expressing and expressing the CD94 molecule, in CVHC, regardless of the HCV genotype, was more consistent with the mechanism of the immune response during this viral infection, then the ratio between cytotoxic NK cells with the absence and presence of CD94 receptor expression showed a greater dependence on the severity of liver fibrosis. This evidence concerns the gene KLRD1 and viral infectious disease.