Comparison of cDNA copies of cytokine genes. cDNA copies of IFN-γ, IL-2, IL-18, and IL-4 were compared by Beijing and non-Beijing groups. The two groups of patients showed no difference in the expression of IFN-γ, IL-2, and IL-18 genes (p > 0.05). But patients infected with non-Beijing strains had significantly higher expressed cDNA copies of IL-4 than those with Beijing strains (p = 0.018). Log medians of cDNA copies are indicated by bars.