While antigen-specific IFN- γ and IL-5 production did not correlate with antibody concentrations for tetanus (p=0.258 and p=0.065), there was a correlation between antibody concentrations and IL-5 (p=0.002), but not IFN-γ production (p=0.036) for diphtheria. This evidence concerns the gene IFNG and diphtheria.