Of the four SNPs, the major G allele of IL17A rs1974226 G/A was significantly associated with increased susceptibility to infection by Gram-positive bacteria (percentages of positive culture: AA 38.5%, AG 46.4%, GG 64.2%, uncorrected P = 0.0037, Bonferroni corrected P = 0.014) (Table 2). Here, IL17A is linked to infection.