Sharp et al. showed that the SNPs in PTPN2/22 genes (protein tyrosine phosphatase non-receptor type 2 and 22) are linked to increased sensitivity to MAP infection and, therefore, increased T lymphocyte response, and IFN-γ expression in RA patients [112] (Figure 1, Table 1). This evidence concerns the gene PTPN2 and rheumatoid arthritis.