PTPN2 and inflammatory bowel disease: In patients with IBD, protein tyrosine phosphatase non-receptor type 2 (PTPN2)-related variants exist in macrophages, and cellular experiments have shown that defects in PTPN2 can cause macrophages to polarize to the M1 phenotype, which can disrupt the IECs barrier when co-cultured with IECs, as evidenced by a decrease in transepithelial electrical resistance (TEER) and an increase in permeability [40].