HLA-C and intestinal disorder: In addition to classical major histocompatibility complex (MHC), MHCY is the second region of polymorphic MHC-like genes associated with bacterial intestinal infection, immune response, and disease incidence (Zhang J. et al., 2021; Goto et al., 2022), the expression of which has a positive correlation with antibody production (Zhang J. B. et al., 2021).