CD8A and immune system disorder: In addition, the lymphoid subset phenotypes of CIA mice were altered both systemically and locally in the gut: T, B, and NK cells in the SP were all affected, and the local changes in the gut were particularly significant, manifested as a marked increase in CD8+T cells in the MLN and IM, and a trend of change was also observed in PPs; in contrast, the changes in PB lymphoid subsets were not significant, suggesting that the gut local area may be the initial site of immune activation, and its changes precede and may drive systemic immune disorders.