To investigate the cell specificity of CTLA-4, we conducted multiple fluorescence immunohistochemistry staining, and the results showed that, similar to AE patients, the co-localization of CTLA-4 with CD4 and CTLA-4 with CD8 molecules can be observed in the infiltrating margin of infected mice (Figures 4C, D), but no co-localization was observed in the liver of the control group (Figures 4C, D). Here, CTLA4 is linked to acrodermatitis enteropathica.