So far, it has been confirmed, among others, that blocking the OX/OX40R interaction prevents the differentiation of CD4+ T cells and the development of inflammation in models of multiple sclerosis, autoimmune diseases of the gastrointestinal tract, GvHD, rheumatoid arthritis and atopic dermatitis [72,73,74,75,76]. Here, CD4 is linked to graft versus host disease.