CD8+ T cell cytotoxicity is damaging in many conditions, including drug-induced cutaneous hypersensitivity [17], experimental cerebral malaria, Trypanosoma cruzi-elicited cardiomyopathy and Coxsackievirus B3-induced myocarditis [2–6], and contributes to the development of artherosclerotic disease, rheumatoid arthritis, chronic kidney disease, diabetes and atopic dermatitis [7–16]. This evidence concerns the gene CD8A and rheumatoid arthritis.