The human CTLA-4 gene is located on chromosome 2q33, in a region that is associated with susceptibility for autoimmune disease [8] and multiple polymorphisms of the CTLA-4 gene have been found to be associated with susceptibility to autoimmune diseases (e.g. the GG allele of the +49 AG polymorphism is associated with decreased expression of CTLA-4 upon T-cell activation and thus a higher proliferation of T-cells) [9]–[12]. This evidence concerns the gene CTLA4 and autoimmune disease.