CTLA4 and myeloid sarcoma: Genes involved in immune function have been shown to confer risk to MS, for example, the MHC class II allele HLA-DRB1*15 (Miljković and Spasojević, 2013) Furthermore, IL-2, IL-7 and CTLA-4 genes have also been linked to MS (Miljković and Spasojević, 2013).