Karabon et al. have studied the association of the CTLA-4 gene polymorphisms −319C/T, +49A/G, (AT)n, CT60A/G, and Jo31G/T with the levels of both membrane CTLA-4 (mCTLA-4) and cytoplasmic CTLA-4 (cCTLA-4) in the CD4+ T lymphocytes of MS patients and with MS susceptibility and clinical course [131]. Here, CTLA4 is linked to myeloid sarcoma.