CD4 and myeloid sarcoma: Regarding the functionality of CD6 SNPs, the intronic rs17824933G allele identified as a susceptibility marker for MS causes over-expression of a CD6 isoform devoid of the CD166/ALCAM-binding domain (CD6Δd3) concomitant with diminished proliferation and long-term activation of CD4+ T cells (71, 72).