To elucidate a potential interaction between CEACAM1 and TIM-3 we next stained PBMCs from RRMS patients for the expression of both CEACAM1 and TIM-3 (Fig. 3H–K, Supplementary Table 4) and observed a significant increase in the fraction of CEACAM1+TIM-3+ B cells and CTLs in RRMS patients (Fig. 3H,I). Here, CEACAM1 is linked to relapsing-remitting multiple sclerosis.