IL-10 levels were similar among CIS, RRMS, and SPMS, and they were significantly higher than PPMS (p = 0.0186, p = 0.0149, p = 0.0247, respectively) and HC (p = 0.0014, p = 0.0006, p = 0.0080, respectively; Figure 1B). Here, IL10 is linked to secondary progressive multiple sclerosis.