CD19 and primary progressive multiple sclerosis: Thus: 1) CD19+/IL-10+ B lymphocytes were significantly reduced in all groups of patients compared to HC (p < 0.05), with the lowest values been observed in PPMS (p < 0.001) (Fig. 4A); and 2) CD19+/IL-10+/TGFβ+ B lymphocytes were significantly reduced in PPMS patients alone compared to all the other groups of patients (p < 0.05) and HC (p = 0.005) (Fig. 4B).