All PPMS subjects’ findings differed from the HCs in the surface expression of CD192 in classical CD14++CD16− monocytes, the percentages of CD14++CD16+ monocytes, and the percentages of CD40+ and CD192+ in nonclassical CD14+CD16++ monocytes differed between treated and untreated PPMS subjects (Table 4). Here, CCR2 is linked to primary progressive multiple sclerosis.