The results showed significantly increased percentages of CTLA-4 and FOXP3 in CD4+CD25+ lymphocytes for PPMS subjects, both treated and untreated, significantly increased percentages of CD4+CD25+highFOXP3+ in untreated PPMS subjects and CD4+CD25+FOXP3+ in all PPMS subjects, and significantly decreased percentages of CD192+ and CD40+ nonclassical monocytes in treated PPMS subjects. Here, CD4 is linked to primary progressive multiple sclerosis.