CTLA4 and primary progressive multiple sclerosis: The present study aimed to investigate the expression of CTLA-4+ and FOXP3+ in CD4+CD25+ in Tregs, and CD40 and CD192 in the classical (CD14++CD16−), intermediate (CD14++CD16+), and nonclassical (CD14+CD16++) monocyte subsets in PPMS (ocrelizumab treated and untreated) subjects.