Altogether, using a highly standardized and previously evaluated method for enumeration of discrete nuclear γ-H2AX foci, we could not observe an association of γ-H2AX foci with CIS/early RRMS, suggesting that γ-H2AX foci in PBMCs do not seem to be a promising diagnostic biomarker for CIS/early RRMS. Here, H2AX is linked to relapsing-remitting multiple sclerosis.