The objectives were to study the expression of very late antigen (VLA)-4, melanoma cell adhesion molecule-1 (MCAM-1) and activated leukocyte cell adhesion molecule (ALCAM) on CD4+ T cells during natalizumab treatment and to investigate the association with disease activity. We find that subgroups of autoreactive T cells are retained in peripheral blood, in particular MOG-reactive CD4+ T cells expressing MCAM-1. The expression of MCAM-1 or ALCAM on CD4+ T cells was, however, not clearly associated with disease activity (clinical or MRI) during natalizumab treatment. We confirm upregulation of MCAM-1 on CD4+ T cells during natalizumab treatment while VLA-4 is downregulated. Display omitted •Natalizumab treated patients had a lower percentage of CD4+ T cells in CSF expressing VLA-4.•Natalizumab treated patients had a higher percentage of CD4+ T cells expressing MCAM-1 in CSF.•Natalizumab treated patients had a higher percentage of MOG-reactive CD4+ T cells in blood.•Stable natalizumab patients had a higher increase of MOG-reactive CD4+ T cells expressing MCAM-1 in blood.•No association between disease activity and expression of MCAM-1 or ALCAM in blood of natalizumab-treated patients