CD49d expression in peripheral and central T cell compartments under long-term natalizumab therapy. (A) Expression of CD49d on peripheral CD4⁺ T cells of either healthy controls (n = 22) or MS patients before the start of natalizumab therapy (MS naive; n = 5), or during natalizumab therapy (n = 322). (B) Soluble VCAM-1 in the serum of healthy controls (n = 10), MS patients before treatment (n = 15), and during treatment with natalizumab (n = 49). (C) Comparison of the expression of CD49d on peripheral and CSF CD4⁺ and CD8⁺ T cells of long-term treated natalizumab patients (n = 18). ***, P ≤ 0.001.