We studied the effect of intravenous methylprednisolone (MP) on the expression of the integrins, LFA-1 and VLA-4, on activated blood T-lymphocytes in 17 patients with relapses of clinically definite relapsing-remitting MS. MP treatment did not induce changes in the expression of CD3, CD4, DR, LFA-1 or VLA-4 markers when measured in the total population of lymphocytes in MS patients in relation to treatment. Treatment influenced neither the LFA-1 nor VLA-4 positive cells within the CD3+ population. MP treatment clearly decreased the DR+ CD3+ cells (P < 0.01) and the percentage of DR+ CD3+ lymphocytes bearing VLA-4 (P < 0.01). However, this was not the case when we studied the percentage of lymphocytes which expressed LFA-1. Glucocorticoids did not influence the mean intensity of the expression of the two integrins quantified in either total or DR+ CD3+ lymphocytes. Although, further research seems warranted to investigate a possible effect of MP on lymphocyte integrin function, this work corroborates the idea that MP treatment may interfere with the mechanisms of T-cell migration into CNS, thus modulating the activity of multiple sclerosis.