Lymphocyte-endothelial cell interactions in multiple sclerosis: disease specificity and relationship to circulating tumour necrosis factor-alpha and soluble adhesion molecules.

This study addressed two questions; first, whether the supranormal adherence of blood lymphocytes from patients with multiple sclerosis (MS) to endothelial cell monolayers treated with tumour necrosis factor-alpha (TNF alpha) was a feature common to other inflammatory disorders; and second, whether the adherence properties of blood lymphocytes from MS patients were related to changes in disease activity and to levels of circulating TNF alpha and soluble adhesion molecules. In the first part of the investigation, lymphocytes from 14 patients with MS were more adherent to TNF alpha-treated endothelial cells (P < 0.01) than those from healthy controls, whereas the adherence properties of lymphocytes from 12 patients with rheumatoid arthritis, eight patients with psoriasis and ten patients with neurological diseases other than MS were normal. In the second phase of the work, measurement of the adhesive properties of lymphocytes isolated at monthly intervals from a further six MS patients over a 5-8 month period, found that changes in binding to TNF alpha-treated endothelial cells, directly paralleled changes in circulating levels of TNF alpha (r = 0.77; P < 0.001) and soluble vascular cell adhesion molecule-I (sVCAM-1) r = 0.67; P = 0.001). An increase in disease activity, measured by T2-weighted and gadolinium-enhanced magnetic resonance imaging of the central nervous system (CNS), occurred in two patients and was associated with heightened lymphocyte adhesiveness and a rise in serum TNF alpha levels. Further analysis of the 34 serum samples from the six MS patients revealed a direct relationship between the concentration of sL-selectin and soluble intercellular adhesion molecule-I (sICAM-I) (r = 0.65; P < 0.001) and between sL-selectin and sTNF alpha (r = 0.42; P < 0.02). These findings support the view that disease activity in MS is associated with an increased adhesive interaction of blood lymphocytes with vascular endothelium at inflammatory sites within the CNS.