T-cell interleukin-6 receptor binding in patients with myasthenia gravis

Abstract Myasthenia gravis (MG) is a T-cell-dependent and antibody-mediated autoimmune disease of the neuromuscular junction, in which the cytokine network may be deranged. Specific receptors for interleukin (IL)-6, a cytokine with several effects on the neuroimmune system, have been found on human lymphocytes. The aim of the present study has been to assay IL-6 binding on peripheral blood T cells from MG patients. We found that T cells from MG patients have significantly more IL-6 receptors than those from controls ( B max : 334±6 vs 251±4 (mean±SEM) receptors/cell). Such IL-6 binding sites are of the same type in patients and healthy subjects ( K d : 26.5±0.7 vs 25.7±0.9 (mean±SEM) pM). The enhanced T-cell interleukin-6 binding is due to an increased number of interleukin-6 receptors on T-helper lymphocytes. These results are discussed in terms of MG immunopathogenesis, since it has been reported that activated T cells have increased amounts of IL-6 receptors.