T-cell tumor necrosis factor-alpha receptor binding in myasthenic patients.

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 tumor necrosis factor (TNF)-alpha, a cytokine with several effects on the neuroimmune system, were found on human lymphocytes. In the present study, we assayed TNF-alpha binding on peripheral blood T-cells from MG patients, finding that T-cells from patients have significantly more TNF-alpha receptors than those from controls (Bmax: 654 +/- 12 vs. 133 +/- 4 (mean +/- SEM) receptors/cell). Such TNF-alpha binding sites are of the same type in patients and healthy subjects (Kd: 68.7 +/- 4.3 vs. 70.1 +/- 4.8 (mean +/- SEM) pM). The enhanced T-cell TNF-alpha binding is due to an increased number of TNF-alpha 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 TNF-alpha receptors.