T-lymphocyte interferon-γ receptor binding in patients with myasthenia gravis

Objective: To investigate some aspects of T-lymphocyte-dependent immune function in patients with myasthenia gravis (MG). Design: Assay interferon-gamma binding on T lymphocytes from patients with MG compared with healthy controls. Setting: The study was performed on ambulatory patients in a tertiary care center, where MG was diagnosed according to Osserman criteria. Patients: Thirty-six patients with MG (19 women and 17 men; mean +/- SD age, 50.2 +/- 17.6 years) were selected consecutively. They were assigned to groups 1, 2A, and 2B. Ten patients were treated with pyridostigmine bromide alone, 18 were treated with pyridostigmine and corticosteroids, and 8 were not yet treated. Thirty-six age- and sex-matched healthy nonsmoking subjects formed the control group. Results: A significant (P < .001) decrease of T-lymphocyte interferon-gamma binding was found in patients with MG compared with healthy controls (483 +/- 14 vs 734 +/- 13 receptors [SEM] per cell), whereas the ligand-receptor affinity values [SEM] were similar in the 2 groups (0.9 +/- 0.05 and 1.0 +/- 0.07 nmol/L). Conclusion: These data indicate a persistent activation of the immune system in patients with MG, since reduced cell surface interferon-gamma receptors seem to be related with enhanced T-lymphocyte immune function.