Steroid-dependent myasthenia gravis patients improved following treatment with etanercept (recombinant human TNF receptor:Fc) in a prospective pilot trial. While the plasma anti-acetylcholine receptor antibody levels remained unaffected, etanercept treatment increased plasma levels of C3, circulating immune complexes, IL-10 and IFN-gamma. There was a direct correlation between plasma IL-6, TNF-alpha and IFN-gamma levels and the post-treatment clinical scores of patients. Moreover, patients with lower pre-treatment plasma IL-6 and IFN-gamma levels attained better clinical improvement following etanercept treatment.