Soluble interleukin-2 receptor (sIL-2R), interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) levels were evaluated in serum from patients affected by myasthenia gravis (MG). sIL-2R titers were significantly increased in generalized and bulbar MG patients while ocular cases were not different from controls. Patients showing a recent clinical worsening had significantly higher sIL-2R titers when compared to the whole MG population. sIL-2R levels did not correlate with the corresponding anti-acetylcholine receptor antibody titer (Anti-AChR Ab). IFN-gamma was not detected in serum of both MG patients and healthy subjects while TNF-alpha levels were not statistically different from controls. The finding of increased sIL-2R levels supports the hypothesis of circulating activated autoreactive T cells in myasthenic patients.