Clinical implications of the type 1/type 2 balance of helper T cells and P-glycoprotein function in peripheral T lymphocytes of myasthenia gravis patients.

Myasthenia gravis is an autoimmune disorder mediated by antibodies against the acetylcholine receptors of the skeletal muscles. Imbalances between T helper type 1 and type 2 cytokine production play a key role in the induction and development of several autoimmune diseases. Peripheral T helper type 1 and type 2 cells in 50 myasthenia gravis patients were estimated by intracellular cytokines. The percentage of T helper type 1 cells in CD4(+) cells was higher than that of type 2 or type 0 cells (P<0.0001). There was a significant correlation between T helper type 1/type 2 ratio and the P-glycoprotein function on CD3(+) T cells (P=0.008). In the patients treated with prednisolone alone (n=12), there was a significant correlation negatively between the percentage of change in the T helper type 1/type 2 ratio and the reduction rate of quantitative myasthenia gravis scores after 12 months of treatment (P=0.012). In contrast, all of the patients treated with prednisolone and calcineurin inhibitor in combination saw reductions in the scores. Our data suggest that the T helper type 1/type 2 ratio was involved in the disease activity of the patients treated with prednisolone alone. On the other hand, the patients treated with prednisolone and calcineurin inhibitor in combination had their disease condition improved regardless of the T helper type 1 predominance. Therefore, the data suggest that supplemental calcineurin inhibitors are effective for the myasthenia gravis patients treated with prednisolone alone when their T helper balance shifts toward to type 1.