CTLA4 and myasthenia gravis: The data accumulated showed that the expressions of CTLA-4 mRNA in the control and MG groups were 1.00 ± 0.06 and 0.58 ± 0.17, respectively (Fig. 2), thus indicating that the expression of CTLA-4 is lower in the MG group in comparison with the control group (P < .05).