Mitogenic response and steroid sensitivity in MS lymphocytes

We investigated mitogenic response and steroid sensitivity in multiple sclerosis (MS) lymphocytes to establish if MS lymphocytes were less steroid responsive. Material and methods - We compared mitogenic response to phytohaemagglutinin (PHA) and inhibition by dexamethasone (DEX) in circulating lymphocytes from both MS patients and healthy subjects. Results - We found a range of responses in each group but no significant differences between the two groups, nor in patients with and without enhancement on magnetic resonance imaging. The mid-inhibitory concentration of DEX in response to 1 mu g/ml PHA was significantly lower than that for 2.5 mu g/ml PHA in the patients. The mid-inhibitory concentrations of DEX in response to 2.5 mu g/ml PHA negatively correlated with endogenous serum cortisol concentrations. Conclusion - These data imply a spectrum of glucocorticoid response that is similar in normal and MS lymphocytes and can partly explain why response to steroid therapy is variable.