Glucocorticoid treatment reduces T-bet and pSTAT1 expression in mononuclear cells from relapsing remitting multiple sclerosis patients

High dose glucocorticoid (GC) treatment has been demonstrated to have a short-term beneficial effect on functional recovery in relapsing multiple sclerosis (MS) patients but the exact mechanism of action of GCs in MS is unclear. We found that high dose intravenous GCs strongly reduced T-bet and pSTAT1 expression in CD4+, CD8+, CD14+ circulating cells in RRMS patients in relapse. pSTAT1 and T-bet reduction was associated with the decline of IFN gamma production by PBMCs. A significant increase of AV-positive CD4+ and CD8+ Tcells was detectable after GC treatment without any variation in the percentage of annexin V-positive monocytes. By in vitro analysis, patients during relapse, either before or after GC treatment, exhibited a tower proportion of apoptotic lymphocytes than remitting patients and controls. Our study suggests that GCs can modulate T-bet and STAT1 expression and that IFN gamma signalling inhibition contributes to anti-inflammatory action of GCs in the treatment of relapses of MS patients. (c) 2007 Elsevier Inc. All rights reserved.