Dehydroepiandrosterone therapy ameliorates experimental autoimmune myasthenia gravis in Lewis rats

To detect a possible effect of dehydroepiandrosterone (DHEA) in the pathogenesis of experimental autoimmune myasthenia gravis (EAMG), DHEA (0.5 mg/rat) was administrated intraperitoneally to Lewis rats every other day from day 4 postimmunization (p.i.) to day 35 p.i. with Torpedo acetylcholine receptor (AChR) and Freund's complete adjuvant. Rats treated with DHEA had a lower clinical score (mean clinic score, 2 versus 0.5 on day 37 p.i.) and a lower body weight loss (mean body weight, 169 versus 142 g on day 37 p.i.) compared with control EAMG rats. DHEA treatment decreased serum anti-AChR IgG and IgG2b antibody titers on days 7, 14, and 21 p.i. and inhibited the levels of anti-AChR IgG antibody secreting cells (60%), accompanied by decreased IL-4 (33%) and augmented TGF-beta1-positive cells (41%) among lymph node mononuclear cells. These results obtained from EAMG in Lewis rats further encourage us to study DHEA treatment in human MG.