Dexamethasone attenuates echinococcosis-induced allergic reactions via regulatory T cells in mice

Cystic echinococcosis (CE), caused by infection with Echinococcus granulosus larvae, is a potentially life-threatening disease in humans. Anaphylactic shock caused by CE is very dangerous, and is highly prevalent during surgery. Dexamethasone (DEX) is used clinically before operations to prevent allergic reactions; Regulatory T cells (Treg cells) are believed to be associated with negative immune response, which play an important role in alleviating allergic reactions. However, the association of Treg cells with DEX remains unknown.

In this study, C57BL/6 mice were divided into uninfected group, untreated group and DEX group which were inoculated with protoscoleces from E. granulosus and sensitized using a cyst fluid suspension to induce anaphylactic shock. In addition, the mice in DEX group were treated with 10 mg/kg DEX by intraperitoneal injection 30 min before being sensitized.

It was found that 93.75 % of all sensitized mice experienced allergic symptoms. The levels of IgE, IgE/IgG, and IgE/IgG1 were significantly higher in both untreated group and DEX group. The proportion of CD4 + CD25 + FOXP3 + Treg cells relative to CD4+ Treg cells, and the levels of interleukin-10 (IL-10) and tumor growth factor-β (TGF-β1) were significantly higher in DEX group. The level of IL-13 was significantly higher in the sensitized mice than in the other groups. These cells may play a key role in alleviating the immune response in CE-induced anaphylactic shock.

The protective effect of DEX may be due to Treg cell upregulating IL-10 and TGF-β1 levels, and inhibiting helper T cell 2 cytokines.