[Eosinophilic gastroenteritis: an example of gastrointestinal toxicity of eosinophils].

Toxicity of polynuclear eosinophils in the digestive tract results from a cascade of immune responses involving various mediators including mastocytes and T-lymphocyte helpers. Polynuclear eosinophils may be implicated in many digestive disorders. This involvement is well established in eosinophilic gastroenteritis which has become the model for study of eosinophil toxicity on the digestive tract. Considered to be of uncertain etiology up until 1998, this mechanism is well illustrated by the case described in this report involving infiltration of all layers of the small intestinal mucosa in a 23-year-old patients who responded well to corticosteroid treatment. This case provides the opportunity to update physiopathologic and therapeutic data concerning this unpredictable syndrome. Current evidence of transition forms from idiopathic hypereosinophilic syndrome casts doubt on the conventional classification of eosinophilic gastroenteritis and underlines the need for careful diagnostic work-up and prolonged follow-up.