Episodic angioedema with eosinophilia is characterized by recurrent angioedema, fever and weight gain with a remarkable eosinophilia. A transient type, predominantly reported in Japan, in which the disease is limited to a single attack, is usually less severe than the episodic type described in the U.S.A. and Europe, and provides an ideal disease model in which to study the mechanisms for resolution of eosinophilic inflammation. The aim of this study was to evaluate the relationship between cytokine responses and clinical course in three patients with the transient type. Serum levels of interleukin (IL) -5 were only marginally elevated even during an attack, unlike those in reported cases of the episodic type. Significant elevations in granulocyte-macrophage colony-stimulating factor levels were also noted during an attack in two cases in which it was measured. A dramatic increase in tumor necrosis factor (TNF) -alpha levels was subsequently observed in relation to resolution of clinical symptoms. No major changes in the serum levels of soluble Fas and soluble Fas ligand were found throughout the course. These results suggest that relatively lower levels of IL-5 and a subsequent increase in TNF-alpha levels are characteristic features of the transient type. The differences in clinical symptoms and course observed between the two types may be partly explained by the differences in the cytokine profiles.