A Possible Role of TARC in Antigen-Specific Th2-Dominant Responses in Patients with Paragonimiasis westermani

Abstract

Background: Paragonimiasis westermani (Pw), a common parasitic zoonosis in Asia, is typically associated with eosinophilia. Th2 cytokines seem to have an important role in the clinical manifestations of this disease. Thymus and activation-regulated chemokine (TARC) is a potential key regulator of Th2-mediated inflammation. The purpose of the present study was to evaluate the antigen-specific Th2-dominant responses in patients with Pw. Methods: The concentrations of cytokines and chemokines in supernatants of peripheral blood mononuclear cell (PBMC) cultures with or without antigen stimulation were measured by enzyme-linked immunosorbent assay (ELISA). TARC levels in serum from Pw patients were also evaluated by ELISA. The number of Th2 cells expressing the CC-chemokine receptor 4 (CCR4) in the peripheral blood was evaluated by flow cytometry. Results: Antigen-stimulation induced production of IL-5 and IL-13, but not IFN-γ from PBMC cultures in patients with Pw. Pw patients had elevated serum TARC levels and a higher proportion of CCR4-expressing cells among CD4+ T cells in the peripheral blood. There were also higher levels of TARC, but not IP-10, in supernatants of antigen-stimulated PBMC culture compared to unstimulated PBMC culture in patients with Pw. Conclusion: Our findings clarify antigen-specific Th2-dominant responses in patients with Pw and suggest a possible role for TARC in Th2-dominant responses.