Effect of Japanese cedar-specific sublingual immunotherapy on allergen-specific TH2 cell counts in blood.

Background: The contribution of antigen-specific T-H cells in peripheral blood to immunologic mechanisms underlying sublingual immunotherapy (SLIT) remains unclear, partly because of the lack of a standardized method for the analysis of this rare lymphocyte subset. Objective: To clarify the role of antigen-specific T-H cells during SLIT using a sensitive method analyzing activation marker CD154-positive T-H cells with multicolor flow cytometry. Methods: We assessed antigen-specific T-H cells using multicolor flow cytometry based on the expression of the activation marker CD154 and intracellular cytokines in patients with Japanese cedar pollinosis receiving SLIT at baseline and during the first pollen season after the initiation of SLIT. Results: A total of 18 patients between 12 and 44 years of age were enrolled in the present study. Of these, 8 patients received SLIT (SLIT group) and 10 patients received symptomatic treatment only (control group). Although seasonal pollen exposure significantly increased the number of Japanese cedarespecific interleukin 5- and interleukin 4-producing T-H cells in the control group (P < .01 for both), SLIT ameliorated this increase in the SLIT group (P - .64 and P - .84, respectively). Conclusion: The present study indicates that allergen-specific T(H)2 cells in peripheral blood are involved in mechanisms underlying SLIT. The analysis of antigen-specific T-H cells using multicolor flow cytometry based on the expression of the activation marker CD154 represents a sensitive and relatively simple, standardized method for monitoring peripheral antigen-specific T-H cells during allergen-specific immunotherapy. (C) 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.