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

Abstract

BackgroundThe contribution of antigen-specific TH 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. ObjectiveTo clarify the role of antigen-specific TH cells during SLIT using a sensitive method analyzing activation marker CD154-positive TH cells with multicolor flow cytometry. MethodsWe assessed antigen-specific TH 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. ResultsA 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 cedar–specific interleukin 5– and interleukin 4–producing TH cells in the control group (P < .01 for both), SLIT ameliorated this increase in the SLIT group (P = .64 and P = .84, respectively). ConclusionThe present study indicates that allergen-specific TH2 cells in peripheral blood are involved in mechanisms underlying SLIT. The analysis of antigen-specific TH 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 TH cells during allergen-specific immunotherapy.