Multicolor flow-cytometric analysis of milk allergen-specific T-helper type 2 cells revealed coexpression of interleukin-4 with Foxp3.
BACKGROUND
Allergen-specific T-helper type 2 (TH2) cells play an important role in the development of allergic inflammation; however, investigations of the properties of allergen-specific T cells have been challenging in humans. Despite clear evidence that forkhead box p3 (Foxp3) is expressed in conventional effector T cells, its function has remained unknown.


OBJECTIVE
To characterize allergen-specific TH2 cells in milk allergy, with particular focus on the expression of Foxp3.


METHODS
Twenty-one children with milk allergy and 11 children without milk allergy were studied. Peripheral blood mononuclear cells from subjects were stimulated with milk allergen for 6 hours and analyzed using multicolor flow cytometry to identify CD154(+) allergen-specific T-helper cells. Simultaneously, the expression of intracellular cytokines and Foxp3 was analyzed.


RESULTS
The milk allergy group had significantly larger numbers of milk allergen-specific interleukin (IL)-4- and IL-5-producing CD4(+) T cells than the control group. Subjects in the milk allergy group had significantly more CD154(+)CD4(+) IL-10-producing cells and CD154(+)Foxp3(+)CD4(+) cells than those in the control group. In addition, the number of milk allergen-specific CD154(+)Foxp3(+)CD4(+) cells strongly correlated with that of CD154(+)IL4(+)CD4(+) cells. Bcl-2 expression in CD154(+)IL-4(+)Foxp3(+) T-helper cells was significantly lower compared with that in total CD4 cells.


CONCLUSIONS
Increased numbers of IL-4-producing allergen-specific T-helper cells were found in patients with milk allergy. In addition, Foxp3 was coexpressed with IL-4 in allergen-specific TH2 cells from patients. This coexpression was associated with lower Bcl-2 levels and could contribute to the phenotype and function of TH2 cells.
Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan.
Kazuo
K
Yamawaki
Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan.
Chisato
C
Inuo
Department of Pediatrics and Neonatology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan.
Takayasu
T
Nomura
Department of Pediatrics, The Second Teaching Hospital, Fujita Health University, Nagoya, Japan.
Kenichi
K
Tanaka
Department of Pediatrics, The Second Teaching Hospital, Fujita Health University, Nagoya, Japan.
Yoichi
Y
Nakajima
Department of Pediatrics, The Second Teaching Hospital, Fujita Health University, Nagoya, Japan.
Yasuto
Y
Kondo
Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan.
Tetsushi
T
Yoshikawa
Department of Pediatrics, The Second Teaching Hospital, Fujita Health University, Nagoya, Japan.
Atsuo
A
Urisu
Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan. Electronic address: itsuge@fujita-hu.ac.jp.
Ikuya
I
Tsuge
D000293:Adolescent; D000485:Allergens / Q000276:immunology; D000818:Animals; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology*; D006801:Humans; D007223:Infant; D015847:Interleukin-4 / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology; D008297:Male; D008892:Milk / Q000009:adverse effects; D016269:Milk Hypersensitivity / Q000276:immunology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology*
D000485:Allergens; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508598:IL4 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D015847:Interleukin-4