House dust mite-specific T cells in healthy non-atopic children.
BACKGROUND
T-helper type 2 (Th2) cells play an important role in the pathogenesis of allergic diseases. Recent studies have demonstrated that allergen-specific T cells can also be found in the blood of healthy individuals. Both IL-10 and IFN-gamma might modulate the induction and maintenance of allergen-specific tolerance.


OBJECTIVE
To study the phenotype and functional characteristics of allergen-specific T cells in healthy non-atopic children.


METHODS
Peripheral blood mononuclear cells (PBMC) from 13 symptomatic house dust mite (HDM)-allergic children and from nine matched healthy control children were stimulated with recombinant (r)Der p 2, a major allergen from HDMs.


RESULTS
Stimulation with rDer p 2 resulted in Th2 cytokine production in cultures of PBMC from allergic but not from healthy children. In contrast, IL-10 and IFN-gamma were induced in PBMC cultures from both healthy and HDM-allergic children. Intracellular staining revealed that IL-10 and IFN-gamma are largely produced by the same T cells. Stimulation of T cells from healthy children with rDer p 2 also induced expression of inducible costimulator (ICOS) on a small T cell subset.


CONCLUSIONS
Allergen-specific memory T cells from healthy non-atopic children produce IL-10 and IFN-gamma (but not Th2 cytokines) and express ICOS upon stimulation. These cells might be responsible for a normal immune balance after allergen encounter in non-atopics.
Bullens
D M A
DM
Clinical Immunology, Department of Pathophysiology, Catholic University of Leuven (KULeuven), Leuven, Belgium. Dominique.Bullens@med.kuleuven.be
De Swerdt
A
A
Dilissen
E
E
Kasran
A
A
Kroczek
R A
RA
Cadot
P
P
Casaer
P
P
Ceuppens
J L
JL
D039741:Antigens, Dermatophagoides / Q000276:immunology / Q000494:pharmacology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D060829:Arthropod Proteins; D016022:Case-Control Studies; D002478:Cells, Cultured; D002648:Child; D016207:Cytokines / Q000276:immunology*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D060889:Inducible T-Cell Co-Stimulator Protein; D007371:Interferon-gamma / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D018793:Interleukin-13 / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D015848:Interleukin-5 / Q000276:immunology; D008297:Male; D039981:Pyroglyphidae; D011994:Recombinant Proteins / Q000494:pharmacology; D013268:Stimulation, Chemical; D013601:T-Lymphocytes / Q000276:immunology*
D039741:Antigens, Dermatophagoides; D000945:Antigens, Differentiation, T-Lymphocyte; D060829:Arthropod Proteins; D016207:Cytokines; C451163:Dermatophagoides pteronyssinus antigen p 2; C556692:ICOS protein, human; D060889:Inducible T-Cell Co-Stimulator Protein; D018793:Interleukin-13; D015848:Interleukin-5; D011994:Recombinant Proteins; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma