T cell proliferation and cytokine responses to ovalbumin and ovomucoid detected in children with and without egg allergy.
BACKGROUND
The specific T cell responses in egg allergy and resolution have not been fully elucidated.


OBJECTIVE
To characterize egg allergen-specific T cells of children with active and resolved egg allergy, in comparison with non-allergic controls.


METHODS
We studied children with active (n=35) or resolved (n=20) egg allergy determined by oral challenge, and non-allergic controls (n=15). Peripheral blood mononuclear cells were labelled with carboxyfluorescein succinimidyl ester (CFSE) and stimulated with ovalbumin (OVA), ovomucoid (OM) or tetanus toxoid. Flow cytometry was used to detect divided CD3+ CFSE(lo) cells that expressed intra-cytoplasmic IL-4 or IFN-gamma. The cell division index (CDI) was calculated as a measure of allergen-specific proliferation. Peanut-specific T cells of a subgroup of children who also had peanut allergy were also studied.


RESULTS
OVA-specific T cells were found in subjects with active (87%) or resolved (75%) egg allergy and in controls (67%), with a trend towards increased T cell proliferation in allergy. OM-induced weaker T cell responses than OVA, stimulating fewer responders (46% allergic, 50% resolved, 60% controls) and 10-fold less proliferation [CDI(OVA) 2.0 (median), 25.6 (maximum) vs. CDI(OM) 0.2 (median), 15.1 (maximum); P<0.01]. Both egg allergens induced significant IL-4+ (median 10%, range 1.4-58%) and IFN-gamma+ (median 28%, range 4.5-63%) cells in responders, including non-allergics. There were no significant differences in IFN-gamma+ or IL-4+ cells or in IFN-gamma/IL-4 ratios between groups. Peanut-specific T cell proliferation was significantly higher in peanut allergy [CDI(CPE) 16.5 (median), 24.8 (maximum)] compared with controls [CDI(CPE) 2.1 (median), 16.1 (maximum)] but cytokine profiles were not different. Tetanus-specific T cells were seen in 90% of the subjects, with no significant inter-group differences in responses.


CONCLUSIONS
Egg allergen-specific T cells are readily detected in all groups and not restricted to egg allergy. In contrast, peanut-specific proliferation was significantly higher in peanut allergy. This suggests that T cell responses in peanut and egg allergy may differ. We did not find T helper type 2-deviated cytokine responses in egg or peanut allergy.
Tay
S S
SS
Department of Medicine, Addenbrookes Hospital, Cambridge University, Cambridge, UK. szunszuntay@hotmail.com
Clark
A T
AT
Deighton
J
J
King
Y
Y
Ewan
P W
PW
D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000378:metabolism*; D021181:Egg Hypersensitivity / Q000276:immunology*; D005260:Female; D006801:Humans; D007223:Infant; D008213:Lymphocyte Activation; D008297:Male; D010047:Ovalbumin / Q000276:immunology*; D010059:Ovomucin / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology
D016207:Cytokines; D010059:Ovomucin; D010047:Ovalbumin