Heterogeneity of cockroach allergen-specific T cell responses in
allergic sensitized children
Abstract
BACKGROUND: Characterization of allergic responses to cockroach (CR), a
common aeroallergen associated with asthma, has focused mainly on IgE
reactivity, but little is known about T cell responses, particularly in
children. We conducted a functional evaluation of CR allergen-specific T
cell reactivity in a cohort of CR allergic children with asthma.
METHODS: Peripheral blood mononuclear cells (PBMCs) were obtained from
71 children, with mild-to-moderate asthma who were enrolled in a CR
immunotherapy (IT) clinical trial, prior to treatment initiation. PBMC
were stimulated with peptide pools derived from 11 CR allergens, and
CD4+ T cell responses assessed by intracellular cytokine staining.
RESULTS: Highly heterogeneous responses in T cell reactivity were
observed among participants, both in terms of the magnitude of cytokine
response and allergen immunodominance. Reactivity against Bla g 9 and
Bla g 5 was most frequent. The phenotype of the T cell response was
dominated by IL-4 production and a Th2 polarized profile in 54.9% of
participants, but IFN production and Th1 polarization was observed in
25.3% of the participants. The numbers of regulatory CD4+ T cells were
also highly variable and the magnitude of effector responses and Th2
polarization were positively correlated with serum IgE levels specific
to a clinical CR extract. CONCLUSIONS: Our results demonstrate that in
children with mild-to-moderate asthma, CR-specific T cell responses
display a wide range of magnitude, allergen dominance, and polarization.
These results will enable examination of whether any of the variables
measured are affected by IT and/or are predictive of clinical outcomes.