Mono-allergic and poly-allergic rhinitis patients have comparable numbers of mucosal Foxp3+CD4+ T lymphocytes

We previously found that allergic rhinitis patients with an isolated pollen sensitization responded more strongly to a nasal provocation with grass pollen (GP) than patients who had an additional house dust mite (HDM) sensitization. To elucidate this phenomenon, we investigated the dynamics of Foxp3+CD4+ T lymphocytes in allergic rhinitis patients with distinct allergen sensitizations.

Three groups of allergic rhinitis patients with skin prick test confirmed allergic sensitizations were investigated and compared to 14 healthy controls: 14 subjects with an isolated grass pollen sensitization (Mono-GP); 9 subjects with isolated housedust mite sensitization (Mono-HDM); 29 subjects with grass pollen and house dust mite sensitization (poly-sensitized). Subjects in the Mono-GP group were challenged with grass pollen extract, subjects in the Mono-HDM group were challenged with house dust mite extract, subjects in the poly-sensitized group and the healthy controls were randomly challenged with either grass pollen or house dust mite. Nasal biopsies were taken before and after nasal provocation. We compared the distribution of FoxP3+CD4+ cells in nasal biopsies before and after nasal provocation using immunohistochemistry.

There was no difference in the number of FoxP3+CD4+ cells between healthy and the three allergic groups at baseline.Nasal provocation did result in an increase in eosinophils in the three allergic groups, but did not result in a change in the number of FoxP3+CD4+ cells in any of the groups or induced differences between any of the groups.

Clinical differences in the response between mono-GP and multiple-sensitized allergic individuals are not related to differences in the number of regulatory T cells in the nasal mucosa.