Expression of Fas ligand and CTLA4 in adenoids has a predictive value for allergic rhinitis development in children

BACKGROUND: The balance of CD28/CTLA4-derived signals and Fas-dependent apoptosis activity is determined by the peripheral defense mechanisms and might play a role in the pathogenesis of allergy. OBJECTIVES: The aim of the study was to investigate the expression of costimulatory and pro- and antiapoptotic molecules in adenoid T cells of children suffering from allergic rhinitis and to find out which of these molecules have a predictive value in the development of allergic rhinitis. METHODS: The adenoids of 60 children, removed because of nasal obstruction, chronic rhinitis and recurrent respiratory infection, were evaluated. Patients were divided into two groups: group 1, suffering from chronic allergic rhinitis, and group 2, suffering from chronic rhinitis, where no specific IgE was detected, including children with a positive family history of allergy (group 2a) and children with neither a personal nor a family history of allergy (group 2b). For immunohistochemical stainings anti-CD3, anti-CD19, anti-CD4, anti-CD8, anti-CD25, anti-CD28, anti-CTLA4 (CD152), anti-bcl-2, anti-Fas, and anti-FasL antibodies were used. The number of cells expressing these molecules was identified in adenoid interfollicular spaces. The results were then analyzed in allergic and nonallergic children. During a 24-month follow-up children were re-examined for allergy and results were compared to previous immunohistochemical evaluations. RESULTS: The expression of CD4, CD25, CD28, FasL, and CTLA4 was significantly increased in group 1 compared to group 2 (p < 0.05). However, the discriminant analysis confirmed that only CTLA4 and FasL expression fully discriminated allergic subjects from the others. During a 24-month period of observation 8 children from group 2a were also diagnosed with allergic rhinitis. All of them, especially those sensitized to mites, had an increased number of FasL+ and CTLA4+ in previously removed adenoids. CONCLUSION: An increased number of cells with intracellular expression of FasL and CTLA4, in interfollicular spaces of adenoids, seems to be a predictive factor of the development of allergic rhinitis.