Co-administration of chenopodium album allergens and CpG oligodeoxynucleotides effects on peripheral blood mononuclear cells of patients with allergic rhinitis treated with intranasal corticosteroids and antihistamines

Objective. Allergic Rhinitis (AR) is one of the most common chronic diseases in the developed countries, associated with substantial economic burden and morbidity. This study was performed to investigate the effect of CpG-ODN in alteration of T-helper (Th)1/Th2 balance of patients with AR treated with intranasal corticosteroids (INCs) and antihistamines.

Methods. Peripheral blood mononuclear cells (PBMCs) of 20 patients with AR were isolated before and after 45 days treatment with INCs and antihistamines. Cytokine production (IL-4, IL-10, IL-13, IFN-γ) and specific Ch.a IgE in response to CpG-ODN co-administration of natural chenopodium album (CpG/Ch.a) or recombinant Ch.a (CpG/rCh.a) allergen were investigated using ELISA method. Intracellular IL-10 was also assessed in CD4⁺ cells using flow cytometry. For statistical analysis SPSS 16 software package was used.

Results. Significant increases in production of IFN-γ and IL-10 and a significant decrease in production of IL-4 were found in PBMCs stimulated with either CpG/Ch.a or CpG/rCh.a compared to stimulated cells with allergens alone, before and after therapy of patients. After therapy, only IFN-γ production with CpG/Ch.a stimulant was significantly increased in comparison with before treatment (237 vs. 44 pg/ml, p=0.001). IFN-γ and IL-10 production with CpG/rCh.a stimulant was significantly increased after therapy compared to before (407.6 vs. 109 pg/ml, p=0.01 for IFN-γ; 171.7 vs. 52.6 pg/ml, p=0.008 for IL-10), whilst production of IL-4 was significantly decreased (2.1 vs. 5.8 pg/ml, p=0.02). Intracellular IL-10 expression was also significantly increased in response to either CpG/Ch.a or CpG/rCh.a. Altogether, the comparison of all results obtained from IL-10 assay with either intracellular or secreted form showed that intracellular assay could be more sensitive than ELISA. Specific IgE was significantly decreased after therapy in response to either CpG/Ch.a or CpG/rCh.a stimulant.

Conclusion. Treatment of PBMCs from AR patients with CpG/Ch.a or CpG/rCh.a inhibits Th2 cytokine responses and induces Th1-biased immune responses. Also, treatment with intranasal corticosteroids and antihistamines could enhance this CpG effect, in vitro. However, further clinical studies are recommended to confirm these findings.