Effect of Intradermal Immunotherapy (IDIT) injections on gene expression profiles of activated T cells derived from skin biopsy explants

A Randomized, Placebo-Controlled Trial of Intradermal Allergen Immunotherapy for Grass Pollen Allergy Background: Repeated intradermal injection of grass pollen (nanograms of allergen) suppresses allergen-induced cutaneous late phase responses, in keeping with effects of conventional high dose subcutaneous and sublingual immunotherapy. We evaluated the efficacy and safety of grass pollen intradermal immunotherapy for treatment of allergic rhinitis.Methods: We randomly assigned 93 adults with grass pollen allergic rhinitis to receive 7 pre-seasonal Intradermal allergen immunotherapy injections (containing 7 ng of Phl p 5 major allergen) or histamine control. The primary end point was daily combined symptom-medication scores during the 2013 pollen season. Skin biopsies were taken after the pollen season following an intradermal allergen challenge. Cutaneous late phase responses were measured 4 and either 7, 10 or 13 months post-treatment. Results No difference in the primary endpoint was observed between treatment arms (median difference, 14; 95% confidence interval [CI], -172.5 to 215.1; P=0.80). Amongst secondary endpoints, nasal symptoms measured with daily scores (median difference, 35; 95% CI, 4.0 to 67.5; P=0.03) and visual-analogue scales (median difference, 53; 95% CI, -11.6 to 125.2; P=0.05) were higher in the intradermal treatment group. Intradermal immunotherapy increased serum Phl p-specific IgE (P=0.001) compared to the control arm and T cells cultured from biopsies showed higher and lower surface of surface markers for Type 2 (P=0.04) and Type 1 (P=0.01) T-helper cells, respectively, Interleukin-5 was differentially expressed by microarray (P=0.03). Late phase responses were still inhibited 7 months after treatment (P=0.03) but not at 10-13 months. Conclusions Grass pollen intradermal allergen immunotherapy was not clinically effective but resulted in immunological priming and worsening of allergic rhinitis symptoms. T-cells were isolated from skin biopsy by explant culture from control subjects (8) and subjects undergoing IDIT (7). After 7 days T-cells were activated with PMA/Ionomycin. Control subjects were compared with IDIT subjects.