Final Activity Report Summary - NICKEL RHINITIS (Functional characteristics of allergen-specific T lymphocytes in nickel-induced allergic rhinitis)
In 40 persons with allergic contact dermatitis to nickel (Ni-ACD), we sought potential correlations between nickel-specific cytokine secretion and the outcome of patch test in the group of patients with allergic contact dermatitis to nickel. The levels of IL-5 and IFN-gamma secreted by peripheral blood lymphocytes (PBMC) in response to nickel measured with ELISA were correlated with the intensity of skin inflammation (patch test score). Additionally 19 patients with nickel-related rhinitis (Ni-Rh) and 22 patients with Ni-ACD, and 17 non-allergic volunteers were studied. The percentage of nickel-reactive cells was assessed in cells expressing CLA (skin-related homing antigen) and cells expressing HML/CD107 (mucosa-related homing antigens). Ni-specific secretion of IL-2 (naive cells), IL-13 (Th2/Tc2), and IFN-gamma (Th1/Tc1) was measured by means of ELISPOT (enzyme-linked immunospot assay). CD14+ monocytes were used as antigen presenting-cells (APC).
We have demonstrated that nickel-specific IL-5 secretion by PBMC determines the intensity of patch test reaction (p=0.05) with no significant effect of IFN-gamma. An increase in the signal of IL-5 by 10 pg/ml is associated with a 24.2% increase in the predicted odds of patient being in upper category of patch test score (p=0.05). IFN-gamma had no significant influence on the odds ratio.
An increase in the nickel-specific IL-5 secretion by 10 pg/ml is associated with a 10-20% increases (depending on statistical model) in the odds ratio of the patient to have a higher patch test score. This supports the assumption that cells secreting IL-5 (e.g. Th2, Tc2) play more important role in the pathogenesis of ACD than previously thought. No clear differences could be found between the cytokine secretion between the lymphocyte subpopulations (CLA+, HML-1+), and between the studied groups (patients with nickel rhinitis, Ni-ACD patients, healthy controls).
We have demonstrated that the level of the allergen-specific IL-5 production is a relevant predictor of patch test score, whereas IFN-gamma is not. This supports the assumption that type 2 cells secreting IL-5 (e.g. Th2, Tc2, possibly also NK2 or NKT2) play an important (if not crucial) role in the pathogenesis of allergic contact dermatitis. We were not able to demonstrate a different cytokine response to nickel of lymphocyte subsets with different homing antigens.