Methods: Peripheral blood mononuclear cells (PBMC) were collected from 12 subjects with allergy to Timothy grass pollen and cultured with grass pollen Phleum pretense extract (10 ug/mL), with or without GLA (1 ug/mL) for 6 days. Cytokine production was measured by ELISA and Luminex assays.
Results: The levels of Th2 cytokines, IL-5 and IL-13, were significantly decreased in the presence of GLA. IL-5 was 213±72 pg/mL in the allergen alone group vs. 60±17 pg/mL in the allergen plus GLA group (p=0.02). IL-13 was 635±140 pg/mL in the allergen alone group vs. 322±75 pg/mL in allergen plus GLA group (p=0.006). Th1 cytokines, IFNγ and IL-12, were significantly increased in the presence of GLA. IFNγ was 1008±378 pg/mL in the allergen alone group vs. 3842±876 pg/mL in the allergen plus GLA group (p=0.001). IL-12p40 was 126±48 pg/mL in allergen alone group vs. 898±179 pg/mL in allergen plus GLA group (p=0.0004). Anti-IL12 neutralizing antibody inhibited GLA-induced IFNy significantly (p=0.0002).
Conclusions: GLA can decrease grass pollen extract induced Th2 cytokines and increase Th1 cytokines. These results support testing of GLA in pollen-allergic patients in the setting of desensitization.