NK cells appear early during the allergic inflammatory response
Leukocyte sub-populations were furthermore identified in nasal lavage samples by FACS (the gating strategy is outlined in Fig. 2, A ). As expected, eosinophils were rapidly recruited, as early as 1 hr post-challenge, and remained elevated for 48 hrs after the challenge (Fig. 2, B ). Neutrophils were the most abundant population, peaking 1 hr after the challenge and returning to baseline levels at 24 hrs (Fig. 2, B ). Monocyte and lymphoid cell recruitment was also observed after the allergen challenge. Interestingly, NK cells were recruited as early as 1 h after the challenge, persisted for 6 hrs before falling to their baseline levels. No significant leukocyte kinetics were observed after diluent challenges.