Background: The capacity of inflammatory cells to adhere involves an array of adhesion molecules, and is critical to the inflammatory responses seen in childhood asthma. We aimed to determine the changes of intercellular adhesion molecule-1 (ICAM-1) and L-selectin expressed on peripheral blood (PB) T lymphocytes and natural killer (NK) cells in asthmatic children with acute exacerbation and after prednisolone therapy.
Methods: Flow cytometric analysis was performed to determine the expression of ICAM-1 (CD54) and L-selectin (CD62L) on T (CD3+) cells and NK (CD3-/CD56+) cells of PB from children with allergic asthma with acute exacerbation and in a stable condition after prednisolone therapy. Atopic subjects without asthma and age-matched controls were also included for comparison.
Results: Percentages of PB non-CD3, CD56+ NK cells, but not CD3+ T cells, increased in asthmatic children with acute exacerbation, compared to those assessed in a stable condition after a course of prednisolone. However, significant decrease of ICAM-1 (P = 0.01) and L-selectin (P = 0.01) expression on PB NK cells, but not on T cells, were found in children with acute asthma compared to those in a stable condition. NK cells in children with acute asthma showed minimal expression of CD69 and CD25.
Conclusions: Results suggests that either NK cells expressing ICAM-1 and L-selectin selectively migrated into inflamed lung tissues, or subsets of NK cells not expressing ICAM-1/L-selectin were expanded during acute exacerbation of childhood asthma.