Prevention of antigen-induced bronchial hyperreactivity and airway inflammation in sensitized guinea-pigs by tacrolimus

WE examined the effect of the immunosuppressive agent, tacrolimus (FK506), on antigen-induced bronchial hyperreactivity to acetylcholine and leukocyte infiltration into the airways of ovalbumin-challenged guinea-pigs, Subcuta neous injection of 0.5 mg/kg of FK506, 1 h before and 5 h after intra-nasal antigen challenge prevented bronchial hyperreactivity to aerosolized acety lcholine, eosinophilia in bronchoalveolar lavage (BAL) fluid and bronchial tissue and the invasion of the bronchial wall by CD4(+) T-lymphocytes, FK50 6 also suppressed ovalbumin-induced increase in the number of leukocytes ad hering to the pulmonary vascular endothelium and expressing alpha 4-integri ns. Inhibition by FK506 of antigen-induced bronchial hyperreactivity in sen sitized guinea-pigs may thus relate to its ability to prevent the emergence of important inflammatory components of airway inflammation, such as eosin ophil accumulation, as well as CD4(+) T-lymphocyte infiltration into the br onchial tissue.