title: A randomized controlled trial to evaluate inhibition of T-cell costimulation in allergen-induced airway inflammation.
abstract: BACKGROUND
  T lymphocytes are important in the pathogenesis of allergic asthma. Costimulation through CD28 is critical for optimal activation of T cells, and inhibition of this pathway with CTLA4Ig has been shown to be effective in preventing airway inflammation and hyperresponsiveness in animal models of asthma. Abatacept, a humanized version of CTLA4Ig, has been approved for treatment of rheumatoid arthritis, providing the opportunity to test whether inhibition of costimulation is an effective strategy to treat people with asthma.
  
  
  OBJECTIVE
  To determine if 3 months of treatment with abatacept reduced allergen-induced airway inflammation in people with mild atopic asthma.
  
  
  METHODS
  Randomized, placebo-controlled, double-blinded study. Bronchoscopically directed segmental allergen challenge was performed on 24 subjects followed by bronchoalveolar lavage 48 hours later. Subjects were randomized 1:1 to receive abatacept or placebo, followed by a second allergen challenge protocol after 3 months of study drug.
  
  
  RESULTS
  There was no significant reduction in allergen-induced eosinophilic inflammation in the abatacept-treated group compared with placebo (17.71% ± 17.25% vs. 46.39% ± 29.21%; P = 0.26). In addition, we did not detect an effect of abatacept on FEV1, provocative concentration of methacholine sufficient to induce a 20% decline in FEV1, or asthma symptoms. Subjects treated with abatacept had an increased percentage of naive and a corresponding decrease in memory CD4(+) T cells in the blood compared with placebo.
  
  
  CONCLUSIONS
  Inhibition of CD28-mediated costimulation with abatacept does not seem to alter the inflammatory response to segmental allergen challenge or clinical measures of asthma symptoms in people with mild atopic asthma. Clinical trial registered with ClinicalTrials.gov (NCT 00784459).
authors.affiliation: Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Amit D
authors.initials: AD
authors.lastname: Parulekar
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Boomer
authors.forename: Brenda M
authors.initials: BM
authors.lastname: Patterson
authors.forename: Huiqing
authors.initials: H
authors.lastname: Yin-Declue
authors.forename: Christine M
authors.initials: CM
authors.lastname: Deppong
authors.forename: Brad S
authors.initials: BS
authors.lastname: Wilson
authors.forename: Nizar N
authors.initials: NN
authors.lastname: Jarjour
authors.forename: Mario
authors.initials: M
authors.lastname: Castro
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Green
mesh_terms: D000069594:Abatacept; D000328:Adult; D001249:Asthma / Q000188:drug therapy* / Q000276:immunology; D018106:CD28 Antigens / Q000037:antagonists & inhibitors*; D004311:Double-Blind Method; D004804:Eosinophils / Q000378:metabolism; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D018796:Immunoconjugates / Q000009:adverse effects / Q000627:therapeutic use*; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D015398:Signal Transduction; D016176:T-Lymphocyte Subsets / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D018106:CD28 Antigens; D018796:Immunoconjugates; D007166:Immunosuppressive Agents; D000069594:Abatacept