RT Journal Article SR Electronic T1 Late-breaking abstract: Role of IL-13-producing BLT1-positive CD8 T cells in asthmatic airway obstruction JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP p3878 VO 38 IS Suppl 55 A1 Azzeddine Dakhama A1 Maureen L. Collins A1 Donald Y.M. Leung A1 Elena Goleva A1 Rafeul Alam A1 E. Rand Sutherland A1 Richard J. Martin A1 Erwin W. Gelfand YR 2011 UL http://erj.ersjournals.com/content/38/Suppl_55/p3878.abstract AB Background: Asthma is characterized by reversible airflow obstruction, persistent inflammation and airway hyperresponsiveness. Recent animal studies identified a subset of CD8 T cells expressing BLT1, the high affinity receptor for leukotriene B4. These cells accumulate in the lungs and alter airway function via interleukin-13 (IL-13) production (Nat Med 2004, 10:865-9).Aims: To determine if a similar subset of CD8 T cells are present in asthmatic human airways and if their presence is associated with evidence for asthmatic airway obstruction.Methods: BAL cells from asthmatics (n=39) and healthy controls (n= 28) were stimulated in culture and immuno-stained for CD8, BLT1 and IL-13. The data were correlated to lung function, serum IgE and airway basement membrane (BM) thickness.Results: Compared to controls, asthmatics showed higher proportion of CD8-positive lymphocytes in BAL fluid (p < 0.001). A significant proportion of these CD8 T cells expressed BLT1 in both groups. Most importantly, the proportion of BLT1-positive CD8 T cells expressing IL-13 was significantly higher in asthmatic airways compared to controls (p < 0.001). Furthermore, the proportion of IL-13-producing BLT1-positive CD8 T cells negatively correlated with FEV1 (% predicted) values and FEF[25-75] values (p < 0.001). Interestingly, a positive correlation was detected between the proportion of these cells and serum IgE levels as well as with BM thickness (p < 0.01).Conclusions: IL-13-producing BLT1-positive CD8 T cells are present in the airways of asthmatics, and their accumulation correlates with airway obstruction, serum IgE levels and BM thickness, suggesting a pathogenic role for these cells in human asthma.