The measurements were performed as described before . Briefly, each patient exhaled FK506 concentration against the fixed expiratory resistance of 16 cm H2O, which resulted in a constant flow of 50 ml/s. A plateau of NO concentration in the exhaled air at the selected exhalation rate was automatically selected by the computer software according to the American Thoracic Society recommendations. The measurements were repeated three times and the mean value expressed as fraction of expired NO (FeNO) was used for analysis. Flow cytometry analysis. Samples of EDTA anticoagulated venous blood for flow cytometry and cytokine analyses were collected before (T0), 6 h (T6) and 24 h (T24) after allergen challenge. Flow cytometry
analysis was performed on the whole-blood samples using combinations of the following labelled monoclonal antibodies anti-CD14 FITC or anti-CD14 PE, anti-CD16 FITC or anti-CD16 PE-Cy5 and anti-CCR4 PE (all from BD PharMingen, Erembodegen, Belgium) as described before . Labelled, isotype-matched BYL719 antibodies were used as negative controls. After
30 min of incubation at room temperature, erythrocytes were lysed using FACS Lysing Solution (BD PharMingen). The remaining white cells were analysed using FACSCalibur cytometer (BD Immunocytometry Systems, San Jose, CA, USA) as described before . Individual PBM subsets were given names according to the nomenclature proposed by Ziegler-Heitbrock et al. . Immune assays. Serum concentration of total (tIgE) and specific anti-Dp IgE PDK4 (sIgE) were evaluated using UniCap (Phadia, Uppsala, Sweden). Plasma concentrations of CCL2, CX3CL1 and CCL17 were evaluated using Quantikine ELISA kits (R&D Diagnostics, Minneapolis, MN, USA). Statistical analysis. The results are expressed as mean with 95% confidence interval (95%CI). Statistical analysis was performed using anova test. Post hoc analysis was performed using Student’s t-test. A probability value of P < 0.05
was taken to indicate statistical significance. Linear correlation by Pearson was used to estimate correlations between studied parameters. Allergen challenge resulted in the development of significant bronchoconstriction in 22 [responders (Rs)] of 34 Dp-APs. Those 22 patients reported both rhinitis and asthma symptoms. In 12 Dp-APs, no asthmatic response could be demonstrated [non-responders (NRs)]. Those patients had never reported asthma symptoms before the study. The baseline clinical and immunologic characteristics of the studied patients are presented in Table 1. There was no difference in age and sex distribution between Rs, NRs and HCs. All Dp-APs had comparable levels of serum tIgE, baseline lung function results and FeNO. The greatest mean eosinophil count was seen in Rs (415 cells/mm3; 95%CI 295–534 cells/mm3) being significantly greater than in NRs (214 cells/mm3; 95%CI 143–321 cells/mm3; P = 0.