Figure 5.

Association of brain-derived neurotrophic factor (BDNF) with changes in PC₂₀ (provocative concentration of histamine causing a 20% fall in the forced expiratory volume in 1 s). Shown are correlations between changes in BDNF concentrations in serum (A) or platelets (B) and changes in the PC₂₀ values (histamine) after 14 days of salmeterol therapy, as compared with the baseline before therapy. Each dot represents one patient; the line is the regression line calculated with SPSS (Chicago, Illinois, USA). Spearman’s rank correlation coefficient (r) and the significance of the correlation (p) are given above each graph.