Beta2-adrenergic receptor haplotype and bronchodilator response to salbutamol in patients with acute exacerbations of COPD.

The role of the beta (β 2 )-adiefieigic receptor (ADRB 2 ) genotype in patients with chronic obstructive pulmonary disease (COPD) is unclear. In patients with acute exacerbations of COPD (AECOPD), we assessed the role of ADRB 9 haplotypes in morning lung function and in the bronchodilator response to salbutamol. In 107 patients with AECOPD, polymorphisms in the amino acid position 16 (Arg16/Gly16) and 27 (Gln27/Glu27) of the ADRB 2 gene were assessed by allele-specific polymerase chain reaction, identifying 31 subjects with the Gly16/Glu27 -negative and 76 with the Gly16/Glu27-positive ADRB 2 haplotype. Pulmonary function and broncliodilator response to salbutamol were assessed using bodyplethysmography. Forced expiratory volume in I second (FEV 1 ) and peak expiratory flow (PEF) were significantly higher in the Gly16/Glu27-negative compared to the Gly16/Glu27-positive haplotype group at baseline (49.7±2.9% vs 42.4±1,8% predicted, P=0.037; 44.0±2.2% vs 36.4±1.6% predicted, P=0.008, respectively). FEV 1 , PEF, and forced vital capacity (FVC) increased from baseline to after salbutamol treatment in both the Gly16/Glu27-negative and the Gly16/Glu27-positive ADRB 9 haplotype groups (P<0.001 for all comparisons). Values for FEV 1 and PEF after administration of the bronchodilator were significantly higher in the Gly16/Glu27-negative haplotype group compared with the Gly16/Glu27-positive haplotype group (P=0.030 and P=0.034, respectively). No differences were observed in DeltaFEV 1 , DeltaPEF, or DeltaFVC after bronchodilation between the 2 ADRB 2 haplotype groups (12.2±1.8% vs 14.5±1.5% predicted, P=0.393; 12.2±3.3% vs 20.8±3.2% predicted, P=0.117; 9.1+2.3% vs 10.4±1.9% predicted, P=0.707, respectively). The present findings suggest that the ADBR 2 gene haplotypes may affect the severity of obstructive ventilatory impairment but not the immediate response to salbutamol during AECOPD.