SERPINA1 and chronic obstructive pulmonary disease: The frequency of the Pi*S and Pi*Z alleles among wheezing children was like the frequency observed among COPD patients: PiS 10.3% (95% CI: 4.0–16.6) vs. 15.8% (95% CI: 6.92–24.6) and PiZ 44.8% (95% CI: 32.1–57.5) vs. 46.1% (95% CI: 31.1–60.9).