In a similar study, Levin et al. showed that reversible obstruction (ΔppFEV1 ≥ 12%) was associated with younger age (p = 0.01) and a severe genotype (p = 0.02), but not with a family history of asthma, serum IgE, blood eosinophils, pancreatic status, ppFEV1 < 40%, Aspergillus or Pseudomonas infection (20). Here, IGHE is linked to Pseudomonas infection.