Asthma and Hypogammaglobulinemia: an Asthma Phenotype with Low Type 2 Inflammation.

Little is known about hypogammaglobulinemia (HGG) in asthma patients. No data are available on the characteristics of adult patients with asthma and HGG.

We conducted a retrospective monocentric study between January 2006 and December 2012. Asthma patients with a serum immunoglobulin (Ig) quantitative analysis were included and classified into two groups depending on their serum IgG concentration: presence or absence of HGG. Clinical, biological, functional, and radiologic characteristics were compared in univariate and multivariate analysis, using a logistic regression model.

In univariate analysis, asthma patients with HGG (n = 25) were older (58 years old ± 18 vs 49 ± 18, p = 0.04) and more frequently active or former smokers as compared to patients with normoglobulinemia (n = 80) (56.0 vs 35.0 %, p = 0.01). Total IgE < 30 kUI/L was more frequently observed in patients with HGG (53.0 vs 18.3 %, p = 0.01). HGG asthma patients had lower fraction of exhaled nitric oxide (p = 0.02), blood eosinophilia (p = 0.0009), and presented with more severe composite score for bronchiectasis (p = 0.01). In multivariate analysis, asthma patients with HGG had increased risk of being smokers [OR = 6.11 (IC 95 % = 1.16-32.04)], having total IgE concentration < 30 kUI/L [OR = 12.87 (IC 95 % = 2.30-72.15)], and a more severe composite score of bronchiectasis [OR = 20.65 (IC 95 % = 2.13-199.74)].

Asthma patients with HGG are older and more often tobacco smoker than asthma patients without HGG. These patients have low type-2 inflammation markers.