Isolated IgG2 deficiency is an independent risk factor for exacerbations in bronchiectasis.

Abstract

BACKGROUND:

Immunoglobulin G (IgG) subclass 2 deficiency is the most frequent IgG subclass deficiency identified in patients with bronchiectasis, but its clinical significance is not known.

AIM:

To analyse if bronchiectasis patients with isolated IgG2 deficiency at risk of recurrent exacerbations and/or hospitalization? Do patients with IgG2 deficiency have worse disease progression?

DESIGN AND METHODS:

This is a retrospective study (2015-20) exploring independent risk factors for recurrent exacerbations (3 or more per year) and/or hospitalization with bronchiectasis exacerbations using multivariable models using binary logistic regression. There was no patient with IgG deficiency, IgG 1, 3 or 4 deficiency, or IgA or IgM deficiency included. In this model, the authors included: serum IgG2 level; lung function; body mass index; MRC breathlessness scale; age; sex; number of bronchiectatic lobes; bacterial colonization; comorbidities; and the use of long-term immunosuppressant drugs or antibiotics for more than 28 days. Analysing 2-year longitudinal data, one-way ANOVA and Mann-Whitney U-test were used to compare bronchiectasis severity between patients with different IgG2 levels.

RESULTS:

Serum IgG2 levels (<2.68 g/l, 2.68-3.53 g/l and 3.54-4.45 g/l); hospital admission in the preceding 2 years; bacterial colonization with potentially pathogenic organisms and asthma were independent predictors for three or more bronchiectasis exacerbations. Those with low IgG2 levels (<2.68 g/l and 2.68-3.53 g/l), had worsening progression of their bronchiectasis, using the Bronchiectasis Severity Index, over 1 year compared with those who were IgG2 replete (>4.45 g/l) (P = 0.003, 0.013).

CONCLUSION:

Reduced IgG2 levels were an independent predictor for bronchiectasis exacerbations and have increased disease progression.

• Authors: Y Zhang, A Clarke, K H Regan, K Campbell, S Donaldson, J Crowe, A G Rossi, A T Hill
• Journal: QJM : monthly journal of the Association of Physicians (QJM) Vol. 115 Issue 5 Pg. 292-297 (May 10 2022) ISSN: 1460-2393 [Electronic] England
• PMID: 33970283 (Publication Type: Journal Article)
• Copyright: © The Author(s) 2021. Published by Oxford University Press on behalf of the Association of Physicians.

Chemical References

• Immunoglobulin G

Topics

• Bronchiectasis
• Disease Progression
• Humans
• IgG Deficiency
• Immunoglobulin G
• Retrospective Studies
• Risk Factors