Abstract

RATIONALE: Serum amyloid A (SAA) is bound to high-density lipoproteins (HDL) in blood. Although SAA is increased in the blood of patients with asthma, it is not known whether this modifies asthma severity.

OBJECTIVE: We sought to define the clinical characteristics of patients with asthma who have high SAA levels and assess whether HDL from SAA-high patients with asthma is proinflammatory.

METHODS: SAA levels in serum from subjects with and without asthma were quantified by ELISA. HDLs isolated from subjects with asthma and high SAA levels were used to stimulate human monocytes and were intravenously administered to BALB/c mice.

RESULTS: An SAA level greater than or equal to 108.8 μg/mL was defined as the threshold to identify 11% of an asthmatic cohort (n = 146) as being SAA-high. SAA-high patients with asthma were characterized by increased serum C-reactive protein, IL-6, and TNF-α; older age; and an increased prevalence of obesity and severe asthma. HDL isolated from SAA-high patients with asthma (SAA-high HDL) had an increased content of SAA as compared with HDL from SAA-low patients with asthma and induced the secretion of IL-6, IL-1β, and TNF-α from human monocytes via a formyl peptide receptor 2/ATP/P2X purinoceptor 7 axis. Intravenous administration to mice of SAA-high HDL, but not normal HDL, induced systemic inflammation and amplified allergen-induced neutrophilic airway inflammation and goblet cell metaplasia.

CONCLUSIONS: SAA-high patients with asthma are characterized by systemic inflammation, older age, and an increased prevalence of obesity and severe asthma. HDL from SAA-high patients with asthma is proinflammatory and, when intravenously administered to mice, induces systemic inflammation, and amplifies allergen-induced neutrophilic airway inflammation. This suggests that systemic inflammation induced by SAA-high HDL may augment disease severity in asthma.

Document Type

Article

Publication Date

4-1-2024

Notes/Citation Information

0091-6749 Published by Elsevier Inc. on behalf of the American Academy of Allergy, Asthma & Immunology

Digital Object Identifier (DOI)

https://doi.org/10.1016/j.jaci.2023.11.917

Funding Information

This research was funded by the Division of Intramural Research at the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Md. Disclosure of potential conflict of interest: US and European provisional patent applications have been filed by the National Heart, Lung, and Blood Institute that include some of the subject matter from this manuscript.

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