# Effect of Aspirin Challenge on Innate Lymphoid Cells in Asthma Patients With Aspirin Hypersensitivity

## TL;DR

This study found that aspirin-induced bronchospasm in asthma patients increases blood ILC1s and reduces sputum eicosanoids, suggesting a role for ILC1s in this allergic reaction.

## Contribution

The study identifies a specific increase in blood ILC1s during aspirin-induced bronchospasm in N-ERD patients.

## Key findings

- Blood ILC1 count and percentage significantly increased during aspirin-induced bronchospasm.
- Sputum ILC counts showed no significant changes due to low detection numbers.
- Sputum eicosanoid levels, including PGE2 and PGD2, decreased during bronchospasm.

## Abstract

Previous studies confirmed increased group 2 innate lymphoid cell (ILC2s) count in nasal scrapings, alongside a reduced blood ILC2 count, in patients with nonsteroidal anti‐inflammatory drug‐exacerbated respiratory disease (N‐ERD) after intranasal administration of cyclooxygenase‐1 inhibitors. This study aimed to assess the role of blood and sputum ILCs in N‐ERD patients during oral aspirin‐induced bronchospasm and to compare patients with eosinophilic and noneosinophilic airway inflammatory phenotypes of asthma. Induced sputum, blood, and urine samples were collected in 24 patients with confirmed N‐ERD at baseline and during aspirin‐induced bronchospasm. Sputum and blood ILC counts were evaluated using flow cytometry. There was a significant increase in blood ILC1 count (p < 0.001) and percentage (p = 0.003) during aspirin‐induced bronchospasm. No significant changes in sputum ILCs were observed, but the number of detected ILCs was very low. There was a significant reduction in induced sputum supernatant (ISS) levels of prostaglandins PGE2 (p = 0.004) and PGD2 (p = 0.045), leukotriene B4 (p = 0.045), and 15‐oxo‐eicosatetraenoic acid (p = 0.045) during aspirin‐induced bronchospasm. Blood ILC1 count is increased during oral aspirin‐induced bronchospasm in patients with N‐ERD, but sputum ILC count at baseline is very low. Therefore, no reliable changes in sputum ILC counts can be detected during bronchospasm.

In N‐ERD patients, oral aspirin‐induced bronchospasm is associated with increased blood group 1 innate lymphoid cells (ILC1s), decreased sputum eicosanoids, and increased urinary leukotriene E4 (LTE4), suggesting a potential role of blood ILC1s in aspirin‐induced bronchoconstriction.