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Persistent asthma related to increased low-density granulocyte levels

Patients with moderate persistent or severe persistent asthma had elevated neutrophil-like low-density granulocytes, according to recent study results.

Researchers studied 20 patients with intermittent (n=9) or mild persistent (n=11) asthma, 20 patients with moderate persistent (MoP; n=10) or severe persistent (SP; n=10) asthma, and 20 controls with no history of allergy or asthma. All participants underwent a medical history and physical examination, spirometry, and measurement of fraction of exhaled nitric oxide (FENO). Polychromatic flow cytometry was used to quantify neutrophil-like low-density granulocytes (LDGs).

“The LDGs displaying the same phenotype as those described previously for LDGs in other diseases were significantly elevated in peripheral blood mononuclear cells of subjects with [MoP] or SP asthma,” the researchers wrote.

Up to 39% of the peripheral blood mononuclear cells were composed of LDGs; the patients with SP asthma had the most prevalent elevated LDG levels, with four of those patients experiencing the highest LDG levels.

Patients with low LDG levels had significantly increased FENO levels and body mass vs. controls. However, the patients with MoP or SP asthma and high LDG levels did not have elevated FENO and body mass compared with controls.

“Although the link between LDG levels and disease severity is not specific to asthma, it is proposed that further investigation of the link between LDG levels and asthma severity could lead to a clinically useful serum biomarker for the identification of severe asthma, in particular neutrophil-associated phenotypes and possibly steroid-resistant asthma.”

Disclosure: The researchers report serving as investigators for Genentech.