This selective CXCR2 antagonist was used in a trial to treat patients with severe asthma, but it was not effective in controlling disease deterioration.[59] The participants in this experiment did not smoke, as smoke exposure can lead to upregulation of CXCL8 levels in the airway mucosa, exacerbating neutrophil recruitment and NET formation. Here, CXCL8 is linked to asthma.