iCAM-1 and vCAM-1 play a part in mediating the recruitment and adhesion of leukocytes to the vessel wall and their blood-to-tissue migration under inflammatory conditions.

The present prospective study compared three groups. The groups included patients with a definite diagnosis of EGPA, non-EGPA patients with phenotypic features suggestive of EGPA, and a control group consisting of patients with non-eosinophilic nasal polyposis. The comparison was made in terms of nasal tissue histology, iCAM-1 and vCAM-1 expression, and blood inflammatory cells.

The study sample included a total of 58 adults who underwent sinus surgery.

Mean tissue eosinophil counts were significantly higher in EGPA patients and suspected cases of EGPA than in controls. Although iCAM-1 and vCAM-1 were diffusely expressed in sinonasal tissues.

The study concluded that we do not yet have blood or tissue markers that differentiate the early phase of EGPA from chronic rhinosinusitis with nasal polyps. Further investigations are mandatory, considering EGPA patients at their initial diagnosis and before any treatment, in terms of nasal histology and inflammatory blood cells, to identify markers useful for an early diagnosis of EGPA.

Reference: https://journals.sagepub.com/doi/full/10.1177/1945892419836819