No differences in nasal tissue inflammatory cells and adhesion molecules (iCAM-1 and vCAM-1) comparing EGPA with eosinophilic chronic sinusitis with polyposis.

Background An example of aggressive eosinophilic polyposis can be found in eosinophilic granulomatosis with polyangiitis (EGPA). Intercellular adhesion molecule-1 (iCAM-1) and vascular cell adhesion molecule-1 (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. Objective This prospective study compared three groups - patients with a definite diagnosis EGPA, non-EGPA patients with phenotypic features suggestive of EGPA, and patients with non-eosinophilic nasal polyposis (controls) - in terms of nasal tissue histology, iCAM-1 and vCAM-1 expression, and blood inflammatory cells. Methods 58 adults underwent sinus surgery (13 patients with EGPA, 23 suspected of having EGPA, and 22 controls). Results Mean tissue eosinophil counts were significantly higher in EGPA patients and suspected cases of EGPA than in controls, and higher in the suspected EGPA cases than in those with confirmed EGPA. Although iCAM-1 and vCAM-1 were diffusely expressed in sinonasal tissues, they did not differently stain EGPA, eosinophilic-type and non-eosinophilic polyposis. Blood basophil and eosinophil levels were high in both the EGPA and the suspected EGPA groups. Inter-group differences were found for eosinophils, but not for basophils. Conclusions We do not have yet blood or tissue markers able to 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 blood inflammatory cells, to identify markers characterizing sinonasal mucosa inflammation and useful for an early diagnosis of EGPA.