Effect of eotaxins and RANTES on blood eosinophil subtypes chemotaxis in allergic asthma

<bold>Introduction:</bold> Eosinophils, in response to chemotactic factors produced locally at the inflammatory site, accumulate in the airways and contribute to the development of bronchial asthma. Blood resident-like (rEOS-like) and inflammatory-like eosinophils (iEOS-like) are distinct in biological properties and may be differently affected by C-C chemokines eotaxin-1, 2, 3 and RANTES in asthma <bold>Aim:</bold> To investigate the effect of eotaxin-1, 2, 3 and RANTES on blood eosinophil subtypes chemotaxis in allergic asthma <bold>Methods:</bold> We included 10 steroid-naive, non-severe allergic asthma (AA) patients, and 8 healthy control subjects (HS). Blood eosinophils were isolated using high-density Ficoll centrifugation and magnetic separation. Eosinophil subtyping was based on magnetic separation against CD62L. Eosinophil chemotaxis was measured by transwell migration assay. AA patients underwent bronchial allergen challenge (BAC) with D. pteronyssinus, and the experiment results were compared before and 24h after BAC <bold>Results:</bold> In both investigated groups iEOS-like cells chemotaxis towards eotaxins 1, 2, 3 and RANTES gradient was significantly increased, p<0.05, but only AA patients rEOS-like cells chemotaxis in chemokine gradient was increased, p<0.05, compared to control eosinophils. In addition, AA patients’ both blood eosinophil subtypes chemotaxis in eotaxin-3 and RANTES gradient were significantly enhanced, compared with HS. Finally, blood iEOS-like cells chemotaxis in eotaxin-3 gradient further increased after BAC <bold>Conclusions:</bold> AA patients' blood eosinophil subtypes display increased chemotactic response towards eotaxin-3 and RANTES, meanwhile eotaxin-3 has a more pronounced effect on allergen activated iEOS-like cells