NKG2A+CD56dimCD16br NK cell subset as a potential prognostic marker of response to benralizumab treatment in severe eosinophilic asthmatic patients.

<bold>AIM:</bold> In the last years, NK cells have shown a key role in the pathogenesis of severe eosinophilic asthma (SEA). The examination regarding the effect of asthma treatments on NK cells has been discussed. In particular, Benralizumab, an anti-IL-5Rα monoclonal antibody, showed changes in NK cell subsets during the first months of treatment. In this research, a long-term follow-up evaluation of NK cells subsets was considered and correlated with clinical and functional parameters. <bold>METHODS:</bold> 7 SEA patients were treated with benralizumab for 24 months and considered “responders” and 10 healthy controls (HC) were enrolled in the study. Clinical, functional parameters, and blood samples were collected at baseline (T0), after 6 (T6) and 24 months (T24) of therapy. NK cell analysis was determined through multi-parametric flow cytometry. <bold>RESULTS:</bold> SEA patients showed an imbalance in CD56dimCD16br mature NK and CD56brCD16neg immature cell subsets when compared with HC. BMI also correlates with different NK cell subsets at baseline. At T24, CD56dimCD16br mature NK increased, as well as the expression of NKG2A and CD57, the latter determining the terminally differentiated status of these cells. NKG2A+CD56dimCD16br also correlated with FEV1% changes in these patients and OCS administration. <bold>CONCLUSIONS:</bold> Our data support the role of NK cells for monitoring patients after 24 months of benralizumab treatments, with the role of NKG2A+CD56dimCD16br NK cell subset as a good prognostic marker of response to treatment.