Introduction

Eosinophils seem to play two different roles: a physiological and an inflammatory role. This concept has raised the theory of  two differentiated populations; inflammatory eosinophils (iEos) and resident eosinophils (rEos). These differences have been shown previously by some authors. This study describes the effect of mepolizumab, omalizumab and dupilumab vs. asthmatic patients with no biological therapy on different eosinophil populations.

Material and methods

Four cohorts were collected; asthmatics without biological treatment and asthmatics treated for at least 3 months with mepolizumab, omalizumab or dupilumab. All subjects who had taken systemic steroids in the last 3 months were excluded. Peripheral blood was studied by flow cytometry for surface protein profiles for eosinophilic differentiation (rEos: Siglec-8+CD62L+IL-3Rlo and iEos:  Siglec-8+CD62LloIL-3Rhi). The IL-5 receptor and CD11b were also measured

Results

The proportion of eosinophils sub-types were different in asthma patients only with mepolizumab (Table 1).  IL3 receptors have decreased in patients with mepolizumab and dupilumab than in asthma patients without monoclonal antibodies. CD11b receptors have decreased only in patients with mepolizumab (Figure 1).

Conclusions

The effect of monoclonal antibodies is different in the eosinophils sub-types. The eosinophils that remain in peripheral blood despite the use of mepolizumab seem to correspond to rEos with homeostatic functions. Omalizumab and dupilumab do not change the proportion of eosinophils subtypes but decrease IL3 receptor.