Efficacy predictions for omalizumab treatment based on basophil CD203c expression in patients with allergic rhinitis...

Basophils are key targets in allergic diseases. Omalizumab blocks IgE binding to FcεRI on basophils, reducing allergic responses. The basophil activation test aids allergy diagnosis, but their role in allergic rhinitis (AR) remains unclear. We assessed omalizumab's impact on basophil reactivity and its clinical associations in moderate-to-severe AR.

This study aimed to determine the predictive value of CD203c and CD63 as basophil activation markers for clinical response to omalizumab in patients with moderate-to-severe allergic rhinitis.

We collected and analyzed clinical symptoms and the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores of 27 patients with moderate-to-severe AR who were treated with omalizumab for more than 12 weeks. Patients were divided into a non-basopenic group (OMA-AR/NB) and a basopenic group (OMA-AR/B) based on peripheral blood basophil counts (basopenic: <8000 cells/mL). FcεRI, CD63, and CD203c expression on blood basophils induced by stimulant were measured at baseline and at 12 weeks after omalizumab treatment using flow cytometry.

The RQLQ score in OMA-AR/NB decreased from 33.0 ± 11.0 at baseline to 5.2 ± 4.2 at 12 weeks, while in OMA-AR/B, the score decreased from 33.8 ± 7.6 at baseline to 19.4 ± 5.9 at 12 weeks. Additionally, the basophil activation assay yielded the best classification accuracy (73.97% sensitivity, 88.89% specificity, cut-off value: 8.0%) for %CD203c+ in patients with AR.

During omalizumab treatment in patients with AR, CD203c was a more suitable marker for the basophil activation test (BAT). Furthermore, %CD203c⁺ > 8.0%, combined with a normal basophil count at baseline, could be used to predict the therapeutic effect of omalizumab.