Elevated, FcεRI-dependent MRGPRX2 expression on basophils in chronic urticaria

Area of Science:

• Immunology
• Dermatology
• Cell Biology

Background:

• Chronic urticaria (CU) is a mast cell and basophil-driven skin condition.
• The precise activation profile of these cells, particularly with anti-immunoglobulin E (IgE) therapy like Omalizumab, remains incompletely understood.

Purpose of the Study:

• To characterize the surface activation profile of basophils in CU patients during Omalizumab treatment.
• To assess basophil responsiveness to both IgE and non-IgE stimuli in the context of CU and Omalizumab therapy.

Main Methods:

• Whole blood basophils from 11 CU patients and 10 healthy controls were analyzed.
• Cells were stimulated with medium, anti-IgE, fMLP, C5a, or Substance P and characterized via flow cytometry.

Main Results:

• CU patients displayed a wider range of basophil counts compared to healthy controls.
• Unstimulated basophils in CU patients showed increased CD69 expression.
• MRGPRX2 expression on unstimulated basophils was higher in CU patients post-Omalizumab treatment.
• Both IgE and non-IgE stimuli upregulated CD63, CD203c, and CD200R, with anti-IgE and other stimuli increasing MRGPRX2-expressing basophils in CU patients.

Conclusions:

• Basophils in chronic urticaria patients demonstrate elevated MRGPRX2 expression after stimulation via both IgE-dependent and independent pathways.
• Findings suggest a role for MRGPRX2 in basophil activation in CU, potentially modulated by Omalizumab treatment.