Basophils from allergic patients are neither hyperresponsive to activation signals nor hyporesponsive to inhibition signals

Publication date: November 2018

Source: Journal of Allergy and Clinical Immunology, Volume 142, Issue 5

Author(s): Lydie Cassard, Katia Sperber, Tan-Phuc Buivan, Aurélie Cotillard, Raphaëlle Bourdet-Sicard, Matthew L. Albert, Estelle Mottez, Jérôme Laurent, Marie-Thérèse Guinnepain, Marc Daëron

Background

Basophil activation contributes to inflammatory reactions, especially in allergy. It is controlled, both positively and negatively, by several mechanisms. High-affinity IgE receptors (FcεRI) generate a mixture of activation and inhibition signals when aggregated, the ratio of which depends on the concentration of allergen recognized by receptor-bound IgE. Low-affinity IgG receptors (FcγRIIA/B) generate inhibition signals when coengaged with FcεRI by allergen-antibody immune complexes. Commensal and probiotic bacteria, such as Lactobacillus paracasei, generate inhibition signals through still unclear mechanisms.

Objective

We sought to investigate whether mechanisms that control, both positively and negatively, basophil activation, which were unraveled and studied in basophils from healthy donors, are functional in allergic patients.

Methods

FcεRI and FcγRIIA/B expression, FcεRI-dependent activation, FcεRI-dependent inhibition, and FcγRIIB-dependent inhibition were examined in blood basophils incubated overnight with or without L paracasei and challenged under 10 experimental conditions. Basophils from healthy donors were compared with basophils from patients who consulted an allergology outpatient clinic over a period of 3 months with respiratory allergy, anaphylaxis antecedents, chronic urticaria, and/or atopic dermatitis.

Results

Patients' basophils expressed neither more FcεRI nor less FcγRIIB than basophils from healthy donors. They were neither hyperreactive to positive regulation nor hyporeactive to negative regulation, irrespective of the receptors or mechanisms involved and the allergic manifestations of the patients.

Conclusion

Regulatory mechanisms that control basophil activation are fully functional in allergic patients. Intrinsic defects in these mechanisms do not explain allergic manifestations. Based on these mechanisms, immune checkpoint modifiers can be developed as novel therapeutic tools for allergy.

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