Increased expression levels of CD300c on basophils from allergic individuals

• Published in: The World Allergy Organization journal Vol. 12; no. 9; p. 100060
• Main Authors: Vitallé, Joana, Terrén, Iñigo, Orrantia, Ane, Segurola, Aritza, Seras, Yolanda, Gamboa, Pedro M., Borrego, Francisco, Zenarruzabeitia, Olatz
• Format: Journal Article
• Language: English
• Published: Milwaukee Elsevier BV 01.09.2019; World Allergy Organization
• Subjects: Allergens; Allergies; Asthma; Biobanks; Conflicts of interest; Cytokines; Food allergies; Kinases; Rhinitis; Seasons
• ISSN: 1939-4551; 1939-4551
• DOI: 10.1016/j.waojou.2019.100060

Clinical responses have been observed after the administration of omalizumab, a humanized anti-IgE antibody, to patients with food allergy, which correlated with the suppression of degranulation of basophils.1,2 These results indicate that actions aimed to blocking or modulating the IgE/FcεRI axis represent a promising strategy for the treatment of allergy and anaphylaxis. [...]in order to develop new immunomodulatory therapies, it is very important to characterize cell surface receptors capable of modulating IgE-mediated activation threshold in basophils and mast cells.3 The human CD300 family of receptors consists of 8 receptors expressed in both myeloid and lymphoid lineages.4 It has been recently demonstrated that the phosphatidylserine and phosphatidylethanolamine binding CD300c receptor acts as a co-stimulatory molecule during basophil activation through the IgE/FcεRI axis. CD300c cross-linking significantly augmented IgE-mediated basophils degranulation and cytokine production in a process involving increased calcium mobilization and phosphorylation of signaling intermediates such as protein tyrosine kinase (Syk) and extracellular signal–regulated kinases (ERK). [...]it was observed that basal expression levels of CD300c on basophils from IgE-dependent cow's milk allergic children are higher than those from healthy control children, suggesting that CD300c could be used as a biomarker in the diagnosis of the IgE-dependent allergic pathology.5 In order to further assess the clinical relevance of those findings, we have studied the expression of CD300c on basophils from patients with two IgE-dependent allergies. [...]we analyzed the expression of CD63, a basophil activation marker which is rapidly mobilized to the cell surface by polyclonal anti-IgE and allergens, as well as other degranulation stimuli.6 In agreement with previous publications,7 we observed that subjects with dust mites and/or grass pollen allergy show a significant increase in the median fluorescence intensity (MFI) of CD63 compared with basophils from non-allergic subjects, indicating that they are activated in vivo (Fig. 1A and online supplementary Figure S2). Furthermore, considering that CD300c is capable of modulating the threshold of IgE-mediated activation in human basophils,5 we believe that, as previously demonstrated,5 an increased expression of CD300c decreases the IgE-dependent activation threshold of basophils in allergic individuals.Conflict of interests The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.Consent for publication and ethics approval Blood samples from healthy donors and allergic patients were collected through the Basque Biobank (http://www.biobancovasco.org).