title: Basophil activation by mosquito extracts in patients with hypersensitivity to mosquito bites.
abstract: Hypersensitivity to mosquito bites (HMB) is a cutaneous disorder belonging to the group of Epstein-Barr virus (EBV)-associated T/natural killer (NK)-cell lymphoproliferative diseases, and is primarily mediated by EBV-infected NK cells. It is characterized by intense local skin reactions accompanied by general symptoms after mosquito bites, and infiltration of EBV-infected NK cells into the bite sites. However, the mechanisms underlying these reactions have not been fully examined. We recently described the activation of circulating basophils by mosquito extracts in vitro in a patient with HMB. To further investigate this finding, we studied four additional patients with HMB. All patients showed typical clinical features of HMB after mosquito bites and they had NK lymphocytosis and high peripheral blood EBV DNA loads. We found evidence of EBV infection in NK cells through in situ hybridization that detected EBV-encoded small RNA-1, and flow cytometry showed HLA-DR expression on almost all NK cells. Basophil activation tests with the extracts of epidemic mosquitoes Culex pipiens pallens and Aedes albopictus showed positive responses to one or both extracts in all samples from patients with HMB, suggesting the presence of mosquito antigen-specific IgE and its binding to basophils. In particular, the extract of Aedes albopictus was able to activate basophils in all available patient samples. These results indicate that basophils and/or mast cells activated by mosquito bites may be involved in initiation and development of severe skin reactions to mosquito bites in HMB.
authors.affiliation: Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Sakakibara
authors.affiliation: Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
authors.forename: Taizo
authors.initials: T
authors.lastname: Wada
authors.affiliation: Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Muraoka
authors.affiliation: Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Matsuda
authors.affiliation: Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Toma
authors.affiliation: Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yachie
mesh_terms: D000818:Animals; D015549:Basophil Degranulation Test; D001491:Basophils / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D009033:Culicidae / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D017403:In Situ Hybridization; D007299:Insect Bites and Stings / Q000276:immunology*; D008297:Male
keywords: Basophils; Epstein-Barr virus; IgE; hypersensitivity to mosquito bites; natural killer cells