BACKGROUND: CD16 was previously suggested to be a new marker of basophils that is subject to downregulation by FcεRI crosslinking. Certain compounds, including supraoptimal concentrations of the PKC inhibitors, bisindolylmaleimides, decouple the release of granules containing CD203c, CD63 and histamine, and may thus help to identify the mechanisms related to the CD16 externalization. OBJECTIVE: We hypothesized that CD16 is differentially expressed on the surface of basophils in patients with birch pollen or insect venom allergy and is subject to a regulation in response to allergens. We also employed CD203c and CD63 externalization decoupling by bisindolylmaleimides. METHODS: We performed a basophil activation test coupled with CD16 and histamine detection using cells isolated from patients with allergy to birch pollen or insect venom and negative controls. We employed two PKC inhibitors, bisindolylmaleimide II and Ro 31-8220 at their supraoptimal concentrations and, after difficulties reproducing previously published data, we analyzed the fluorescence of these inhibitors alone. We identified the CD16 isoforms by sequencing nested RT-PCR amplicons from flow cytometry sorted basophils and by cleaving the CD16b GPI anchor using a phospholipase C. RESULTS: We provide the first evidence that CD16a is expressed as a surface antigen on a small subpopulation of human basophils in patients with respiratory and insect venom allergy, and this antigen shows increased surface expression following allergen challenge or FcεRI crosslinking. We rejected the apparent decoupling of the surface expression of basophil activation markers following the administration of bisindolylmaleimides. CONCLUSIONS & CLINICAL RELEVANCE: The inclusion of αCD16 in negative selection cocktails selects against a subset of basophils that are CD16+ or CD16dim . Using CD16dim basophils and unstained leucocytes, we show that previous studies with supraoptimal concentrations of bisindolylmaleimides are likely flawed and are not associated with the differential expression of CD203c and CD63.

• MeSH
• alergie imunologie   patologie   MeSH
• antigeny CD63 imunologie   MeSH
• bazofily imunologie   patologie   MeSH
• dospělí MeSH
• fosfodiesterasy imunologie   MeSH
• GPI-vázané proteiny imunologie   MeSH
• indoly chemie   MeSH
• jedy členovců toxicita   MeSH
• kousnutí a bodnutí hmyzem imunologie   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• maleimidy chemie   MeSH
• pyrofosfatasy imunologie   MeSH
• receptory IgG imunologie   MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH