title: Overexpression of complement receptors and related antigens on the surface of bone marrow mast cells in patients with systemic mastocytosis.
abstract: Depending on their stage of maturation and other factors, mast cell (MC) subsets differ from each other in terms of the expression of complement-associated antigens. This study analysed the expression of various complement-related cell surface antigens (CD11b/CR3, CD11c/CR4, CD35/CR1, CD55/DAF, CD59/MIRL, CD88/C5aR) on bone marrow mast cells (BMMC) in patients suffering from systemic mastocytosis (SM), other haematological diseases and non-haematological disorders (control groups). Expression of complement-associated cell surface antigens was analysed by flow cytometry. There were clear immunophenotypic differences between BMMC obtained from patients with SM and those from the control subjects: the percentage of patients expressing surface CD11c, CD35 and CD88 was significantly higher in patients with SM (76%, 100%, 54%) than in the control subjects (58%, 11%, 18%) (P < 0.05). In addition, the levels of CD11c, CD35 and CD88 expressed per MC (sites per cell) were significantly higher (P < 0.05) in SM than in the control group. Expression of the complement regulatory molecules CD55 and CD59 was detected in BMMC in all patients analysed. However, the levels of CD59 per BMMC were higher in patients with SM as compared with the control subjects, which could help to explain the formation of BMMC aggregates in the former group of individuals. Together, our results showed that BMMC in systemic mastocytosis overexpressed the cell surface membrane receptors involved in binding of complement components and complement-mediated cell activation. Whether this pathological expression of complement receptors is of pathophysiological significance remains to be determined.
authors.affiliation: Mast Cell Unit, Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Núñez-López
authors.forename: Luis
authors.initials: L
authors.lastname: Escribano
authors.forename: Gerit-Holger
authors.initials: GH
authors.lastname: Schernthaner
authors.forename: Aránzazu
authors.initials: A
authors.lastname: Prados
authors.forename: Ramón
authors.initials: R
authors.lastname: Rodríguez-González
authors.forename: Beatriz
authors.initials: B
authors.lastname: Díaz-Agustín
authors.forename: Antonio
authors.initials: A
authors.lastname: López
authors.forename: Alexander
authors.initials: A
authors.lastname: Hauswirth
authors.forename: Peter
authors.initials: P
authors.lastname: Valent
authors.forename: Julia
authors.initials: J
authors.lastname: Almeida
authors.forename: Pilar
authors.initials: P
authors.lastname: Bravo
authors.forename: Alberto
authors.initials: A
authors.lastname: Orfao
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D001854:Bone Marrow Cells / Q000276:immunology*; D039521:CD11c Antigen / Q000032:analysis; D018958:CD55 Antigens / Q000032:analysis; D018957:CD59 Antigens / Q000032:analysis; D016022:Case-Control Studies; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008407:Mast Cells / Q000276:immunology*; D008415:Mastocytosis / Q000276:immunology*; D008875:Middle Aged; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000032:analysis* / Q000276:immunology; D017463:Receptors, Complement 3b / Q000032:analysis
chemical_list: D015703:Antigens, CD; D039521:CD11c Antigen; D018958:CD55 Antigens; D018957:CD59 Antigens; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D017463:Receptors, Complement 3b