title: Adhesive interaction between peripheral blood mononuclear cells and activated platelets in the presence of anti-human leukocyte antigen Class I alloantibody causes production of IL-1β and IL-8.
abstract: BACKGROUND
  Activated platelets form heterogeneous aggregates of platelets and monocytes, which are involved in a variety of inflammatory disorders. Some anti-human leukocyte antigen (HLA) Class I antibodies have been shown to activate platelets.
  
  
  METHODS
  Human leukocyte antigen-A2-positive or HLA-A2-negative platelets were incubated with HLA-A2-negative peripheral blood mononuclear cells (PBMNCs) in the presence of anti-HLA-A2 serum at 37°C. The binding of platelets to monocytes was analysed by flow cytometry. The levels of IL-1 β and IL-8 in the culture supernatant were determined by ELISA.
  
  
  RESULTS
  Anti-HLA-A2 serum increased the formation of aggregates between monocytes and HLA-A2-positive platelets, but not HLA-A2-negative platelets, in a dose-dependent manner. Antiserum also increased the number of platelets bound to monocytes in a time-dependent manner. The addition of anti-P-selectin glycoprotein ligand (PSGL-1) mAb almost completely inhibited the formation of platelet-monocyte aggregates as well as the number of platelets bound to monocytes. When HLA-A2-positive or HLA-A2-negative platelets were incubated with HLA-A2-negative PBMNCs in the presence of anti-HLA-A2, the level of IL-1β and IL-8 in the supernatant of coculture was significantly higher in HLA-A2-positive platelets than in HLA-A2-negative platelets. The addition of anti-PSGL-1 mAb partially but significantly inhibited the production of both IL-1β and IL-8.
  
  
  CONCLUSIONS
  The activation of platelets with anti-HLA Class I alloantibody caused the formation of platelet-monocyte aggregates, followed by the production of IL-1β and IL-8, in a cognate antigen-antibody manner. The adhesive interaction of P-selectin and PSGL-1 at least partially contributed to these phenomena.
authors.affiliation: Japanese Red Cross, Hokkaido Red Cross Blood Center, Sapporo, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Fujihara
authors.forename: H
authors.initials: H
authors.lastname: Azuma
authors.forename: S
authors.initials: S
authors.lastname: Wakamoto
authors.forename: S
authors.initials: S
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Kato
authors.forename: H
authors.initials: H
authors.lastname: Ikeda
mesh_terms: D058846:Antibodies, Monoclonal, Murine-Derived / Q000276:immunology / Q000494:pharmacology; D001792:Blood Platelets / Q000276:immunology / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D015789:HLA-A2 Antigen / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D053583:Interleukin-1beta / Q000096:biosynthesis* / Q000276:immunology; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000276:immunology; D007518:Isoantibodies / Q000276:immunology / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism; D010974:Platelet Aggregation
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; C508606:CXCL8 protein, human; D015789:HLA-A2 Antigen; C508585:IL1B protein, human; D053583:Interleukin-1beta; D016209:Interleukin-8; D007518:Isoantibodies; D008562:Membrane Glycoproteins; C084882:P-selectin ligand protein