Functional expression of IgA receptor FcalphaRI on human platelets

J Leukoc Biol. 2008 Dec;84(6):1492-500. doi: 10.1189/jlb.0508327. Epub 2008 Sep 10.


FcalphaRI (CD89) is a human IgA FcR expressed on cells of myeloid lineage such as neutrophils, monocytes, tissue macrophages, eosinophils, and subpopulations of dendritic cells. FcalphaRI mediates cell activation through Src family kinases and downstream tyrosine-based phosphorylation pathways. However, the role of IgA and the expression and role of its cognate receptor FcalphaRI (CD89) in platelet activation are undefined. In the current study, we demonstrate that human platelets express FcalphaRI mRNAs and proteins. Furthermore, we show that the platelet FcalphaRI is associated with the FcR gamma-chain, and cross-linking of FcalphaRI leads to Syk phosphorylation. Clustering of FcalphaRI induces pre-mRNA splicing and protein production of tissue factor and IL-1beta, suggesting novel roles for human platelet FcalphaRI and serum IgA in thrombosis and inflammation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Antigens, CD / genetics*
  • Antigens, CD / metabolism
  • Blood Platelets / metabolism*
  • Cross-Linking Reagents
  • Flow Cytometry
  • Humans
  • Immunoblotting
  • Immunoglobulin A / immunology*
  • Immunoglobulin A / metabolism
  • Immunoprecipitation
  • Interleukin-1beta / genetics
  • Interleukin-1beta / metabolism
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Phosphorylation
  • Platelet Activation
  • Protein-Tyrosine Kinases / metabolism*
  • RNA Precursors / genetics
  • RNA Splicing / genetics*
  • RNA, Messenger / metabolism
  • Receptors, Fc / genetics*
  • Receptors, Fc / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Syk Kinase
  • Thromboplastin / genetics
  • Thromboplastin / metabolism


  • Antigens, CD
  • Cross-Linking Reagents
  • Fc(alpha) receptor
  • Immunoglobulin A
  • Interleukin-1beta
  • Intracellular Signaling Peptides and Proteins
  • RNA Precursors
  • RNA, Messenger
  • Receptors, Fc
  • Thromboplastin
  • Protein-Tyrosine Kinases
  • SYK protein, human
  • Syk Kinase