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Platelet-bound lipopolysaccharide enhances Fc receptor-mediated phagocytosis of IgG-opsonized platelets

Semple, John W. LU ; Aslam, Rukhsana ; Kim, Michael ; Speck, Edwin R. and Freedman, John (2007) In Blood 109(11). p.4803-4805
Abstract

Platelets express Toll-like receptor 4 (TLR4), and this has been shown to be responsible for the thrombocytopenia induced by lipopolysaccharide (LPS) administration in vivo. We studied the role of LPS in mediating platelet phagocytosis by THP-1 cells in vitro by flow cytometry. Opsonization of platelets with an IgG monoclonal (W6/32) antibody or with IgG autoantibody-positive sera from patients with autoimmune thrombocytopenia (AITP) significantly enhanced platelet phagocytosis (P < .001). In contrast, platelet phagocytosis did not occur if platelets were bound with only LPS. If, however, the LPS-bound platelets were also opsonized with either W6/32 or autoantibody-positive sera with titers greater than 4, there was a significant and... (More)

Platelets express Toll-like receptor 4 (TLR4), and this has been shown to be responsible for the thrombocytopenia induced by lipopolysaccharide (LPS) administration in vivo. We studied the role of LPS in mediating platelet phagocytosis by THP-1 cells in vitro by flow cytometry. Opsonization of platelets with an IgG monoclonal (W6/32) antibody or with IgG autoantibody-positive sera from patients with autoimmune thrombocytopenia (AITP) significantly enhanced platelet phagocytosis (P < .001). In contrast, platelet phagocytosis did not occur if platelets were bound with only LPS. If, however, the LPS-bound platelets were also opsonized with either W6/32 or autoantibody-positive sera with titers greater than 4, there was a significant and synergistic increase in Fc-dependent platelet phagocytosis (P < .001, P = .003, P = .048, and P = .047). These results suggest that, in the presence of antiplatelet antibodies, bacterial products can significantly alter platelet phagocytosis, and this may have relevance to how Gram-negative infections enhance platelet destruction in some patients with AITP.

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author
; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
in
Blood
volume
109
issue
11
pages
4803 - 4805
publisher
American Society of Hematology
external identifiers
  • pmid:17299089
  • scopus:34249310057
ISSN
0006-4971
DOI
10.1182/blood-2006-12-062695
language
English
LU publication?
no
id
7996c47d-3bef-4627-b2fb-543cd7bc8771
date added to LUP
2019-12-03 10:19:03
date last changed
2024-04-17 01:19:45
@article{7996c47d-3bef-4627-b2fb-543cd7bc8771,
  abstract     = {{<p>Platelets express Toll-like receptor 4 (TLR4), and this has been shown to be responsible for the thrombocytopenia induced by lipopolysaccharide (LPS) administration in vivo. We studied the role of LPS in mediating platelet phagocytosis by THP-1 cells in vitro by flow cytometry. Opsonization of platelets with an IgG monoclonal (W6/32) antibody or with IgG autoantibody-positive sera from patients with autoimmune thrombocytopenia (AITP) significantly enhanced platelet phagocytosis (P &lt; .001). In contrast, platelet phagocytosis did not occur if platelets were bound with only LPS. If, however, the LPS-bound platelets were also opsonized with either W6/32 or autoantibody-positive sera with titers greater than 4, there was a significant and synergistic increase in Fc-dependent platelet phagocytosis (P &lt; .001, P = .003, P = .048, and P = .047). These results suggest that, in the presence of antiplatelet antibodies, bacterial products can significantly alter platelet phagocytosis, and this may have relevance to how Gram-negative infections enhance platelet destruction in some patients with AITP.</p>}},
  author       = {{Semple, John W. and Aslam, Rukhsana and Kim, Michael and Speck, Edwin R. and Freedman, John}},
  issn         = {{0006-4971}},
  language     = {{eng}},
  month        = {{06}},
  number       = {{11}},
  pages        = {{4803--4805}},
  publisher    = {{American Society of Hematology}},
  series       = {{Blood}},
  title        = {{Platelet-bound lipopolysaccharide enhances Fc receptor-mediated phagocytosis of IgG-opsonized platelets}},
  url          = {{http://dx.doi.org/10.1182/blood-2006-12-062695}},
  doi          = {{10.1182/blood-2006-12-062695}},
  volume       = {{109}},
  year         = {{2007}},
}