Platelet-bound lipopolysaccharide enhances Fc receptor-mediated phagocytosis of IgG-opsonized platelets
(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
- Semple, John W. LU ; Aslam, Rukhsana ; Kim, Michael ; Speck, Edwin R. and Freedman, John
- publishing date
- 2007-06-01
- 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 < .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.</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}}, }