The exposure of autoantigens by microparticles underlies the formation of potent inflammatory components: the microparticle-associated immune complexes.
Bottom Line: Rather, mpICs display autoantigens vimentin and fibrinogen, and recognition of these targets by anti-citrullinated peptide antibodies contributes to the production of mpICs.Functionally, platelet mpICs are highly pro-inflammatory, eliciting leukotriene production by neutrophils.Taken together, our data suggest a unique role for platelet MPs as autoantigen-expressing elements capable of perpetuating formation of inflammatory ICs.
Affiliation: Faculté de Médecine de l'Université Laval, Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Québec, Québec, Canada.Show MeSH
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Mentions: Having visualized mpICs, we employed hs-FCM to analyse them (Fig 3A). We measure 39,400 ± 9400 mpICs/µl in RA SF (Fig 3B). The quantification of the ICs in these same fluids (Supporting Information Fig S1) reveals that the majority (62 ± 7%) of the detectable ICs are in fact mpICs (Fig 3C). These observations provide an explanation for the presence of two subpopulations of MPs evident in RA SF. Specifically larger particles (from ∼700 to 3000 nm; upper inset in Fig 3A) contain mpICs. Conversely, the MPs not associated with IgG are characterized by smaller dimensions (100–300 nm; lower inset in Fig 3A) and represent the majority of the total Annexin-V+ MPs (93% ± 1.4; Supporting Information Fig S2). Interestingly, although MPs and IgG are both present in PA SF, only 2000 ± 900 mpICs/µl could be detected (Fig 3B and D).
Affiliation: Faculté de Médecine de l'Université Laval, Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Québec, Québec, Canada.