Disruption of PF4/H multimolecular complex formation with a minimally anticoagulant heparin (ODSH).
Recent studies have shown that ultra-large complexes (ULCs) of platelet factor 4 (PF4) and heparin (H) play an essential role in the pathogenesis of heparin-induced thrombocytopenia (HIT), an immune-mediated disorder caused by PF4/H antibodies. Because antigenic PF4/H ULCs assemble through non-specific electrostatic interactions, we reasoned that disruption of charge-based interactions can modulate the immune response to antigen. We tested a minimally anticoagulant compound (2-O, 3-O desulfated heparin, ODSH) with preserved charge to disrupt PF4/H complex formation and immunogenicity. We show that ODSH disrupts complexes when added to pre-formed PF4/H ULCs and prevents ULC formation when incubated simultaneously with PF4 and UFH. In other studies, we show that excess ODSH reduces HIT antibody (Ab) binding in immunoassays and that PF4/ODSH complexes do not cross-react with HIT Abs. When ODSH and unfractionated heparin (UFH) are mixed at equimolar concentrations, we show that there is a negligible effect on amount of protamine required for heparin neutralisation and reduced immunogenicity of PF4/UFH in the presence of ODSH. Taken together, these studies suggest that ODSH can be used concurrently with UFH to disrupt PF4/H charge interactions and provides a novel strategy to reduce antibody mediated complications in HIT.
Division of Hematology, Duke University Medical Center, Durham, North Carolina, USA.
M V
MV
Joglekar
P M
PM
Quintana Diez
S
S
Marcus
R
R
Qi
B
B
Espinasse
M R
MR
Wiesner
E
E
Pempe
J
J
Liu
D M
DM
Monroe
G M
GM
Arepally
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D001665:Binding Sites; D001703:Biophysics / Q000379:methods; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D006493:Heparin / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007700:Kinetics; D010978:Platelet Factor 4 / Q000378:metabolism*; D011479:Protamines / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism; D013921:Thrombocytopenia / Q000378:metabolism
D000925:Anticoagulants; C520325:N-desulfated,2-O,3-O-desulfated heparin; D011479:Protamines; D010978:Platelet Factor 4; D006493:Heparin; D013917:Thrombin