... thrombocytopenia during renal replacementtherapy in the intensive care unitAndrew DavenportRoyal Free and University College Medical School, UCL Centre for Nephrology, Hampstead Campus, Rowland ... factor 4 (PF4) and,although used as an anticoagulant, paradoxically causesplatelet activation. When patients are first exposed toheparins, therefore, typically there is a mild fall in the peripheral ... 1 mg PF4, then cross-linking of surface-bound PF4leads to conformational change and to the exposure of novelepitopes, with the potential to form pathogenic IgG1anti-bodies to the heparin/PF4...