Heparin-induced thrombocytopenia: Further evidence for a unique immune response

Abstract

Cardiopulmonary bypass surgery (CPB) is associated with a high incidence of IgG Abs against platelet factor 4/heparin (PF4/H) complexes by day 6 after surgery. These Abs are associated with an immune-mediated adverse drug reaction, heparin-induced thrombocytopenia. Although the early onset of the anti-PF4/H IgG response is compatible with a secondary immune response, the rapid decline of Ab titers thereafter is not. To shed light on the origin of these Abs, in the present study, we prospectively compared the kinetics of these Abs with that of Abs against 2 recall Ags and to that of autoantibodies in 166 CPB patients over 4 months. Surgery induced strong inflammation, as shown by an increase in mean C-reactive protein levels. Consistent with previous studies, anti-PF4/H IgG optical density transiently increased between baseline and day 10 (P