Anti-heparin/PF4 complexes by ELISA in patients with disseminated intravascular coagulation

Heparin-induced thrombocytopenia (HIT) is known to complicate disseminated intravascular coagulation (DIC), but rarely to be complicated by DIC. We measured the titers of anti-PF4/hepatin complex antibodies by ELISA (HIT-Elisa) and examined 4 parameters of coagulation and fibrinolysis [D-dimer, thrombin/antithrombin complex (TAT), plasmin/alpha2-plasmin inhibitor complex (PIC), and antithrombin levels] in 80 patients with DIC diagnosed by a DIC scoring system. Fourteen patients were HIT-Elisa-positive, 11 of whom received heparin. In 3 of these 11 patients, platelet counts were < or =10 x 10(9)/l and/or reduced by more than 50% for 5-10 days after the heparin (2 patients treated with renal replacement therapy for chronic uremia and postoperative renal failure, and 1 with DIC from a solid tumor). The 3 patients had an optical density reading of >1.0 and a high level of IgG for HIT antibodies, and were thus considered to have DIC complicated with HIT (DIC-HIT). The other 8 patients had optical density readings of 0.4-1.0, and it was unclear whether their thrombocytopenia was caused by HIT alone or by sustained DIC. There were no significant differences in platelet counts and the 4 parameters of coagulation and fibrinolysis between the patients with DIC-HIT and DIC patients with a weakly positive result (0.4-1.0). No differences were observed in platelet counts, or levels of D-dimer and antithrombin between HIT-Elisa-positive and -negative DIC patients. However, the HIT-Elisa-negative patients showed significantly higher levels of TAT and PIC, presumably reflecting DIC-related hypercoagulability. In conclusion, DIC patients treated with heparin occasionally showed HIT antibody seroconversion and developed HIT. HIT-Elisa could assist in the diagnosis of HIT.