Report of a Patient With Heparin-induced Thrombocytopenia Type II Associated With IgA Antibodies Only

Abstract

Heparin-induced thrombocytopenia type II (HIT II) is usually mediated by immunoglobulin G (IgG) antibodies that lead to platelet activation via the FcγIIA-receptor. Here we describe a patient who developed HIT II after aortocoronary bypass surgery. His serum contained an antibody that was detectable by the heparin-induced platelet activation assay (HIPA) and by the ID-HPF4 particle agglutination assay. The flow cytometric analysis showed that the antibody was of the IgA class.

Keywords

Heparin-induced thrombocytopenia Heparin/PF4-antibodies Immunoassay Platelet activation assay

References

Amiral J , Bridey F , Dreyfus M , et al. Platelet factor 4 complexed to heparin is the target for antibodies generated in heparin-induced thrombocytopenia. Thromb Haemost 1992;168:95-95.

Greinacher A . Antigen generation in heparin-associated thrombocytopenia: The nonimmunologic type and the immunologic type are closely linked in their pathogenesis. Semin Thromb Hemost 1995;21:106-106.

Chong BH , Grace CS , Rozenberg MC . Heparin-induced thrombocytopenia: Effect of heparin platelet antibody on platelets. Br J Haematol 1981;49:531-531.

Kelton JG , Sheridan D , Santos A , et al. Heparin-induced thrombocytopenia: Laboratory studies. Blood 1988; 72:925-925.

Amiral J , Wolf M , Fischer A , et al. Pathogenicity of IgA and/or IgM antibodies to heparin-PF4 complexes in patients with heparin-induced thrombocytopenia. Br J Haematol 1996;92:954-954.

Lindhoff-Last E , Gerdsen F , Ackermann H , et al. Determination of heparin-platelet factor 4-IgG antibodies improves diagnosis of heparin-induced thrombocytopenia. Br J Haematol 2001;113:886-886.

Untch B , Ahmad S , Jeske WP , et al. Prevalence, isotype, and functionality of antiheparin-platelet factor 4 antibodies in patients treated with heparin and clinically suspected for heparin-induced thrombocytopenia. The pathogenic role of IgG. Thromb Res 2002;105:117-117.

Greinacher A , Michels I , Kiefel V , et al. A rapid and sensitive test for diagnosing heparin-associated thrombocytopenia. Thromb Haemost 1991;66:734-734.

Meyer O , Salama A , Pittet N , et al. Rapid detection of heparin-induced platelet antibodies with particle gel immunoassay (ID-HPF4). Lancet 1999;354:1525-1525.

10.

Tazzari PL , Ricci F , Vitale M , et al. Heparin-induced thrombocytopenia: Detection of antiheparin/PF4 antibodies by means of heparin/PF4-coated beads and flow cytometry. Transfus Med 2002;12:193-193.

11.

Warkentin TE . Heparin-induced thrombocytopenia: Pathogenesis and management. Br J Haematol 2003;121:535-535.