Heparin‐associated thrombocytopenia in a patient treated with polysulphated chondroitin sulphate: evidence for immunological crossreactivity between heparin and polysulphated glycosaminoglycan

Heparin-associated thrombocytopenia (HAT) type II, a severe side effect of heparin therapy, is thought to be induced by an immunological mechanism. By crossreactivity studies we have demonstrated that sera of patients with HAT type II activate platelets in vitro not only after the addition of heparin but also after addition of a chemically polysulphated chondroitin-like substance, Arteparon, used for treatment of degenerative joint disease. In addition here, we describe a patient who developed deep venous thrombosis and pulmonary embolism following administration of Arteparon and typical HAT type II with thrombocytopenia, 36 h after the first administration of heparin. This patient had never received heparin, but had repeatedly been treated with Arteparon for degenerative joint disease. We conclude that this patient had been presensitized by Arteparon, as indicated by his clinical course. In vitro studies again confirm crossreactivity between heparin and Arteparon.