Anti-PF4 mediated thrombocytopenia and thrombosis associated with acute cytomegalovirus infection displays both HIT-like and VITT-like characteristics.

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is one of several anti-platelet factor 4 (anti-PF4)-associated immune thrombocytopenia and thrombosis (PITT) syndromes. As well as following adenoviral vector vaccines, VITT has recently been described following acute adenovirus infection. We describe a patient with PITT following acute cytomegalovirus infection. The antibody clonotype and PF4 epitopes were distinct from those identified in VITT, and they were detectable as a paraprotein. PITT should be considered in all patients with thrombocytopenia and thrombosis, even without preceding vaccination or heparin, but who otherwise meet the VITT criteria defined by the British Society of Haematology Expert Panel.