Common cold virus associated with potentially fatal blood clotting disorder: Study

Thrombocytes, or platelets are specialised cellular fragments that produce blood clots in the event of an injury. Platelet levels may decrease throughout the body as a result of viral infections, autoimmune diseases, and other disorders. This condition is known as thrombocytopenia.
After a robust clinical and research collaboration, Stephan Moll, MD, and Jacquelyn Baskin-Miller, MD, both in the UNC School of Medicine, have linked adenovirus infection with a rare blood clotting disorder. This is the first time the common respiratory virus, which causes mild cold-and flu-like symptoms, has been reported to be associated with blood clots and severe thrombocytopenia.
“This adenovirus-associated disorder is now one of four recognized anti-PF4 disorders,” said Moll, professor of medicine in the Department of Medicine’s Division of Hematology. “We hope that our findings will lead to earlier diagnosis, appropriate and optimized treatment, and better outcomes in patients who develop this life-threatening disorder.” Their new observation, which was published in the New England Journal of Medicine, sheds new light on the virus and its role in causing an anti-platelet factor 4 disorder.
Antibodies are large Y-shaped proteins that can stick to the surface of bacteria and other “foreign” substances, flagging them for destruction by the immune system or neutralizing the threat directly. In anti-PF4 disorders, the person’s immune system makes antibodies against platelet factor-4 (PF4), a protein released by platelets. When an antibody forms against PF4 and binds to it, it can trigger the activation and rapid removal of platelets in the bloodstream, leading to blood clotting and low platelets.
Sometimes, the formation of anti-PF4 antibodies is triggered by a patient’s exposure to heparin, called heparin-induced thrombocytopenia (HIT), and sometimes it occurs as an autoimmune condition without heparin exposure, which is referred to as “spontaneous HIT.”
In the last three years, thrombocytopenia has rarely occurred after injection with COVID-19 vaccines made with inactivated pieces of an adenoviral vector. These vaccines are different from those made in the United States, such as Moderna and Pfizer. The condition is referred to as vaccine-induced immune thrombotic thrombocytopenia (VITT).