Scientists at McMaster University have discovered a new blood-clotting disorder that could change how doctors diagnose and treat patients with unexplained and persistent blood clots.

Their findings, published on February 12, 2025, in The New England Journal of Medicine, shed light on why some people continue to develop dangerous blood clots even when they are on full-dose blood thinners.

A Mysterious Clotting Condition

Blood clots are a serious medical concern, especially when they occur unexpectedly or don’t respond to treatment. Typically, blood thinners help prevent and break down clots, but some patients continue to experience clotting despite being on medication. This new study explains why.

The researchers found that some patients develop a rare immune response that produces harmful antibodies similar to those seen in Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT), a severe clotting disorder linked to certain COVID-19 vaccines that are no longer in use.

However, unlike VITT, these patients had no known triggers like prior vaccination or heparin exposure (a common blood thinner).

The scientists named this newly identified disorder VITT-like monoclonal gammopathy of thrombotic significance (MGTS). It is caused by monoclonal proteins (M proteins), which are typically linked to plasma cell disorders. These proteins act like the harmful antibodies in VITT, leading to abnormal blood clotting that persists over time.

How the Study Was Conducted

To investigate this condition, the researchers at the McMaster Platelet Immunology Laboratory conducted specialized tests on blood samples from patients who had unusual blood clotting despite being on blood thinners. They studied five patients from Canada, New Zealand, France, Spain, and Germany.

A key finding was that the harmful antibodies remained in these patients’ blood for over a year—an unusual pattern for most clotting-related antibodies. This persistence suggested an ongoing disease process rather than a temporary immune reaction.

Dr. Theodore Warkentin, a leading researcher on the study, emphasized the importance of recognizing this disorder early. “By understanding how to diagnose VITT-like MGTS, we can develop more effective treatment strategies that go beyond traditional anticoagulation,” he explained.

Potential New Treatments

One of the most remarkable discoveries was that standard blood thinners were not effective for these patients. Instead, they responded better to unusual treatments, including:

• High-dose intravenous immunoglobulin (IVIG) – a treatment that modifies the immune system.
• Bruton tyrosine kinase inhibitors (ibrutinib) – a drug usually used for blood cancers.
• Plasma cell-targeted myeloma therapy – a treatment designed for multiple myeloma, a type of blood cancer.

These alternative therapies could be life-saving for patients with this condition, as they address the underlying immune problem rather than just thinning the blood.

Implications for the Future

This discovery could change how doctors evaluate and treat patients with unusual or stubborn blood clots. Instead of only using blood thinners, doctors may need to test for VITT-like antibodies and M proteins in patients who continue to experience clotting. Identifying MGTS early could lead to more effective treatments and better outcomes.

Dr. Ishac Nazy, co-lead author of the study, highlighted how this research bridges laboratory science with real-world patient care. “This approach enables precise patient diagnosis and informs timely treatment strategies, even for previously unidentified diseases,” he said.

What’s Next?

The research team is continuing to study this condition to understand its full impact and refine treatment options. More research will help determine how common this disorder is and how best to treat it.

For now, this study provides critical insight into why some people develop unexplained blood clots and how they might be treated more effectively in the future. It marks an important step in improving care for patients with clotting disorders that don’t respond to standard treatments.

The research findings can be found in the New England Journal of Medicine.

Copyright © 2025 Knowridge Science Report. All rights reserved.