Brad Forster, 60, has cold agglutinin disease (CAD). Here, he poses with his wife, Cori, who is vice president of the CAD Foundation, and their dogs at the family’s home in Victoria, British Columbia. Credit: Sanofi Genzyme

In 2013, Cori Forster’s husband, Brad—then a search and rescue specialist in the Canadian Coast Guard—was diagnosed with cold agglutinin disease (CAD), changing both of their lives in an instant.

“Unfortunately, his career had to come to an end as a result of this disease and exposure to the cold,” said Forster, speaking from her home in Victoria, British Columbia. Today, she is vice president of the Cold Agglutinin Disease Foundation (CADF).

Pat Watson of Atlanta, Georgia, some 2700 miles to the southeast, had never heard of CAD until her own diagnosis in 2014 at the age of 66.

Continue Reading

“Most people have symptoms years and years before they’re diagnosed. In my case, it was only 2 or 3 years,” said Watson, president of CADF. “I became weaker and weaker, and my primary care doctor sent me to a gastroenterologist, thinking it was bleeding ulcers. But it wasn’t. Finally, I was sent to a hematologist, and I was very lucky in that this hematologist had seen a CAD patient during his residency and recognized what it was.”

Brad Forster, 60, and Pat Watson, 74, are among 12,000 people in the US, Canada, and Europe with CAD, “a rare type of autoimmune hemolytic anemia in which the body’s immune system mistakenly attacks and destroys its own red blood cells,” according to the National Organization for Rare Diseases (NORD). That leads to anemia and other symptoms such as extreme fatigue, muscle weakness, trouble breathing, dizziness, rapid heartbeat and pulse, bluish skin, and pain­—particularly in areas exposed to cold temperatures.

An Unknown Etiology

As a result, CAD patients are more susceptible to blood clots, strokes, and heart issues than most other people. Surprisingly, despite the role of cold in triggering such attacks, it matters little where patients live, because CAD has been diagnosed in people all over the world.

“We have members in Florida, and their response to cold is based on the climate which they’re in,” Forster said. “Some people respond when it’s 75 degrees. [For] others could be 60, or 80.”

Apparently, there’s no genetic component to CAD, nor any geographic or ethnic risk factor. The average age of onset is 58, though the disease has been known to strike much younger and much older people as well.

“CAD can be caused by lymphoma and cold or flu viruses, but the cause in some cases is unknown,” said Forster, adding that people with CAD shed their red blood cells within 20 days, as compared with 120 days for healthy people. “The red blood cells don’t feed your body full of energy, and that’s what causes fatigue, difficulty breathing, and muscle weakness.”

In her husband’s case, it took 8 months to get a diagnosis, and it only came because he was seen at the Urgent Medical Assessment Center in Victoria.

“Many other patients, sometimes it’s a year before they have a diagnosis,” Forster said, adding that even if a doctor has heard of CAD, “there is very little information about the disease and how people respond to it. And there is no known cure.”

To address that information gap, in 2007 a group of individuals supported by NORD created a dedicated website for CAD patients as well as a private Facebook group called CADdy Chatter.

That group, which now has around 1300 members, evolved in 2019 into the nonprofit CAD Foundation. Headquartered in Cherry Hill, New Jersey, it consists entirely of volunteers and strives to advance knowledge about CAD for doctors, researchers, patients, and caregivers.

Therapeutic Possibilities

For now, the US Food and Drug Administration (FDA) has not approved any specific therapy to treat CAD. Rather, most patients try off-label rituximab, an intravenous infusion for treating non-Hodgkin lymphoma, rheumatoid arthritis, and other conditions and sold as Rituxan in the US market.

“Sometimes, that works for people very quickly and long‑term. In other cases, it only lasts for a few months, and then they do it again,” said Forster, adding that CAD patients also take folic acid “to help retain those red blood cells active and engaged for as long as they can.” 

Sanofi Genzyme is now conducting clinical trials of potential CAD drugs; so is Sweden’s Sobi, in collaboration with Apellis of Waltham, Massachusetts.

Watson, former regional vice president of a consumer packaging firm, said “Rituxan, for me, worked tremendously.”

Following a blood transfusion, she said, “I went in for a once-a-week infusion over 8 weeks, and that lasted a year and a half. Some people have to wait months for it to actually kick in, but in my case, I felt better after the first week. And the last time I took it was 3 years ago.”

Watson, who’s been president of the CAD Foundation since its founding last year, said her disease is triggered by a slow-growing lymphoma.

“It’s very annoying, running out of stamina before I finish what I need to finish,” she said. “You can’t escape it. And you have to always be careful about getting cold, because that’s one of the triggers. For some people, it’s devastating.”

That’s something the Forsters have to live with every day.

“My husband has an underlying condition brought on from CAD called urticaria, which is a rash that sits underneath his skin 24/7. That rash appears the moment he’s exposed to cold,” said Cori Forster, explaining that the cold could be triggered by air conditioning, opening the door of a freezer. or simply stepping out of a hot shower into a room that’s just a few degrees cooler.

“Brad’s throat becomes quite scratchy, and his voice changes if he has a cold drink, or a drink with ice,” she said. “We just hope that very soon, there’ll be some kind of cure or treatment for this.”