Oct. 22, 2014 -- Three Americans who have survived Ebola may have one man to thank for their recoveries: Kent Brantly, MD.
Brantly, the first person to be treated for and recover from Ebola in the U.S., donated his blood -- and the potentially lifesaving proteins it contains -- for their treatment.
Ashoka Mukpo, a freelance cameraman infected as he covered the Ebola outbreak in West Africa for NBC, thanked Brantly in a statement Oct. 22 as Mukpo was released from an Omaha, NE, hospital.
Mukpo said Brantly’s “generous blood donation played a pivotal role in my recovery ... May his health flourish and his compassion be known to us all.”
Brantly, a doctor with the Samaritan’s Purse aid organization, has also given blood to Nina Pham, the Dallas nurse who caught Ebola as she treated a Liberian man, and Rick Sacra, MD, another Samaritan’s Purse doctor who was also infected in Liberia.
In each case, Brantly was paying it forward. Early in his treatment, he was the recipient of a blood donation from one of his young patients who survived the disease. And he’s said he would continue to give his blood as long as it’s needed and he’s an appropriate match.
Another survivor, British nurse William Pooley, reportedly has also donated blood in a bid to help victims recover.
New Hope in an Old Idea
The idea behind blood donations from disease survivors to those who are still sick is an old one. Doctors have been using so-called convalescent transfusions since at least the late 1800s to treat bacterial and viral infections after scientists realized that there was something in survivors’ blood that they could pass on to help others.
That special something turned out to be proteins called antibodies, which the immune system makes in response to an infection. Antibodies stick to viruses, and that prevents them from multiplying.
But sometimes, in a fast-moving infection, the body can’t make enough of its own antibodies to successfully fight off the disease. In those cases, getting a boost from someone else’s antibodies might help, at least in theory.
The approach was first tried to treat Ebola in 1976. A young woman infected with the virus in the Democratic Republic of Congo was given blood from a survivor of a closely related viral disease called Marburg. She had less bleeding than other Ebola patients, but died soon after her transfusion.
In 1995, doctors gave blood from recovered patients to eight people who were fighting Ebola in Congo. Seven of the eight survived.
But when scientists tried to repeat those results in monkeys -- giving blood from monkeys who had survived Ebola to animals newly infected with the virus -- all the monkeys who received the transfusions died.
“Is this proven therapy in Ebola virus? No,” says James Landmark, MD. Landmark is the director of Clinical Laboratory Support Services at the University of Nebraska Medical Center in Omaha, the hospital which has supervised two transfusions of Brantly’s blood.
“In my own experience, patients have benefited. ... I see no reason why it wouldn’t also work here. There’s just no data to say conclusively ... that it works,” he says.
That may soon change.
With no proven vaccine for Ebola, and experimental treatments in short supply, the World Health Organization recently prioritized research on blood transfusions as perhaps the best hope to curb the epidemic, which continues to outpace relief efforts in Sierra Leone, Guinea, and Liberia.
Many aren’t waiting for the evidence. According to news reports, survivors’ blood has become a hot commodity in Ebola-affected countries, where it is being sold on the black market.
But experts say that strategy is potentially dangerous.
Blood donations aren’t without risk. If a donor and recipient don’t have compatible blood types, it can cause a dangerous allergic reaction. Blood may also carry diseases like hepatitis and HIV, which is why it should be properly screened before it is shared.
Brantly’s Blood is an 'Investigational Drug'
Brantly has been able to give to so many people because he has a common blood type. He recently told ABC News that he’s A+.
There are four basic blood types, Landmark says. “Two of them, Os and As, are very common." They make up about 85% of blood types in whites.
Brantly wasn’t able to donate to Duncan, the Liberian man who died of Ebola in Dallas earlier this month, because Duncan had B+ blood. People with type B blood can't take donations of type A blood.
Brantly has been able to donate so often because he’s actually giving his plasma, rather than whole blood. Plasma is the pale yellow fluid in blood. It contains proteins, clotting factors, and antibodies.
The FDA recommends that people who give their whole blood wait at least 8 weeks between donations. That’s because whole blood contains iron-rich red blood cells, and it takes the body at least that long to make more.
Plasma is replenished more quickly, so it can be donated more frequently. Federal law allows donors to give up to a liter of plasma each week, Landmark says.
Brantly’s plasma may even contain some of the antibodies he received when he got the experimental drug ZMapp, though the levels of those antibodies would drop over time. By now, Landmark figures Brantly has less than one-eighth of the antibodies he would have received when he got ZMapp, if he has any left at all. But the natural antibodies Brantly's body made as he fought the virus will continue to be made.
Landmark says the CDC has been keeping tabs on the antibody levels in Brantly’s blood. “That’s important information for them,” he says. “His blood is considered to be an investigational drug.”