Cup by cup, Emory University is collecting bags of liquid gold from the small club of American Ebola survivors.
They’re collecting the plasma as part of an experiment to see if transfusing blood from people who have lived through the horrific infection can save the newly ill. Many of the survivors have been given this so-called convalescent plasma, but no one knows if it’s actually helping.
The deep yellow serum being collected at Emory may hold the answer.
“The protocol allows us to collect and transfuse convalescent plasma from U.S. Ebola survivors,” says Dr. Anne Winkler, the Emory pathologist overseeing the study. “This is a completely voluntary process.”
The experiment officially started this month. Of the 10 Ebola patients treated in the U.S., Emory treated four in its biocontainment unit: medical missionaries Nancy Writebol and Dr. Kent Brantly, infected in Liberia; nurse Amber Vinson, infected while treating Ebola victim Thomas Eric Duncan at a Dallas hospital; and Dr. Ian Crozier, infected while working for the World Health Organization in Sierra Leone. And British nurse William Poole, another Ebola survivor, flew to Emory to donate plasma to Crozier.
Most of the patients treated in the U.S. have received plasma.
“No one’s really used it because everybody’s been so focused on vaccination."
Emory isn’t saying precisely whose blood it is banking, but patients can donate when they are there for follow-up visits. “In total, we have collected from six donors,” Winkler told NBC News.
So far, Emory has 18 units of plasma — the liquid part of the blood that has the red blood cells taken out. A unit’s usually roughly equivalent to a pint, and the average adult has about 10 units of blood.
Patients can donate plasma as often as every other day or so. The red blood cells are filtered out and reinfused into the donor. The remaining plasma contains the goodies — the antibodies and immune system cells that fight disease, as well as the clotting factors. (Blood serum has the clotting factors filtered out, as well.)
The idea of transfusing convalescent plasma isn’t new. It dates back to the 1800s. But it’s not clear at all if it helps against Ebola. “No one’s really used it because everybody’s been so focused on vaccination,” Winkler said.
And transfusing blood is messy because it can contain a range of other pathogens, from malaria parasites to hepatitis or the AIDS virus.
Doctors also have no idea how much to give, or whether one patient’s plasma may be more potent than another’s. “Some patients have received two units and some patients have received more,” Winkler said. “We don’t know the optimal dose.”
Emory’s using a device made by a company called Cerus to clean pathogens from the plasma. It’s just been approved in the U.S. and has been used in Europe.
The program is being run in parallel with a similar trial using plasma at the ELWA2 hospital outside Monrovia in Liberia. That trial will be able to include more people as Ebola’s still spreading in Liberia. Winkler is consulting to that study, also, and the two trials are sharing information.
The hope is to create a network of plasma collection centers across the U.S.
“If we can understand this for Ebola, we can understand it for other things."
It's a low-tech approach that is already being used in West Africa, where Ebola has infected more than 21,000 people and killed more than 8,400. But it makes doctors nervous to see widespread use of a therapy that may not even be helping.
Once enough plasma is on hand, researchers can study it to see if some patients produce more antibodies and immune cells that fight Ebola. And it might be possible to filter out the important cells and antibodies— a principle that’s produced experimental drugs such as ZMapp.
“If we can understand this for Ebola, we can understand it for other things,” says Dr. Colleen Kraft, one of the doctors on the Ebola team at Emory. “There’s a little bit of a dispute over what characterizes a good donor and a good antibody response.”
And is it possible to freeze-dry the plasma and reconstitute it? Would antibodies survive? That would make it much easier to distribute and stockpile plasma treatments.
“To do any of this, we need the plasma,” Winkler said.
To start with, the Emory team simply wants to be ready to help any future Ebola patients. “This really is just for therapeutic clinical use,” Kraft said. The last Ebola patient treated in the U.S., Sierra Leonean Dr. Martin Salia, died in November.
