Thanks to Lucie Lecomte for the link to this Vanguard report: How Ebola patients survived - Experts. Excerpt:
Following the recovery and discharge of the first Ebola Virus Disease (EVD) patient from the isolation centre at the Mainland Hospital in Lagos, facts have emerged as to how the patients are recovering.
Meanwhile, more patients undergoing medical treatment at the centre may be discharged this week, investigations revealed.
Experts, who commented on the development, said although 60-90 per cent of people infected with the Ebola virus die, some people do recover from infection.
“Doctors don’t know for certain who will survive Ebola, and there is no specific treatment or cure for the disease. But studies suggest there are some biological markers linked with a higher chance of surviving Ebola,” the experts say.
In the view of Derek Gatherer, a Bioinformatics researcher at Lancaster University in the United Kingdom, who studies viral genetics and evolution, “when a person becomes infected with Ebola, the virus depletes the body’s immune cells, which defend against infection.
“In particular, the Ebola virus depletes immune cells called CD4 and CD8 T lymphocytes, which are crucial to the function of the immune system”, Gatherer noted, arguing that “if a person’s immune system can stand up to this initial attack — meaning their immune cells are not as depleted in the first stages of infection — then they are more likely to survive the disease.
“The patients that survive it best are the ones who don’t get such a bad immune deficiency. But if the body is not able to fend off this attack, then the immune system becomes less able to regulate itself”, Gatherer said.
Another marker linked with people’s ability to survive Ebola is a gene called human leukocyte antigen-B, which makes a protein that is important in the immune system. A 2007 study found that people with certain versions of this gene, called B*07 and B*14, were more likely to survive Ebola, while people with other versions, called B*67 and B*15, were more likely to die.
Some people may be resistant to Ebola infection entirely, if they have a mutation in a gene called NPC1. Studies show that, when researchers take cells from people with the NPC1 mutation and try to infect them with Ebola in a laboratory dish, these cells are resistant to the virus.
Gatherer said in European populations, about 1 in 300 to 1 in 400 people has this mutation.
“But in some populations, this mutation is more common: in Nova Scotia, between 10 and 26 per cent of people have this mutation. But the frequency of this mutation in African populations is not known,” he said.