What Is Convalescent Plasma?
Convalescent plasma refers to blood plasma taken from someone who has recovered from COVID-19.
It can be used to treat another person who has an active infection.
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The higher the titeror presence of antibodiesthe more effective the plasma will be.
Davis treated the patient and reported his findings on the case in the journalCell Reports Medicine.
“The sickest people were generating the highest antibody levels.
After receiving initial treatments, she was discharged, but her condition continued to decline.
She was later readmitted to the hospital after she developed severepneumoniaand was still testing positive for the virus.
She was just generating virus for weeks, Davis says.
“And she had zero immunity against it and could not generate any antiviral immunity.
However, Davis patients B-cells were not up to the task.
She has got a problem where all of her B-cells are leukemic.
And so they are basically useless in the sense of defending her against infection.
Both of the individuals were tested at a local blood donation center.
The patient’s son-in-law turned out to be a compatible donor.
His donated convalescent plasma was then designated to go to the patient.
She received the infusion 33 days from the time that she first developed COVID-19 symptoms.
She promptly recovered, Davis says.
She had no fever within 48 hours.
She hadnt been eating and had lost about 15 pounds.
And she was craving brownies the next day.
Within three days of the infusion, SARS-CoV-2 was no longer detectable in her respiratory swabs.
And she was discharged on the fourth day.
[She] went home and has been doing great ever since, Davis says.
Her recovery is unusual because of the timeframe from symptom onset to infusion with convalescent plasma on day 33.
For example, an editorial published in theBritish Medical Journallast October stated that convalescent plasma is ineffective.
The FDAs EUA only allows for neutralizing antibody titers above 250 to be used.
Unfortunately, theres been a lot of plasma roulette, Davis says.
For Davis' study, researchers looked at titers from 64 remnant convalescent plasmas collected by two blood banks.
Of the remnant plasmas from one blood bank, they found that only 37% had titers above 250.
From the second blood bank, only 47% of the remnant plasmas made that cut.
Randall Davis, MD
The sickest people were generating the highest antibody levels.
In the study, researchers screened outpatient older adults.
And so if theres no virus, theres nothing for the antibodies to remove.
Cohn adds that an individual’s body eventually mounts its own immune response against SARS-CoV-2.
And once the inflammatory response has started cascading in the wrong direction, the antibodies arent going to help.
The interim guidelines will be available in the coming weeks.
“But we understand that since theres a need, we are developing interim recommendations.
They are a consensus of expert opinion, and there are about 20 or so people on the panel.
So your titer will probably be higher.
Experts say that plasma is especially needed if you were very sick.
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