CP therapy for severe COVID-19
COVID-19 continues to spread worldwide with rising positive cases and deaths. Researchers are on the race to develop antidotes for the SARS-COV-2 virus. One of the most mooted treatments that is in focus right now is convalescent plasma (CP) therapy. Researchers found that CP therapy was well tolerated and could potentially improve the clinical outcomes through neutralising viraemia in severe COVID-19 cases.
Plasma therapy for COVID-19 consists of the idea of using plasma from a person who has recovered from COVID-19 to transfuse into a patient who is currently having the infection. Nobel prize recipient German physiologist Emil Adolf von Behring is considered the inventor of plasma therapy who was the first to use plasma to treat diphtheria.
Plasma is the pale yellowish liquid part that consists of about 55% of the body's total blood volume and carries minerals, proteins, nutrients and hormones to the different parts of the body. It maintains blood pressure, electrolyte and pH balance, protein supply, blood clotting and immunity system.
Plasma contains antibodies that are highly specific in action and these antibodies are formed when we get infected by any antigen or foreign particles. The 'B' cell of our immune system produces vast quantities of antibodies. It specifically focuses on transferring antibodies from a donor who has antibodies against COVID-19 to the recipient via the plasma. The World Health Organisation (WHO) provides guidelines on the appropriate use of plasma from recovered patients and this therapy has been trialed in previous coronavirus and Ebola outbreaks in 2013-2016. Like many countries, Bangladesh is also pitching towards plasma therapy as an effective mode of treatment.
Plasma donation is similar to blood donation but due to complexity, it takes more time than blood donation as the donor's blood goes through a special machine for extracting the plasma from the rest of the blood. The remaining components of the blood are returned to the donor's body. It is possible to donate plasma 2-3 times a week.
According to WHO, collected plasma should be transfused in the patient's body within 8 hours or should be immediately made frozen at a specific temperature in blood bank refrigerators for up to 40 days and at or below -180C for up to 12 months. Although, the physician does not recommend it because storing the plasma cause the antibodies to be less effective.
However, the pre-formed antibodies can block the patient's body's immune system to respond or grow. Receiving plasma from another person is risky for transmission of blood-borne infection, to minimise the risk screening the donor plasma to find out compatibility is mandatory. About 60 clinical trials are ongoing worldwide on the effect of plasma in COVID-19 and according to research published in the American Journal of Pathology, the administration of convalescent plasma is a safe treatment option for those with severe COVID-19 disease.
It is safe to be prudently hopeful about convalescent plasma therapy for treating severe COVID-19.
The author is an undergraduate student at the Department of Pharmacy, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, Bangladesh.
E-mail: iffat.phr@yahoo.com
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