Understanding Blood Plasma And Its Components

Plasma, also known as blood plasma, is the liquid and the main component of blood. It is derived when all the cells, namely, red blood cells (RBCs), white blood cells (WBCs), and platelets are separated from whole blood. 

Plasma contains 90% water and the remaining 10% is made up of ions, proteins, hormones, enzymes, salts, and antibodies (specifically known as immunoglobulins).

Immunoglobulins are proteins produced by plasma cells, in response to foreign substances (antigens) like harmful viruses, bacteria, and microorganisms, and are an important part of your body’s immune system (key processes that defend your body against foreign invaders). 

The two main types of immunoglobulins are:

  • Immunoglobulin M (IgM) – These antibodies are produced as your body's first response to new infection or to a new antigen that provides short-term protection. IgM is produced for several weeks and starts to decline as another immunoglobulin (IgG) production begins.

  • Immunoglobulin G (IgG) – Specific IgG antibodies are produced during the initial stages of an infection, which rises for a few weeks and then decreases and stabilizes.
    IgG antibodies provide long-term protection by retaining the memory of the antigen that stimulated its production. When your body is exposed to the same antigen in the future again, your immune system has enough IgG antibodies to fight the re-infection. 

The IgG and the IgM antibodies present in the plasma, make the plasma a key component of the blood and your immune system.

The Current Rush For Plasma Therapy For Treating COVID-19

Doctors and researchers across the globe and in India, are urging fully recovered individuals from the COVID-19 infection, to come forward and donate their plasma.

Although the application of Plasma Therapy, also known as Convalescent Plasma Treatment (CPT), for COVID-19 patients has been under study, since the outbreak of the pandemic, experts believe there is still a lot of hesitancy among the public, when it comes to plasma donation. 

The lack of awareness about the use of plasma therapy in the treatment of severe symptoms and complications of COVID-19, clearly explains the shortage of blood plasma that India is facing during the ongoing second wave of COVID-19. 

Here’s an attempt to shed some light on plasma therapy for COVID-19 by answering a few of the most commonly asked questions.

Convalescent Plasma Therapy for COVID-19: Frequently Asked Questions

1. What is convalescent plasma therapy?

Convalescent refers to a person who is recovering or getting better after a serious illness or disease. Plasma is the yellowish, liquid part of the blood that contains antibodies.

CPT is a medical procedure in which the blood of a recovered individual (from any particular illness) is transfused into the body of a patient who is currently fighting the infection. This treatment uses the antibodies present in the blood of the recovered patient to aid or speed the recovery of another infected individual.

It is a popular method and has been used to treat various infectious diseases like H1N1 influenza, Ebola, SARS (Severe Acute Respiratory Syndrome), and MERS (Middle East Respiratory Syndrome). It is currently being employed in treating COVID-19 patients across the world.

2. Who can donate plasma for COVID-19?

Any individual, who has fully recovered from the COVID-19 infection and shows no symptoms for a minimum of 14 days after recovery, is a potential donor of plasma for COVID-19 treatment. 

Besides this, the other criteria for being a plasma donor include:

  • Having a proof of negative test report for COVID-19

  • Having high antibody levels in the plasma

  • Having compatible blood types or blood groups with that of a patient, if plasma is donated for a particular patient

  • Being in the age group between 18 to 45 years

Know that studies have suggested that patients who have fully recovered must donate their plasma shortly after the recovery, within 30 to 40 days, to successfully extract plasma that is highly rich in antibodies. 

Specialists are of the opinion that antibodies formed in recovered patients are most likely to wane off anywhere between 2 to 4 months after recovering from the infection.

3. How is plasma therapy given to COVID-19 patients?

The main steps involved in the administration of COVID-19 convalescent plasma therapy include:

  • The blood sample collected from a donor is screened and checked for:

    • The qualitative and quantitative (presence and the amount) parameters of virus-neutralizing antibodies against the SARS-CoV-2 virus (the virus responsible for causing the COVID-19 infection).

    • The presence of any existing harmful diseases or infections in the blood of the donor.

  • After the preliminary check is done, the donated blood is processed to separate the liquid plasma and antibodies from the blood cells.

  • The extracted plasma is stored and injected into infected COVID-19 patients, especially those who have severe symptoms or complications, to support their immune system and speed up the recovery. 

  • Once these infected patients have recovered, they too can be encouraged to donate their blood to extract the plasma, after ensuring they fulfill all the criteria of becoming a plasma donor.

4. Is plasma therapy being used during the current second wave of the COVID-19 infection?

As per reports, plasma therapy was administered during the first wave of the COVID-19 infection in 2020, with a success rate ranging from 60% to 90% across different states in the country. 

During the first wave, plasma therapy was given to patients only after 1 to 2 weeks when their symptoms were critical. 

Currently, experts recommend plasma therapy at an earlier stage of the infection, to decrease complications from the COVID-19 infection and to prevent deaths. Most of the infections of the second wave are severe, with patients having breathlessness and multiple-organ failure in the first few days. 

5. Are there any side effects of COVID-19 convalescent plasma therapy?

Although CPT has been proved to be safe and effective for most COVID-19 infected patients, it has to be carried out under medical supervision to mitigate the possible risks, which include:

  • The risk of transmitting the remnants of COVID-19 and other infections from a recovered person’s blood. Clinicians and doctors have to carefully assess the health of potential donors before collecting their blood samples for transfusion.

  • Infected individuals can be at risk of contracting the infection once again. There is not enough data to prove that re-infection will not occur after undergoing plasma therapy for COVID-19, and thus, more research is in progress.

It is said that the plasma collected from one person can help save the lives of 1 to 3 infected people. Plasma therapy is a safe procedure and people should be encouraged to come forward to donate their plasma. 

References:

1. U.S. Food and Drug Administration. 2021. Donate COVID-19 Plasma. [online] Available at: <https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/donate-covid-19-plasma> [Accessed 22 April 2021].

2. Sah.org.ar. 2021. [online] Available at: <http://www.sah.org.ar/pdf/covid-19/bibliografia_25961.pdf> [Accessed 22 April 2021].


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