Overview

During the recent Covid-19 pandemic, one of the several forms of treatment that was explored by doctors is Convalescent Plasma Therapy or CPT for short. CPT is not a new concept and has been used to treat other viral infections in the past, but the scale of the Covid-19 pandemic, and the media attention it gathered, brought into focus all forms of treatment including CPT. In this article, we will understand more about this and plasma therapy in general.

What is plasma?

The blood is not a homogenous fluid as many would imagine. It’s a complex compound with various components:

• Red Blood corpuscles, also called erythrocytes: These are cells that are used by the body to transport oxygen to other cells of the body. Oxygenated blood is required by every cell of the body and is what sustains life. These are red in colour due to the haemoglobin and impart blood its characteristic scarlet colour. RBCs constitute 40-45% of the volume of blood.
• White blood corpuscles, also called leukocytes: These protect the body from infection and are an important member of the body’s immune system. WBCs constitute just 1% of the volume of blood.
• Platelets, also called thrombocytes: These are not real cells but small fragments of cells. They help the blood to clot when an injury happens thereby preventing blood-loss.
• Plasma: This is a straw-coloured, transparent liquid that forms nearly 55% of the volume of blood. It is made up of salts, water, proteins, lipid and glucose. It prevents infection, helps remove waste, distributes nutrients and helps the body recover from any injury.

What is Convalescent Plasma Therapy?

Convalescent is the term given to a person who is recovering or convalescing from an illness, injury, infection, surgery, procedure, therapy, treatment or any health situation. The recovery period is called convalescence. The plasma of such a person is rich in antibodies that were produced by the body, in order to fight the pathogen concerned (virus or bacteria).

Interestingly, these antibodies can be harvested from a convalescent’s plasma and injected into the blood of another person suffering from the same infection. The latter’s body may not be able to produce enough antibodies to fight the infection, due to various reasons. So, by harvesting antibodies from another person who has successfully fought the infection and injecting it here, this person’s immunity is boosted. This approach and procedure are what’s called Convalescent Plasma Therapy (CPT).

CPT was first used during the Spanish pandemic of influenza A pneumonia in 1918-1920. Thereafter it has been used to treat various viral infection outbreaks across the world.

Also Read: Convalescent Plasma Therapy: A possible cure for Covid-19?

How is CPT done?

Plasma has a very long shelf life of nearly 10 years if refrigerated and preserved in a sterile environment. This gives hope to patients and the medical fraternity, who require large quantities of convalescent plasma to treat viral outbreaks that occur all the time. Also, unlike red-blood-cells which require some time to regenerate after an instance of blood donation (so there must be a 1-month gap between 2 blood donations), plasma regenerates quickly from the food and water we consume. So, convalescents and healthy people can safely donate blood as often as twice a week.

During the procedure, the convalescent donates blood. The blood is then centrifuged after the addition of an anticoagulant to prevent clotting. The centrifuging helps separate plasma from the RBC, WBC and platelets. The plasma is collected separately while the other components are injected back into the donor. The procedure is 100% safe for the donor. During CPT, the bottle of plasma is hung upside down and the plasma is passed into the recipient’s blood, drop by drop, similar to any intravenous injection (or ‘drips’).

Who is eligible to donate plasma?

While plasma donations are safe for the donor, there are some restrictions, which means, not every convalescent can donate plasma. This is for the safety and health of the recipient.

• The donor must be between 18 to 60 years of age, as the immunity levels are better in this age-bracket. Hence the quality and quantity of antibodies are also optimum.
• The person should weigh around 50kgs. Again, overweight or underweight people may have known or unknown health conditions which increases the risk for recipients.
• The pulse rate should be normal, preferably between 50-100 and not show any irregularities as in conditions like arrhythmias, tachycardia or bradycardia.
• Body temperature, blood pressure and blood sugar should be normal. A diabetic or hypertensive convalescent is not generally preferred for CPT.
• The donor should not be suffering from any chronic or infectious disease presently. He/she should have recovered completely from the infection for which antibodies are being harvested.
• The donor should not have got a tattoo or piercing done in the last 6 months due to the risk of Hepatitis virus which may be dormant in his/her blood.
• The donor should have a haemoglobin level of 12.5 g/dL or above, not lesser.

Diseases treated by CPT and/or plasma therapy

Respiratory Viral Outbreaks

• SARS Cov-2, also called Covid-19, between 2020 and 2022
• Ebola virus in 2014, although this showed mixed results
• Middle-East Respiratory Syndrome (MERS) in 2012 and 2015
• SARS 1 in 2001

Other serious diseases

Measles, mumps, polio and HIV

Alpha-1 Proteinase Inhibitor therapies are used to treat:

Alpha-1 Antitrypsin Deficiency, or genetic emphysema, a hereditary disease which manifests as life-threatening liver disease in children as well as adults and lung disease in adults alone.

C1 Esterase Inhibitor therapies are used to treat:

Hereditary Angioedema, caused by a missing C1 esterase inhibitor protein (C1-INH). Patients suffer from edema or severe swelling which can become fatal if the airways become blocked.

Coagulation Factors are used to treat bleeding or blood-clotting disorders such as:

• Haemophilia A
• Haemophilia B
• Von-Willebrand Disease
• Antithrombin III Deficiency

Immune Globulins are used to treat auto-immune disorders such as:

• Primary Immunodeficiency Disease (PID), a genetic condition that impairs an individual’s immune system
• Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), or Guillain-Barre Syndrome. This affects the peripheral nervous system and causes nerves in the arms and legs to become weak, leading to paralysis.
• Idiopathic Thrombocytpenic Purpura (ITP), which results in reduced blood platelet levels essential for blood clotting.
• Kawasaki Disease, which affects children below 5 years of age, leading to heart disease, heart damage and death in rare cases.

Other applications of plasma-derived therapies

Plasma proteins are also used to treat patients recovering from burns, shock, trauma, major surgery, animal bites, RH incompatibility, hepatitis, paediatric HIV, liver conditions and organ transplant.

Side-effects

CPT is a popular form of treatment and offers hope to patients of several ailments or health conditions as listed above. For some recipients however, there is a small risk of:

• Allergic reactions or new allergies
• Lung damage and breathing issues
• Infections such as HIV, Hepatitis B or Hepatitis C
• Recurring infections
• Suppressed immune system leading to re-infections

Outlook

In-spite of the above risks, plasma therapies are very popular, and in countries like the US, healthy people and convalescents alike are encouraged to donate plasma as often as possible. It is even necessary, as large quantities of plasma are required to treat patients with the above conditions.

If you would like to donate plasma, get in touch with a reputed hospital in your vicinity. Remember, plasma can be stored for long and used whenever the need arises.

Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai, Hosur, Salem and Bengaluru, the hospital also renders adult and pediatric trauma care.

Chennai – 044 4000 6000 • Trichy – Cantonment – 0431 4077777 • Trichy – Heartcity – 0431 4003500 • Trichy – Tennur – 0431 4022555 • Hosur – 04344 272727 • Salem – 0427 2677777 • Tirunelveli – 0462 4006000 • Bengaluru – 080 6801 6801

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