Convalescent Plasma Therapy - A stoppage measure for COVID 19

This article talks about convalescent plasma therapy which is a hope for the patients of COVID 19. It discusses the process, challenges and limitations involved in convalescent plasma therapy.

What is Convalescent Plasma Therapy?

Why in news?

Components of Blood

Mechanism of Convalescent Plasma Therapy

Limitations of Convalescent Plasma Therapy

What is Convalescent Plasma Therapy?

Convalescent plasma therapy is a technique useful for treatment of infected patients. The whole concept is based on utilisation of adaptive immune system. Let us first understand above terminology. "Convalescent" means recovering from an illness or medical condition. "Plasma" is a yellowish component of blood carrying variety of ingredients like proteins, antibodies, blood clotting factors, hormones, vitamins etc. Thus, convalescent plasma therapy is a medical treatment involving use of plasma taken from those recovered from an infection. When a person is exposed to a foreign body called antigen, then the immune system of body becomes active and generate antibodies to fight against that foreign body. Antibodies are Y shaped proteins. They have antigen binding sites. Once antigens bind to the antibody, a chemical signal is generated to other cells like macrophages which attack antigens. In this therapy, antibodies collected from a recovered patient are transferred in to infected patients.

Why in news?

ICMR (Indian Council of Medical Research) has approved clinical trial of convalescent plasma therapy in relation to COVID 19. Approval has been given to states of Kerala, Delhi while Tamil Nadu has also asked for approval.

Components of Blood

Blood has three components:

Plasma

It makes up 55% of body's total blood volume. It is yellowish in colour. It carries cells and proteins throughout the body. The ingredients found in plasma are albumin,  globulins, prothrombin, fibrinogen, hormones, vitamins, sugar, amino acids, fatty acids, antibodies, uric acid etc.

RBCs 

Red blood corpuscles constitute 45% of total blood volume.

WBCs and platelets

White blood corpuscles and platelets constitute less than 1% of total blood volume.

Mechanism of Convalescent Plasma Therapy

The process of convalescent plasma therapy in treatment of COVID 19 is discussed here:

1. Approximately 800 ml of blood is collected from donors who have recovered from illness and are free of symptoms for at least 14 days.
2. Plasma is separated from blood by a process called "plasmapheresis".
3. It is tested to identify any other infection. If other infections like hepatitis, HIV etc. are present then such blood is rejected.
4. It is make sure through testing that enough antibodies are present to effectively treat or prevent COVID 19.
5. Plasma is infused in to recipient and response is observed.

Limitations of Convalescent Plasma Therapy

There are few limitation of this therapy also which are enumerated below:

1. This technique of convalescent plasma therapy needs resources like machines for plasmapheresis.
2. Patients need to be followed up.
3. They are need to be convinced for blood donation.
4. The donated blood must be free from other infections.
5. The most important point is narrow time window. It means that a recovered patient has enough antibodies only for a short duration. Collection of blood in that narrow time period is challenging.

See Other Posts: Ebola Virus Disease, Novel Corona Virus