Question: Consider the following statements:
(1) Convalescent-plasma therapy, the treatment aims at using the immune power gained by a recovered person to treat a sick person.
(2) This therapy is akin to passive immunization.
Choose the correct:
(a) Only(1)
(b) Only(2)
(c) Both (1) and (2)
(d) None of the above
Answer:(c)
Related facts:
- SreeChitraTirunal Institute for Medical Sciences and Technology (SCTIMST) an Institution of National Importance under the Department of Science and Technology has obtained a go-ahead for taking a bold step to provide innovative treatment to patients suffering from COVID-19 disease.
- Technically called “convalescent-plasma therapy”, the treatment aims at using the immune power gained by a recovered person to treat a sick person.
- Indian council for medical research (ICMR) the top authorising body in India has given approval to the SCTIMST for carrying out the novel treatment.
Convalescent-plasma therapy:
- When a pathogen like novel coronavirus infects, our immune systems produce antibodies.
- Like the police dogs, the antibodies span out to identify and mark the invading virus.
- White blood cells attach the identified intruders, and the body gets rid of the infection.
- The therapy, like blood transfusion, harvests the antibody from a recovered patient and ingest into a sick person.
- Helped by the antibody, the immune system mounts robust combat on the virus.
Antibodies:
- Antibodies are one of the front-line immune response to an infection by a microbe. They are a particular type of proteins secreted by immune cells called B lymphocytes when they encounter an invader, such as a novel coronavirus.
- The immune system designs antibodies that are highly specific to each invading pathogen. A particular antibody and its partner virus are made for each other.
Treatment procedure:
- Blood is drawn from a person who has recovered from COVID-19 sickness.
- The serum is separated and screened for virus-neutralizing antibodies.
- Convalescent serum, that is the blood serum obtained from one who has recovered from an infectious disease and especially rich in antibodies for that pathogen, is then administered to a COVID-19 patient.
- The sick acquires passive immunisation.
- Potential donor would be examined before the blood serum is extracted and given to a sick person.
- First, the swab test must be negative and the potential donor has to be declared as cured.
- Then the recovered person has to wait for two weeks.
- Or else the potential donor should be asymptomatic for at least 28 days.
- Either of the two is mandatory.
- Initially the treatment will be tried in a small number of patients. At present it is permitted as an experimental therapy for restricted use for severely affected patients only.
How is it different from vaccination?
- This therapy is akin to passive immunization.
- When a vaccine is administrated, the immune system produces the antibodies.
- Thus, in a later date, when the vaccinated person is infected by that pathogen, the immune system releases the antibodies and neutralise the infection.
- Vaccination provides lifelong immunity.
- In the case of passive antibody therapy, the effect lasts only up to the time the antibodies injected remain the bloodstream.
- The protection given is temporary.
- The mother transfers antibodies through breast milk to an infant before the child could build her own immunity.
History:
- Way back in 1890, Emil von Behring, a German physiologist, discovered that the serum obtained from a rabbit infected with diphtheria was effective in preventing the diphtheria infection. Behring was awarded the first-ever Nobel prize for medicine in 1901.
- Antibodies were not known at that time. Convalescent serum therapy was less effective and had substantial side effects.
- It took many years before the antibody fraction could be separated. Still, the unintended antibodies and impurities caused side effects.How long the antibodies will remain in the recipient?:
- After the antibody serum is given, it will stay on the recipient for at least three to four days
Challenges:
- This therapy is not simple to harness, primarily due to the difficulty of obtaining significant amounts of plasma from survivors. In diseases like COVID-19, where most of the victims are aged, suffering from other medical conditions such as hypertension, diabetes, and so on, not all recovered patients can volunteer to donate blood.
By-Achyutanand Pandey
Links:
https://pib.gov.in/PressReleseDetail.aspx?PRID=1613216