IMMUNE AMNESIA POST MEASLES INFECTION AIM: IMMUNE PROFILING TO IDENTIFY LYMPHOPENIA IN PAEDIATRIC

ABSTRACT: IMMUNE AMNESIA POST MEASLES INFECTION AIM: IMMUNE PROFILING TO IDENTIFY LYMPHOPENIA IN PAEDIATRIC SUBJECTS (aged 0-5 yrs)

RELEVANCE Measles is caused by a virus in the paramyxovirus family. The virus is normally passed through direct contact and through the air. Measles is a human disease and is not known to occur in animals.The world has had a safe, proven measles vaccine for over 50 years. There is a political, practical and financial commitment to stamp out measles for good. Beyond responding to outbreaks, nations and the global health community must continue to invest in high quality national immunization programmes and disease surveillance.

Despite the presence of such robust prophylaxis, in 2018, there were more than 140 000 measles deaths globally, mostly among children under the age of five. Democratic Republic of Congo is suffering the world’s largest, most severe measles outbreak. The outbreak is compounded by low rates of immunization and high levels of malnutrition which push up the number of deaths. We need a robust plan to curb the world’s second- worst outbreak amid persistent insecurity. As of March 2, 2020, there have been 12 confirmed cases in 7 US jurisdictions including New York City, and the District of Columbia. (WHO, Measles: fighting a global resurgence, 2019; Immunization and Respiratory Diseases (NCIRD) Home | CDC, 2020)

PURPOSE

RESETTING THE IMMUNE DEFENCE —- potential for research In addition to being a serious disease in its own right, measles can also virtually wipe out a person’s immune system, leaving them with “immune amnesia” that makes them more susceptible to other diseases, according to the research.(Ducharme, 2020) Measles resets the immune system and it becomes more baby-like, limiting how well it can respond to new infections. Measles effect is so strong that it alters the immune apparatus - similar to being given powerful immunosuppressive drugs. (Petrova et al., 2019) The measles virus, however, seems to attack these memory cells, effectively leaving sufferers with an immune system that no longer remembers the pathogens to which it has already built up immunity, “immune amnesia” that makes patients more susceptible to other diseases, such as pneumonia. Blood sample testing of children who had recovered from measles show that they have the right number of white blood cells, crucial to mounting an immune response and fighting off disease. However, they have Lymphopenia of memory T and B cells (results to be confirmed by sequencing).

METHODS

LIFE CYCLE OF MEASLES VIRUS STAGES IN VIRUS LIFE CYCLE

1. The pathogen virus infects human epithelial cells, endothelial cells and macrophages.

2. The hemagglutinin (H) and Fusion (F) proteins mediate transmission of measles virus into host cells in the human respiratory tract.

3. Human host cell receptors CD46 and CD150

4. Once uncoated, the virus uses the host cell machinery (enzymes, transcription factors energy sources) to carry out viral mRNA synthesis, translation and manufacture of viral proteins.

5. Viral proteins assemble into helical capsids, which them leave the host cell by budding.

TRANSMISSION 1. The mode of transmission is through airborne droplets.