Question

Why does a patient of ADA deficiency require a repeated infusion of genetically engineered lymphocytes? Suggest a possible permanent remedy.

Answer 1

Hint: it is an autosomal recessive metabolic disorder where the patient’s immune system weakens due to the absence of functional T-lymphocytes and is not able to fight infectious diseases.

Complete answer: Adenosine deaminase (ADA) deficiency is an autosomal recessive metabolic disorder which causes immunodeficiency.
1. Adenosine deaminase is an important factor that helps the function of a healthy immune system. The function of adenosine deaminase is to convert the molecules, which are toxic to the functional T-lymphocytes, to non-toxic molecules.
2. As long as adenosine deaminase is present in the body the harmful molecules are getting converted to non-harmful molecules which contributes to the proper healthy functioning of the immune system in identifying and fighting against infectious pathogens.
3. When there is a deficiency in the adenosine deaminase in the body there will be production and accumulation of toxic molecules which in turn destroys the functional T-lymphocytes.
4. A decrease in the number of lymphocytes in the body increases the chances of infectious diseases since there are no many lymphocytes to fight against infectious pathogens.
5. To overcome this decrease in lymphocytes due to the ADA deficiency, lymphocytes extracted from the patient’s bone marrow, functional ADA gene is inserted in these lymphocytes using retroviruses( a group of viruses used for gene cloning experiments in biotechnology) by the process of gene therapy, is repeatedly infused.
6. The possible permanent cure can only be done in the early embryonic stages. This is done by extracting the gene responsible for the production of ADA from the bone marrow cells and incorporating it into the cells in early embryonic stages.

Note: ADA deficiency in children can be cured by bone marrow transplant method. Another treatment method involves the enzyme replacement therapy, in which the functional ADA is injected into the patient, but this is not a permanent cure.