65.In gene therapy of Adenosine Deaminase (ADA) deficiency the patient requires periodic infusion of genetically engineered Lymphocytes because: A. Gene isolated from marrow cells producing ADA is introduced into cells at embryonic stages B. Lymphocytes from patient’s blood are grown in culture, outside the body. C. Genetically engineered Lymphocytes are not immortal cells D. Retroviral vector is introduced into these Lymphocytes
Option C Adenosine deaminase deficiency is an autosomal recessive metabolic disorder that causes immunodeficiency. ADA is very crucial for the immune system to function. The patient lacks functional T-lymphocytes and fails to fight the infectious pathogens. Using gene therapy, lymphocytes are extracted from the patient's bone marrow and a normal functional gene for ADA is introduced into these Iymphocytes with the help of the retrovirus. The lymphocytes of bone marrow contain the functional ADA gene and reactivate the patient's immune system. In some children, ADA deficiency can be cured by bone marrow transplantation. In others, it can be treated by enzyme replacement therapy, in which functional ADA is given to the patient by injection. But the disease is not completely cured. Possible permanent therapy to be suggested is if the gene isolated from marrow cells producing ADA is introduced into the cells in early embryonic stages, then it could be a permanent cure.
