During the gene therapy for Adenosine Deaminase (ADA) deficiency, the patient requires periodic infusion of genetically engineered lymphocytes. This is primarily because:

Step-by-step solution

In gene therapy for Adenosine Deaminase (ADA) deficiency, lymphocytes from the blood of the patient are extracted and grown in a culture outside the body. A functional ADA cDNA is introduced into these lymphocytes using a retroviral vector, and the cells are then returned to the patient. Since these genetically engineered lymphocytes are not immortal, they have a definite life span and eventually die. Therefore, the patient requires periodic infusions of such genetically engineered lymphocytes to maintain functiona