Explain this statement with "NO-BIO wordings but just simple english" Pls.
Lymphocytes are not immortal. Therefore, repeated infusion of genetically engineered lymphocytes is required.
NO LINKS. AND PROPER EXPLAINATION PLS.Of about 3 to 4 lines ONLY.

Lymphocytes are not immortal, i.e. they do not have the tendency to live forever. Thus, it is important to infuse the genetically engineered lymphocytes. This is done to treat the ADA deficiency by culturing the lymphocytes of patient in vitro and introducing the functional ADA cDNA into the cultured lymphocytes followed by reintroduction of the lymphocytes into the patient.