Diseases amenable to treatment by gene therapy:
1. Must be relatively mild.
2. Must be caused by a defect in cells that are clinically accessible.
3. Must have other types of treatments available in case gene therapy fails.
4. Must lower the humoral and cell mediated immune responses

Which of the following is commonly used as a vector for introducing a DNA fragment in human lymphocytes? 
1. Λ phage
2. Ti plasmid
3. Retrovirus
4. pBR 322 

The first clinical gene therapy was given for treating:
1. Diabetes mellitus
2. Chicken pox
3. Rheumatoid arthritis
4. Adenosine deaminase deficiency

Which kind of therapy was given in 1990 to a four-year-old girl with adenosine deaminase (ADA) deficiency?
1. Radiation therapy
2. Gene therapy
3. Chemotherapy
4. Immunotherapy