Isabella, a 6-year-old child who has been raised in a germ-free environment from birth, has one of the most severe examples of an abnormal immune system. Isabella also suffers from cancer caused by...

Isabella, a 6-year-old child who has been raised in a germ-free environment from birth, has one of the most severe examples of an abnormal immune system. Isabella also suffers from cancer caused by the Epstein-Barr virus. Relative to this case: (a) Why is Isabella’s brother chosen as the hematopoietic stem cell donor? (b) Why is her physician planning to use umbilical cord blood as a source of stem cells for transplant if her brother’s stem cells fail (what are the hoped-for results)? (c) Attempt to explain Isabella’s cancer. (d) What similarities and dissimilarities exist between Isabella’s illness and AIDS?

Caroline, a pregnant 29-year-old, has been HIV-positive for at least 10 years, dating back to when she was homeless and injecting heroin. While she currently has no symptoms of AIDS, she is taking several medications and is worried about the possibility that her baby might be infected. How do you think the HIV virus might be transferred from a mother to her offspring? Which of Caroline’s cells are infected by the virus and why is the viral attack on these cells so devastating? Why is Caroline taking medication even though she has no symptoms?