Question 1

Why do Rh-negative but not Rh-positive mothers sometimes have babies with hemolytic disease of the newborn?

Accepted Answer

Rh-negative mothers can develop antibodies against Rh-positive fetal blood cells if their immune system is primed by exposure to Rh-positive blood, such as during a previous pregnancy or transfusion. This can occur even if the current baby is Rh-negative, as the mother's immune system may have already been sensitized. Rh-positive mothers do not develop these antibodies since they have the Rh antigen on their own red blood cells.

Question 2

MHC plays a pivotal role in transplant rejection.

Accepted Answer

MHC (Major histocompatibility complex) molecules play a critical role in the recognition of cells as self or non-self by the immune system. When a transplant is performed, the recipient's immune system recognizes the transplanted cells as foreign and attacks them, causing transplant rejection. The MHC molecules on the cells of the transplant are the primary molecular target for the immune system in recognizing the foreign cells, leading to transplant rejection.

Question 3

What is NOT a reason that the kidneys are particularly prone to damage caused by immune complexes?

Accepted Answer

Kidney blood vessel wall cells do not have specific receptors for antibodies to cause them to "soak up" antibodies or immune complexes from the bloodstream. This explanation is incorrect regarding the mechanism of kidney damage by immune complexes.

Question 4

Multiple myeloma is a plasma cell tumor in which a clone of malignant plasma cells produces large amounts of immunoglobulin. With all this excess immunoglobulin, how can a person with multiple myeloma be immunodeficient?

Accepted Answer

The excess immunoglobulin produced by the malignant plasma cells in multiple myeloma is most likely specific to one antigen, which limits the ability to respond to the diversity of antigens encountered. Additionally, the multiplication of the malignant plasma cells may crowd out normal production of other immune cells required for protective responses. Therefore, both A and B are correct.

Question 5

If a patient received a kidney transplant that was matched well across each of the major histocompatibility complex (MHC) molecules, but they stopped taking their anti-rejection drugs, what would happen and why?

Accepted Answer

Even with a well-matched kidney transplant, the recipient's immune system can still recognize the graft as foreign due to minor histocompatibility antigens and other proteins that cannot be perfectly matched between individuals. This recognition can lead to a gradual rejection process, necessitating the continued use of anti-rejection drugs to suppress the immune response and maintain the health of the transplanted organ.

Question 6

A lack of T cells makes one more vulnerable to intracellular parasites.

Accepted Answer

T cells are a type of white blood cell that play a key role in the immune response to intracellular parasites, such as viruses and some bacteria. Without sufficient T cells, the body may struggle to effectively fight off these types of infections.

Question 7

In the tuberculin skin test, what would be the most likely reason why a positive test would NOT necessarily indicate an infection in progress in a patient in the United States?

Accepted Answer

The TB skin test measures the presence of memory T cells that are formed during an active infection or remnants of a prior infection that may be cleared. Even if the patient is cleared of the infection, the memory of the immune response can still cause a positive test. Therefore, a positive skin test does not necessarily indicate an infection in progress.

Question 8

What might be an advantage to using an individual's own stem cells instead of pancreatic cell allografts to treat Type I diabetes?

Accepted Answer

Using an individual's own stem cells would be considered an autograft, eliminating the need for HLA/MHC matching and long-term anti-rejection drugs. The other options are not accurate.

Quiz 17: Immunologic Disorders