L6_Immunodeficiency & Infection

Question 1

What is the difference between primary and secondary immunodeficiency?

Answer 1

• primary = an inherited developmental or genetic defect affecting the immune system.
• secondary = the loss of the immune function that results from exposure to external agents.

Question 2

Define severe combined immunodeficiency (SCID).

Answer 2

• genetic defect causing dysfunctional or attenuated T cell and B cell function in the peripheral blood.

Question 3

What causes SCID?

Answer 3

• a mutation in the genes transcribing the cytokines released by the cells or a mutation in the cytokine receptors.

Question 4

What is the most common cause of SCID?

Answer 4

• IL-2 receptor defect.

- most commonly in the gamma chain of the IL-2 receptor.

Question 5

Which three cell types would be affected in an IL-2 receptor defect caused by a genetic mutation?

Answer 5

• T cells, B cells and NK cells.

Question 6

What can delayed umbilical cord separation lead to?

Answer 6

• neutrophil adhesion defect.

Question 7

Why is family history significant in immunodeficiency investigations?

Answer 7

• bc history of early infant death is linked with ID.
• consanguinity is also linked with ID.
• ID can be x-linked inherited.

Question 8

What is the most common cause of acquired immune deficiency?

Answer 8

• HIV.

Question 9

What test is used to detect the presence of antibodies directed against proteins of HIV-1?

Answer 9

• ELISA.

Question 10

Which test is used to detect the presence of antibodies directed against protein of HIV-1 in infants? And why?

Answer 10

• PCR.
• Bc the maternal antibody still lingers in the infants blood which may confuse diagnosis.
• to prevent this, the actual viral particles will be detected using PCR.

Question 11

Name 4 features of AIDS?

Answer 11

• HIV high viral load in blood.
• CD4 cells <200 cells / microL of blood.
• impaired/delayed-type hypersensitivity reaction.
• occurrence of OI.