unit 4 immunodeficiency and autoimmunity

Question 1

primary vs secondary immunodeficiencies

Answer 1

primary: results from genetic or developmental defects (inherited)

secondary: loss of function after exposure of agent/substance (acquired)

Question 2

SCID

Answer 2

severe combined immunodeficiency in which both humoral and cell mediated immune response are affected
–> results from defect in lymphocyte develop (T/B cell)

Question 3

why does a defect in Th cells lead to SCID

Answer 3

Th cells play a role in activating B cells which will lead to defect in immune response

Question 4

indicators of immunodeficiency

Answer 4

chronic or recurrent infections especially with less pathogenic pathogens

increased incidence of tumors

Question 5

x-linked agammaglobulinemia

Answer 5

cause: defect in protein tyrosine kinase which tells B cells to mature
effect: lack of circulating B cells and low levels of antibodies

Question 6

selective IgA

Answer 6

cause: inherited
effect: lack of mucosal IgA leads to upper respiratory tract infections

Question 7

x-linked hyper IgM syndrome

Answer 7

cause: defect in CD40L on activated T cells
effect: high levels of IgM

Question 8

SCID

Answer 8

cause: DiGeorge syndrome –>microdeletion of 22 chromosome
effect: thymus does not develop (T Cells)

Question 9

ADA

Answer 9

cause: accumulation of toxic deoxyadenosine in cells
effect: low number of functioning T cells because it is toxic

Question 10

ataxia telangiectasia

Answer 10

cause: mutation in ATM gene leads to no response to double strand DNA breaks
effects: impaired VDJ recombination and risk of lymphoma and leukemia

Question 11

wiskott-aldrich syndrome

Answer 11

cause: WAS gene mutation
effect: loss of impairment of cell signaling and actin cytoskeleton function

Question 12

diagnosing suspected immunodeficiencies

Answer 12

1. clinical manifestations (repeated infections)
2. evaluation of B cells
3. evaluation of T cells

Question 13

evaluating HMI vs CMI

Answer 13

HMI: measure antibody concentrations, measure antibody production, and B cell quantitation which measures effectiveness

CMI: T cell quantitation and T cell functioning (skin testing)