Immunodeficiency

Question 1

In X-linked Agammaglobulinemia (XLA), ____ are usually absent

Answer 1

circulating B cells

Question 2

In XLA, ____ are present in reduced numbers in the ____

Answer 2

pre-B cells; bone marrow

Question 3

the defect in XLA is associated with a loss of function of ____ that is important for pre-B cell expansion and maturation into Ig-expressing B cells

Answer 3

Bruton Tyrosine Kinase (Btk)

Question 4

characterized by very low serum IgG, IgA, and IgE, but markedly elevated concentration of polyclonal IgM

Answer 4

X-linked immunodeficiency with hyper-IgM

Question 5

in contrast to patients with XLA, hyper-IgM patients have ____

Answer 5

lymphoid hyperplasia

Question 6

The defect in hyper-IgM is associated with a loss of function of _____ that is expressed on helper T cells

Answer 6

CD40 ligand (aka CD154)

Question 7

the loss of CD40 ligand prevents T cells from costimulating _____ (through CD40L)

Answer 7

antigen-specific B cells

Question 8

because of loss of B cell costimulation, B cells are not signaled by the T cell to go through ____ and only produce ____

Answer 8

isotype switching; IgM

Question 9

deficient ____ usually results in increased susceptibility to infection by pyogenic bacteria

Answer 9

humoral immunity

Question 10

treatment for humoral immunodeficiency

Answer 10

prophylactic antibiotics and/or gamma-globulin therapy

Question 11

deficient cell-mediated immunity usually results in increased susceptibility to ____ and other _____

Answer 11

viruses; intracellular pathogens

Question 12

developmentally-related disease associated with tissue morphogenesis – the thymus does not develop

Answer 12

digeorge’s syndrome

Question 13

Thymic hypoplasia results from defects in morphogenesis of the third and fourth ______ during early embryogenesis

Answer 13

pharyngeal pouches

Question 14

____ is a rare, fatal syndrome characterized by profound deficiencies of T- and B-cell function; ____ is the most common form

Answer 14

severe combined immunodeficiency; X-linked recessive severe combined immunodeficiency disease (XSCID)

Question 15

infants with XSCID have persistent infections with ____ organisms

Answer 15

opportunistic

Question 16

infants with XSCID lack the ability to ____ and are therefore at risk for ____ which can result from maternal T cells that cross into fetal circulation while the XSCID infant is in utero

Answer 16

reject foreign tissue; GVHD (graft vs host disease)

Question 17

XSCID patients have few/no ____ or ____, but they usually have elevated percentages of ____ (which are dysfunctional)

Answer 17

few/no T cells or NK cells

B cells

Question 18

2 aims of current treatments for immunodeficiencies

Answer 18

1. to minimize and control infections

2. replace defective or absent components of the immune system by adoptive transfer and/or transplantation

Question 19

____ with pooled ____ is valuable for agammaglobulinemic patients and has been life saving for many with this disease

Answer 19

passive immunization; gamma globulin

Question 20

_____ is currently the treatment of choice for various immunodeficiency diseases and has been successful in the treatment of SCID and other similar diseases

Answer 20

bone marrow transplantation

Question 21

cellular reservoirs of HIV that contribute to plasma virus

Answer 21

1. activated CD4+ T cells (most abundant in plasma virus- half life about one day)
2. monocytes/macrophages (half life about 2 weeks)
3. resting/memory CD4+ T cells (least abundant- half life >50 yrs)

Question 22

AIDS is characterized by ____ and _____

Answer 22

destruction of lymphoid tissue; depletion of CD4+ T cells