Immunodeficiency

Question 1

failures of the immune system

Answer 1

hypersensitive i.e. damaging overreaction

immunodeficiency i.e. fail to produced an adequate repose

Question 2

types of immunodeficiency

Answer 2

primary immunodeficiency

secondary immunodeficiency

Question 3

primary immunodeficiency

Answer 3

instrinsic genetic defects in the immune system affecting T and B cells (Ab production)
e.g. phagocytes affected

Question 4

secondary immunodeficiency

Answer 4

external factors that an deleteriously affect the immune system e.g. drugs

Question 5

specific vs non specific immunodeficiency

Answer 5

specific is the adaptive immune system i.e. B/T cells

non specific immunodeficiency is abnormalities of phagocyte or complement i.e. innate system

Question 6

what categories do people with immunodeficiency fall into

Answer 6

1) Defects in Ig, C’ (complement) phagocytes
- susceptible to recurrent bacterial infections (H influenzae..)
- termed Pyogenic infections (pus formation)
2) Defects in cell mediated immunity (T cells)
- susceptible to commensal organisms eg candida, viruses
- opportunistic infections

Question 7

B cell deficiens

Answer 7

X linked agammaglobulinemia
IgA deficency
X liked dominant gene

Question 8

X linked B cell deficiency ( x linked agammaglobulinemia)

Answer 8

affects males(on X chromosome)
no B cells therefore little IgG in serum
defective btk gene so no maturation of B cell so no IgG
get pyogenic infections

therapy
- injection of gamma globulin throughout life

Question 9

Hyper IgM immunodeficiency

Answer 9

B cell deficieny
- deficiency in IgG/A with hyper IgM
X linked recessive condition with mutations

succeptible to pyogenic infections and autoimmune disease
Cd40 needed for Ig class switching

Question 10

IgA deficiency

Answer 10

failure to terminal differentiation of B cells to plasma cells
Mainly affects IgA secretion
develop type III hypersensitivity
pyogenic infections

Question 11

T cell deficiences

Answer 11

severe combined immunodeficiency
digeorge syndrome
MHC II deficiency

Question 12

severe combined immunodeficiency.

Answer 12

no /poor T cell function
B cell function depends on T cell funciton
suffer from commensal organisms infections

Question 13

digeorge syndrome

Answer 13

Affected thymus in foetal develoment

Question 14

MHC II deficiency

Answer 14

failure to express MHCII antigens on APC
CD4 cells require MHC II for positive selection in thymus
lack of CD4 cells, Ab deficiency

Question 15

complement deficienies lead to

Answer 15

pyogenic infections

most common condition is HAE

Question 16

HAE

Answer 16

hereditary angioneurotic edmea
C1 inhibitor (first initiator of competent pathway)
inhibit complement activity and elements of kinin/clotting system
severe oedema due to plasma leakage, recurrent swelling

Question 17

defects in phagocytes

Answer 17

can affect neutrophils or macrophages

genetic defetcs include:

1) Chronic granulomatous disease
2) Leukocyte adhesion deficiency

Question 18

chronic granulomatous disease

Answer 18

defective NAPDH oxidase
phagocytes cannot form ROS to kill microbes
organisms alive in phagocytes

infection and granulomas form

Question 19

how to diagnose chronic granulomatous

Answer 19

nitroblue tetraozlium die
remains yellow in CGD
goes purple in normal

Question 20

leukocyte adhesion deficicieny types

Answer 20

LAD type 1
- deficient in cd18
LAD type 2
defective in CD15

Question 21

LAD type 1

deficient in CD18

Answer 21

- lack of functional CD18
defective complete receptor 3
cannot phagocytose bactiera
recurrent infections
- immune cells also not able to extravate, can't leave blood stream

Question 22

LAD type 2

Answer 22

defective receptors that bind selectors

phagocytes cannot leave BS as they can’t roll on endothelium

Question 23

effects of corticosteroids on immune system

Answer 23

lymphocytopenia (can lead to opportunistic pathology)
monocytopenia
neutrophilia (due to release of neutrophils from bone marrow)

Question 24

what does radiotherapy do

Answer 24

DNA strand breaks
cells cannot proliferate and repair
increased apoptos
targeted at high proliferation rates (so also affects the bone marrow and lymphoid tissue)

stops immune cell produce, proliferation and differentiatin

Question 25

chemotherapy chemicals and what they do

Answer 25

cyclophospamde
- DNA stops proliferation and increases apoptosis
mainly affects lymphocytes (B cells mostly)
azathioprine
- stops DNA replication, therefore induced cell apoptosis

Question 26

drugs used in organ transplantation

Answer 26

immunosuppressant drug used in transplants to reduce immune system
affects T cells via IL2 produciton

Question 27

T cell and ag recognition

Answer 27

T cell binds to APC
IL2 secreated and binds to IL2R on T cells
leads to differentiation etc

Question 28

what does malnutritiondo

Answer 28

damage lymphoid tissue

Question 29

malnutrition affects

Answer 29

lymphoid atrophy ( T cell abornlaities, reduced CD4levels, reduced complement )

Question 30

zinc effects

Answer 30

co factor involved in enzyme reactions

• reduction in delayed type IV hypersensivity (cell mediated)
• Low CD4 and CD8 numbers
• impaired Ab responses (low plasma cell numbers)

Question 31

iron

Answer 31

needed for superoxide generation

Question 32

vit B6 and folate deficiency

Answer 32

reduced cell mediated immunity

Question 33

AIDS HIV replication

Answer 33

1) binds to CD4 in a complex with chemokine receptor (CCR5 or CXCR4)
2) once bound, can undergo conformational change and fusion
3) HIV gets injected into the cell
4) leads to replication

Question 34

what does HIV bind to

Answer 34

CD4 and chemokine receptor to gain entry

1) X4 tropic – CXCR4 (coreceptor)with CD4
- mainly affects T cells
2) R5 tropic
- CD4 with CCRD
- mainly with macrophages

5 first, then 4 as infection carries on