Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pathology > Immunodeficiency and Immunosuppression > Flashcards

Immunodeficiency and Immunosuppression Flashcards

1
Q

What is a T cell immunodeficiency?

A

Cause susceptibility to infections by viruses and facultative intracellular pathogens: decreased function of individual T cells decreased cell-mediated immunity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is an inherited T cell immunodeficiency?

A

e.g thymic aplasia. Thymus is underdeveloped or involuted.

Predisposes to mTb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an acquired T cell immunodeficiency?

A

e. g loss of CD4+ T cells due to HIV/AIDS

e. g Herpes simplex virus, rotavirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What clinical sign may someone with a T cell immunodeficiency show?

A

Delayed hypersensitivity skin test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What may B cell deficiencies increase susceptibility for?

A

Pyogenic infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an inherited B cell immunodeficiency?

A

Agammaglobulinaemia (X linked) : Complete or near complete lack of proteins called gamma globulins, including antibodies.

Increased Sinusitis, sepsis, impetigo, pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Treatment for Agammaglobulinaemia?

A

Treatment includes intravenous infusion of Immunoglobulin and antibiotics.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What may a complement deficiency lead to infection with?

A

Streptococcus pneumoniae, Staphylococcus aureus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is Iatrogenic and therapeutic immunosuppression?

A

Complication of the use of cytotoxic drugs or irradiation in tumour therapy (neutropenic sepsis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are Calcineurium inhibitor?

A

Inhibit signal transduction in T cells and IL-2 secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the role of Rapamycin?

A

targets mTOR signalling pathway in dendritic cells preventing their maturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What drugs can be given to induce therapeutic immunosupression?

A

Rapamycin, calineurium inhibitor, corticosteroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Defective interferon alpha receptor likely to be seen with ?

A

Mycobacterial infections e.g TB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

C3 deficiencies results in what type of infections?

A

Recurrent pyogenic infections e.g staph aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Splenectomy results in…

A

More prone to bacterial infections such as streptococcus pneumonia, Neisseria meningitidis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Defects in interferon gamma receptor predisposes to

A

Mycobacterial infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Hypercacute rejection results from…

A

Preformed IgM antibodies from the recipient.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Histological features of hyperactute rejection are characterised by

A

Widespread capillary thrombosis and necrosis, PMN infiltrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

IPEX syndrome

A

Dysfunction of the transcription factor FOXP3, widely considered to be the master regulator of the Treg lineage.

Dysfunction of Treg cells and subsequent autoimmune disorders.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What disorders to individuals with IPEX get?

A

Autoimmune disorders E.g psoriasiform, excematous dermatitis, nail dystrophy, autoimmune endocrinopathies, alopecia universalis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Deficiencies in MAC are prone to what infections?

A

Prone to meningococcal infection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Autografts are

A

Tissues derived from the patient themselves e.g. skin to treat life threatening burns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Isografts are

A

Tissues or organs harvested from an identical twin and for which immune intervention is not required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Allografts

A

Tissues or organs taken from unrelated members of the same species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Xenografts

A

Organs harvested from an unrelated species e.g. the use of replacement heart valves harvested from pigs

26
Q

What is the major immunological basis of allograft rejection?

A

Polymorphism in the MHC

27
Q

How many genes encode MHC ?

A

6

28
Q

How are maternal and paternal MHC alleles expressed?

A

Maternal and paternal alleles are co-dominantly expressed

29
Q

What defines a unique haplotype?

A

An individual’s immunological identity - based on the MHC alleles they express from their parents

30
Q

What assures that no two individuals express the same HLA phenotype?

A

Polymorphism

31
Q

Why is it advantageous for each individual to have a unique haplotype?

A

Can detect when there is foreign antigens

32
Q

What underpins the direct pathway of rejection?

A

Dendritic cells in transplanted organ carried into host

33
Q

Who’s DCs are involved in the direct pathway?

A

Donor APC

34
Q

How do donor APC leave the transplanted organ? Why?

A

Lymphatics not joined so leave organ via vasculature

35
Q

Where does direct pathway occur?

A

Spleen

36
Q

What happens when DC reach the spleen (direct pathway)?

A

Present foreign MHC to foreign T cell repertoire in the spleen.

10% of T-cells often respond and are activated, leading to destruction of the organ

37
Q

Why is the direct pathway transient?

A

Controlled by DCs with limited lifespans (1-2weeks) not being replaced by recipient bone marrow.

38
Q

What happens in the indirect pathway of rejection?

A

When DCs die, release the alloantigens (foreign MHC), these are acquired by recipients own APCs.

Activates a different set of alloreactive T-cells.

39
Q

Who’s DCs are involved in the indirect pathway?

A

Host

40
Q

Does direct or indirect produce a larger T cell response

A

Indirect less destructive as less T-cells (one in 10^6) will respond compared to 10% in direct

41
Q

Is direct or indirect rejection pathway more long lasting?

A

Indirect permanent chronic response - alloantigen can be released through the full lifespan of organ.

42
Q

What are minor Histocompatibility (mH) Antigens? (5)

A

ABO blood group antigens

Epitopes from naturally-occurring polymorphic proteins

Retrovirally-encoded antigens

Mitochondrial proteins

Male-specific gene products encoded on the nonrecombining arm of the Y chromosome (women are not tolerant of these - women reject tissues from male donors)

43
Q

Who is the best transplant donor and why?

A

Identical twin is the best source of tissues since all HLA loci and mH antigens are shared, avoiding transplant rejection

44
Q

How good are sibling donors?

A

Siblings are ‘haploidentical’ since they share approximately half of their HLA loci and are the next best option

45
Q

Effector Mechanisms in Allograft Rejection

A

CD4+ Th cells

CD8+ Cytotoxic T cells (all cells express MHC I)

NK cells (inhibitory NK receptors)

Alloantibodies and complement

Activated macrophages (release pro-inflammatory cytokines and ROS, largely responsible for damage which leads to the positive feedback in rejection)

46
Q

What is a hyperacute rejection time span?

A

Hours

47
Q

What does a hyperactue rejection involve?

A

Involves pre-formed or ‘natural’ antibodies of the IgM isotype

Binding to endothelial cells causes formation of thrombi in small vessels and organ infarcts.

48
Q

Why do you get RBC lysis in hyperacute rejection?

A

Natural antibodies specific for ABO blood group antigens can fix complement causing RBC lysis

49
Q

What is an acute rejection time span?

A

2-3 weeks

50
Q

What is acute rejection driven by?

A

Driven by the direct pathway of alloantigen presentation

The high precursor frequency of alloreactive T cells inflicts rapid and significant tissue damage (polyclonal response)

51
Q

What is a chronic rejection time span?

A

Occurs over months or years (full lifespan)

52
Q

What is chronic rejection driven by?

A

Driven by the indirect pathway of alloantigen presentation

53
Q

What is Graft vs Host Disease (GvHD)?

A

Rejection of host tissues by mature T cells from the donor carried over in the graft e.g. liver

54
Q

Why is GvHD so dramatic?

A

Up to 10% of donor T cells are recipient’s own MHC resulting in a dramatic polyclonal response and cytokine storm

55
Q

When is GvHD most frequently seen?

A

Most frequently observed following bone marrow transplantation for the treatment of haematological malignancy: bone marrow contains mature donor T cells.

56
Q

Infection most likely to show increased incidence in an immunodeficient child suffering from CGD

A

Staph aureus infection

57
Q

Infection most likely to show increased incidence in an immunodeficient child suffering from defective interferon-gamma receptor

A

TB

58
Q

Infection most likely to show increased incidence in an immunodeficient child suffering from inability to synthesise IgA

A

E. coli gastro-enteritis

59
Q

Infection most likely to show increased incidence in an immunodeficient child suffering from congenital thymic aplasia

A

TB

60
Q

Infection most likely to show increased incidence in an immunodeficient child suffering from inability to make complement C3

A

Staph aureus infection

Pathology (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions