Immuno Flashcards
1
Q
What characterizes the innate immune system?
A
Non-specific response to any pathogen and the first line of defence.
2
Q
Name the cell types involved in the innate immune system.
A
- Phagocytes (macrophages, neutrophils, dendritic cells) * Eosinophils * Basophils
3
Q
What is the function of phagocytes like neutrophils?
A
They have the ability to destroy pathogens within their cell.
4
Q
What is the oxidative burst in neutrophils?
A
Granules can degranulate to cause an oxidative burst, releasing superoxides that lyse pathogens.
5
Q
What type of cells are natural killer cells?
A
Lymphocytes that belong to the innate immune system and have no specificity.
6
Q
What is the mechanism of action for natural killer cells?
A
Direct cytotoxicity by insertion of perforins into cells without MHC receptors.
7
Q
What do eosinophils target?
A
Invasive helminths.
8
Q
What do IgE immunoglobulins do?
A
Bind to helminth parasites.
9
Q
What are pattern recognition receptors (PRRs)?
A
Receptors on innate antigen presenting cells that recognize pathogen-associated molecular patterns (PAMPs).
10
Q
Do PRRs undergo clonal selection?
A
No, PRRs do not undergo clonal selection.
11
Q
What are DAMPs?
A
Damage-associated molecular patterns released by host cell damage, apoptosis, and lysis.
12
Q
What are Toll-like receptors (TLRs)?
A
Transmembrane forms of PRRs present on macrophages to bind PAMPs and DAMPs.
13
Q
What is the key outcome of innate immune system activation?
A
Inflammation.
14
Q
What is the inflammasome?
A
A complex that mediates inflammatory responses, consisting of intracellular receptors and proteins.
15
Q
What cytokines are released by the activation of the inflammasome?
A
- IL-1b * IL-6 * TNF-a
16
Q
What does IL-1 do?
A
Increases local production of adhesion molecules and acute phase reactants like CRP and fibrinogen.
17
Q
What is Chronic Granulomatous Disease (CGD)?
A
A condition characterized by recurrent skin infections and granuloma formation due to a defect in NADPH oxidase.
18
Q
What is the diagnostic test for CGD?
A
Negative nitroblue tetrazolium (NBT) test.
19
Q
What are the treatments for CGD?
A
- Long-term prophylactic antibiotics * Broad-spectrum antifungals * Allogeneic hematopoietic stem cell transplant
20
Q
Where do B-cells develop?
A
In the bone marrow from hematopoietic stem cells.
21
Q
What can B-cells become after antigen specificity?
A
- Memory B-cells producing specific antibodies * Bone marrow plasma cells
22
Q
What is the function of B-cells as antigen-presenting cells?
A
They bind antigen, digest it, and present it on MHC surface molecules.
23
Q
What is the structure of immunoglobulins?
A
Each Ig is composed of 2 heavy chains and 2 light chains.
24
Q
What are the five major forms of immunoglobulins?
A
- IgA * IgM * IgG * IgE * IgD
25
What is the primary role of membrane-bound IgM?
To activate B-cells.
26
What is the process of isotype switching in B-cells?
The process where B-cells change from producing IgM to IgG.
27
What is Chronic Variable Immunodeficiency (CVID)?
An immunodeficiency characterized by low immunoglobulin levels and recurrent infections.
28
What is Linked Agammaglobulinemia (Bruton's)?
A condition presenting in infants with severe, recurrent infections due to absence of Bruton's tyrosine kinase.
29
What is IgA Deficiency?
The most common immunodeficiency, affecting 1 in 750 people, characterized by selective deficiency of IgA.
30
What are the main treatments for IgA Deficiency?
* Vaccination * Prophylactic antibiotics for recurrent infections
31
Where do T-cells develop?
In the bone marrow and mature in the thymus.
32
What is VDJ rearrangement?
The process by which T-cell receptors (TCRs) are produced through different translation and recombination patterns.
33
What is positive selection in T-cell development?
The process where TCRs must bind and interact with host MHC.
34
What is negative selection in T-cell development?
The process that eliminates T-cells with very high affinity for MHC to prevent autoimmunity.
35
What determines whether a T-cell displays CD4 or CD8 surface proteins?
The type of MHC they react to: MHC Class I (CD8) or MHC Class II (CD4).
36
What is the role of the AIRE protein?
Regulates against autoimmunity
## Footnote
AIRE stands for Autoimmune Regulator protein.
37
What happens to T-cells with too high affinity?
They are either deleted or recruited to become regulatory T-cells (Treg)
## Footnote
Regulatory T-cells help maintain tolerance in the immune system.
38
Which surface proteins do TCR that react to MHC Class I preferentially display?
CD8 surface proteins
39
Which surface proteins do TCR that react to MHC Class II preferentially display?
CD4 surface proteins
40
What is positive selection in thymocytes?
Surviving thymocytes become double positive (+ +) as they receive both CD4 and CD8 receptors.
41
What occurs during negative selection of thymocytes?
Thymocytes that bind with self-antigens undergo apoptosis.
42
What is peripheral tolerance?
Tolerance that occurs outside of the thymus.
43
What is the effect of chronic exposure to antigens?
Produces tolerance and can lead to T-cell deletion in the absence of costimulation.
44
What is the function of Treg cells?
Suppress increased T-cell activity against non-pathogenic antigens.
45
What gene do Treg cells express?
FoxP3 gene
46
What is the role of the FoxP3 gene?
Inhibits T-cells from producing an autoimmune response against host tissues.
47
What are the major subgroups of CD4 positive T-cells?
Four major subgroups, depending on the presence of different tissue cytokines.
48
What are the possible outcomes when a T-cell binds to an APC?
* No response (no co-stimulation)
* IL-2 secretion causing T-cell survival and proliferation (co-stimulation)
* Inhibition of T-cell activity (inhibitory co-stimulation)
49
What is the most severe form of immunodeficiency?
Severe Combined Immunodeficiency (SCID)
50
What is a common cause of SCID?
Mutation of the RAG gene
51
What condition is characterized by impaired ability to combat fungal infections?
Chronic Mucocutaneous Candidiasis (CMC)
52
What is the most common manifestation of CMC?
Candidiasis
53
What is the treatment for CMC?
Prophylactic antifungal medications such as fluconazole.
54
What does HIV infection primarily affect?
CD4 T-lymphocytes
55
What is Autoimmune Polyendocrinopathy with Candidiasis and Ectodermal Dystrophy (APECE D)?
A rare condition caused by mutation of the AIRE gene.
56
What are common manifestations of APECE D?
* Chronic mucocutaneous candidiasis
* Autoimmune thyroiditis
* Autoimmune hypoparathyroidism
* Autoimmune adrenal insufficiency (Addison's)
57
What is the mutation involved in Immunodysregulation, Polyendocrinopathy, Enteropathy, X-linked (IPEX)?
Mutation of the FoxP3 gene.
58
What are the three distinct pathways that trigger complement activation?
* Alternate pathway
* Classical pathway
* Lectin pathway
59
What is the key point where all complement pathways converge?
Production of C3a by C3-convertase.
60
What is opsonization in the complement system?
Coats pathogens with complement proteins, promoting phagocytosis.
61
What is Terminal Complement Deficiency?
Lack of terminal complement factors resulting in inability to form the membrane attack complex.
62
What is Atypical Hemolytic Uremic Syndrome (aHUS)?
Absence of inhibitory complement factors leading to uncontrolled complement binding.
63
What are the four major forms of hypersensitivity reactions?
* Type I: IgE-mediated
* Type II: IgG-mediated cytotoxic
* Type III: Immune complex-mediated
* Type IV: Cell-mediated
64
What is the mechanism of Type I hypersensitivity?
IgE binds to mast cells and degranulation occurs upon allergen binding.
65
What common allergens are associated with allergic rhinitis?
* Dust mites
* Pollen
* Moulds
66
What are the most common food allergens?
* Gluten
* Lactose
* Egg
* Soy
* Seafood
* Nuts
67
What is the gold standard test for food allergy?
Oral food challenges.
68
What are the most common food allergens?
Gluten, lactose, egg, soy, seafood, nuts
## Footnote
These allergens are frequently associated with food allergies.
69
What is the gold standard test for food allergies?
Oral food challenges
## Footnote
This test involves administering the suspected allergen in a controlled setting.
70
What does skin prick testing offer in terms of food allergy diagnosis?
High negative predictive value
## Footnote
This means a negative result is a good indicator that the allergy is not present.
71
What is the role of RAST testing in food allergies?
Available for common food antigens, with similar results to skin prick testing
## Footnote
RAST testing is a blood test that measures specific IgE antibodies.
72
What are the management options for food allergies?
Allergen avoidance, Epipen for anaphylaxis
## Footnote
Epinephrine auto-injectors are critical for treating severe allergic reactions.
73
What does emerging evidence suggest about desensitization for food allergies?
May be safe and effective in some patients
## Footnote
The PALISADE Trial showed a significant reduction in allergic responses to peanut protein.
74
What percentage of drug reactions are not true allergies?
>90%
## Footnote
Most drug reactions are not caused by the immune system.
75
What are the signs of true hypersensitivity to drugs?
Inflammatory cascades with skin rash, urticaria, angioedema, anaphylaxis
## Footnote
These symptoms indicate a true allergic reaction.
76
Which testing method is most accurate for penicillin hypersensitivity?
Skin prick testing
## Footnote
This method is preferred for evaluating drug allergies.
77
What does an elevated tryptase level indicate following drug administration?
Highly suggestive of true hypersensitivity
## Footnote
Tryptase is a marker released from mast cells during allergic reactions.
78
What is DRESS syndrome?
Drug reaction with eosinophilia and systemic symptoms
## Footnote
This syndrome is characterized by fever, rash, lymphadenopathy, and organ involvement.
79
What is a common cause of DRESS syndrome?
Medications such as carbamazepine, allopurinol, doxycycline, phenytoin, dapsone
## Footnote
These drugs are frequently implicated in DRESS syndrome.
80
What are the typical blood test findings in DRESS syndrome?
Eosinophilia with atypical lymphocytes and thrombocytopenia
## Footnote
These findings help in diagnosing DRESS syndrome.
81
What is essential in the management of anaphylaxis?
Advanced life support protocols, including adrenaline
## Footnote
Adrenaline is the first-line treatment in anaphylaxis.
82
What is the typical initial dose of adrenaline for anaphylaxis?
0.5mg, repeated every 5 minutes as required
## Footnote
This is administered intramuscularly.
83
What mediates angioedema?
Bradykinin, but histamine may also be responsible in some cases
## Footnote
Bradykinin is a potent vasodilator leading to swelling.
84
What is hereditary angioedema (HAE) characterized by?
Autosomal dominant inheritance and attacks of angioedema
## Footnote
HAE typically presents in childhood.
85
What are the three major forms of inherited HAE?
* Deficiency of C1 esterase
* Dysfunction of C1 esterase
* Factor XII gene mutation
## Footnote
Each form has distinct laboratory findings.
86
What is the management for acute episodes of HAE?
Recombinant C1 inhibitor (icatibant), Fresh frozen plasma (FFP)
## Footnote
FFP is used second line due to low C1 inhibitor levels.
87
What is the most common cause of drug-induced angioedema?
ACE-Inhibitors
## Footnote
These drugs block the enzyme that degrades bradykinin.
88
What is the effectiveness of the BCG vaccine for tuberculosis?
Approximately 60% effective in preventing active disease
## Footnote
The vaccine is widely used in developing countries.
89
What is herd immunity?
Protection provided to unvaccinated individuals when a significant percentage of the population is vaccinated
## Footnote
It helps reduce the spread of infectious diseases.
90
What is a common adverse effect of vaccines?
Pain at the injection site
## Footnote
This is the most frequently reported side effect.
91
What is the recommended vaccination schedule for Hepatitis B?
Three closely scheduled vaccinations
## Footnote
Checking Anti-HBs following vaccination is also recommended.
92
What are the common causes of death in SJS and TEN?
* Infection
* Acute respiratory distress syndrome (ARDS)
* Multiorgan failure
## Footnote
These complications arise from severe skin loss.
93
What are the indications for the HPV vaccine?
All adolescent females prior to first sexual intercourse, increasing evidence for male vaccination
## Footnote
The vaccine significantly reduces cervical cancer rates.
94
What is a rare adverse effect recognized after influenza vaccination?
Guillain-Barre syndrome
## Footnote
This is a neurological condition that can occur post-vaccination.
95
What is the role of immunosuppressed individuals regarding live vaccines?
Live vaccines are contraindicated
## Footnote
Immunosuppressed individuals have a higher risk of severe infections from live vaccines.
96
What are the common vaccines available for bacterial infections?
* Pneumococcus
* Meningococcus
* Tuberculosis (BCG)
## Footnote
These vaccines are critical for preventing serious bacterial diseases.
