Immunology Flashcards
The difference between secondary and primary immunodeficiency disorders?
Secondary are induced by the environment
Primary are caused by defects in your innate or adaptive immunity
What is neutropenia?
An abnormally low concentration of neutrophils in the blood
Describe presentation of severe congenital neutropenia and treatment
- Severe chronic neutropenia from birth
- Will have a low neutrophil count
- Will present with recurrent bacterial/ fungal infections but no pus within two weeks of birth
- Treatment with recombinant G-CSF reduces infections and improves survival
Describe treatment and presentation of leukocyte adhesion deficiency
- Integrin deficiency means failure of neutrophil adhesion and migration
- Patients will have severe recurrent infections that can’t be cleared
- Really high neutrophil population in the blood
- No pus at the site of infection
Describe treatment and presentation of chronic granulomatous disease
- Deficiency of the intracellular killing mechanism of phagocytes - absent respiratory burst. Mechanism mediated by NADPH complex
- Clinical features include recurrent deep bacterial infections especially Staphylococcus, Aspergillus, pseudomonas cepacian, mycobacteria, atypical mycobacteria
- Recurrent fungal infections
- Failure to thrive
- Lymphadenopathy and hepatosplenomegaly (liver, spleen and lymph nodes abnormally large)
- Granuloma formation
Leukocyte adhesion deficiency is ______ common than CGD and severe congenital neutropenia
much less
The most severe form of immunodeficiency is _______ and is failure _________ and is fatal unless corrected with __________
Reticular dysgenesis
of production of all leukocytes
stem cell transplantation
Severe combined immunodeficiency is ________ and is most commonly caused by _______
failure of production of lymphocytes
x-linked mutation
DiGeorge syndrome causes defects in _____ and is a result of an absent ______ and means _____-
t cell development
thymus
macrophages are very susceptible to intracellular bacteria and there will be lots of viral infections as no t cells to kill off infected tissue cells
X-linked agammaglobulinaemia is _____ Typical presentations include _______ Infections are typically caused by___________
failure of production of mature b cells
• Typical presentations include upper and lower respiratory infections, diarrhea, cellulitis, meningitis, and sepsis.
• Infections are typically caused by Gram-positive, highly pathogenic encapsulated organisms such as Streptococcus pneumonia and Haemophilus influenzae type b.
Defects in t cell effector functions involve ____
Types of infection include ________
• Deficiency in IL-12 receptor or IFNg Tuberculosis Atypical mycobacteria BCG infection after vaccination Deep fungal infections e.g. aspergillus
Defects in B cell effector function are from defects in ____ and can be ______ or ______
Class switch recombination
Hyper IgM- severe reduction in IgG and IgA and normal/ elevated IgM
Defective IgA deficiency- 2/3rd individuals asymptomatic, 1/3rd have recurrent respiratory tract infections
Overall clinical features of T cell deficiencies are
• Recurrent infections – Viral – Fungal – Bacterial – Intracellular pathogens eg mycobacteria • Opportunistic infections • Malignancies at young age • Autoimmune disease
Overall clinical features of B cell deficiencies are
• Recurrent infections – Primarily bacterial infections – Often very common organisms • Opportunistic infections • Antibody-mediated autoimmune disease
Gram versus host disease?
You see your own body as foreign
Describe type 1 hypersensitivity
Ig-E response to an external antigen
• Adaptive immune mediators are CD4+ T cells, TH2 cells, B cells, IgE antibodies
• Innate immune mediators are mast cells and eosinophils
Reaction is caused by binding of allergen to Ig-E coated mast cells
Describe treatment of type 1 hypersensitivity
- Avoidance of allergen
- Montelukast for leukotriene receptors, anti-histamines for histamine, sodium cromoglicate, prednisolone)
- Management of anaphylaxis is with epi pen
- Immunotherapy
Describe type 2 hypersensitivity reaction
- Immune system generates antibodies to self-antigens
- Adaptive immune mediators are CD4+ T cells, TFH cells, B cells, IgM and IgG antibodies
- Innate immune mediators are complement, phagocytes, NK cells
Describe type 3 hypersensitivity reaction
- Immune complexes are deposited in the blood vessel walls
- The presence of immune complexes activates complement and attracts inflammatory cells such as neutrophils
- Enzymes released from neutrophils cause damage to endothelial cells of basement membrane
- Acute hypersensitivity pneumonitis is an example
- Adaptive immune mediators are CD4+ T cells, TFH cells, B cells, IgG antibodies
- Innate immune mediators are complement and neutrophils
Describe treatment of type 2 hypersensitivity
Corticosteroids, Cyclophosphamide, Plasmapheresis
Describe type 4 hypersensitivity
This is a delayed response e.g. TB or sarcoidosis
Driven by macrophages, CD4, TH1
Describe central and peripheral tolerance
- Central tolerance: Deletion of self-reactive lymphocytes in primary lymphoid tissues
- Inactivation of self-reactive lymphocytes in peripheral tissues that escape central tolerance is by peripheral tolerance and is carried out by regulatory t cells
Describe goodepasture’s syndrome
Anti-GBM
Type 2 hypersensitivity reaction affects the lungs and kidneys
– pulmonary alveolar haemorrhage
– kidney disease (glomerulonephritis)
• Defined by the presence of autoreactive antibodies to the α3 chain of type IV collagen present in the basement membranes of alveoli and glomeruli
• Thought to result from an environmental insult (smoking, infections, exposure to certain drugs) in a person with genetic susceptibility
Treatment of goodepastures syndrome?
Corticosteroids, Cyclophosphamide, Plasmapheresis, Stop smoking
Describe Systemic lupus erythematosus (SLE)
Target= nuclear antigens
Prototypic multi-system autoimmune disease
Skin rashes, nephritis, alveolitis
Type 3 hypersensitivity disease
Describe rheumatoid arthritis resp effects
Type 4- rheumatoid nodules within the lung, inflammation of the pleural cavity
What is a mast cell degranulation product that can be measured during an acute episode of anaphylaxis?
Serum tryptase
What is transient hypogammaglobulinemia of infancy?
Relatively common primary immunodeficiency disease that affects infants and young children. Following birth, maternal immunoglobulin G (IgG) is catabolized, and IgG synthesized by the infant gradually accumulates. In the time it takes for reaccumulation there will be chronic infections.
