Immunology, Hypersensitivity, Autoimmunity and Immunosupressants Flashcards
What chemical barrier do cells at the surface e.g. Panneth cells, epithelial cells have which can penetrate bacteria cell walls and lyze them?
Antimicrobial peptides
What does a neutrophil look like under a microscope?
Multi-lobular nucleus and granular cytoplasm
What are the 3 pathways that cause complement activation in the innate immune response?
1st - Alternate pathway (pathogen surface creates environment for complement activation)
2nd - Lectin pathway (mannose-binding lectin binds to pathogen surface)
3rd - Classical pathway (antibody binds to antigen)
What does complement activation in the innate immune response cause?
- Recruitment of inflammatory cells
- Opsonization of pathogens, facilitating uptake and killing by phagocytes
- Peroration of pathogen cell membranes
What do lymphocytes look like?
Small white blood cells with large nuclei
What is the function of these differentiated T cells?
a) TH17
b) Treg
c) TH1
d) TH2
e) TFH
a) Reinforce innate immunity
b) Suppression of immune response
c) Macrophage activation
d) Mast cell/ B cell activation
e) B cell activation in lymph nodes
What is meant by T cells being
a) mutually regulated?
b) having phenotypic plasticity?
a) if you have expansion of one T cell type the others are suppressed
b) effector cells can change their function depending on type of infection
What do NK cells do?
Suppress expansion of the virus but doesn’t clear it, need antigen specific T cells for that
What is affinity maturation of plasma cells?
Mutation at the genetic level to produce antibodies with the highest affinity for antigens i.e. isotype switching from IgM to IgG or IgA
What is the function of memory B cells?
- Long lived (quiescent), high affinity class switched Ig ready for immediate neutralising of infections
- Secondary immune response quicker
- IgG response predominates
- Memory T cells also produced
What does the therapeutic monoclonal antibody Rituximab do?
Anti CD20 - kills tumour cells in lymphoma
What does the therapeutic monoclonal antibody Infliximab do?
Anti TNF - blocks inflammation in rheumatoid arthritis
What does the therapeutic monoclonal antibody Impilimumbab do?
Anti CDLA-4 - blocks immunosuppression in melanoma
What drugs can be used in immunotherapy
- Therapeutic monoclonal antibodies
- Corticosteroids
- Cytotoxics
- T cell immunosuppressants e.g. ciclosporin
What are the
a) Central/primary lymphoid organs?
b) Secondary lymphoid organs?
a) Where lymphocytes are produced i.e. Bone marrow = B cells, Thymus = T cells
b) Where adaptive responses start e.g. adenoids, tonsils, spleen, peyers patch, appendix
What is the role of
a) CD4+ T cells
b) CD8+ T cells
a) Help others by producing activating cytokines - recognise antigen presented by dendritic cells
b) Recognise and kill infected cells
What are the symptoms of immunodeficiency?(SPUR)
Serious infections
Persistence of infections (often medication resistant)
Unusual sites or unusual organisms
Recurrent infections
What are the warning signs for immunodeficiency?
- Antibiotics for 2 months without effect
- Persistent thrush in the mouth or elsewhere on skin
- Failure to thrive in babies
- 2 or more pneumonias, deep-seated infections (e.g. cellulitis) or serious sinus infections in a year
- Recurrent deep skin or organ abscesses (cold with no erythema markers)
In primary immunodeficiency, what are patients at risk of when antibody/B cells are affected?
- Bacterial infections - capsulated organisms e.g. streptococci, meningococci, staphylococci
- Protozoal infections
- Abscesses
- Fungi and viruses uncommon
In primary immunodeficiency, what are patients at risk of when T cells are affected?
- Fungi - pneumonia, meningitis, toxoplasma (eye and brain), candida
- Viral infections e.g. Poliovirus, EBV, Herpes etc
- Bacteria infections uncommon and no abscesses
In primary immunodeficiency, what are patients at risk of when phagocytic cells/ neutrophils are affected?
- Bacterial infection - staphylococci, pseudomonads
- Fungi - aspergillus
- Abscesses - cold with little inflammation
- Viral infection uncommon
In primary immunodeficiency, what are patients at risk of when complement is affected?
- Classical pathway - bacterial infections but viral and fungal rare
- Alternate pathway - Neisseria infection (meningitis)
What is SCID?
Primary immunodeficiency disorder where T cells and B cells absent. Difficult to fight viral fungal and bacterial infections - must be isolated and bone marrow transplant.
What is X-linked agammaglobulaemia?
Primary immunodeficiency disorder where there is low/absent B cells and reduced immunoglobulins. Present in boys, absent tonsils and recurrent bacterial infections.
What is common variable immunodeficiency?
Primary immunodeficiency disorder. Low immunoglobulins and multiple gene defects. Autoimmunity, recurrent bacterial infections, high risk of malignancy.
What is chronic granulomatous disease?
Primary immunodeficiency disorder affecting neutrophil oxidative burst that kills the organisms. Recurrent abscesses deep-seated in liver and soft tissue. Fungal. Gingivitis and tooth loss.
What is chronic mucotaneous candidiasis?
Primary immunodeficiency disorder where there’s an inability to clear candida. Cytokine abnormalities and endocrine abnormalities. Can have oesophageal malignancies.
What is DiGeorge syndrome?
Primary immunodeficiency disorder from gene deletion where thymus doesn’t develop, palate doesn’t form properly (speech difficulties), cardiac abnormalities. Viral, fungal and bacterial infections.
What drugs can cause secondary immunodeficiency?
- Cytotoxics
- Anti-convulsants (B cells can’t produce antibodies so will need immunoglobulin replacement)
- Carbimazole for hyperthyroidism (causes mouth ulcers and sepsis)
- Monoclonal antibodies
- Immunosuppressive drugs e.g. ciclosporin and tacrolimus, methotrexate, cyclophosphamide e.tc.
What are the causes of oral candida?
- Dentures
- Connective tissue syndromes e.g. Sjogren’s syndrome
- Secondary immunodeficiency e.g. HIV, drugs
- Steroid inhalers
- Antibiotic therapy
- Primary immunodeficiency
- Dietary
- Xerostomia
- Endocrine
- Others: alcohol, caffeine, Hep C, smoking
What are the causes of mouth ulcers?
- Cancer
- Infection, viral (HSV) or bacterial
- Trauma
- Medications e.g. methotrexate
- SLE
- Crohns disease
- Nutritional deficiencies
- Aphthous
- Oral dermatoses e.g. lichen planus, pemphigoid etc.
What are the causes of gingivitis and tooth loss?
- Scurvy
- Pregnancy
- Chronic granulomatous disease (primary immunodeficiency)
- Ciclosporin
- Poor oral hygiene
- Anti-convulsants
What is Type 1 hypersensitivity?
IgE antibody mediated degranulation of mast cells and basophils. Releases histamine, heparin, lysosomal enzymes and proteases. Allergic reaction.