immuno path Flashcards
liver macrophage is …
kupffer cell
kidney macrophage is…
mesangial cell
spleen macrophage is…
sinusoidal-lining cell
bone macrophage is….
osteoclast
lung macrophage is…
alveolar macrophage
CNS macrophage is….
microglia
skin macrophage is….
langerhans cell
connective tissue macrophage is..
histiocyte
what types of T cell recognise what type of HLA ??
- CD8+ T cells recognise peptide presented by HLA class I molecules
- CD4+ T cells recognise peptide presented by HLA class II molecules
CD4+ T cells help B cell differentiation – requires what ligand receptor interaction?
CD40L:CD40 interaction
what is the mantoux test and outline its basic principles ..
- Inject 0.1 ml of 5 tuberculin (=purified protein derivative) units intradermally, examine arm 48-72 hrs after
- A positive result is indicated by induration (swelling that can be felt) of at least 10 mm in diameter (erythema around not measured). This implies previous exposure to tuberculin protein - thus it could represent previous BCG exposure
3 barrier immune deficiencies and outline
- Burns –> keratinsied cells and sebaceous glands –> increased risk of infection since barrier detsroyed
- IgA deficiency –> this is sectreted in mucosal surfaces to defend
- antibiotic use –> detsroys good bacteria and allows other organisms to colonise an undefended niche (e.g. candida, C Difficile )
give an overview of how you would break down the phagocyte deficiencies (in the topic of immuno deficiency)
go through every stage of a phagocyte
- production - reticular dysgenisis (Failure of production of: Neutrophils, Lymphocytes, Monocyte/macrophages, Platelets)
- maturation - Kostman syndrome (Autosomal recessive severe congenital neutropenia) / cyclic neutropenia (Autosomal dominant episodic neutropenia every 4-6 weeks)
- migration to site of infection - Leukocyte adhesion deficiency (nuetrophils dont have adhesion molecules so can’t bind to vessel wall endothelium and escape the circulation )
- oxidative killing - chronic granulomatous disease (absent respiratory burst - deficient in NADPH oxidase so can’t make superoxide therefore impaired killing of microorganisms)
- cytokine production - Deficiency of IL-12 and IFNγ and their receptors (Susceptibility to infection with mycobacteria (TB and atypical), BCG, Salmonella - inabliity to form granulomas)
give an overview of how you would break down the lymphocyte deficiencies (in the topic of immuno deficiency)
- Production in Bone Marrow
Reticular dysgenisis
Severe combined immune deficiency (Effect on different lymphocyte subsets (T, B, NK) depend on exact mutation e.g. X-linked SCID .. Very low or absent T cell + NK cell numbers, Normal or increased B cell numbers)
Adenosine Deaminase deficiency - can’t respond to cytokines –> * Very low or absent T cell and NK cell numbers + Very low or absent B cell numbers - Thymus (maturation and selection)
DiGeorge - Normal numbers of B cells and reduced numbers of T cells cause thymus is fucked
Bare lymphocyte syndrom - defect in regulatory genes, absent HLA class II, there reduced CD4+ T cells - Cytokine release problem
Deficiency of IL-2 and IFNy
Wiskott-Aldrich Syndrome (WAS) - problem with Tb cell - APC interaction - B cell maturation -
Bruton’s X-linked hypogamma globulinaemia -
Common variable immune deficiency - class switching
Hyper IgM syndrome - failure to express CD40L so cant do class switch. due to a T cell defect
Selective IgA Deficiency
how does leukocyte adhesion defieicny present ?
A rare autosomal recessive immunodeficiency.
Neutrophils are unable to adhere to vascular endothelial - hence they cannot transmigrate into tissues to fight infection.
This leads to a high level of neutrophils in the blood (neutrophilia). As a result, there is no abscess formation or pus.
The neutrophils function normally (so will be be normal in the NBT test) but simply cannot get to where they are needed.
Clinically, this may present with delayed umbilical cord sloughing as neutrophils are involved in this process.
There is often infections of the skin (particularly omphalitis, infection of the umbilical cord), pneumonia or gums. The only curative therapy is haematopoietic stem cell transplantation.
how does common variable immunodeficiency present ?
Common Variable Immunodeficiency (CVID) is a diagnosis of exclusion in patients greater than 4 years old. The diagnostic criteria are:
- Decrease in serum IgG and a decrease in one of IgM or IgA.
- There is a lack of antibody response to antigens or immunisation
-more than 4 years old.
Patients will have increased infections with bacteria such as Haemophilus, Strep (usually immunized against) and Staph. There is an increased rate of autoimmune conditions and malignancies. Treatment is with normal human IVIg for life.
Bruton’s Agammaglobulinaemia - how does it present ?
Blood tests reveal a low lymphocyte count, with very low B cells but normal T cell levels.
There as very low levels of IgM, IgA and IgG.
how does Nitroblue-tetrazolium (NBT) or dihydrorhodamine (DHR) tests work??
In CGD, these tests are negative. In the NBT or DHR tests, the presence of reactive oxygen species will cause a colour change. A positive (normal) NBT test will stain neutrophils blue. A negative (abnormal) test will remain colourless
test for chronic granulomatous disease
which organisms are you suseptible to if you have chronic granulomatous disease ?
Catalase positive organisms express catalase and therefore are resistant to some methods of hydrogen peroxide based killing. Examples include:
E coli
Staphylococcus Aureus
Listeria spp
Klebsiella spp
Serratia marcescens
Candida spp
They are a common cause of infections in patients with chronic granulomatous disease.
features of rheumatoid artrhitisi
- Symmetrical polyarthritis
- DIP sparing
- Hand deformities:
o Swann neck, Boutinnier’s, Z-thumb and ulnar deviation - Extra articular
o Fibrosis
o Pericardial effusions
o Rheumatoid nodules
Sjogren’s
- Dryness and rash
- Schirmer’s test
