Path: Immuno Flashcards
How do you treat chronic granulomatous disease?
interferon gamma
What is deficient in chronic granulomatous disease?
NADPH oxidase
What is the underlying pathophysiology in chronic granulomatous disease?
deficiency in NADPH oxidase -> absent respiratory burst and superoxide production in neutrophils and macrophages -> impaired killing of IC micro-organisms
Excessive inflammation -> persistent neutrophil/macrophage accumulation, failure to degrade antigens.
What particular organisms are like to to cause infections in chronic granulomatous disease?
catalase +ve bacteria (PLACESSSS -> Pseudomonas, Listeria, Aspergillus, Candida, E.coli, Staph aureus, Serratia)
What is the role of catalase?
hydrogen peroxide to water and oxygen
found in almost all organisms exposed to oxygen
Name catalase positive organisms
PLACESS H
Pseudomonas
Listeria
Aspergillus
Candida
E coli
Staph aureus
Serratia
H pylori
inheritance pattern of chronic granulomatous disease
X-linked recessive or AR (2:1)
Signs and symptoms of chronic granulomatous disease
recurrent severe infections (chronic skin, LN, bone, resp, with catalase +ve organisms
e.g. recurrent severe pneumonia before the age of 5
lymphadenopathy
Granulomas of the skin/GI/GU tract
Investigations for chronic granulomatous disease
NBT (nitro-blue tetrazolium test) -> NEGATIVE (dye changes from yellow to blue in contact with free radicals e.g. hydrogen peroxide therefore negative in CGD)
DHR (dihydrorhodamine) flow cytometry test -> decreased green fluorescence (flow cytometry test showing abnormal NADPH oxidase activity (inability to metabolize dihydrorhodamine to fluorescent product, rhodamine)
genotyping is confirmatory
What is the underlying pathology in leukocyte adhesion syndrome?
Leukocytes lack adhesion molecules and are unable to exit the bloodstream
Deficiency in:
CD18 (LAD1) - b2 integral subunit
CD11a, CD1b, CD11c
these are found on the surface of neurophils, bind to ligands on endothelial cells and regulate neutrophil adhesion/transmigration
Investigations for leukocyte adhesion syndrome
Flow cytometry: absent CD18 (Cd11a, CD11b, CD11c)
Leukocytosis: however, neutrophils are absent at the site of infections
Treatment of Leukocyte adhesion deficiency
prevention of further infections (e.g. adequate dental hygiene)
treatment of infections
BM transplant
Which primary immune deficiency has delayed umbilical cord separation as a feature
leukocyte adhesion deficiency
What is the mutation seen in leukocyte adhesion deficiency
CD18 missing on the surface on neutrophils (LAD-1)
can also be CD11a, CD11b, CD11c
Which cytokine is important in the pathogenesis of rheumatoid arthritis, anyklosing spondylitis and inflammatory bowel disease?
TNF-alpha
What is the specific antigen recognised by the immune system in Goodpasture’s syndrome?
type IV collagen
How long before skin prick testing must antihistamines be stopped to allow for accurate interpretation?
48h
inheritance pattern of reticular dysgenesis
AR
What is the most common inherited immunodeficiency
(selective) IgA deficiency
presentation of SIgAD (selective IgA deficiency)
often asymptomatic
associated with recurrent respiratory and GIT infections in 30%
increased susceptibility to parasitic infections e.g. by Giardia lamblia
What might patients with SIgAD have an anaphylactic reaction to?
products containing IgA e.g. IVIg
To prevent transfusion reactions, IgA-deficient patients must be given washed blood products without IgA or obtain blood from an IgA-deficient donor.
How common in SIgAD?
1:600 caucasians affected
it is the most common primary/inherited immunodeficiency
The Six A’s of selective IgA deficiency:
Asymptomatic, Airway infections, Anaphylaxis to IgA-containing products, Autoimmune diseases, Atopy
What HLA allele is found in 90% of patients with coeliac disease?
HLA DQ2
