Immunology Flashcards
Which TH cell is implicated in asthma?
TH2
- Asthma and allergies
- IL 4-6, IL10, IL13
- helminths
The importance of CD25 cells?
These are T regulatory cells. Also known as CD25
- Provide immune tolerance, down regulates T-cells by CTLA4 interaction. Mutant Treg leads to autoimmunity
- secrete IL35, IL10, TGF-beta
- potential target for MS treatment. Daclizumab in MS (anti-CD25)
Daclizumab
Anti CD25 used in MS
How does reduced C1 esterase manifest?
Hereditary angio odema
- recurrent angioedema
- excess bradkinin prod ( hence can be precipitated by an ACE-I). No mast cells
- C3 normal, C4 low, deficient/non functioning C1 esterase inhibitor
How are B cells activated
- Exposed to antigen, endocytoses antigen
- Presents on MHCII for Thelper cell recognition
- Thelper cells activate via co-stimulation of CD40-CD40L
- Bcell activation and proliferation
IgA deficiency
1 primary immunodeficiency
Associated with IgG subclass def (1&4)
90%asymtpmatic
10% recurrent LRTI, GI issues (coeliac)
BEWARE blood transfusion, risk anaphylaxis. Screen IgA antibodies
IgG subclass deficiency
Associated with IgA deficiency
Associated with wiskott Aldrich and ataxia telangietasia
IgG4 related diseases
Fibroid laminator due to IgG4 plasmacytomas
Eyes: Lacrimal gland enlargement, proptosis
Enlarged salivary glands
Thyroid/hashimotos
PSC, AI pancreatitis,
Retro peritoneal fibrosis
IgG4 lymphadenopathy
Why bother knowing wiskott Aldrich and ataxic telangiectasia?
Wiscott Aldrich
- low IgM, high IgA/E, variable IgG
- thrombocytopenia, ezcema
Ataxic telangiectasia
- one or more Ig classes are low
- ataxic, telangiectasia
What complement deficiency will put you at a Higher risk of recurrent infections with
- Pyodermic lesions
- Pneumococcus
- Neisseria meningitidis
MBL deficiency
- Pyogenic infection
- MBL pathway
C3 deficiency
- Encapsulated bacteria
- C3 cleavage initiates alternative pathway
C5-9 deficiency
- Neisseria meningitidis
- Terminal complements for MAC
Tell me a little about the R5 strain and X4 strain in HIV
R5
- most frequently transmitted
- less aggressive
- infects macrophages and Tcells
- used CXCR5 for CD4 entry
X4
- infects only T cells
- more aggressive
- uses CXC4 for CD4 entry
HIV strains; which is more common and aggressive?
HIV1
- most common
- more virulent
- type M (Australia), type O, type N
HIV2
- less virulent
- lower viral load
- less transmission rate
- slower profession
- Western Africa and India
A young girl who had sex with a HIV positive man. What test is most helpful?
HIV RNA load has issues with false positives
P24 antigen is 100%specific but not sensitive
HIV antibodies form months after exposure
What are the sequence of markers that can identify a HIV infection?
Viral RNA>p24>anti HIV
P24: low sensitivity, high specificity
CD 8 importance?
Poor prognostic indicator in HIV and lymphoma
