Immunology Flashcards
What are Complements ??
Proteins that circulate in plasma; involved in inflammatory & immune reactions. eg.- Chemotaxis, cell lysis, Opsonization
Name few complement deficiencies
- C1 inhibitor (C1-INH)
- C1q, C1rs, C2, C4 (Classic pathway components)
- C3 (Recurrent Bacterial infection)
- C5
- C5 to 9
Name the Complement system disorders
C protein deficiency
- Early C def. (C1 to C4): increased risk of severe, recurrent pyogenic sinus & resp. tract infection.
- Terminal C def. (C5 to C9): increased risk of Neisseria bacteremia
C regulatory protein def.
- C1 esterase inhibitor def.
- PNH (C mediated intravascular hemolysis => decrease Haptoglobin, dark urine
Features of Hereditary Angioedema ??
- AD inheritance
- C1 esterase inhibitor deficiency (a multifunctional Serine Protease inhibitor)
- unregulated Kallikrein activation => increased release of BRADYKININ => Oedema of tissue
Features of C1q, C1rs, C2, C4 deficiency ??
These are Classical pathway components
- Predisposes to Immune Complex diseases
- Eg. SLE, HSP
Hallmark of C5 deficiency ??
- predisposes to Leiner Disease
- Recurrent Diarrhoea, Wasting, Seborrhoeic dermatitis
Hallmark of C5 to C9 defeciency ??
Encodes the Memb. Attack Complex (MAC)
- prone to N Meningitidis infection
Name the diseases a/w the following HLA
- A3
- B27
- B51
- B57
- Haemochromatosis
- ‘PAIR’ Psoriasis, Ank. Spon., Acute anterior uveitis, IBD- a/w arthritis, Reactive arthritis.
- Behcet’s dosease
- Abacavir hypersensitivity
Name the diseases a/w the following HLA
- DQ2/ DQ8
- DR2
- DR3
- Coeliac’s disease
- Goodpasture’s, Narcolepsy
- Dermatitis Herpetiformis, Sjogren’s, PBC
Which disease is a/w HLA- DR4 ??
- Type 1 DM (also a/w DR3 but DR4» DR3)
- RA (in particular DRBI04:01 & 0404)
- Addison disease
Cytokines produced by Th2 cells ??
IL-4, 5, 6, 10, 13
Th-2 cells are Involved in mediating Humoral (antibody) immunity
- eg. stimulating IgE production in asthma
Cytokines produced by Macrophages ??
IL-1,6,8,12 & TNF-alpha
Cytokines produces by Th-1 cells ??
Th-1 is involved in CMI & Delayed HS
- IL-2 (Stimulates growth & differentiation of T cell response)
- IL-3
- IFN- gamma (activates Macrophages)
Name the Cytokine produced by
- B-cells
- Dendritic cells
Both produces IL-12
- Activates NK-cells & stimulates differentiation of naive T cells into Th 1 cells
Types of HS reactions ??
“ACID” - Anaphylaxis, Cytotoxic (Immune cells attacks), Immune Complex, Delayed ,
T-1 (Anaphylactic) eg- Contact dermatitis
T-2 (Cell bound: IgG/IgM binds to antigen on cell surface)
T-3 (Immune complex: antigen + antibody IgG/IgA)
T-4 (Delayed : T-cell mediated) eg. Atopic Der.
T- 5 (Antibodies that recognize & bind to cell surface receptor)
Where is Type 5 HS reaction seen ??
Grave’s & Myasthenia gravis
- Antibodies recognizes & binds to cell surface receptor ==> Stimulates them / blocks ligand binding
What are the types of Immunoglobulins ??
G(75%) : Monomer
A(15%) : Monomer/ Dimer
M(10%) : Pentamer
D(1%) : Monomer (involved in B-cell activation)
E(0.1%) : Monomer
Which is the MC produced Ig & most abundant Ig ??
IgA (MC produced)
IgG (most abundant)
Which is the 1st Ig to be produced in response to an infection ??
IgM (is a Pentamer when secreted)
- Fixes complement but does NOT pass to Fetal circulation
- Anti-A, B blood antibodies will not cause haemolysis as they do not pass to fetal circulation
What immunological changes are seen in Progressive HIV ??
- Reduced CD-4 count
- Reduced IL-2 production
- Reduced NK-cell function
- Reduced Type 4 HS responses
- Increase in B2-microglobulin
- Activation of Polyclonal B-cells
Name B-cell disorder
- Bruton’s agammaglobulinaemia (X-linked Recessive)
- Selective IgA def. (MC primary immunodefeciency)
- Common Variable ID (B-cell DIFFERENTIATION defect)
Name T-cell disorders
- Thymic aplasia (DiGeorge & Velocardiofacial synd.)
- IL-12 receptor def. (A Recessive)
- Job synd. (or) A D Hyper IgE synd.
- Chr. Mucocutaneous Candidiasis
Name the combined B & T cell disorders
- SCID {X-linked R (IL-2R gamma defect)»>A Recessive (Adenosine deaminase def.)}
- Ataxia Telangiectasia (A R): ATM gene defect
X-linked R - Hyper IgM synd.- defective CD40L on Th cells
- Wiscott-Aldrich synd. (WAS gene mutation)
Disorders with Phagocyte dysfunction ??
Autosomal Recessive
- Leucocyte Adhesion Def. (type 1): LFA-1 integrin defect
- Chediak-Higashi synd. (Microtubule dysfunction)
Chr. Granulomatous Disease (X-linked is the MC form): NADPH oxidase defect=> decreased ROS
What are TORCH infection ??
Toxoplasma gondii
Other agents
- Syphilis
- Parvovirus B-19
- Varicella Zoster Virus
- Listeria
Rubella
CMV
Herpes Simplex Virus 2
Which is the MC Congenital infection in the UK ??
CMV
- LBW baby + Microcephaly + SNHL + Purpuric skin rash
Features of Congenital Toxoplasmosis ??
Imp.- Cerebral Calcification + Chorioretinitis + Hydrocephalus
Anaemia, HS-megaly, C Palsy
Features of Congenital Rubella infection ??
SNHL + Cataract + PDA + Glaucoma
HS-megaly, Growth retardation, Purpuric skin lesion, C Palsy
‘Salt & Pepper’ chorioretinitis, Microphthalmia
Actions of IL-1 ??
Secreted by Macrophages & Monocytes
- Co-stimulator of T & B cells proliferation
- Increases expression of Adhesion molecules
- Vasodilation & Increased vascular permeability (by stimulating release of PAF, Nitric oxide & Prostacyclins)
- Mediator of Shock in sepsis
Name some IL-1 inhibitors
Anakinra
- IL-1 receptor antagonist
- used in the Rx. of RA
Canakinumab
- Monoclonal antibody against IL-1 Beta
- used in Systemic Juvenile Idiopathic Arthritis & Adult onset Still’s disease
Which is the Slow Reacting Substance of Anaphylaxis [SRS-A] ??
Leukotriene D4
{Leukotrienes are secreted by Leukocytes}
Which cytokines causes fever ??
Il-1, 6 & TNF => acts in Hypothalamus => Fever
Which type of cells express MHC class II ??
Antigen Presenting Cells (responsible for processing antigen & presenting them on their cell surface so that it can be recognized by T-lymphocytes
- Dendritic cells, B-cells, Macrophages
Which cells do not possess either MHC-1 or MHC-2 ??
RBCs
