Immunology Flashcards
Bordetella Pertussis
Whooping cough
Gram negative
Primary Antibody Deficiency associated with sinusitis and ottis media
Selective IgA deficiency
Common variable immundeficieny
Specific antibody deficiency
X linked agammaglobulinemia
Complement system disorders
Patients with laryngeal angioedema
Severe congenital Neutropenia
Kostman Syndrome
Rare genetic disorder
Accumulation of precursor cells in bone marrow
Recurrent bacterial/fungal infections
Leukocyte adhesion deficiency
Caused by defect in CD18 integrin gene
Failure of neutrophil adhesion and migration
Chronic granulomatous disease
Deficiency of intracellular killing mechanisms of phagocytes - absent respiratory burst
Impaired killing of intracellular microorganisms
How can adaptive immune system go wrong?
Defects in leukocyte development
Defects in leukocyte effector functions
DiGeorge syndrome
Failure of production of CD4+ and CD8+ T cells
Developmental defect of pharyngeal pouch
Low set folded ears, high forehead, cleft pallet, small mouth and jaw
Hypocalcaemia
Oesophageal atresia
X linked agammaglobulinaemia
Failure to produce b cells
Hyper IgM syndrome
Severe reduction in serum IgG and IgA
Clinical features of T cell deficiencies
Recurrent infections
Opportunistic infections
Malignancies at a young age
Autoimmune disease
Clinical features of b cell deficiencies
Recurrent infections
Opportunist infections
Antibody mediated autoimmune disease
Hypersensitivity
Immune response resulting in damage to bystander
Usually exaggeration of normal immune mechanism
Pathophysiological basis for chronic diseases (allergy and autoimmunity)
Gel and Coomb’s Classification
- Immediate Hypersensitivity
- Direct cell effects
- Immune Complex Mediated
- Delayed Hypersensitivity
Type 1
Immediate Hypersensitivity
Allergy
IgE mediated antibody response to external antigen
2 stages of allergic disease
- Sensitisation
2. Allergic
Sensitisation stage
Mast cells and eosinophils express receptors for IgE antibody
First encounter allergen, B cells produce antigen specific IgE antibody
Allergen is cleared
Residual IgE antibodies bind to circulating mast cells
Allergic stage
Re-encounter antigen
Allergen binds to IgE-coated mast cells and disrupt cell membrane
Release of vasoactive mediators (histamine)
Increased expression of pro-inflammatory cytokines and leukotrines
Clinical features of allergic disease
Muscle spasm
Mucosal inflammation
Inflammatory Cell infiltrate
Type 2
Direct Cell Effects
Cell surface antigens
Involve IgM or IgG
Normal adaptive immune response
Goodpastures Syndrome
Type 2 Hypersensitivity
Autoimmune disease affecting lung and kidneys
Presence of auto-reactive antibodies to the alpha 3 chain of type IV collagen present in basement membranes of alveoli
From environmental insult
Treatment of Goodpastures Syndrome
Corticosteroids
Plasmapheresis
STOP SMOKING
Type 3
Immune Complex Mediated
Soluble Antigens
In presence of excess antigen, antibody binds forming small immune complexes
Trapped in small blood vessels, joints and glomeruli
Activation of complement system, opsonisation and neutrophils and macrophages
Acute Hypersensitivity Pneumonitis
TYPE 3 HYPERSENSITIVTY
Inhaled antigens deposited in lungs
Stimulate antibody formation
Antibodies form immune complexes with antigen
Complement activation, inflammation etc
Leukocyte accumulation and inflammation within alveoli
Type IV
Delayed Type Hypersensitivity
TB and Sarcoidosis
Sarcoidosis
Multi-system granulomatous disease
Small patches of red and swollen tissue to develop in organs
Affects lungs and skin
Management of sarcoidosis
Wait
NSAIDS
Systemic Corticosteroids
Autoimmunity
Presence of immune responses against self-tissue/cells
How does immune system deal with presence of auto-reactive T cells and B cells
Self tolerance mechanisms:
- Deletion of self-reactive lymphocytes in primary lymphoid tissues (central tolerance)
- Inactivation of self -reactive lymphocytes in peripheral tissues that escape central tolerane
Regulatory T cells
Essential in suppressing hyper-reactive or auto-reactive T cells
Via production of anti-inflammatory cytokines
Pathogenesis of autoimmune disease
Genetic Susceptibility
Breakdown of immune tolerance to self-antigens
Autoimmune disease
IPEX Syndrome
Monogenic Disorder (Single gene defect causes autoimmune disease) Symptoms = severe infections, excess etc Treatment = hematopoeietic stem cell transplant, Immunosuppressive drugs, parenteral nutrition
Pathogenesis of IPEX syndrome
X linked
Mutation in FOXP3 gene, needed for development of regulatory T cells
IPEX = failure of peripheral tolerance mechanisms due to defective T cells
HLA genes
Highly polymorphic
Graves disease
Hyperthyroidism
Auto-antibodies generated that bind to thyroid stimulating hormone receptor
Systemic Lupus Erythematosus
Type III
Severe relapsing autoimmune disease
Increased apoptosis, defective clearance of apoptotic material and dysregulation of neutrophil NETs
Rheumatoid Arthritis
Type IV
Complication = inflamamtion in lungs and heart
