Immune overview, autoimmunity, and primary immune deficiencies Flashcards
Th1: cytokines produced
IFN-gamma
Th2: cytokines produced
IL-4, IL-5, IL-13
Th17: cytokines produced
IL-17, IL-22, chemokines
IFN-gamma and IL-12 induce what Th subtype?
Th1
IL-4 induces what Th subtype?
Th2
TGF-beta, IL-6, IL-1, and IL-23 induce what Th subtype?
Th17
Th1: immunologic reactions triggered
- macrophage activation 2. stimulation of IgG 3. antibody production
Th2: immunologic reactions triggered
- IgE production 2. activation of mast cells 3. activation of eosinophils
Th17: immunologic reactions triggered
- recruitment of neutrophils 2. recruitment of monocytes
Th1 is used by the host to defend against what?
intracelluar microbes
Th2 is used by the host to defend against what?
helminthic parasites
Th17 is used by the host to defend against what?
extracellular bacteria, fungi
Th1: role in disease
immune-mediated chronic inflammatory diseases (often autoimmune)
Th2: role in disease
allergies
Th17: role in disease
immune-mediated chronic inflammatory diseases (often autoimmune)
Describe each of the four major Ig subtypes
- IgM: low affinity, activates the classical complement pathway 2. IgG: neutralizes microbes and toxins, opsonizes antigens, activates classical complement pathway, responsible for antibody-dependent cellular cytotoxicity (ADCC) 3. IgA: mucosal transport, neutralizes mucosal microbes and toxine 4. IgE: ADCC of parasites, responsible for allergy reaction (mast cell degranulation)
Name the three complement pathways and what is responsible for activating them
- Classical pathway: IgM and IgG 2. Alternative pathway: C3b 3. Lectin pathway: mannose-binding lectin (MBL)
All complement pathways converge on what?
Activation of C5-C9, forming the membrane attack complex (MAC)
Describe APECED
Autoimmune polyendocrinopathy candidiasis ectodermal dystropy (APECED): Cause: AIRE gene defect -> example of failure of central tolerance Autoimmune adrenal and parathyroid disease Can also induce autoimmune hypothryroidism, hypogonadism, vitiligo, and pernicious anemia Also associated with fungal infections (candidiasis)
APECED is caused by what?
AIRE gene defect -> thymic medullary cells do not express self-antigen -> self-reactive T-cells are not deleted (failure of central tolerance)
Name the major clinical features of APECED
- bradycardia, hypotension (salt craving) 2. bronzed skin 3. thrush in mouth 4. abnormal nails
Lab findings of APECED
- low cortisol 2. low calcium, low PTH 3. hyponatremia, hypocalcemia, hyperkalemia
Describe ALPS
Autoimmune lymphoproliferative syndrome (ALPS): Cause: mutations in Fas or FasL -> example of failure of peripheral tolerance Widespread lymphadenopathy, splenomegaly, and autoimmune cytopenias (hemolytic anemia and thrombocytopenia). High IgG, IgA, and IgM common Increased percentages of double-negative T-cells
Clinical features of ALPS
- Pallor 2. diffuse lymphadenopathy 3. splenomegaly