Immunology Flashcards
What does delayed separation of the umbilical cord suggest?
LAD (leukocyte adhesion deficiency)
Defect in integrins normally expressed on leukocytes (CD18)
Chediak Higashi Syndrome
Defect in microtubules prevents neutrophil phagosome-lysosome fusion
Inc risk of pyogenic infections, neutropenia, giant granules in leukocytes, defective primary hemostasis, partial albinism (melanocytes can’t pass pigment to keratinocytes), peripheral neuropathy, nystagmus
DiGeorge syndrome
Maldevelopment of the 3rd and 4th pharyngeal pouches
Thymic and parathyroid hypoplasia, abnormalal facies, and cardiac defects
T cell deficiency = immunosuppression
CATCH 22 Cardiac defects Abnormal facies Thymic dysplasia Cleft palate Hypocalcemia Deletion in chromosome 22
Chronic Granulomatous Disease Cause? Susceptible to? Test? Treatment?
Neutrophils have a defect in NADPH oxidase and can’t kill catalase positive organisms
Most common: pseudomonas and staph aureus and aspergillus
Test: nitroblue tetrazolium dye test or Dihydrorhodamine flow cytometry test
Treatment: IFN gamma
Nitroblue tetrazolium dye test
Used to evaluate for chronic granulomatous disease
Turns blue if NADPH oxidase works
Stays clear if NADPH oxidase is defective
HLA B27
PAIR: Psoriatic arthritis Ankylosing spondylitis Inflammatory bowel disease Reactive arthritis
HLA DR4
Rheumatoid Arthritis
4 walls in a “rheum”
Hyper IgE syndrome
Deficiency of Th17 cells - impaired recruitment of neurotrophils and decreased IgG production and decreased IFN-gamma
FATED course Facies staph Abscesses retained primary Teeth inc igE Dermatologic problems (eczema)
Foscarnet
Anti-viral (pyrophosphate analog)
Inhibits DNA polymerase in herpes virus and reverse transcription in HIV.
*Does not require intracellular activation by viral OR cellular kinases
Enteracept
TNFa inhibitor that impairs cell-mediated immunity. Before starting this medication, important to screen for latent TB to prevent reactivation
Mechanism of fever
- Macrophages release IL1 and TNF in response to a pyrogen (ex. LPS on bacteria)
- Inc COX activity in hypothalamus
- Inc production of PGE2
- Inc body temp (fever)
What are the anaphylatoxins in the complement cascade?
C3a and C5a
Trigger mast cell degranulation resulting in vasodilation and increased vascular permeability
What is the mechanism of the mast cell DELAYED response?
Production of arachidonic acid metabolites
Especially leukotrienes that cause increased bronchial tone/bronchospasm
What in the arachidonic acid pathway leads to increased chemotaxis of neutrophils?
LTB4
“Neutrophils arrive B4 others”
Where does vasodilation in inflammation occur?
Arterioles
Which prostaglandin mediates fever?
PGE2 (FEEEver)
Also mediates pain
Which prostaglandins mediate pain?
PGE2 and bradykinin
Where does vascular permeability occur during inflammation?
Post capillary venules
What causes inc susceptibility to recurrent Neisseria infections?
MAC complex (C5-C9) deficiency
Pathogenesis of granuloma formation (cells and products involved)
TH1 cells release IFN gamma –> activates macrophages
Macrophages release TNF alpha –> induces and maintains granuloma formation
Considerations when starting a patient on TNFa inhibitors (Enteracept)
Test for latent TB – lack of TNF alpha can lead to granuloma breakdown and leads to systemic disease
Hypercalcemia and granulomas
Granulomas produce calcitriol (1,25 OH2 vitamin D3) which causes an increase in calcium levels
c-ANCA
p-ANCA
(Anti-neutrophil cytoplasmic antibodies)
c-ANCA: target antigen is proteinase 3
p-ANCA: target antigen is MPO
Child is being evaluated for an eczematous skin rash. His past medical hx is significant for several bouts of severe respiratory infections. Initial evaluation reveals increased bleeding time. His CBC shows a WBC count of 9,000 and a platelet count of 40,000. His platelets are small and deformed on blood smear. What is the most likely diagnosis?
Wiskott Aldrich syndrome: X linked, combined B and T cell immunodeficiency.
WATER Wiskott Aldrich Thrombocytopenia Eczema Recurrent infections
