Immuno 1 Flashcards
Leukocyte adhesion deficiency
[Px, presentation, labs]
AR; absence of CD18 antigens, w/c promote integrin formation on endothelial cells – leukocyte adhesion and migration.
>Recurrent skin and mucosal infxns (S. aureus).
>No pus, Poor wound healing.
>Persistent leukocytosis since no migration.
>Late separation of umbilical cord (>21 days).
What physiologic events happen in Anaphylaxis? Lab diagnosis?
> Type I HSR; inc. vascular permeability and multisystem edema.
Widespread mast cell and basophil degranulation – histamine, tryptase.
Dx: inc. Tryptase
How does degranulation of mast cells and basophils occur in type I HSR?
> IgE-receptor is found on the surface of mast cells and basophils – binds to circulating IgE.
When a multivalent antigen comes into contact w/ the cell, the membrane-bound IgE crosslink and aggregate on the surface – triggers degranulation and release of mediators.
SCID
[Genetic inheritance, Pathogenesis, presentation]
XLR (defect in IL-2 receptor), AR (ADA deficiency).
Defective T cell dev. – absent T cells – absent Th cells – B cell dysfxn.
>High risk for recurrent infections.
>Chronic diarrhea, failure to thrive in infancy.
Candida antigen skin test.
How is it useful in dx SCID?
Assesses T cell-mediated immunity (Type IV HSR) via recruitment of macrophages and CD4+ and CD8+ T cells.
>Anergy (failure to respond) – typical to SCID.
How do you diagnose for Myasthenia gravis?
MG is an autoimmune type II HSR, w/ antibodies against skeletal myocyte postsynaptic ACh receptors.
>Dx: administer Acetylcholinesterase inhibitor – inc. ACh at NMJ, reversal of ssx
What is the appearance of the lymph node paracortex in DiGeorge Syndrome?
Normally, T cells mature in the thymus then migrate to lymph node paracortex for eventual differentiation and proliferation – paracortex enlarged.
In DiGeorge Syndrome, the paracortex is poorly developed since no mature T cells. There is deficiency in mature T cells due to thymic aplasia.
Why do live attenuated oral vaccines (Sabin polio) have stronger mucosal immunity than inactivated vaccines (Salk polio)?
Local secretory IgA prodn is better promoted when mucosal surface is directly stimulated by antigen – live attenuated ORAL vaccine for better duodenal mucosal protection.
Live attenuated vaccines also offer constant stimulus that activate Th and Tc cells.
Chediak-Higashi Syndrome
[px, peripheral blood smear, ssx]
AR; defect in neutrophil-phagosome-lysosome fusion.
Immunodeficient, Recurrent pyogenic infxns.
>PBS: giant lysosomal inclusions
>Neuro deficits (nystagmus); Partial albinism (abnormal melanin storage in melanocytes)
Patients w/ severe asthma and difficulty w/ symptom control (taking corticosteroids) should take what type of drug?
Anti-IgE antibody (Omalizumab, for allergic asthma)
>Omalizumab binds to IgE and inhibits its action on mast cells and basophils.
>Effective in reducing dependency on oral and inhaled steroids.
How are multinucleated giant cell granulomas formed in TB?
Macrophages can’t kill intracellular TB, so present antigens to naive T cells – secrete IL-12 to induce Th1 diff. – Th1 secrete IFN-gamma – more macrophages activated to improve ability to kill ingested bacteria.
*Macrophages also secrete TNF-alpha: more monocyte and macrophage recruited
What is the pathogenesis of Toxic shock syndrome?
TSST is a superantigen: interacts w/ MHC on APCs, T-cell receptors on T cells – widespread T cell activation.
>Macs: IL-1, TNF
>T cells: IL-2
>Capillary leakage, hypotension, shock, fever, skin findings, multiorgan failure
How is Sirolimus effective in transplant patients?
Immunosuppression
>Targets mTOR, w/c is normally triggered by IL-2 to induce cell growth and proliferation.
>Sirolimus inhibits mTOR signal transduction (G1 doesn’t move onto S phase).
>Inhibits lymphocyte proliferation
