immunology Flashcards
CD8+ cytotoxic T-lymphocytes function
binds to MHC I on virus-infected cells
directly kill virus-infected, neoplastic, and donor graft cells by inducing apoptosis
CD4+ T cells function
help B cells make antibodies and produce cytokines to recruit phagocytes and activate other leukocytes
thymoma is associated with which two diseases/disorders
myasthenia gravis and superior vena cava syndrome
what is X-linked (Bruton) agammaglobulinemia
defect in B cell maturation, resulting in the absence of mature B cells with severe deficiency of all immunoglobulin types
T cell numbers and function remain intact
absence of B cells–> primary lymphoid follicles and germinal centers will not form within lymph nodes
what is the Jarisch-Herxheimer reaction
acute inflammatory reaction that occurs within hours of treatment for spirochetal (eg, syphilis) infection
rapid lysis of spirochetes releases inflammatory bacterial lipoproteins into the circulation and causes acute fevers, rigors, and myalgias
what does interferon-gamma do and where does it come from?
produced by activated T lymphocytes (both CD4+ and CD8+) and natural killer cells
activates macrophages, increases MHC expression, and promotes Th1 differentiation
what do IFN-gamma release assays (IGRAs) test for
latent TB infection by measuring the response of T lymphocyte when exposed to antigens unique to mycobacterium tuberculosis
have comparable sensitivity and specificity to TB skin tests but does not cross-react with Bacille Calmette Guerin (BCG) vaccine
can’t distinguish between active TB and latent TB (same thing with the skin test)
pneumococcal conjugate vs. pneumococcal polysaccharide vaccines
conjugate: strongly immunogenic in infancy due to both B and T cell recruitment; provide higher, longer-lasting antibody titers; allows for development of memory B cells; recommended for immunocompromised patients and adults >65 and children <2
polysaccaride: protects against wider range of serotypes, but antibody levels decline over about 5 years; have relatively immature humoral antibody response; recommended for all adults age >65 and for those age 2-64 with certain medical conditions
Henoch-Schonlein purpura- associated to what with the immune system
immune complex vasculitis associated with IgA and C3 deposition
affect children 3-11–> palpable skin lesions, with or without abdominal pain and athralgias
self-limiting, but kids must be observed for glomerulonephritis and even end-stage renal disease
C1 inhibitor (C1INH) deficiency increases
bradykinin
the deficiency causes increased cleavage of C2 and C4–> inappropriate activation of complement casecade
C1 blocks kallikrein-induced conversion of kininogen to bradykinin so deficiency leads to bradykinin
symptoms: bradykinin-associated angioedema (facial swelling, life-threatening laryngeal edema, and GI manifestations
treat with : manage acute attacks with supportive care and administer C1INH concentrate or a kallikrein inhibitor
what is hyperimmunoglobulin M (hyper-IgM) syndrome
defective immunoglobulin class switching due to defect in the CD40 ligand-CD40 interaction
X-linked recessive
clinical features: sinopulmonary, GI, and opportunistic infections
why use epinephrine to treat anaphylactic shock
its ability to reverse all of the pathophysiologic mechanisms of anaphylaxis
stimulation of alpha1 receptors counteracts the vasodilatation of cutaneous and viscera vasculature, thus increasing blood pressure
increases cardiac contractility (beta1 effect) an dcardiac output increase blood pressure and improve peripheral perfusion
stimulation of beta2 receptors results in bronchodilatation, so help with asthmatic reactions
which complement is important or opsonization
C3b
also need IgG
which complement is important for anaphylactic reactions?
C3a and C5a
anaphylaxis results from widespread mass cell and basophil degranulation and release of preformed inflammatory mediators such as
histamine and tryptase
tryptase: relatively specific to mast cells and can be used as a marker for mast cell activation
