Immunology Flashcards
Lymph node structures:
Follicle
Paracortex
Medulla
Follicle: B cells (in outer cortex). Primary follicles dense, dormant; 2ndary active and have germinal centers
Paracortex: T cells, high endothelial venules (allow T and B cells to enter from blood). Enlarges w/ viral infxn, poorly dvlped w/ DiGeorge
Medulla:
- medullary cords: lymphocytes, plasma cells
- medullary sinuses: reticular cells, macrophages; communicate w/ efferent lymphatics
Selective IgA deficiency
Most common primary immunodeficiency; most asymptomatic, but can see airway and GI infxns (giardia), AI disease (celiac), atopy, anaphylaxis to IgA containing products (e.g. blood transfusions which contain small amounts of IgA)
What steps of protein synthesis do each of these block?
Aminoglycosides Tetracyclines Chloramphenicol Clindamycin Macrolides Linezolid
Linezolid: 50 initiation
Aminoglycosides: 30s initiation; also cause misreading of mRNA
Tetracyclines: 30s elongation
Chloramphenicol: 23s peptidyl transferase of the 50s subunit (catalyzes peptide bond formation/transfers growing polypeptide onto amino acid during elongation)
Macrolides: 50s translocation
Clindamycin: 50s translocation
LA TC MC (initiation, elongation, termination): “come to LA, Their Chipotle’s More Cultured”
Common serum tumor markers:
- AFP
- CA 19-9
- CA 125
- CEA
- hCG
- PSA
- AFP: HCC, germ cell tumors
- CA 19-9: pancreatic
- CA 125: ovarian
- CEA: GI (e.g. colorectal)
- hCG: choriocarcinoma, germ cell tumors, testicular cancer (can stimulate TSH receptors and cause PNPS hyperthyroidism)
- PSA: prostate
Antifungal targets
- Terbinafine
- Azoles
- Echinocandins
- Polyenes
- Flucytosine
- Terbinafine: lanosterol synthesis (squalene epoxidase)
- Azoles: ergosterol synthesis (14-a-demethylase)
- Echinocandins (e.g. caspofungin): cell wall synth (beta glucan)
- Polyenes (ampho B, nystatin): cell membrane integrity. directly act on ergosterol in membrane
- Flucytosine: DNA/RNA synthesis in nucleus
Antigenic shift vs. drift
- Antigenic shift: reassortment of viral genome e.g. when segments of human flu A virus reassort w/ swine flu A virus –> can cause a pandemic (more severe)
- Antigenic drift: minor changes based on random mutation in HA or NA genes; can cause epidemics
Neonatal conjunctivitis in NG vs. Chlamydia
- NG: purulent, occurs earlier (within 5 days)…“after 5 days, it’s gonnawaya (gonorrhea)!”
- Chlamydia (serovars D-K): watery, occurs later (1-2 wks)
Filgrastim, Sargramostim
aka GM-CSF. Used in leukopenia to recover granulocyte and monocyte counts
IL-2 as immunotherapy
Used for RCC and metastatic melanoma
Uses of IFN-alpha, beta, gamma as immunotherapy
- IFN-alpha: for chronic hep C (not preferred) and B, RCC, hairy cell leukemia and malignant melanoma, kaposi sarcoma, condyloma accuminata (HPV)
- IFN-beta: for MS
- IFN-Gamma: chronic Granulomatous disease
Actions of endogenous IFN-alpha, beta and gamma
- IFN-gamma: made by NK and T cellls in response to macrophages/IL-12 or Ag. Increases macrophage intracellular killing ability & MHC II xprssn
- IFN-alpha/beta: made by most human cells in response to viral infxn. Halt protein synthesis & promote apoptosis of infected cells to limit viral replication and spread
Wiskott-Aldrich syndrome
Mutated WASp gene; leukocytes and plt unable to reorganize actin cytoskel –> defective Ag presentation. XLR. Increased risk of AI dz & cancer. Decreased to normal IgG/M, increased IgE/A
WATER: Wiskott-Aldrich, Thrombocytopenia (fewer & smaller), Eczema, Recurrent (pyogenic) infxns. E and A in “wAtEr” for increased IgE/A
Respiratory vs. non-respiratory fluoroquinolones; which are active against pseudomonas
Levo and Moxi are respiratory (active against CAP, atypical pneumonia); Cipro is non-respiratory
Cipro and Levo are active against pseudomonas
Characteristics in each stage of syphilis
- painless chancre
- palm/sole maculopapular rash, condyloma lata (painless, warty white genital lesions)
- gumma (chronic granulomas), aortitis, argyll-robertson pupil (accomodates but unreactive to light); neurosyphilis (tabes dorsalis) common late manifestation but can occur at ANY stage
Congenital syphillis
snuffles, saddle nose, rhagades (linear scars at angles of mouth), hutchinson notched teeth, mulberry molars, sensorineural deafness. Tx mom in FIRST tri w/ Pen G
Organisms that cause infection with small dose
Shigella (10-500 cells)
C. jejuni (500 cells)
E. histolytica (1-10 organisms)
Giardia lamblia (10 organisms)
Side effects of amphotericin B
- Fever/chills
- Hypotension
- Nephrotoxicity (distal RTA and low GFR; reduce w/ hydration) –> arrhythmias (hypoK/Mg d/t increased DCT permeability), anemia (decreased Epo)
- IV phlebitis
Less side fx w/ liposomal amphotericin
Beta-lactams vs. vanco: mechanism of action
- Beta-lactams bind PBPs (e.g. transpeptidases) and prevent cross-linking of peptidoglycan in the cell wall
- Vanco binds terminal D-ala residues of cell wall glycoproteins and prevents transpeptidases from forming cross-links
Primary CNS lymphoma
AIDS-defining illness, pathogenesis involves EBV infection (but unlike abnormal T cells on peripheral smear, will see abnormal population of B cells in brain biopsy). May be ring-enhancing/must distinguish from Toxo via CSF/other lab tests
Primary vs. secondary TB
- Primary: hilar nodes + ghon focus (usually mid-lower lobes) = ghon complex. Either heals by fibrosis and calcification (Ranke complex) or progresses (e.g. w/ AIDS, malnutrition - insuff immune response) –> miliary TB (widespread dissemination
- Secondary: fibrocaseous cavitary lesion usually in upper lobes; can cause caseation and scarring in lung, kidney caseation, etc (localized destructive disease)
Apoptosis pathways
- Intrinsic (mitochondrial): inactivation of bcl2 –> cyt c leaks out of cell to activate caspases
- Extrinsic (receptor-ligand): FASL binds FAS (CD95) on target cell, or TNF-a binds its receptor on target cell activating caspases.
- Cytotoxic (cell-mediated): perforins create memb pores; granzyme enters pores –> activates caspases. Occurs w/ viral infected cells
Caspase activation –> activation of protease (destroys cytoskeleton) and endonuclease (destroys DNA)
IPEX syndrome
Genetic deficiency of FOXP3 on Treg cells. Immune dysregulation, Polyendocrinopathy (thyroiditis or T1DM), Enteropathy (diarrhea), X-linked (male infants). Also p/w AI dermatologic conditions e.g. eczema
Diagnostic features of Sjogren syndrome
2/3 criteria:
- dry eyes/mouth
- ANA and antiSSA or antiSSB or RF
- lymphocytic sialadenitis
Also at increased risk for B cell (marginal zone) lymphoma; late in dz course
Factors released by mast cells upon degranulation
Histamine, heparin, tryptase (can use as marker for mast cell activation; relatively specific), eosinophil chemotactic factors
