#1 immunology Flashcards Preview

UWorld mixed > #1 immunology > Flashcards

Flashcards in #1 immunology Deck (103)
Loading flashcards...
1
Q

delayed separation of the umbilical cord

A

leukocyte adhesion deficiency
– along w/ poor wound healing, recurrent skin infections w/o pus, and gingivitis / periodonitis.

autosomal recessive, deficiency of CD18, needed for INTEGRIN formation

2
Q

steps for leukocyte exiting blood stream

A
  1. margination: increased vascular leakage –> hemoconcentration, decreased wall shear stress, improved contact of neutrophils w/ endothelial lining
  2. rolling - loose binding of sialylated carbohydrate groups (sialyl lewis X or PSGL-1 to L-selectin on neutrophils or E-selectin/P-selectin on endothelial cells
  3. activation - sense chemokine, will be able to bind
  4. tight adhesion and crawling - CD18 beta 2 integrins (Mac-1 and LFA-1) to intercellular adhesion molecule-1 (ICAM-1) on endothelial cells
  5. transmigration - PECAM-1, peripheral intercellular junctions of endothelial cells
3
Q

myeloperoxidase deficiency

A

similar to chronic granulomatous disease (NADPH deficiency), but since MPO is missing, can’t kill catalase + or catase - microbes (while NADPH def, can kill catalse - )

4
Q

alpha-2 globulins (name 3)

A

haptoglobin, ceruloplasmin, alpha-2 macroglobulins.

  • haptoglobin – scavenger molecule for hemoglobin released from RBC in hemolysis
  • ceruloplasmin – serum carrier protein for Copper ions, decreased in Wilson’s disease
5
Q

anterior mediastinal mass in graves patient

A

thymus abnormalities, (eg thymoma, thymic hyperplasia)

6
Q

polymyositis clinical presentation & implicated pathophys

A

autoimmune disease w/ symmetric proximal muscle weakness (CD8+ lymphocyte mediated damage)

7
Q

eosinophilic infiltration of skeletal muscle

A

eosinophilic myositis, rare disorder associated w/ parasitic infxn. present w/ myalgia

8
Q

IL-2 (aldesleukin) mechanism of action against tumor cells and therapeutic use

A

IL-2 anti-tumor effect by increasing T cell and NK activity.

immunotherapy for metastatic melanoma and renal cell carcinoma

9
Q

alemtuzumab

A

anti CD-52, used for treatment of chronic lymphocytic leukemia. initiates direct cytotoxic effect

10
Q

what agent increases MHC I and II presentation?

A

IFN gamma

11
Q

describe serum sickness

A

most serum sickness is now caused by drugs acting as haptens

type III hypersensitivity rxn
– fever, urticaria (hives), arthralgia, glomerulonephritis, lymphadenopathy 5-10 days after exposure to antigen. can have fibrinoid necrosis and neutrophil infiltration of arteries

decrease C3 (immune complex + complement)

sulfonamides can cause this

12
Q

graft vs. host disease commonly occurs after [3]

A
  1. allogeneic bone marrow transplantation
  2. transplantation of organs rich in lymphocytes (like liver)
  3. transfusion of non-irradiated blood

skin, liver, and GI tract commonly affected

acute gvhd – 1 wk post transplant

13
Q

distinguish (1) sarcoidosis (2) hypersensitivity pneumonitis (3) lymphocytic interstitial pneumonitis (AIDS)

A
(1) sarcoidosis
high CD4:CD8 T cell ratio (5:1 to 20:1)
(2) hypersensitivity pneumonitis
decreased CD4:CD8 ratio
(3) lymphocytic interstitial pneumonitis (AIDS)
decreased CD4:CD8 ratio 

look in bronchoalveolar lavage

14
Q

CD8+ T cell predominance in bronchoalveolar lavage fluid

A

lung transplant patient w/ bronchiolitis obliterans due to chronic rejection

15
Q

CD22+

A

immunological marker for ALL

16
Q

CD14+

A

monocyte macrophage lineage

17
Q

CD7+

A

multi-chain complex T cell marker

18
Q

Henoch-Schonlein purpura (HSP)

A

palpable skin lesion
abdominal pain
arthralgia
renal involvement

antigen exposure (bacterial / viral infxn) preceedig

deposition of IgA immune complexes

19
Q

delayed hypersensitivity occurs against which organisms

A

intracellular: m. tuberculosis and fungi. mediated by activated macrophages that form granulomata

most common vasculitis in 3-10 y/o

20
Q

recurrent mycobacterial or salmonella infxn? rx?

A

IL-12 receptor deficiency; ultimately have decrease IFN-gamma

macrophages infected w/ mycobacteria make IL12 –> stimulates T cells and NK cells to make IFN-gamma.

rx: lifelong treatment w/ antimycobacterial antibiotics.

21
Q

X-linked agammaglobulinemia

A

X-linked recessive; Brutons
defect in BTK tyrosine kinase, no B cell maturation

recurrent bacterial and enteroviral infxn after 6 months

small lymph nodes / tonsils

susceptible to lower respiratory infxn and giardia

22
Q

C3 deficiency

A
  • recurrent pyogenic sinus and respiratory tract infections

- increased type III hypersensitivity (b/c C3 helps clear immune complexes)

23
Q

symptoms of staphylococcal scalded skin syndrome (exfoliatin exotoxin)

A
  • Nikolsky sign (skin slipping off w/ gentle pressure)
  • epidermal necrolysis
  • fever
  • pain w/ skin rash

protease cleaves desmoglein in desmosomes

24
Q

langerhans cells

A
  • stellar cells w/ intracytoplasmic “tennis-shaped” Birbeck granules on EM
  • ## a form of dendritic cell (t cell interaction)
25
Q

Kupffer cells

A

macrophage-derived cells in liver, compose part of reticuloendothelial system
- lie in hepatic sinusoids

26
Q

Merkel cells

A

neuroendocrine cells of the basal layer of the epidermis, role in touch.
- associated w/ rare but highly malignant Merkel cell carcinoma

27
Q

Melanocytes

A

neural crest cells, migrate to basal layer of epidermis

  • dendritic processes that intercalate between cells of epidermis
  • deliver pigment-laden melanosomes to keratinocytes

darkening of skin does NOT mean more melanocytes. it means more MELANIN PRODUCTION

28
Q
  • (negative) nitroblue tetrazolium test on neutrophils
A

NADPH oxidase deficiency (chronic granulomatous disease) recurrent infxn w/ PLACESS NK
psuedomonas, listeria, aspergillus, candida, e. coli, s. aureus, serratia

X-linked

29
Q

cytochrome C oxidase deficiency

A

rare autosomal recessive disease, causes mitochondrial dysfunction

symptoms: weakness, hypotonia, and encephalopathy

30
Q

pyruvate kinase deficiency

A

common cause of hemolytic anemia caused by enzyme deficiency

31
Q

adenosine deaminase deficiency

A

primary cause of SCID. autosomal recessive. profound deficiency of both B and T lymphocytes

32
Q

define severe asthma. what is a novel treatment strategy?

A

severe asthma: needing ORAL steroids. symptoms throughout the day, nighttime symptoms daily, symptoms w/ limited activity, frequent exacerbations requiring ORAL STEROIDS, evidence of decreased lung function on pulmonary function tests, frequent use of short-acting beta-agonists

resistant to inhaled steroids & beta-agonists. NEED ORAL STEROIDS.

omalizumab (IgG1 against IgE) effective for moderate-to-severe persistent asthma (igE mediated)

33
Q

use of H1 blockers

A

even though histamine is a bronchoconstrictor, we don’t use H1 blockers in asthma.

treatment for chronic urticaria and allergic symptoms and sleep aid (if first generation)

34
Q

bortezomib

A

proteasome inhibitor treatment for multiple myeloma and waldenstrom macroglobulinemia

35
Q

embryological structure that fails to develop with digeorge

A

3rd-4th pharyngeal pouch (thymus and parathyroids)

36
Q

clinical presentation of diGeorge (2)

A
  • tetany (hypocalcemia; parathyroid gland aplasia

- recurrent viral/fungal infxn

37
Q

2nd branchial cleft (pharyngeal groove)

A

obliterated in normal human development. persistence = formation of branchial cleft cyst at angle of mandible

38
Q

3rd branchial arch

A

tissues innervated by CN9 (stylopharngeus muscle, portions of hyoid, posterior 1/3 of tongue

39
Q

4th branchial arch

A

tissue innervated by superior laryngeal branch of CN X, inclu most of the muscles of the soft palate and pharynx. also posterior 1/3rd of tongue

notable exceptions: tensor veli palatini muscle (CN V: 1st arch) and stylopharyngeus (CN IX: 3rd arch)

40
Q

septum transversum

A

mesodermally-dervived tissue that extends ventral to gut tube from umbilicus to pericardium. gives rise to myoblasts that form diaphragm and exists as a vestige of central tendon of diaphragm

liver grows into the septum transversum as an outpouching of the embryonal forgut

41
Q

why does too MUCH IgA increase risk for disseminated infection?

A

IgA fixation prevents IgM / IgG fixation. only IgM and IgG can fix complement to kill bacteria

42
Q

hypersensitivity pneumonitis produces serum IgG Abs which ppt what antigen?

A

actinomyces species antigen. type III hypersensitivity, deposition in vessel walls

43
Q

pathogenesis of contact dermatitis

A

repeated binding of small foreign molecules (haptens) applied to the skin surface to proteins on the surfaces of cutaneous cells. Langerhan cells bound to hapten + protein migrate to lymph node and generate circulating Th1 memory cell. upon cutaneous reexposure of hapten, Th! cells release inflammatory cytokines at site of exposure

type IV hypersensitivity

44
Q

atopic dermatitis

A

chronic, pruitic, eczematous skin condition that almost always begins in childhood, uncertain pathogenesis, can, but need not be type I

45
Q

candida extract injection tests for..

A

intact T-lymphocyte fxn, if an induration forms

will have + candida extract injection in Bruton’s agammaglobulinemia

46
Q

how does adenosine deaminase deficiency lead to SCID

A

needed for purine metabolism. adenosine -> inosine for elimination. adenosine accumulation is toxic, leads to death of T and B lymphocytes

47
Q

xanthine oxidase

A

responsible for the formation of uric acid from hyoxanthine and xanthine. essential as final step of purine degradation.

inhibited by allopurinol.

deficiency –> low uric acid level of serum & renal calculi due to relative insolubility of xanthine at urine pH

48
Q

transport of tetanospasmin (toxin produced by C. tetani) and pathogenesis of tetanus

A

retrograde axonal transport into CNS.

tetanospasmin heavy chain binds ganglioside receptors on neuronal membranes, and light chain inhibits glycine and GABA release from inhibitory interneurons

    • lockjaw (masseter muscle spasm)
    • opisthotonos
    • dysphagia
    • risus sardonicus

vaccine – formaldehyde inactivated tetanus toxin –> elicits humoral immunity

49
Q

antimitochondrial antibodies

A

primary biliary cirrhosis

50
Q

anti-nuclear antibodies

A

nonspecific in many connective tissue disorders

51
Q

anti-centromere antibodies

A

CREST

52
Q

anti-phospholipid antibodies

A

SLE and antiphospholipid antibody syndrome

53
Q

antiphospholipid antibody syndrome presentation

A

hypercoagulability, paradoxical PTT prolongation, recurrent miscarriages (spontaneous abortions)

54
Q

antibodies against DS-DNA

A

specific for SLE

55
Q

extrinsic pathway of apoptosis (FAS mediated)

A
  • Fas receptors aggregate and reveal death domain for Fas-associated death domain (FADD)
  • receptor-bound FADD stimulates activation of caspcase 8&10 (initiators) that begin an activation cascade culminating in activation of executioner caspase (3&6).

–> cleavage of DNA, fragmentation of nucleus, organelle autodigestion, plasma membrane blebbing

56
Q

describe the role of Fas and FasL on T-lymphocytes (along w/ activation-induced death)

A

Fas receptor on T-lymphocytes play an impt role in cancer and autoimmune disorders

activated T lymphocytes express Fas L.

initial clonal expansion, activated T-lymphocytes are resistant to Fas-induced apoptosis. become more sensitive w/ progressive stimulation

activation induced death: in the presence of stimulating self-antigens, activated T-lymphocytes eventually undergo apoptosis

57
Q

deficiency of Fas or Fas-L

A

impaired activation-induced death of self-reactive T cells –> autoimmune disease

58
Q

describe anergy vs. activation-induced death

A

state of prolonged unresponsiveness that occurs in T-lymphocytes as a form of immune tolerance. when self-reactive T cells bind to MHC w/o costimulation signal (CD28 w/ B7)

activation induced death: self-reactive T lymphocyte undergoes apoptosis

59
Q

loading of MHC I

A

cytoplasmic proteins are degraded in proteasome, transported into rough ER, loaded into MHC I, sent to cell surface via Golgi

60
Q

deficient DNA repair enzymes in Ataxia-telangectasia (ATM) is characterized by…

A

DNA hypersensitivty to ionizing radiation, but not UV

61
Q

deficient DNA repair enzymes in xeroderma pigmentosum is characterized by…

A

DNA hypersensitivity to UV radiation (premature skin aging, increased risk of skin cancer: malignant melanoma and squamous cell carcinoma)

62
Q

deficient DNA repair enzymes in Fanconi anemia is characterized by..

A

hypersensitivity of DNA to cross-linking agents

63
Q

deficient DNA repair enzymes in Bloom syndrome is characterized by…

A

generalized chromosomal instability, increased susceptibility to neoplasms

64
Q

deficient DNA repair enzymes in hereditary nonpolyposis colorectal cancer is characterized by…

A

defect in DNA mismatch enzymes. increased susceptibility to colon cancer

65
Q

ataxia telangiectasia

A

AR, defect in DNA-repair genes. hypersensitive to ionizing radiation. cerebellar ataxia, oculocutaneous telangiectasias, repeated sinopulmonary infections, increased incidence of malignancy

66
Q

which two things have posterior column involvement

A

vitamin B12 deficiency & syphilis

67
Q

what types of antigens can be presenting on MHC class I

A

viruses, tumor proteins, endogenous

68
Q

describe conjugate vaccine? name some protein carriers.

A

polysacch + diptheria toxoid

    • induce immunity against encapsulated bacteria (s. pneumoniae, n. meningitidis, h. flu)
  • protein needed to stimulate T cell response

protein carriers: mutant nontoxic diptheria toxin, n. meningitidis outer membrane protein complex, tetanus toxoid

69
Q

pertussis vaccine

A

acellular, contains purified components of Bordetella pertussis and detoxified pertussis toxin

70
Q

hepatitis B vaccine

A

purified inactivated HBsAg obtained from yeast through recombinant DNA technology

71
Q

varicella vaccine

A

live attenuated varicella virions

72
Q

BCG vaccine

A

live attenuated vaccine obtained from a strain of Mycobacterium bovis. used in young children to immunize against TB

73
Q

describe the two polio vaccines

A

Sabin oral polio vaccine (OPV) –> live attenuated virions
Salk inactivated polio vaccine (IPV) –> inactivated (killed) virions

only IPV is approved for use in US

74
Q

T-cell maturation:
arrive to thymus as?
1. positive selection 2. negative selection

A

arrive as double negative Pro-T cells in subcapsular zone. then, TCR beta gene rearrangement occurs w/ simultaneous expression of CD4 and CD8

  1. positive selection: can bind to MHC (thymic cortical epithelial cells)
  2. negative selection: binds to MHC + self antigen OR binds to MHC too strongly (thymic medullary epithelial and dendritic cells)
75
Q

what is affinity maturation? in which cell types does it occur?

A

enhaving the hypervariable region binding affinity. occurs after initial binding of antigen to membrane bound immunoglobulin on naive B lymphocyte and subsequent migration of that B-lymphocyte to a lymph node.

within the germinal center, affinity maturation is accomplished by the process of somatic hypermutation, DNA coding for the immunoglobulin variable region is mutated randomly at a very high rate.

does NOT occur in T-lymphocyte maturation

76
Q

TCR DNA rearrangement

A

10^15 diff possible antigen binding sites, similar to immunoglobulin gene rearrangement in that it involves VDJC regions of TCR gene & processes of junctional flexibility & P-region nucleotide addition, alternative joining of genes, mult peptides combining to form receptor

has an a and b protein segment

77
Q

when is the complement binding site on IgM Ab revealed

A

C1 binding site revealed only after antigen binding

78
Q

what is the Fab region of the Ab also known as?

A

complementarity-determining region

79
Q

Fc binding site of the Ab also serves as..

A

binding site for J chain of immunoglobulins in dimer (IgA) or pentameric (IgM) forms

80
Q

can C1 binding to 1 Ab stimulate classical cascade?

A

no, need at least 2 Ab

81
Q

who kills cells w/ decreased or absent MHC class I proteins?

A

NK cells; do not directly LYSE cell. instead, granzyme and perforins stimulate apoptosis

82
Q

NK cell marker? activated by?

A

CD 16 or CD 56. activated by IFN-gamma and IL-12

83
Q

eosinophil functions (2) what do their granules contain

A
  1. parasite defense. bound by free IgE when enters. binds IgE Fc on eosinophil. release major basic protein and other enzymes from granules (macrophages and NK cells also rely on ADCC)
  2. regulation of hypersensitivity reactions. granules have histaminase (degrades histamine, reduce severity of atopy). granules also have leukotrienes and peroxidases that facilitate inflammation
84
Q

lymph node anatomy: 4 major pieces. what is contained in each?

A

capsule, subcapsular sinus, cortex & paracortex, medulla & medullary sinuses

cortex: germinal follicles, B cells
paracortex: T lymphocytes and DC

subcapsular sinus (surround cortex: direct communication w/ afferent lymphatic vessels and cortical sinuses that line trabeculae

85
Q

what portion of the lymph node is enlarged during viral infections

A

paracortex

86
Q

describe primary and secondary follicles in lymph nodes

A

primary: dense and dormant
secondary: pale germinal center w/ proliferating B cells and follicular dendritic cells

87
Q

medullary cords in lymph nodes contain (3 cells)? medullary sinuses (2 cells)

A

medullary cord: B cells, plasma cells, macrophages

medullary sinus: reticular cells and macrophages

88
Q

what region of lymph node is in direct communication w/ affterent lymphatic vessels and cortical sinuses that line trabecuae

A

subcapsular sinus.

cortical sinus continuous w/ medullary sinus and single efferent lymphatic drain from hilum

89
Q

what does bradykinin do?

A

vasodilation, increased vascular permeability, stimulation of nonvascular smooth muscle contraction, mediates pain

90
Q

what do C3a, C4a, C5a do?

A

inflammatory anaphylotoxins that trigger histamine release from mast cells –> vasodilation and enhanced vascular permeability

C5a recruits and activates neutrophils, monocytes, eosinophils, and basophils

C3a recruits and activates eosinophils and basophils, not neutrophils

91
Q

leukotriene C4, D4, E4 triggers which 3 things?

A

vasoconstriction, vascular permeability, bronchospasm

think – constricts a lot of things

92
Q

leukotriene B4 & leukotriene precursor 5-HETE

A

stimulate neutrophil migration to site of inflammation

93
Q

neutrophilic chemtactic agents (5)

A

IL8, n-formylated peptides, leukotriene B4, 5-HETE, complement C5a

94
Q

Wiskott-Aldrich syndrome 3 cardinal features? main pathophysiology? Rx?

A
  • eczema
  • recurrent infections
  • thrombocytopenia

X-linked
WATER mnemonic
problem w/ actin cytoskeleton rearrangement & tethering of membrane proteins

rx: HLA-matched bone marrow transplant

95
Q

triad of hemolytic uremic syndrome

A
  • thrombocytopenia
  • microangiopathic hemolytic anemia
  • acute renal failure
96
Q

Chediak-Higashi

  1. gene defect
  2. inheritance
  3. clinical presentation
A

autosomal recessive

defect in LYST lysosomal trafficking regulator gene

microtubule dysfxn in phagosome-lysosome fusion

Bleeding and Bruising
oculocutaneous Albinism
Leukopenia
Infxn w/ staph & strep
peripheral Neuropathy
97
Q

poison ivy, poison oak, poison suman cause..

A

all produce common allergenic substance known as urushiol. 50% of individuals are sensitized. pruritic, erythematous, excoriation

delayed type IV hypersensitivity

98
Q

what would we see on muscle biopsy of a patient w/ polymyositis? serum?

A

MHC I class overexpression on sarcolemma and CD8+ T cell infiltration.

serum, see increased creatinine kinase and anti-jo-1 antibodies

99
Q

symptoms of polymyalgia rheumatica

A

bilateral stiffness of the shoulder and pelvic girdle muscles, fever, weight loss, increased ESR. association w/ temporal arteritis

100
Q

ankylosing spondylitis – (1) affected joints (2) demographic (3) common presentation (4) associated w/ MHC

A

chronic inflammatory disorder of sacroiliac joints and axial skeleton.

erosions, sclerosis, narrowing, and ultimately fusion.

spine x-ray –> bamboo spine, fused vertebrae

affects young & middle aged men, presents most commonly w/ morning stiffness and lower back pain. last 30 min and improves w/ exercise.

associated w/ HLA B-27 (PAIR - seronegative spondyloarthropathies

101
Q

where is the secretory piece of IgA made?

A

epithelial cells, all other components made by plasma cells

102
Q

when does the fetal thymus (derived from bone marrow) begin in gestation? when are mature naive T cells released into circulation?

A

begin in 9th wk of gestation, mature cells not realized until 16th week at earliest

103
Q

what is the best way to prevent neonatal tetanus?

A

ensure that all pregnant women have been vaccinated w/ tetanus toxoid. allows IgG antitoxin Abs to cross placenta