2-Immunopathology Flashcards
types of grafts
- autograft- own tissues
- isograft- id twin, same genetic background
- allograft- same species, diff genetics
- xenograft- diff species
cellular mechanisms rejection
type IV hypersensitivity
- cell med cytotoxicity- host cytotoxic lymphs destroy graft parenchymal and endo cells by releasing perforins and granzymes = apop
- delayed type - helper lymphs > cytokines = recruit mononuc cells, inflamm mediators, tissue damage
inflamm meds = TNF, INF-gamma, IL-2
destruction pathways transplants
kidney
- direct = APC in graft from donor, leads to CD8 damaging tenal tubule epi cells, endothelitis, activated macros
- indirect = APC of recipient, leads to act macros, Ab’s injury endo cells of renal blood vessels
humoral mechanism
target graft vasculature
1. Ab binds HLA moles in graft endo to act complement = acute inflamm, vasculitis like type II hypersens
2. Ag-Ab complexes fix complement = necrotize, immune complex vasculitis
hyperacute rejection
-recipient sensitized from prior transplants, transfusions, pregnancies
-immediate/within minutes
-complement act, vasculitis with fibrinoid necrosis, thormbosis, ischemia
avoid by cross matching recip serum with donor lymphs to find cytotoxic Ab
acute rejection
days/months post transplant/withdrawal of immunosupp theapy
-progress rapidly
-cellular + humoral + combo mechanisms
-tubular damage and endothelitis from CD9, extensive interstitial inflamm from CD4 cytokines
acute humoral rejection
anti-graft Ab deposit in graft vasculature
patterns= necrotizing vasculitis + intimal thickening from fibros, foamy macros, myocytes
chronic rejection
months-years after transplant
-humoral injury = prolif vascular lesions
-cellular injury- cytokine induced prolif of vascular SM + collagen in ECM
vascular changes + intersititial fibrosis + tubular atrophy + chronic inflamm
heart transplantations
for advanced irreversible myocardial disease + intractable congestive heart failure
-get myocyte necrosis and coronary artery disease from intimal prolif
-also silent MI’s leading to heart failure or sudden death bc no nerve innervation of SA node
cyclosporine
blocks nuclear factor of activated T cells
-transcription factor for IL-2 stim of T cells
hematopoietic cell transplants
for treating hematologic disorders, non hematologic malignancies, immunodefs
-stem cells from donor marrow or peripheral blood + stim by hematopoietic growth factors
graft versus host disease, infection, immunodef complications
graft vs host disease
cell mediated rxn where donor T cells recog host HLA antigens as foreign = type IV rxn
targets epi of skin, GI tract, liver
actue GVHD
days-weeks post engraftment via donor cytotoxic T cells/cytokines destroy epi cells
rashes, exfoliation, ulcerative gastroenteritis, bile duct necrosis, profound immunosuppr
chronic GVHD
with or without acute GVHD
-from autoreactive T cells from donor stem not clonally deleted bc minimal immune fxn
mimics systemic sclerosis bc fibrosis of dermis/skin appendages, GI mucosa, bile ducts, lungs
self antigen intracellular molecules
- double stranded DNA = SLE
- histones = SLE
- topoisomerase I = diffuse scleroderma
- centromere proteins = limited scleroderma
criteria for dx autoimmune disease
- immunologic rxn to a self Ag or native tissue
- rxn primary to pathogenesis not secondary to tissue damage
- no other well defined cause/etiology
triggers of autoimmune disease
- genetics- certain MHC alleles on D locus, esp PTPN-22 gene for protein tyrosine phosphatase
- microbes - cross reactivity, tissue damage, inc APC co stim moles, non specific B and T stimulation
- gender- higher in females, hormones?
mechanisms of autoimm
- fail of tolerance/immune reg
- fail of T cell anergy
- fail of apop of self reactive cells
- fail/dysfxn of reg CD4 T cells
- molecular mimicry
- polyclonal lymphs activation
- emergence of sequestered Ag
- exposure of cryptic antigenic determinants
ANA testing
uses human tissue cell culture nuclei aka Hep 2 for specificity of nucleus componenets targeted by Ab
-either pos or neg
-titers
-fluorescent staining
peripheral staining
aka rim staining
-Ab to double strand DNA
-SLE active flares
homogenous/diffuse staining
Ab to chromatin, double strand DNA, histones
-anti histone specfic to drug induced LE
RA and SLE
speckled staining
Ab to ribonucleoproteins and DNA topoisomerase
-sjogrens syndrome
-if small nuclear RNP particles then SLE
-topo = systemic sclerosis diffuse
centromere staining
Ab to centromeres
-limited scleroderma, systemic sclerosis
nucleolar staining
Ab to nucleolar RNA
-SLE, systemic sclerosis, limited scleroderma
SLE diagnostic criteria
- malar rash/butterfly- flat or raised, fixed erythema
- discoid rash- raised patches with adherent keratotic scaling/follicular plugging, maybe atrophic scarrng
- photsensitivity
- oral ulcers- painless
- arthritis- nonerosive of 2+ joints with tender and swelling
- serositis- pleuritis or pericarditis
- renal disorder- proteinuria
- neurologic disoder- seizures or psychosis
- hematologic disorder- hemolytic anemia, leukopenia, lymphopenia, thrombocytopenia
- immunologic disoder- anti DNA, anti Sm, anti phospholipid
- antinuclear Abs- abnormal titer
lupus ANAs
- to double stranded DNA- rim, active flare ups
- histones- homogenous, drug induced lupus
- ribonucleoproteins- speckled, anti-Smith, anti nucleolar
- blood cells
- phospholipid proteins- plasma proteins so prothrombin, protein C, protein S
SLE common presentations
- hematologic - 100% of pts
- arthritis, arthalgia, myalgia
- skin
- fatigue
and literally everything else rip
lupus effects
organs involved = skin, joints, kidney, serous membranes
type II hypersens vs blood cells so hematologic abnormal
type III hypersens in visceral lesions
SLE in joints
arthritis common in hands, knees, ankles
-immune complexes deposit in synovium = inflamm
-no deformities like RA
lupus vascular changes
circulating immune complexes deposit in vascular beds and act complement = acute damaging inflamm rxn type III
-ANA-nuclear proteins
if acute then vasculitis + fibrinoid necrosis of arteries
if chronic then layered fibrous thickening
onion skin appearance
SLE in kidneys
immune complex depo in glomeruli, basement mem, large blood vessels
-lupus nephritis: protoype of immune complex glomerulonephritis
major cause of morbidity and mortality
lupus nephritis patterns
- membranous
- diffuse proliferative
both have prolif of endo, epi, mesangial cells
SLE in serosal membranes
serositis with effusions of pleura and pericardium
acute = exudation of fibrin
chronic = prolif of fibrous tissue so thickened membranes, adhesions
SLE in heart
frequent pericarditis, occasional myocarditis
-nonbacterial endocarditis affects both sides of valves anywhere but usually atrioventricular (Libman and Sacks)
accelerated coronary artery disease from steroid therapy or immune damage
libman sacks endocarditis
small/medium sized vegetations on either or both sides of valve leaflets
SLE-lungs
pleuritis with effusion
acute = pneumonitis + alveolar damage, edema, hemorrhage
chronic = interstitial and vascular fibrosis > pulmonary fibrosis and hypertension
SLE- CNS
usually seizures or neuropsychiatric symptoms but mech is unclear
small vessel thickening by intimal prolif = ischemia, microinfarcts
SLE- CNS
usually seizures or neuropsychiatric symptoms but mech is unclear
small vessel thickening by intimal prolif = ischemia, microinfarcts
SLE cause of deaths
- renal failure
- infection
- CAD (coronary artery disease?)
cutaneous forms of lupus
- chronic discoid- variety of skin lesions without systemic features
- plaques, erythema, scaling, atrophy - subacute cutaneous- diffuse, superficial, nonscarring, photosensitive lesions, mild systemic disease
drug induced lupus
lupus like syndrome with multi organ involvement
-antihistone ANAs
-rash, fever, arthralgias, serositis, but no renal or CNS pathology
-if stop drug then stop symptoms
D-penicillamine, procainamide, hydralazine, isoniazid
sjogrens syndrome
autoimm destruction of exocrine glands + primarily lacrimal + salivary glands
usually female middle aged
primary form is sicca syndrome with dec in tears and saliva
sjogrens syndrome mechanism
- CD4 T cell vs glandular epi self Ag, maybe induced by viral infection like EBV or Hep C
- systemic B cell hyperactivity > ANAs, rheumatoid factor positive usually too
- specific ANA to ribonucleoproteins like SS-A Ro and SS-B La
sjogrens morphology
CD4, B cells, plasma cells, infiltrate ducts and vessels in glands
-follicle formation with germinal centers
-ductal epi hyperplasia = obstruction
-acinar atrophy + fibrosis + fat replacement of parenchyma
clinical course of SS
-dry mucous mems > xerostomia, keratoconjunctivitis sicca, nasal septal erosion, perforation, dysphagia, dyspareunia
-lymph nodes massively hyperplastic
-inc risk B cell lymphoma
-systemic vasculitis with extraglandular kidneys, lungs, skin, CNS, muscle
-interstitial nephritis
-pulmonary fibrosis
-peripheral neuropathy
-synovitis
SS-A Ab
Systemic Sclerosis
autoimm with chronic inflamm + destruction small vessels and progressive tissue fibrosis
-skin and CT = rigid, loss of function
-GI, kidneys, heart, lungs, musculo = morbidity/mortality
CREST syndrome
limited variant of systemic sclerosis
-face, forearms, fingers, later visceral
-anti centromere Ab
CREST symptoms
- calcinosis- dystrophic in tissue
- raynauds phenomenon- vasospasm > intermitt digital ischemia
- esophageal dysmotility >acid reflux
- sclerodactyly- tighten skin hands
- telangiectasia- purple lesions skin + mucous
diffuse variant systemic sclerosis
-widespread skin involve at onset
-early visceral involve instead of later like limit
-rapid progression
-anti DNA topoisomerase Ab
diffuse variant symptoms
- early - edema, lymphocyte CD4 infiltrates
- late- epi thinning, dermal/appendage fibrosis, subq calcification, ultimate contractures (claw fingers)
- autoamputation of digits from ischemia
GI changes in systemic sclerosis
90% of cases
-esophagus collagenize and fibrosis of muscularis > dysmotility, LES dysfunction so reflux
-small bowel mucosal thinning, lose villi/microvilli, submucosal fibrosis so malabsorption
musculoskeletal changes systemic sclerosis
- early stage- nondestructive hyperpasia, inflamm of synovium
- late- fibrosis of synovial and periarticular CT
3.
renal changes systemic sclerosis
thick interlobular arteries by concentric prolif of intimal cells
-depo of collagen or mucinous material and hyaline cart
-maybe hypertension
pulmonary changes systemic sclerosis
mild interstitial pneumonitis
-alveolar fibrosis = resp insufficiency
-pulmonary hypertension from endo dysfxn = cor pulmonale/ R heart failure
cardiac changes systemic sclerosis
pericarditis + effusion
-perivascular lymphoid infiltrated
-arteriolar thickening
-interstitial fibrosis = restrictive cardiomyopathy
systemic sclerosis causes of death
renal, cardiac, pulmonary, GI
SAD clinical features
- asymptomatic OR recurrent GI/resp/GU infections
- weakened mucosal defenses
- anaphylactic rxn if transfused blood with IgA or given immunoglob therapy
- inc risk dev AI disorders
DiGeorge Syndrome
aplasia/hypoplasia of thymus and parathyroiid
-abnormalities of face and aortic arch bc interruption of 3rd and 4th pharyngeal pouch
T cell defect + hypocalcemia + cardiac abnorm + cleft palate
-normal immunoglob levels still
digeorges clinical features
- viral and fungal infections
- facial- low set ears, midline clefs, small mandible
- cardiac- VSD, R subclavian A from pulmonary
- hypoplasia
- aplasia- need transplant of fetal thymus
severe combined immunodeficiency
SCID
deficient cellular and humoral immune resp
-more common to have severe T cell defect than have both def in B and T
- X linked pattern bc mut of common y chain of cytokine receptor so ILs affected = impair lymph dev
- auto recessive pattern from adenosine deaminase def = lymphtoxic metabolites + fail class II MHC expression
SCID clinical features
- early onset- thrush, diaper rash, fail to thrive
- recurrent infections from all microbes
treat with marrow trans, gene therapy for ADA or y-chain mutations
wiskott aldrich syndrome
defect in protein gene for cytoskeletal maintenance and link membrane receptors
= progrssive depletion of T and B
x linked for males
Wiskott aldrich syndrome features
- immunodef
- thrombocytopenia
- eczema
- normal or elevated Ab except IgM low
- poor Ab resp to protein Ag
- T cell deficit, peripheral depletion in blood and nodal tissue
WAS symptoms
- hemorrhagic diathesis
- recurrent resp infections
- pyogenic bact/virus/fungi
- early death
- inc lymph alignancies in survivors
secondary immunodef
general
-more common than primary
-potentially reverse if underlying condition correct
-extremely young or old are targeted
-inc risk alcoholism or other metabolic states
-drug induced
-burns, traumas, chronic infections like EBV
-hematologic disorders
AIDS
-HIV 1 retroviral infection that targets immune sys and CNS
-immunosuppression > opportunistic infection, and neurologic abnormal
AIDS transmission
- sexual contact/mucosal
- parenteral inoculation/blood
- vertical- transplacental, intrapartum, perinatal
AIDS high risk groups
- homosex/bisex males
- intravenous/subq drug users
- recipients of transfused blood or blood products
- heterosexual contacts
AIDS effects
- selective lymphopenia of CD4 T with dec fxn
- polyclonal B cell act + hypergammaglob but impaired specific B cell resp to new Ag
- alter macro fxn with dec MHC II expr so dec Ag present
AIDS phases
- early/acute - viral rep, viremia, viral seeding of lymph tissue, fever, sore throat,
- middle chronic- repl in lymph tissue cont, weight loss, severe night sweats, fatigue, fever
- final/crisis- deplete T cells, fever, fatigue, weight loss, neoplasms
AIDS neoplasms
- kaposi sarcoma
- B celll lymphomas- bc hyperplasia, burketts, EBV > large cell and hodgkins, KSHV > primary effusion lymphoma
- primary lympoma brain
- invasive carcinomas of cervix and anus
pneumocystis pneumonia
alveoli fill with foamy exudate + interstitium thickened
-show cluster of fungi
symptom of AIDS
luxol fast blue stain
for leukoencephalopathy
@brain with HIV
kaposi sarcoma
purple dark lesions filled with blood anywhere in body usually hands or feet
kaposi sarcoma associated herpes virus from herpes type 8
amyloid characteristics
starch like fibrils form beta sheet + glyoprotein
congo red, green in fluroescent
amyloid pathogenesis
conversion of soluble circulating protein precursors into insoluble fibrillar form
-accum and deposit in organs
amyloid classification
amyloid light chain type
Ig light chains from abnormal clones from Ig plasma cells
@heart, GI, peripheral nerves, skin, tongue
amyloid associated
with inflamm or infectious
-fibrils non immuno AA protein and precursor SAA
ATTR
AB-2
@joints, tendons
A-beta
@cerebral blood vessels
alzheimers
Rheumatoid arthritis
systemic autoimm inflamm disorder @ joints, skin, vessels, heart, lungs, soft tissue
-unknown antigenic triggers
-mediated by CD4 T cells and connected to citrullinated peptides in chronic
-TH17, TH1, B cells/Ab
rheumatoid factor = IgM auto-Ab to Pc portion of IgG
RA morphology
prolif, destructive syn
