Transplant Immunopathology Flashcards

1
Q

Class 1 general

A

A,B,C nucleated cells

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2
Q

Class 2 general

A

DR, DP, DQ APCs

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3
Q

T vs B HLA markers

A
T - only class 1 
B - both
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4
Q

Inheritance of HLA antigens

A

25% chance that a brother or sister has a perfect match

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5
Q

Low res HLA typing

A

Used for solid organ

Serological equivalent

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6
Q

High res HLA typing

A

Allele level

Needed for stem cell

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7
Q

Serological typing def

A

What is expressed on the actual cell surface is tested

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8
Q

HLA antibody formation

A

Pregnancy - more pregnancy = better chance
Blood transfusions - use LRBCs in order to decrease risk
Prvious transplant - 90% within two weeks of allograft failure (more likely for HLA-DP antibodies)…cut off immunosuppression then better chance of prudcing ABS

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9
Q

HLA antibody screen process

A

Patient serum tested against a bunch of HLA antigens coupled to beads…specificities determined and listed

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10
Q

cPRA

A

Panel reactive antibodies….greater value means less probanbility of successful match

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11
Q

COld ischemic time

A

Longer that organ goes without oxygen and blood flow, greater chance it won;t work

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12
Q

MFI

A

Mean fluorescnece intensity…higher value means more antibodies and more concern

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13
Q

Virtual Crossmatch

A

Compare on paper

Look at donor HLAs and antibodies in recipient

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14
Q

Corssmatch

A

Detects preformed donor specific HLA antibodies in recipient
Utilize donor lymphocytes and recipient serum
Minimizes risk of hyperacute rejection

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15
Q

AHG-CDC crossmatch

A

Take lymphos from donor and separate into B and T…add patient serum and enhancing agent…use complement…if cell is dyed then determines if cell isdamaged…if damaged then incompatible

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16
Q

Flow cytometry crossmatch

A

Take lymphos from donor…add antibodies (1 to T and 1 to B)…add patient serum…add flueorescent anti0IgG antibody that sticks to antibodies and can see if shift vs. negative control

17
Q

Problem with crossmatch

A

Takes a few hours…okay for kidneys but not ideal for heart transplant

18
Q

Direct pathway T cell activation

A

Donor APCs will find way into recipient will find way into circulation…stimulates recipient helper T cells to amount response

19
Q

Indirect pathway T cell activation

A

INjured tissue cells are processed by recipient APCS and then presented to helper T cells

20
Q

Immunosuppressive agents

A

Cyclosporine A or tacrolimus (calcineurin inhibitor) used with mycophenolate and steroids

Predipose to infections and neoplasms

21
Q

Infections most common

A

In first 6 months post transplant

22
Q

Neoplasms

A

Skin (Basal cell carcinoma or squamous cell carcinoma)

Viral (cervical squamous cell carcinoma from HPV, Post-transplant lymphproliferative disoder from EBV, Kaposi’s sarcoma from HHV 8)

23
Q

Types of rejection

A

Hyperacute - AB mediation…secs to min
Acute - Cell or AB mediated…weeks to months or anytime with nonadherence
Chronic - multifactorail…months to years
Graft vs. host dz - cell mediated in stem cell trasnplant s

24
Q

Hyperacute rejection xenotransplantation

A

We have naturally occurring antiboides to animal HLAs so rapidly attack

25
Q

Hyperacute rejection

A

to HLA, ABO, xeno

Necrosis, vascular injury and thrombosis, interstital neutrophils

26
Q

Acute rejection

A

Immune cells encounter molecules like seelectiins that slow them down and then find target…majority will be cytotoxic T cells

27
Q

Acute rejection (AB)

A

Individual develops antibodies
Peritubular capillaritis in the kidney
C4d positivity by immunohistochemical stain or immunofluorescne

28
Q

DSA

A

Donor specific antibody screen

Can determien where there were mismatches

29
Q

Chronic rejection in kidiney leads to

A

Increased basmenet membrane

Peritubular capillary layering and glomerulitis

30
Q

Chronic rejection in heart

A

Cardiac allograft vasculopathy

Narrowed lumens of coronary arteries (circumferential vs eccentric of atherosclerosis),…must retransplant

31
Q

Chronic rehjection in lung

A

Obliterative bronchiolitis

Bronchioles narrow and must retrnaplant

32
Q

Liver chronic rejection

A

Bile duct loss (mostly in portal areas) and obliterative arteriopathy

33
Q

Chronic rejection in kidney

A

Don’t need to retransplant as urgently because can go back on dialysis

34
Q

Autologous stem cell transplantation

A

Use own stem cells to transplant…not subject ot GVHD

35
Q

Allogenic T cell depletion of donor

A

May reduce risk of GVHD
Increase risk of filaure to engraft (because T cells must find their home)
Increase risk of malginant tumor relapse because of leukemia vs T cell effect

36
Q

GVHD pathophysiology

A

Treat patient with conditioning…causes tissue injury…causes activation of APCs…donor T cells and host APCs lead to immune reaciton…a bunch of cytotoxic T cells ofdonor origin that circulate to tissues and cause damaage

37
Q

Acute GVHD

A

Less than 100 post transplant

Skin, GI, and liver

38
Q

Chronic GVHD

A

More than `00 days

Give immunosuppressant