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IHO Week 5 > Immune Diseases #3 > Flashcards

Immune Diseases #3 Flashcards

1
Q

Autograft

A

self to self (ie skin)

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2
Q

Isograft

A

syngeneic, between identical twins

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3
Q

allograft

A

between genetically different individuals of same species

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4
Q

xenograft

A

between two species (ie porcine heart valve to human)

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5
Q

Major barrier to transplant success

A

rejection

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6
Q

what kinds of immunity involved in rejection of transplant

A

can involve both cell-mediated and antibody-mediated immunity

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7
Q

State the two groups of antigens that are most important in determining the likelihood of transplant rejection.

A

ABO and HLA

Key HLA loci involved in transplant rejection include HLA-A, HLA-B, HLA-C (minor importance), and HLA-DR.

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8
Q

T cell-mediated graft rejection is called

A

cellular rejection

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9
Q

Cellular rejection involves

A

destruction of donated graft cells by recipient CD8+ cytotoxic T lymphocytes and delayed hypersensitivity reactions triggered by activated recipient CD4+ T helper lymphocytes

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10
Q

Major antigenic differences between donor and recipient that results in rejection of transplants

A

differences in the highly pleomorphic HLA alleles

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11
Q

Two pathways for recipients T cells to recognize donor alloantigens

A

direct and indirect

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12
Q

Direct pathway

A

Donor class I and class II MHC antigens on antigen-presenting cells in the graft are recognized by host CD8+ cytotoxic T cells and CD4+ helper T cells, respectively. CD4+ cells proliferate and produce cytokines (e.g., IFN-γ), which induce tissue damage by a local delayed hypersensitivity reaction. CD8+ T cells responding to graft antigens differentiate into CTLs that kill graft cells.

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13
Q

Indirect pathway

A

In the indirect pathway graft antigens are picked up, processed, and displayed by host APCs and activate CD4+ T cells, which damage the graft by a local delayed hypersensitivity reaction and stimulate B lymphocytes to produce antibodies.

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14
Q

Antibodies produced against alloantigens in the graft are part of ____ rejection

A

humoral rejection

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15
Q

Important preformed anti-donor antibodies include:

A

Antibodies to ABO blood group antigens (naturally occurring)

Preformed anti-HLA antibodies (pregnancy, previous transfusion, previous transplant)

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16
Q

if preformed antibodies are present, a ________ reaction is possible

A

hyperacute rejection

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17
Q

How can antibodies to HLA antigens cause injury following transplantation?

A

several mechanisms, including complement-dependant cytotoxicity, inflammation, and antibody-dependant cell-mediated cytotoxicity. Antibody-mediated acute rejection is usually manifested in the vasculature, resulting in rejection vasculitis

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18
Q

key immunological factors affecting graft survival

A

ABO compatibility and close matching of HLA loci, along with an absence of preformed anti-HLA antibodies

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19
Q

Pre-transplant testing may include

A

ABO compatibility
HLA typing of donor and recipient
Detection of preformed anti-HLA antibodies
Lymphocyte cross-match (detect anti-HLA abs in recipients vs donor)

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20
Q

Hyperacute rejection d/t

A

ABO incompatibility and preformed anti-HLA abs in recipient

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21
Q

Hyperacute rejection steps

A

preformed ab bind endothelial antigens, activate complement, and result in vessel thrombi and ischemic necrosis (type II antibody-mediated hypersensitivity reaction).

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22
Q

hyperacute rejection when

A

minutes to hours following transplant

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23
Q

acute rejection can result from

A

from T cell-mediated hypersensitivity reactions (host CD4+ T-cells release cytokines, activating host macrophages, and CD8+ T-cells) or from antibody-mediated hypersensitivity reactions (host CD4+ T-cells release cytokines which promote B-cells to differentiate into plasma cells that produce anti-HLA antibodies that bind to endothelial antigens).

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24
Q

acute rejection when

A

days to weeks

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25
chronic rejection
occurs over months and years and is often secondary to vascular injury, as a result of both cell-mediated and antibody-mediated hypersensitivity reactions.
26
Chances of graft survival are improved by
ABO and HLA matching, with absence of preformed anti-HLA antibodies Use of immunosuppressive agent
27
Long term immunosuppressive therapy potential complications
increased susceptibility for opportunistic infections and malignancies
28
Autologous HCT
(auto-HCT) uses hematopoietic progenitor cells derived from the individual with the disorder.
29
Allogeneic HCT
allo-HCT) uses hematopoietic progenitor cells collected from someone other than the individual with the disorder.
30
underlying pathogenesis GVHD
the immunologically competent donor T cells recognize the recipient’s HLA antigens as foreign and react against them. Because the recipient (host) is immunocompromised (typically from myeloablative therapy), the host is incapable of mounting a reaction against the grafted lymphocytes, thus allowing the graft lymphocytes to attack the host.
31
autologous HCT and GVHD
Patients undergoing autologous HCT do not get GVHD
32
GVHD seen in what
allogeneic HCT, also liver transplants or transfusion of blood or platelets to immunocompromised host
33
Acute GVHD
occurring in the first 100 days following allogeneic hematopietic cell transplantation. The mechanisms of injury involves direct cytotoxicity by CD8+ T cells as well as cellular injury caused by cytokines released from activated CD4+ T cells.
34
Acute GVHD in what systems and symptoms
the skin, liver, and GI tract epithelium are most affected. Patients may experience severe dermatitis, destruction of small bile ducts with jaundice, and GI tract mucosal ulceration with bloody diarrhea.
35
chronic GVHD
more than 100 days after allogeneic HCT, may follow acute GVHD or occur insidiously.
36
chronic GVHD systems and symptoms
The skin may exhibit loss of skin appendages with dermal fibrosis. Chronic liver disease may result in cholestatic jaundice. The GI tract may exhibit fibrous strictures, along with malabsorption and chronic diarrhea. The lungs may show obliterative bronchiolitis.
37
Explain why patients undergoing HCT are immunodeficient.
of prior treatment, myeloablative therapy in preparation for the graft, and delay in the repopulation (reconstitution) of the recipient’s immune system
38
Common long-term toxicities of allogeneic HCT
●Chronic graft-versus-host disease (GVHD) ●Infections ●Treatment-related myelodysplasia/secondary leukemia ●Secondary solid tumors ●Cardiac disease ●Pulmonary toxicity
39
Autologous HCT survivor long term toxicities
``` ●Treatment-related myelodysplasia/secondary leukemia ●Secondary solid tumors ●Cardiac disease ●Pulmonary toxicity ●Infection ```
40
group of disorders characterized by the deposition of amyloid in the extracellular space of tissues and organs, resulting in tissue and organ dysfunction
amyloidosis
41
group of pathologic proteins that share similar physical properties
amyloid
42
H&E Amyloid
On H&E staining, amyloid appears as an amorphous, eosinophilic, hyaline, extracellular substance that can result in pressure atrophy of adjacent cells.
43
Amyloid Congo Red
It appears red with the Congo red stain and on polarization, the red stained amyloid exhibits a green birefringence.
44
Amyloid structure
It consists of linear, non-branching fibrils in a characteristic cross-beta-pleated sheet configuration. This physical configuration is seen regardless of the chemical composition and results in characteristic staining properties.
45
Is amyloidosis a single disease entity, or a group of diseases?
The various chemical types of amyloid are due to different pathogenic mechanisms. Thus amyloidosis is not a single disease, but a group of diseases having in common the deposition of similar appearing proteins.
46
How does amyloid injure adjacent cells?
amorphous, eosinophilic, hyaline, extracellular substance that can result in pressure atrophy of adjacent cells.
47
5 types of amyloid listed in class
``` AL AA beta-amyloid Transthyretin B2-microglobulin ```
48
AL made up of
Amyloid Light Chain either complete immunoglobulin light chains, the amino-terminal fragments of light chains, or both usually lambda
49
AL creation
is produced from free immunoglobulin light chain protein secreted by a monoclonal population of plasma cells (monoclonal lambda or kappa free light chain protein).
50
AA made from
Amyloid-associated derived by proteolysis of a larger precursor protein in the serum called SAA (serum amyloid-associated) protein that is synthesized in the liver and circulates in the serum associated with high density lipoprotein
51
AA/SAA increased when
The production of SAA is increased in inflammatory conditions as part of the acute phase response; thus, this form of amyloidosis is associated with chronic inflammation.
52
beta-amyloid protein made from
derived by proteolysis of a larger precursor protein called amyloid precursor protein.
53
beta-amyloid found where
This form of amyloid is found in the cerebral plaques of Alzheimer disease as well as in the walls of the cerebral vessels of patients with Alzheimer disease.
54
Transthyretin (TTR) amyloid from
normal serum protein that binds and transports thyroxine and retinol. Mutations of TTR can result in amyloid deposition, and these genetically determined disorders are referred to as heritable neuropathic and/or cardiomyopathic amyloidosis. TTR can also be deposited in the heart of aged individuals (as part of senile systemic amyloidosis) without mutation of TTR.
55
B2-microglobulin from
this normal serum protein cannot be filtered through dialysis membranes and can accumulate in patients on long term dialysis (>20 years) and the condition is known as hemodialysis-associated amyloiodosis.
56
prion diseases
In some cases of prion disease, amyloid protein can accumulate in the CNS as a localized form of amyloidosis.
57
amyloidosis involving several organ systems
systemic
58
amyloidosis involving a single organ (e.g. heart).
localized
59
subclassifications systemic amyloidosis
primary | secondary
60
primary amyloidosis
when associated with an clonal proliferative disorder of plasma cells producing light chain immunoglobulin
61
secondary amyloidosis
when it occurs as a complication of an underlying chronic inflammatory process
62
a group of heterogenous, heritable forms of amyloidosis with several distinctive patterns of organ involvement.
hereditary (familial) amyloidosis
63
Typical distribution of amyloid deposition AL (primary)
Sites typically affected include heart, kidney, peripheral nerve, gastrointestinal tract, respiratory tract, but nearly any other organ can be involved. (Systemic)
64
Underlying pathogenesis AL (primary)
Monoclonal proliferation of plasma cells (MM or underlying monoclonal plasma cell proliferation which produces an abnormal light chain protein, or ig secreting Bcell lymphomas)
65
Reactive Systemic Amyloidosis AKA
as AA amyloidosis, secondary amyloidosis, second most common type of amyloidosis in the USA
66
Reactive Systemic Amyloidosis is secondary to
chronic inflammatory condition, such as rheumatoid arthritis, other CT disordrs, IBD Can also be seen associated with renal cell carcinoma and Hodgkin lymphoma
67
Most common type of amyloidosis in developing world
AA amyloidosis is the most common cause of amyloidosis, due to chronic inflammation associated with infectious disease (e.g. TB, leprosy, osteomyelitis).
68
Sites commonly affected with reactive, systemic, amyloidosis
Kidney, liver, spleen
69
hemodialysis-associated amyloidosis deposition of what
to deposition of amyloid derived from beta-2 microglobulin, which accumulates in patients with end-stage renal disease who are being maintained for prolonged periods of time by dialysis
70
where does Hemodialysis-associated amyloidosis deposit
osteoarticular structures
71
Familial Mediterranean Fever
Autoinflammatory syndrome Autosomal recessive Mutation in gene that produces proteins that regulate inflammatory reactions (AA protein)
72
Familial amyloidotic neuropathies
disorders associated with mutant forms of TTR
73
Age-related (senile) Systemic amyloidosis due to
amyloid deposition associated with normal (wild-type) TTR protein.
74
Senile systemic amyloidosis normally involves
heart --> restrictive cardiomyopathy and arrhythmias | renal rarely
75
Localized amyloidosis
Amyloid deposits limited to a single organ or tissue without involvement of other tissues or sites.
76
clinical symptoms of systemic amyloidosis
waxy skin and easy bruising, enlarged muscles (e.g. tongue, deltoids), symptoms and signs of heart failure, cardiac conduction abnormalities, hepatomegaly, renal dysfunction (heavy proteinuria or the nephrotic syndrome), peripheral and/or autonomic neuropathy, and impaired coagulation (acquired factor X deficiency due to this coagulation factor binding to amyloid)
77
Diagnosis of amyloidosis
tissue biopsy with staining for amyloid. Biopsy can be directed at a suspected clinically involved organ (e.g. kidney, nerve) or a clinically uninvolved site if systemic disease is suspected (fat pad aspiration, rectal biopsy)
78
Treatment amyloidosis
Varies with the cause of amyloid production. Treat underlying infectious or inflammatory disorder in AA amyloidosis Treat monoclonal plasma cell proliferation in AL amyloidosis Either alter mode of dialysis or consider renal transplantation in patients with dialysis-related amyloidosis

IHO Week 5 (3 decks)

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