What causes acute graft rejection?
CD8+ cells or newly produced antibody against donor MHC
What causes chronic rejection?
Host T cells recognize donor MHC as self then react against the donor antigens presented on those MHCs
Both cellular and humoral
What causes hyperacute graft rejection?
Pre-formed antibodies against donor antigen (type II)
Biopsy of lung undergoing chronic rejection would show:
Bronchiolitis obliterans = inflammation and fibrosis of small airways
How long does it take for serum sickness to occur?
(Takes some time for antibody to be produced and to complex with antigen)
Biopsy of a graft undergoing acute rejection would reveal:
Dense interstitial lymphocytic infiltrate and vasculitis of graft vessels
What is the manifestation of chronic rejection of a heart transplant?
What are some symptoms of serum sickness?
Fever, arthralgia, proteinuria, lymphadenopathy, urticaria occuring 5-10 days after antigen exposure
Biopsy of kidney undergoing chronic rejection would show:
Obliterative vascular fibrosis + glomerulopathy
(Gross exam would show shrunken kidney)
Biopsy of kidney undergoing acute rejection would show:
Dense interstital lymphocyte infiltration + destruction of tubules
Describe the Arthus reaction
Immune complexes deposit locally after an intradermal injection causing edema, necrosis, and complement activation
(Antibody against antigen in whatever was injected)
What causes acute hemolytic transfusion reaction?
Host antibodies against donor ABO (intravascular) or antigen on RBC (extravascular)
What must occur before an Arthus reaction can occur?
Previous exposure to the antigen
(think about a man with previous snake bites forming a reaction against antivenom)
A child with a history of chronic URI's develops an anaphylactic reaction after a cross-matched blood tranfusion. What might be the cause?
IgA deficiency - donor blood had IgA in it so patient's blood mounted an attack
Describe serum sickness
A systemic Arthus reaction = antibodies bind antigen in blood and form immune complexes that deposit in various tissues throughout the body
What is the result of hyperacute rejection?
Widespread thrombosis of the graft --> ischemia and necrosis
Graft must be removed
How do you manage each stage of rejection?
Hyperacute - remove graft
Acute - immunosuppression
Chronic - supportive because damage is irreversible
What causes febrile non-hemolytic transfusion reactions?
Host antibody response against donor HLA and leukocytes (type II HS)
What is the major cause of serum sickness
What is the manifestation of chronic rejection of a lung transplant?
Biopsy of lung undergoing acute rejection would show:
Perivascular and peribronchial infiltrates
Cellular or humoral?
What is the manifestation of chronic rejection of a liver transplant?
Vanishing bile ducts
How can one test for the Arthus reaction?
What is the manifestation of chronic rejection of a renal transplant?
Vascular fibrosis and glomerulopathy