TransplantatioTransplantationn

TransplantationTransplantation

= transfer of tissue or organ= transfer of tissue or organ

●● autologousautologous - donor = recipient - donor = recipient

● ● syngeneicsyngeneic - genetically identical donor and - genetically identical donor and recipient recipient (identical twins) (identical twins)

● ● allogeneicallogeneic - genetically nonidentical donor of - genetically nonidentical donor of the the same species same species

● ● xenogenicxenogenic - the donor of another species - the donor of another species

● ● implantimplant - artificial tissue compensation - artificial tissue compensation

AllotransplantationAllotransplantation

●● differences in donor-recipient MHC gp and differences in donor-recipient MHC gp and secondary secondary histocompatibility Ag histocompatibility Ag

●● alloreactivity of T lymphocytesalloreactivity of T lymphocytes - the risk of rejection - the risk of rejection and and graft-versus-host graft-versus-host diseasedisease

●● direct detection direct detection ofof alloantigens alloantigens – recipient T – recipient T lymphocytes lymphocytes recognize the different MHC gp and non-MHC recognize the different MHC gp and non-MHC molecules molecules on donor cells on donor cells

●● indirect recognition indirect recognition ofof alloantigens alloantigens - APC absorb - APC absorb different different MHC gp MHC gp fromfrom donor cells and present the fragments donor cells and present the fragments to to T lymphocytes T lymphocytes

●● CD8+ T cells recognize MHC gp I.CD8+ T cells recognize MHC gp I.●● CD4+ T cells recognize MHC gp II.CD4+ T cells recognize MHC gp II.

Recognition Recognition ofof alloantigens alloantigens

Testing before transplantationTesting before transplantation

●● ABOABO compatibility compatibility -risk of hyperacute or accelerated -risk of hyperacute or accelerated rejection rejection (= formation of Ab against A or B Ag on graft vascular (= formation of Ab against A or B Ag on graft vascular endothelium) endothelium)

●● HLA typingHLA typing (determining of MHC gp alelic forms) (determining of MHC gp alelic forms) phenotyping and genotyping by PCR phenotyping and genotyping by PCR

●● Cross-matchCross-match - lymphocytotoxic test – detection of - lymphocytotoxic test – detection of preformed Abpreformed Ab (after blood transfusions, transplantation, repeated (after blood transfusions, transplantation, repeated childbirth)childbirth) ●● Mixed lymphocyte reactionMixed lymphocyte reaction - testing of T lymphocytes - testing of T lymphocytes

alloreactivity, monitor for alloreactivity, monitor for reactivity of lymphocytesreactivity of lymphocytes to allogeneic HLA to allogeneic HLA

HLA typingHLA typing

a) phenotypinga) phenotyping: Evaluation of HLA molecules using : Evaluation of HLA molecules using typing typing serums serums Typing antiserums = alloantiserums of multipar Typing antiserums = alloantiserums of multipar (created (created cytotoxic Ab against paternal HLA Ag of their children), cytotoxic Ab against paternal HLA Ag of their children), serum serum of patients after repeated blood transfusions, of patients after repeated blood transfusions, monoclonal Abmonoclonal Ab

- molecules HLA class I: separated T lymphocytes- molecules HLA class I: separated T lymphocytes - molecules HLA class II: separated B lymphocytes- molecules HLA class II: separated B lymphocytes

b) genotypingb) genotyping: evaluation of specific alleles: evaluation of specific allelesDNA typing of HLA class II: DR, DP, DQ by PCRDNA typing of HLA class II: DR, DP, DQ by PCR

Cross-match testCross-match test

●● determination of preformed antibodiesdetermination of preformed antibodies

●● recipient serum + donor lymphocytes + rabbit recipient serum + donor lymphocytes + rabbit complement complement → if cytotoxic Ab against donor HLA Ag are present in → if cytotoxic Ab against donor HLA Ag are present in

recipient serum (called recipient serum (called alloantibodiesalloantibodies = Ab = Ab activating activating complement) → lysis of donor lymphocytes. complement) → lysis of donor lymphocytes. Visualization of dye penetration into lysis cells. Visualization of dye penetration into lysis cells.

●● positive testpositive test = the presence of preformed Ab → = the presence of preformed Ab → risk of risk of hyperacute rejection!hyperacute rejection! → → contraindication to contraindication to transplantation transplantation

Mixed lymphocyte reaction (MRL)Mixed lymphocyte reaction (MRL)

●● determination of T lymphocytesdetermination of T lymphocytes alloreactivityalloreactivity

●● mixed donor and recipient lymphocytes → T mixed donor and recipient lymphocytes → T lymphocytes lymphocytes after recognition of allogeneic MHC gp activate and after recognition of allogeneic MHC gp activate and proliferateproliferate

One-way MRLOne-way MRL

●● determination of recipient T lymphocytesdetermination of recipient T lymphocytes reactivity reactivity against against donor cells donor cells

●● donor cells treated with chemotherapy or irradiated donor cells treated with chemotherapy or irradiated lose the lose the ability of proliferation ability of proliferation

Mixed lymphocyte reaction (MRL)Mixed lymphocyte reaction (MRL)

Immunologically privileged sites and Immunologically privileged sites and

tissuestissues • Transplantation of some tissues don´t lead to the induction Transplantation of some tissues don´t lead to the induction

of allogeneic reactivityof allogeneic reactivity• minimal content of lecocytesminimal content of lecocytes• mechanisms that prevent to the development of mechanisms that prevent to the development of

injurious inflammation injurious inflammation

• Evolutionarily significant, protection of vital organs (brain, Evolutionarily significant, protection of vital organs (brain, eye, gonads)eye, gonads)

• Factors protecting immunologically privileged structuresFactors protecting immunologically privileged structures• isolation from the immune systemisolation from the immune system

• preference of Tpreference of THH2 reactoin, supression of T2 reactoin, supression of THH1 reaction1 reaction

• FasL expressionFasL expression• production of TGFproduction of TGF

Rejection Rejection

Factors:Factors:

●● The genetic difference between donor and recipient, The genetic difference between donor and recipient, especially in the genes coding for MHC gp (HLA) especially in the genes coding for MHC gp (HLA)

●● Type of tissue / organ - the strongest reactions Type of tissue / organ - the strongest reactions against against vascularized tissues containing many APC (skin) vascularized tissues containing many APC (skin)

●● The activity of the recipientThe activity of the recipient immune system - the immune system - the immunodeficiency recipient has a smaller rejection immunodeficiency recipient has a smaller rejection reaction; reaction; immunosuppressive therapy after transplantation – immunosuppressive therapy after transplantation – suppression of rejection suppression of rejection

●● State of transplanted organ - the length of ischemia, State of transplanted organ - the length of ischemia, the the method of preservation, method of preservation, traumatization of organ at traumatization of organ at collectioncollection

Hyperacute rejectionHyperacute rejection

●● minutes to hours after transplantationminutes to hours after transplantation●● humoral mediatedhumoral mediated immune response immune response

mechanism:mechanism:●● if in recipients blood are present if in recipients blood are present preformed preformed oror natural natural Ab Ab (IgM anti-carbohydrate Ag) before (IgM anti-carbohydrate Ag) before transplantationtransplantation → → Ab + Ag of graft (MHC gp or endothelial Ag) → Ab + Ag of graft (MHC gp or endothelial Ag) → graft graft

damage by activated complement damage by activated complement (lysis of (lysis of cells)cells)

●● the graft endothelium: activation of coagulation the graft endothelium: activation of coagulation factors and factors and platelets, formation thrombi, accumulation of platelets, formation thrombi, accumulation of neutrophil neutrophil granulocytes granulocytes

prevention:prevention:●● negative negative cross match cross match before transplantation, before transplantation, ABOABO

compatibility compatibility

Accelerated rejectionAccelerated rejection

●● 3 to 5 days after transplantation3 to 5 days after transplantation

●● caused by caused by antibodiesantibodies that don´t activate that don´t activate complementcomplement

●● cytotoxic and inflammatorycytotoxic and inflammatory responses triggered responses triggered by by binding of antibodies to Fc-receptors on phagocytes binding of antibodies to Fc-receptors on phagocytes and and NK cells NK cells

prevention:prevention:●● negative negative cross matchcross match before transplantation, before transplantation, ABOABO compatibility compatibility

Acute rejectionAcute rejection

●● days to weeks after the transplantation or after a days to weeks after the transplantation or after a lack of lack of immunosuppressive treatment immunosuppressive treatment

●● cell-mediatedcell-mediated immune response immune response

mechanism:mechanism:●● reaction of recipient Treaction of recipient THH1 and T1 and TCC cells against Ag cells against Ag of graft of graft tissue tissue●● infiltration by lymphocytes, mononuclears, infiltration by lymphocytes, mononuclears, granulocytes granulocytes around around smallsmall vessels vessels → destruction of tissue → destruction of tissue transplanttransplant

Chronic rejectionChronic rejection

●● from 2 months after transplantationfrom 2 months after transplantation

●● the most common cause of graft failurethe most common cause of graft failure

mechanismmechanism is not fully understood: is not fully understood:●● non-immunological factors (tissue ischemia) and non-immunological factors (tissue ischemia) and TTHH2 2 responses with production alloantibodies, responses with production alloantibodies, pathogenetic pathogenetic role of cytokines and growth factors (TGF β)role of cytokines and growth factors (TGF β)

●● fibrosis of the internal blood vessels of the fibrosis of the internal blood vessels of the transplanted transplanted tissue, endothelial damage →impaired perfusion tissue, endothelial damage →impaired perfusion of of graft → gradual loss of its function graft → gradual loss of its function

dominating findings: vascular damagedominating findings: vascular damage

Bone Marrow TransplantationBone Marrow Transplantation

●● Collection of hematopoietic stem cellsCollection of hematopoietic stem cells

●● Myeloablation Myeloablation

●● Transplantation Transplantation

●● Engraftment Engraftment

●● Rejection Rejection

●● Graft-versus-host reaction Graft-versus-host reaction

Graft-versus-host (GvH) diseaseGraft-versus-host (GvH) disease

●● after bone marrow transplantationafter bone marrow transplantation

●● GvH also after blood transfusion to GvH also after blood transfusion to immunodeficiency immunodeficiency recipients recipients

●● T-lymphocytes in the graft bone marrow recognize T-lymphocytes in the graft bone marrow recognize recipient recipient tissue Ag as foreign (alooreactivity) tissue Ag as foreign (alooreactivity)

Acute GvH diseaseAcute GvH disease

●● days to weeks after the transplantation of stem days to weeks after the transplantation of stem cellscells

●● damage of liver, skin and intestinal mucosadamage of liver, skin and intestinal mucosa

●● prevention: appropriate donor selection, the prevention: appropriate donor selection, the removal removal of T lymphocytes from the graft and effective of T lymphocytes from the graft and effective immunosuppressionimmunosuppression

Chonic GvH diseaseChonic GvH disease

●● months to years after transplantationmonths to years after transplantation

●● infiltration of tissues and organs by Tinfiltration of tissues and organs by THH2 2 lymphocytes, lymphocytes, production of alloantibodies and cytokines → production of alloantibodies and cytokines → fibrosisfibrosis

●● process like autoimmune disease: vasculitis, process like autoimmune disease: vasculitis, scleroderma, scleroderma, sicca-syndrome sicca-syndrome

●● chronic inflammation of blood vessels, skin, chronic inflammation of blood vessels, skin, internal internal organs and glands, which leads to fibrosis, blood organs and glands, which leads to fibrosis, blood circulation disorders and loss of functioncirculation disorders and loss of function

Graft versus leukemia effect (GvL)Graft versus leukemia effect (GvL)

● ● donor T lymphocytes react against residual donor T lymphocytes react against residual

leukemick cells of recipient (setpoint leukemick cells of recipient (setpoint

response)response)

● ● mechanism is consistent with acute GvHmechanism is consistent with acute GvH

● ● associated with a certain degree of GvH associated with a certain degree of GvH

(adverse (adverse

reactions) reactions)

Immunologic relationship Immunologic relationship

between mother and between mother and

allogenic fetusallogenic fetus

Immunologic relationship between mother Immunologic relationship between mother and allogenic fetusand allogenic fetus

●● fetal cells have on the surface alloantigens fetal cells have on the surface alloantigens inherited from his father inherited from his father

●● pregnancy = "semiallogenic transplantation“pregnancy = "semiallogenic transplantation“ Tolerance of fetus by mother allow the following Tolerance of fetus by mother allow the following mechanisms:mechanisms:●● the relative isolation of the fetusthe relative isolation of the fetus from maternal from maternal immune immune system (no mixing of blood circulation) system (no mixing of blood circulation)

●● trophoblasttrophoblast - immune barrier witch protects against - immune barrier witch protects against mother mother alloreactive T lymphocytes alloreactive T lymphocytes - don´t express classical MHC gp, expresses - don´t express classical MHC gp, expresses non-classical HLA-E and HLA-G non-classical HLA-E and HLA-G

●● transfer of small doses of fetal antigens in maternal transfer of small doses of fetal antigens in maternal circulation circulation causes tolerance ... suppressin of T causes tolerance ... suppressin of THH1 and preference of T1 and preference of THH2 2

immune mechanisms in pregnancy immune mechanisms in pregnancy

Rh incompatibilityRh incompatibility • Complications in pregnancy: Complications in pregnancy: production of anti-production of anti-

RhD antibodiesRhD antibodies by RhD- mother carrying an RhD+ by RhD- mother carrying an RhD+ fetus (hemolytic disease of newborns)fetus (hemolytic disease of newborns)

• Fetal erythrocytes penetrate into the maternal Fetal erythrocytes penetrate into the maternal bloodstream during pregnancy - a bloodstream during pregnancy - a small amount, small amount, don´t immunizedon´t immunize

• During childbirth or abortionDuring childbirth or abortion (after 8 weeks of (after 8 weeks of gestation) fetal erythrocytes can penetrate into gestation) fetal erythrocytes can penetrate into the bloodstream of mother → the bloodstream of mother → immunizationimmunization, , formation of anti-RhD antibodiesformation of anti-RhD antibodies

• After childbirth, investigate Rh factor of born After childbirth, investigate Rh factor of born child, if is child Rh+, mother gets up to 72 hours child, if is child Rh+, mother gets up to 72 hours after birth after birth injection of anti-Rh antibodiesinjection of anti-Rh antibodies (administered after abortion too)(administered after abortion too)

Rh incompatibilityRh incompatibility

• Anti-Rh(D) injectionAnti-Rh(D) injection, this antibodies bind to RhD Ag , this antibodies bind to RhD Ag on baby´s red blood cells, this Ag than can´t bind to on baby´s red blood cells, this Ag than can´t bind to BCR and can´t activate B lymphocytes, this immune BCR and can´t activate B lymphocytes, this immune comlexes also actively inhibit B lymphocytescomlexes also actively inhibit B lymphocytes

• During next childbirths, if fetus is Rh+ and mother During next childbirths, if fetus is Rh+ and mother

produce anti-Rh antibodies, this Abb destroy red produce anti-Rh antibodies, this Abb destroy red blood cells of fetus, which can lead to fetal death, blood cells of fetus, which can lead to fetal death, or in severe or in severe postpartum anemiapostpartum anemia (anemia (anemia neonatorum)neonatorum) and and neonatal jaundiceneonatal jaundice ( (icterus gravis icterus gravis neonatorumneonatorum))

• For each pregnant woman during the first trimester For each pregnant woman during the first trimester investigate blod Rh factor and the presence of investigate blod Rh factor and the presence of antibodies, in Rh- women performed a test for antibodies, in Rh- women performed a test for antibodies also in II. and III. trimester antibodies also in II. and III. trimester

Immunopathological Immunopathological

reactionsreactions

Classification by Coombs and GellClassification by Coombs and Gell

Immunopathological reactionsImmunopathological reactions: immune response, : immune response, which caused damage to the body (secondary which caused damage to the body (secondary consequence of defense responses against pathogens, consequence of defense responses against pathogens, inappropriate responses to harmless antigens, inappropriate responses to harmless antigens, autoimmunity)autoimmunity)

IV types of immunopathological reactions:IV types of immunopathological reactions:

Type I reactionType I reaction - a response based on IgE antibodies - a response based on IgE antibodies

Type II reactionType II reaction - a response based on antibodies, IgG - a response based on antibodies, IgG and IgMand IgM

Type III reactionType III reaction - a response based on the formation - a response based on the formation of immune complexes of immune complexes

Type IV reactionType IV reaction - cell-mediated response - cell-mediated response

Immunopathological reactions based on Immunopathological reactions based on

antibodies IgG and IgM (reaction type II)antibodies IgG and IgM (reaction type II)

Cytotoxic antibodies IgG and IgMCytotoxic antibodies IgG and IgM::

● ● complement activationcomplement activation

● ● ADCCADCC

● ● binding to Fc receptors on phagocytes and NK cellsbinding to Fc receptors on phagocytes and NK cells

Examples of immunopathological Examples of immunopathological reaction Type IIreaction Type II

• Transfusion reactions in administration of Transfusion reactions in administration of incompatibile bloodincompatibile blood: : binding of antibodies to antigens on erythrocytes binding of antibodies to antigens on erythrocytes → activation of the classical way of complement → activation of the classical way of complement → cell lysis → cell lysis

• Hemolytic disease of newbornsHemolytic disease of newborns:: caused by antibodies against RhD antigencaused by antibodies against RhD antigen

Autoimmune diseases:Autoimmune diseases:

● ● organ-specific organ-specific cytotoxic antibodiescytotoxic antibodies (antibodies (antibodies against against erythrocytes, neutrophils, thrombocytes, glomerular erythrocytes, neutrophils, thrombocytes, glomerular basement basement membrane ...) membrane ...)

● ● blocking or stimulating antibodiesblocking or stimulating antibodies Graves - Basedow's disease - stimulating antibodies Graves - Basedow's disease - stimulating antibodies against the against the receptor for TSH receptor for TSH

Myasthenia gravis - blocking of acetylcholin receptor→ Myasthenia gravis - blocking of acetylcholin receptor→ blocking blocking of neuromuscular transmission of neuromuscular transmission

Pernicious anemia - blocking the absorption of vitamin Pernicious anemia - blocking the absorption of vitamin B12B12

Antiphospholipid syndrome - antibodies against Antiphospholipid syndrome - antibodies against fosfolipidsfosfolipids

Fertility disorder - antibodies against sperms or oocytesFertility disorder - antibodies against sperms or oocytes

Immunopathological reactions based on Immunopathological reactions based on immune complexes formation (reaction type immune complexes formation (reaction type III)III)

●● caused by IgG antibodiescaused by IgG antibodies → bind to antigen → creation → bind to antigen → creation of immune complexes of immune complexes

● ● immunocomplexesimmunocomplexes - - bind to Fc receptors on phagocytesbind to Fc receptors on phagocytes - - activate complementactivate complement

● ● immune complexes, depending on the quantity and immune complexes, depending on the quantity and structure, structure, are eliminated by phagocytes or stored in tissues are eliminated by phagocytes or stored in tissues

● ● pathological pathological immunocomplexesimmunocomplexes response arises when is a response arises when is a large dose large dose of antigen, or antigen in the body remains; arise 10-14 days of antigen, or antigen in the body remains; arise 10-14 days after after aplication of Ag and induced inflamation can get to chronic aplication of Ag and induced inflamation can get to chronic statestate

● ● immune complexes are deposited in the kidneys immune complexes are deposited in the kidneys (glomerulonephritis), (glomerulonephritis), on the surface of endothelial cells (vasculitis) and in synovie on the surface of endothelial cells (vasculitis) and in synovie joint joint (arthritis) (arthritis)

Serum sicknessSerum sickness● ● the therapeutic application of xenogeneic the therapeutic application of xenogeneic serum (antiserum to snake venom) serum (antiserum to snake venom)● ● creation of immune complexes and their creation of immune complexes and their storage in the vessel walls of different organs storage in the vessel walls of different organs● ● clinical manifestations: urticaria, arthralgia, myalgiaclinical manifestations: urticaria, arthralgia, myalgia

Systemic lupus erythematosusSystemic lupus erythematosus● ● antibodies against nuclear antigens, ANA, anti-dsDNAantibodies against nuclear antigens, ANA, anti-dsDNA

Farmer's lungFarmer's lung● ● IgG antibody against inhaled antigens (molds, hay)IgG antibody against inhaled antigens (molds, hay)

Post-streptococcal glomerulonephritis, Post-streptococcal glomerulonephritis, cryoglobulinemia, revmatoid arthritis, post-cryoglobulinemia, revmatoid arthritis, post-infectious arthritis infectious arthritis

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