HOME

TheInfoList



OR:

Transplant rejection occurs when
transplanted ''A.N.T. Farm'' is a Disney Channel original series that follows Chyna Parks (China Anne McClain) and her two best friends, Olive Doyle (Sierra McCormick) and Fletcher Quimby (Jake Short), who are in the "Advanced Natural Talents" (A.N.T.) program ...
tissue is rejected by the recipient's
immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
, which destroys the transplanted tissue. Transplant rejection can be lessened by determining the molecular similitude between donor and recipient and by use of
immunosuppressant drugs Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent activity of the immune system. Classification Immunosuppressive drugs can be classified into ...
after transplant.


Types of transplant rejection

Transplant rejection can be classified into three types: hyperacute, acute, and chronic. These types are differentiated by how quickly the recipient's immune system is activated and the specific aspect or aspects of immunity involved.


Hyperacute rejection

Hyperacute rejection is a form of rejection that manifests itself in the minutes to hours following transplantation. It is caused by the presence of pre-existing
antibodies An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
in the recipient that recognize
antigen In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. ...
s in the donor organ. These antigens are located on the endothelial lining of blood vessels within the transplanted organ and, once antibodies bind, will lead to the rapid activation of the
complement system The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and at ...
. Irreversible damage via thrombosis and subsequent graft necrosis is to be expected. Tissue left implanted will fail to work and could lead to high fever and malaise as immune system acts against foreign tissue. Graft failure secondary to hyperacute rejection has significantly decreased in incidence as a result of improved pre-transplant screening for antibodies to donor tissues. While these antibodies preformed antibodies may result from prior transplants, prior blood transfusions, or pregnancy, hyperacute rejection is most commonly from antibodies to ABO blood group antigens. Consequently, transplants between individuals with differing ABO blood types is generally avoided though may be pursued in very young children (generally under 12 months, but often as old as 24 months who do not have fully developed immune systems. Shortages of organs and the morbidity and mortality associated with being on transplant waitlists has also increased interest in ABO-incompatible transplantation in older children and adults.


Acute rejection

Acute rejection is a category of rejection that occurs on the timescale of weeks to months, with most episodes occurring within the first 3 months to 1 year after transplantation. Unlike hyperacute rejection, acute rejection is thought to arise from two distinct immunological mechanisms as
lymphocyte A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic ad ...
s, a subset of white blood cells, begin to recognize antigens on transplanted organ/graft. This recognition occurs due to the
major histocompatibility complex The major histocompatibility complex (MHC) is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. These cell surface proteins are calle ...
(MHC), which are proteins on cell surface that are presented to the T-cell receptor found on
T-cells A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell rec ...
. In humans, this is known as the human leukocyte antigen (HLA) system and over 17,000 HLA alleles or genetic variants have been described such that it is extremely uncommon for any two people to have identical alleles. Other non-HLA proteins, known as minor histocompatibility antigens, do exist but generally are unable to cause acute rejection in and of themselves unless a multitude of non-HLA proteins are mismatched. As such, HLA matching (in addition to matching ABO groups) is critical in preventing acute rejection. This process of recognition by T-cells can happen directly or indirectly and lead to acute cellular and acute humoral rejection respectively. Direct allorecognition is a phenomenon within transplant immunology where the
dendritic cell Dendritic cells (DCs) are antigen-presenting cells (also known as ''accessory cells'') of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. ...
s, which are the body's antigen-presenting cells (APCs), migrate from ''donor'' tissue to
lymphoid tissue The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system, and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphatic or lymphoid o ...
(
lymphoid follicles A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that include ...
and
lymph nodes A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...
) in the ''recipient'' and present their MHC peptides to recipient lymphocytes. In comparison, indirect allorecognition is more analogous to how foreign antigens are recognized by the immune system. Dendritic cells of the ''recipient'' come across peptides from donor tissue whether in circulation, lymphoid tissue, or in donor tissue itself. Since not the result of direct antigen presentation, these may not necessarily be intact MHC molecules but instead other proteins that are deemed different enough from recipient may engender a response. This process leads to the priming of T-cells to respond to the peptides secondarily going forward. A third semi-direct pathway has been described in which recipient APCs present fully intact donor MHCs, yet its relative contribution to acute rejection is not as well understood. Acute cellular rejection occurs following direct allorecognition of mismatched donor MHC by
cytotoxic T-cells A cytotoxic T cell (also known as TC, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or killer T cell) is a T cell, T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected by intracel ...
that begin to secrete
cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...
s to recruit more lymphocytes as well as cause apoptosis or cell death directly. The greater the difference in MHC between donor and recipient, the more cytotoxic T-cells are recruited to damage the graft, which may be seen via biopsy in solid organ transplants, with increased lymphocyte infiltration indicative of more severe acute cellular rejection. Acute humoral rejection is a process usually initiated by indirect allorecognition arising from recipient helper T-cells. These helper T-cells have a crucial role in the development of B-cells that can create donor-specific antibodies. The antibodies deposit themselves within the donor graft and lead to activation of the complement cascade alongside antibody-mediated cytotoxicity with
neutrophil Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in ...
s, a type of white blood cell separate from lymphocytes, predominantly infiltrating into tissues. Barring genetically identical twins, acute rejection is to be expected to some degree. Rates of clinically significant acute rejection that could endanger transplant have decreased significantly with the development of immunosuppressive regimens. Using kidney transplants as an example, rates of acute rejection have declined from >50% in the 1970s to 10-20%. Singular episodes of acute rejection, when promptly treated, should not compromise transplant; however, repeated episodes may lead to chronic rejection.


Chronic rejection

Chronic rejection is an insidious form of rejection that leads to graft destruction over the course of months, but most often years after tissue transplantation. The mechanism for chronic rejection is yet to be fully understood, but it is known that prior acute rejection episodes are the main clinical predictor for the development of chronic rejection. In particular, the incidence increases following severe or persistent acute rejection, whereas acute rejection episodes with return to function back to baseline do not have major effects on graft survival. Chronic rejection is generally thought of as being related to either vascular damage or parenchymal damage with subsequent fibrosis. While it is unknown the exact contribution of the immune system in these processes, the indirect pathway of allorecognition and the associated antibody formation seems to be especially involved. When examining chronic rejection, it is important to note that it has widely varied effects on different organs. At 5 years post-transplant, 80% of lung transplants, 60% of heart transplants and 50% of kidney transplants are affected, while liver transplants are only affected 10% of the time. Therefore, chronic rejection explains long-term morbidity in most lung-transplant recipients, the median survival roughly 4.7 years, about half the span versus other major organ transplants. Airflow obstruction not ascribable to other cause is labeled
bronchiolitis obliterans Bronchiolitis obliterans (BO), also known as obliterative bronchiolitis, constrictive bronchiolitis and popcorn lung, is a disease that results in obstruction of the smallest airways of the lungs (bronchioles) due to inflammation. Symptoms include ...
syndrome A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". When a syndrome is paired ...
(BOS), confirmed by a persistent drop—three or more weeks—in ''forced expiratory volume'' (FEV1) by at least 20%. First noted is infiltration by
lymphocytes A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adap ...
, followed by
epithelial cell Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellula ...
injury, then inflammatory lesions and recruitment of
fibroblasts A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells o ...
and
myofibroblasts A myofibroblast is a cell phenotype that was first described as being in a state between a fibroblast and a smooth muscle cell. Structure Myofibroblasts are contractile web-like fusiform cells that are identifiable by their expression of α-sm ...
, which proliferate and secrete proteins forming scar tissue. A similar phenomenon can be seen with liver transplant wherein fibrosis leads to jaundice secondary to the destruction of bile ducts within the liver, also known as vanishing bile duct syndrome.


Rejection due to non-adherence

One principal reason for transplant rejection is non-adherence to prescribed immunosuppressant regimens. This is particularly the case with adolescent recipients, with non-adherence rates near 50% in some instances. A pilot study conducted by Michael O. Killian PhD from Florida State University and Dr. Dipankar Gupta from University of Florida published in April 2022 in ''Pediatric Transplantation'' studied the acceptability and feasibility of an asynchronous directly observed therapy mobile health application among adolescent heart transplant recipients. Patients in the study utilized emocha Health's digital medication adherence program which included asynchronous video messages and chat messages exchanged with a care team. Patients completing the study achieved a 90.1% adherence rate. The researchers noted that further randomized trials are required to confirm the initial findings. However, the results were very promising considering few options exist to support pediatric patients in taking their medications.


Rejection detection

Diagnosis of acute rejection relies on clinical data—patient signs and symptoms but also calls on laboratory data such as
blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...
or even tissue
biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a diseas ...
. The laboratory pathologist generally seeks three main
histological Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...
signs: (1) infiltrating
T cells A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell re ...
, perhaps accompanied by infiltrating
eosinophils Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. A ...
,
plasma cells Plasma cells, also called plasma B cells or effector B cells, are white blood cells that originate in the lymphoid organs as B lymphocytes and secrete large quantities of proteins called antibodies in response to being presented specific substan ...
, and
neutrophils Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in ...
, particularly in telltale ratios, (2) structural compromise of tissue anatomy, varying by tissue type transplanted, and (3) injury to blood vessels. Tissue biopsy is restricted, however, by sampling limitations and risks/complications of the invasive procedure. Cellular
magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...
(MRI) of immune cells
radiolabeled A radioactive tracer, radiotracer, or radioactive label is a chemical compound in which one or more atoms have been replaced by a radionuclide so by virtue of its radioactive decay it can be used to explore the mechanism of chemical reactions by tr ...
''in vivo'' might—similarly to Gene Expression Profiling (GEP)—offer noninvasive testing.


Rejection treatment

Hyperacute rejection manifests severely and within minutes, and so treatment is immediate: removal of the tissue. Acute rejection is treated with one or several of a few strategies. Despite treatment, rejection remains a major cause of transplant failure. Chronic rejection is generally considered irreversible and poorly amenable to treatment—only retransplant generally indicated if feasible—though inhaled
ciclosporin Ciclosporin, also spelled cyclosporine and cyclosporin, is a calcineurin inhibitor, used as an immunosuppressant medication. It is a natural product. It is taken orally or intravenously for rheumatoid arthritis, psoriasis, Crohn's disease, ...
is being investigated to delay or prevent chronic rejection of lung transplants.


Immunosuppressive therapy

A short course of high-dose
corticosteroids Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involve ...
can be applied, and repeated. ''Triple therapy'' adds a
calcineurin inhibitor Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent activity of the immune system. Classification Immunosuppressive drugs can be classified int ...
and an anti-proliferative agent. Where calcineurin inhibitors or steroids are contraindicated,
mTOR inhibitors mTOR inhibitors are a class of drugs that inhibit the mechanistic target of rapamycin (mTOR), which is a serine/threonine-specific protein kinase that belongs to the family of phosphatidylinositol-3 kinase (PI3K) related kinases (PIKKs). mTOR re ...
are used. Immunosuppressive drugs: *
Corticosteroids Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involve ...
**
Prednisolone Prednisolone is a steroid medication used to treat certain types of allergies, inflammatory conditions, autoimmune disorders, and cancers. Some of these conditions include adrenocortical insufficiency, high blood calcium, rheumatoid arthrit ...
**
Hydrocortisone Hydrocortisone is the name for the hormone cortisol when supplied as a medication. Uses include conditions such as adrenocortical insufficiency, adrenogenital syndrome, high blood calcium, thyroiditis, rheumatoid arthritis, dermatitis, asthma, ...
*
Calcineurin Calcineurin (CaN) is a calcium and calmodulin dependent serine/threonine protein phosphatase (also known as protein phosphatase 3, and calcium-dependent serine-threonine phosphatase). It activates the T cells of the immune system and can be bloc ...
inhibitors **
Ciclosporin Ciclosporin, also spelled cyclosporine and cyclosporin, is a calcineurin inhibitor, used as an immunosuppressant medication. It is a natural product. It is taken orally or intravenously for rheumatoid arthritis, psoriasis, Crohn's disease, ...
**
Tacrolimus Tacrolimus, sold under the brand name Prograf among others, is an immunosuppressive drug. After allogeneic organ transplant, the risk of organ rejection is moderate. To lower the risk of organ rejection, tacrolimus is given. The drug can also ...
* Anti-proliferatives **
Azathioprine Azathioprine (AZA), sold under the brand name Imuran, among others, is an immunosuppressive medication. It is used in rheumatoid arthritis, granulomatosis with polyangiitis, Crohn's disease, ulcerative colitis, and systemic lupus erythematosus, ...
**
Mycophenolic acid Mycophenolic acid (MPA) is an immunosuppressant medication used to prevent rejection following organ transplantation and to treat autoimmune conditions such as Crohn's disease and lupus. Specifically it is used following kidney, heart, and liv ...
*
mTOR The mammalian target of sirolimus, rapamycin (mTOR), also referred to as the mechanistic target of rapamycin, and sometimes called FK506-binding protein 12-rapamycin-associated protein 1 (FRAP1), is a kinase that in humans is encoded by the ''MT ...
inhibitors **
Sirolimus Sirolimus, also known as rapamycin and sold under the brand name Rapamune among others, is a macrolide compound that is used to coat coronary stents, prevent organ transplant rejection, treat a rare lung disease called lymphangioleiomyomatosi ...
**
Everolimus Everolimus, sold under the brand name Afinitor among others, is a medication used as an immunosuppressant to prevent rejection of organ transplants and as a targeted therapy in the treatment of renal cell cancer and other tumours. It is the 40 ...


Antibody-based treatments

Antibody specific to select immune components can be added to immunosuppressive therapy. The
monoclonal Monoclonality refers to the state of a line of cells that have been derived from a single clonal origin. Thus "monoclonal cells" can be said to form a single clone. The term ''monoclonal'' comes from the Ancient Greek ''monos'', meaning "alone" o ...
anti-T cell antibody
OKT3 Muromonab-CD3 (trade name Orthoclone OKT3, marketed by Janssen-Cilag) is an immunosuppressant drug given to reduce acute rejection in patients with organ transplants. It is a monoclonal antibody targeted at the CD3 receptor, a membrane protein on ...
, once used to prevent rejection, and still occasionally used to treat severe acute rejection, has fallen into disfavor, as it commonly brings severe
cytokine release syndrome Cytokine release syndrome (CRS) is a form of systemic inflammatory response syndrome (SIRS) that can be triggered by a variety of factors such as infections and certain drugs. It refers to cytokine storm syndromes (CSS) and occurs when large numb ...
and late
post-transplant lymphoproliferative disorder Post-transplant lymphoproliferative disorder (PTLD) is the name given to a B cell proliferation due to therapeutic immunosuppression after organ transplantation. These patients may develop infectious mononucleosis-like lesions or polyclonal polymor ...
. (OKT3 is available in the
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
for named-patient use only.) Antibody drugs: * Monoclonal anti-IL-2Rα receptor antibodies **
Basiliximab Basiliximab (trade name Simulect) is a chimeric mouse-human monoclonal antibody to the α chain (CD25) of the IL-2 receptor of T cells. It is used to prevent rejection in organ transplantation, especially in kidney transplants. Uses Basiliximab ...
**
Daclizumab Daclizumab (trade name Zinbryta) is a therapeutic humanized monoclonal antibody which was used for the treatment of adults with relapsing forms of multiple sclerosis (MS). Daclizumab works by binding to CD25, the alpha subunit of the IL-2 receptor ...
* Monoclonal anti-IL-6R receptor antibodies **
Tocilizumab Tocilizumab, sold under the brand name Actemra among others, is an immunosuppressive drug, used for the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis, a severe form of arthritis in children, and COVID19. It is a huma ...
* Polyclonal anti-T-cell antibodies **
Anti-thymocyte globulin Anti-thymocyte globulin (ATG) is an infusion of horse or rabbit-derived antibodies against human T cells and their precursors (thymocytes), which is used in the prevention and treatment of acute rejection in organ transplantation and therapy of ...
(ATG) **
Anti-lymphocyte globulin Anti-lymphocyte globulin (ALG) is an infusion of animal- antibodies against human T cells which is used in the treatment of acute rejection in organ transplantation. Its use was first reported by Thomas Starzl in 1966. Its use in transplant was su ...
(ALG) * Monoclonal anti-CD20 antibodies **
Rituximab Rituximab, sold under the brand name Rituxan among others, is a monoclonal antibody medication used to treat certain autoimmune diseases and types of cancer. It is used for non-Hodgkin lymphoma, chronic lymphocytic leukemia (in non-geriatric p ...


Blood transfer

Cases refractory to immunosuppressive or antibody therapy are sometimes treated with photopheresis, or extracorporeal photoimmune therapy (ECP), to remove antibody molecules specific to the transplanted tissue.


Marrow transplant

Bone marrow transplant Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood in order to replicate inside of a patient and to produce ...
can replace the transplant recipient's immune system with the donor's, and the recipient accepts the new organ without rejection. The marrow's
hematopoietic stem cells Hematopoietic stem cells (HSCs) are the stem cells that give rise to other blood cells. This process is called haematopoiesis. In vertebrates, the very first definitive HSCs arise from the ventral endothelial wall of the embryonic aorta within ...
—the reservoir of
stem cells In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type o ...
replenishing exhausted blood cells including
white blood cells White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from mult ...
forming the immune system—must be of the individual who donated the organ or of an
identical twin Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two em ...
or a clone. There is a risk of graft-versus-host disease (GVHD), however, whereby mature
lymphocytes A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adap ...
entering with marrow recognize the new host tissues as foreign and destroy them.


Gene therapy

Gene therapy Gene therapy is a medical field which focuses on the genetic modification of cells to produce a therapeutic effect or the treatment of disease by repairing or reconstructing defective genetic material. The first attempt at modifying human DN ...
is another method that can be used. In this method, the genes that cause the body to reject transplants would be deactivated. Research is still being conducted, and no gene therapies are being used to date to treat patients. Current research tends to focus on Th1 and Th17 which mediate allograft rejection via the CD4 and CD8
T cells A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell re ...
.


See also

* Graft-versus-host disease *
Graft-versus-tumor effect Graft-versus-tumor effect (GvT) appears after allogeneic hematopoietic stem cell transplantation (HSCT). The graft contains donor T cells (T lymphocytes) that can be beneficial for the recipient by eliminating residual malignant cells. GvT might d ...
*
Immunosuppression Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse react ...
* Transplant engineering


References


External links

{{DEFAULTSORT:Transplant Rejection Immune system disorders Transplantation medicine de:Transplantation#Immunreaktionen