21.7 Transplantation and Cancer Immunology
3 min read•june 18, 2024
Blood transfusions and tissue typing are crucial medical procedures that save lives. Matching blood types and tissues prevents dangerous reactions and rejection. Understanding these processes helps us grasp how the body recognizes foreign substances and maintains balance.
Cancer immunology explores how our immune system fights cancer cells. New therapies boost the body's natural defenses against tumors. Learning about these approaches sheds light on the complex interplay between cancer and immunity, opening doors to more effective treatments.
Blood Transfusions and Tissue Typing
Consequences of mismatched blood transfusions
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Top images from around the web for Consequences of mismatched blood transfusions
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Blood Typing · Anatomy and Physiology View original
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- Agglutination occurs when red blood cells clump together due to antibody-antigen interactions (ABO blood group system)
- involves the rupture of red blood cells leading to the release of hemoglobin (Rh blood group system)
- are immune-mediated adverse effects that can cause fever, chills, and kidney damage
- Mismatched blood transfusions can lead to life-threatening complications such as and multiple organ failure
Tissue typing for organ transplantation
- Tissue typing matches donor and recipient to minimize the risk of transplant rejection
- HLAs are proteins on the surface of cells that help the immune system distinguish self from non-self (major histocompatibility complex, MHC)
- (A, B, and C) are expressed on all nucleated cells
- (DP, DQ, and DR) are expressed on (, )
- HLAs are proteins on the surface of cells that help the immune system distinguish self from non-self (major histocompatibility complex, MHC)
- Anti-rejection medications, or , suppress the immune system to prevent transplant rejection
- inhibit T-cell activation and proliferation (, )
- inhibit lymphocyte proliferation (, )
- reduce inflammation and suppress the immune response ()
- Balancing the risk of rejection with the increased susceptibility to infections and other side effects is crucial when using anti-rejection medications
- can occur when donor immune cells attack the recipient's tissues, particularly in stem cell transplants
Types of transplants
- Allografts are transplants between genetically different individuals of the same species
- Xenografts involve transplanting organs or tissues between different species, which poses significant immunological challenges
Cancer Immunology and Immunotherapies
Immune system vs cancer
- is the immune system's ability to recognize and eliminate cancer cells
- Innate immune response involves non-specific defense mechanisms such as and macrophages
- Adaptive immune response involves specific defense mechanisms such as and
- can directly kill cancer cells
- Antibodies produced by can target cancer cell antigens and promote
- Cancer cells can evade the immune system through various mechanisms
- Downregulation of MHC class I molecules reduces cancer cell recognition by CTLs
- Expression of immunosuppressive factors such as and inhibits immune response
- Recruitment of suppresses the immune response
- The plays a crucial role in cancer immune evasion by creating an immunosuppressive milieu
- Cancer immunotherapies harness the immune system to fight cancer
- are antibodies that block inhibitory signals (, ) to enhance T-cell activation
- involves the infusion of immune cells such as or genetically modified T cells ()
- stimulate the immune system to recognize and attack cancer cells by presenting or
- are genetically modified viruses that selectively infect and kill cancer cells while stimulating an anti-tumor immune response
- is the process by which the immune system shapes tumor development and progression through elimination, equilibrium, and escape phases
Key Terms to Review (51)
Adoptive Cell Therapy: Adoptive cell therapy is a type of immunotherapy that involves the transfer of a patient's own immune cells, which have been modified or expanded ex vivo, back into the patient to treat various diseases, particularly cancer. It harnesses the power of the body's immune system to recognize and destroy target cells.
Allograft: An allograft is a tissue or organ transplant from one individual to another of the same species, but with a different genotype. Allografts are commonly used in the context of transplantation and cancer immunology to understand the body's immune response to foreign tissues.
Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC): Antibody-dependent cell-mediated cytotoxicity (ADCC) is an immune response mechanism in which antibodies bound to target cells, such as cancer cells or virus-infected cells, trigger the destruction of those cells by effector cells, such as natural killer (NK) cells or macrophages. This process is a crucial component of the immune system's defense against certain diseases.
Antigen-Presenting Cells: Antigen-presenting cells (APCs) are a diverse group of immune cells that play a crucial role in the adaptive immune response by processing and presenting antigens to T lymphocytes, triggering their activation and initiation of an immune response. These cells are central to the link between the innate and adaptive immune systems.
Antiproliferative Agents: Antiproliferative agents are a class of drugs or compounds that inhibit or prevent the proliferation, or rapid and uncontrolled growth, of cells. These agents are particularly important in the context of transplantation and cancer immunology, where they play a crucial role in regulating the body's immune response and controlling the growth of abnormal cells.
Azathioprine: Azathioprine is an immunosuppressant drug primarily used to prevent organ rejection in transplant recipients and to manage autoimmune disorders. It works by inhibiting the synthesis of DNA and RNA, thereby reducing the proliferation of immune cells and suppressing the body's immune response.
B cells: B cells are a type of white blood cell, part of the adaptive immune system, responsible for producing antibodies that target specific antigens (foreign substances). They play a crucial role in the body's defense mechanism by recognizing and binding to antigens, leading to their neutralization or destruction.
B Cells: B cells, also known as B lymphocytes, are a type of white blood cell that play a crucial role in the adaptive immune response. They are responsible for producing antibodies, which are proteins that recognize and bind to specific foreign substances, neutralizing them or marking them for destruction by other immune cells.
Calcineurin Inhibitors: Calcineurin inhibitors are a class of immunosuppressant drugs that work by blocking the activity of the enzyme calcineurin, which is essential for the activation and proliferation of T cells. These drugs are commonly used to prevent organ rejection in transplant recipients and to manage certain autoimmune conditions.
Cancer vaccines: Cancer vaccines are a type of immunotherapy designed to stimulate the body's immune system to recognize and attack cancer cells. These vaccines work by introducing specific antigens associated with cancer cells, prompting an immune response that can help eliminate tumors or prevent cancer recurrence. By harnessing the body’s natural defenses, cancer vaccines represent a promising approach in both the prevention and treatment of various cancers.
CAR T-cell Therapy: CAR T-cell therapy is an innovative cancer treatment that genetically engineers a patient's own T cells to recognize and attack cancer cells. It involves extracting T cells from the patient, modifying them to express chimeric antigen receptors (CARs), and then infusing the engineered CAR T cells back into the patient to target and eliminate cancer cells.
Checkpoint inhibitors: Checkpoint inhibitors are a class of drugs that help to enhance the immune system's response against cancer by blocking proteins that act as 'checkpoints' on immune cells. These proteins, such as PD-1, PD-L1, and CTLA-4, normally serve to dampen immune responses, preventing overactivity that could harm normal tissues. By inhibiting these checkpoints, checkpoint inhibitors can effectively unleash the immune system to attack cancer cells more aggressively, making them a crucial tool in cancer immunotherapy.
Class I HLAs: Class I HLAs, or Major Histocompatibility Complex (MHC) Class I molecules, are cell surface proteins that play a crucial role in the immune system's recognition and response to foreign antigens. These molecules are found on the surface of nearly all nucleated cells in the body and are responsible for presenting peptide fragments to cytotoxic T cells, initiating an immune response against infected or cancerous cells.
Class II HLAs: Class II HLAs (Human Leukocyte Antigens) are a group of major histocompatibility complex (MHC) proteins found on the surface of certain immune cells, primarily antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells. These proteins play a crucial role in the immune system's ability to recognize and respond to foreign or abnormal substances, making them a key factor in transplantation and cancer immunology.
Corticosteroids: Corticosteroids are a class of steroid hormones that are produced naturally in the body by the adrenal glands. They have a wide range of effects on the body, including regulating the immune system, reducing inflammation, and maintaining homeostasis. Corticosteroids are also commonly used as pharmaceutical drugs to treat a variety of medical conditions.
CTLA-4: CTLA-4, or Cytotoxic T-Lymphocyte-Associated Protein 4, is a critical regulator of the immune system that plays a crucial role in both transplantation and cancer immunology. It functions as an immune checkpoint, providing a crucial brake on T-cell activation and preventing autoimmunity.
Cyclosporine: Cyclosporine is an immunosuppressant drug primarily used to prevent rejection in organ transplant recipients. It works by inhibiting the activation and proliferation of T-cells, a key component of the body's immune response, thereby reducing the risk of the transplanted organ being rejected.
Cytotoxic T Lymphocytes (CTLs): Cytotoxic T lymphocytes, also known as CD8+ T cells, are a type of T cell that play a crucial role in the adaptive immune response by directly killing infected or cancerous cells. They are a key component of cell-mediated immunity, functioning as the 'attack dogs' of the immune system.
Dendritic Cells: Dendritic cells are a type of antigen-presenting immune cell that play a crucial role in the body's innate and adaptive immune responses. They act as sentinels, patrolling the body for foreign substances and initiating the appropriate immune reactions against potential threats.
Disseminated intravascular coagulation (DIC): Disseminated intravascular coagulation (DIC) is a serious disorder characterized by the abnormal activation of the clotting cascade, leading to the formation of small blood clots throughout the body. This excessive clotting depletes platelets and clotting factors, resulting in an increased risk of bleeding. DIC can occur in various clinical contexts, such as severe infections, trauma, and complications associated with transplantation and cancer, making its understanding crucial in managing these conditions.
Erythroblastosis fetalis: Erythroblastosis fetalis is a severe hematological condition in fetuses or newborns resulting from the incompatibility between the blood types of the mother and her baby, primarily involving the Rh factor. This condition leads to the mother's immune system attacking the red blood cells of the fetus, causing anemia and other serious complications.
Graft-versus-host disease: Graft-versus-host disease is a condition that occurs when donor immune cells from a transplant attack the recipient's body tissues and organs. It commonly arises after an allogeneic bone marrow or stem cell transplant, where the donor's immune cells recognize the recipient's body as foreign and initiate an attack.
Graft-Versus-Host Disease: Graft-versus-host disease (GVHD) is a serious complication that can occur after a stem cell or bone marrow transplant, where the donated cells (the graft) recognize the recipient's body (the host) as foreign and mount an immune response against it.
Hemolysis: Hemolysis is the process of red blood cells (RBCs) breaking down, either in the bloodstream or while still in the vascular system. This breakdown results in the release of hemoglobin and other internal components into the surrounding fluid.
Hemolysis: Hemolysis is the rupture or destruction of red blood cells, leading to the release of their contents, including hemoglobin, into the surrounding fluid. This process can occur in various contexts, including within the body or during laboratory testing.
Human Leukocyte Antigens (HLAs): Human leukocyte antigens (HLAs) are a group of proteins found on the surface of cells in the human body, especially on the surface of white blood cells (leukocytes). These proteins act as markers that help the immune system distinguish the body's own cells from foreign or potentially harmful cells, making them crucial for transplantation and cancer immunology.
Immune Surveillance: Immune surveillance is the process by which the immune system continuously monitors the body for the presence of abnormal or foreign cells, such as cancer cells or transplanted tissues, and initiates an immune response to eliminate them. It is a crucial mechanism that helps maintain homeostasis and prevent the development of diseases like cancer and the rejection of transplanted organs.
Immunoediting: Immunoediting is a process by which the immune system interacts with and shapes the development of cancer cells. It is a dynamic process that encompasses three distinct phases: elimination, equilibrium, and escape, which together determine the outcome of the interaction between the immune system and cancer cells.
Immunosuppressants: Immunosuppressants are a class of drugs that inhibit or prevent the normal function of the immune system. They are commonly used to prevent the rejection of transplanted organs and tissues, as well as to manage autoimmune disorders and certain types of cancer.
Interleukin-10 (IL-10): Interleukin-10 (IL-10) is an anti-inflammatory cytokine that plays a crucial role in regulating the immune response and maintaining homeostasis within the body. It is primarily produced by various immune cells, including T cells, B cells, and monocytes, and is essential for modulating inflammatory processes and preventing excessive tissue damage.
Macrophages: Macrophages are a type of large white blood cell that play a crucial role in the body's immune response. They are responsible for engulfing and digesting pathogens, cellular debris, and other foreign materials, serving as the first line of defense against infection and disease.
Major Histocompatibility Complex (MHC): The major histocompatibility complex (MHC) is a set of genes that encode cell surface proteins responsible for the regulation of the immune system. These proteins play a crucial role in the recognition of self and non-self molecules, which is essential for the body's ability to distinguish its own cells from foreign or abnormal cells, such as those found in transplanted organs or cancerous growths.
MHC polygeny: MHC polygeny refers to the presence of multiple genes in an organism that encode for the Major Histocompatibility Complex (MHC) proteins, which are crucial for immune system function. These genes ensure a wide variety of MHC molecules that can present different peptides to T cells, enabling the immune system to recognize a broad range of pathogens.
MHC polymorphism: MHC polymorphism refers to the variation in the Major Histocompatibility Complex (MHC) genes among individuals in a population. These variations play a crucial role in determining the efficacy of the immune response to pathogens, as well as compatibility in organ transplantation.
Mycophenolate Mofetil: Mycophenolate mofetil is an immunosuppressant medication primarily used to prevent organ rejection in transplant recipients. It works by inhibiting the proliferation of T and B lymphocytes, key players in the immune response, thereby reducing the risk of rejection after organ transplantation. This drug is also used in the management of certain autoimmune disorders.
Natural Killer (NK) Cells: Natural killer (NK) cells are a type of cytotoxic lymphocyte that plays a crucial role in the body's innate immune response. They are capable of recognizing and destroying infected or cancerous cells without prior sensitization, making them an important component of the body's defense against disease.
Oncolytic Viruses: Oncolytic viruses are a class of viruses that have the ability to selectively infect and destroy cancer cells, while leaving healthy cells unharmed. These viruses are engineered or naturally occurring, and they play a crucial role in the field of cancer immunology and transplantation.
PD-1/PD-L1: PD-1 (Programmed Cell Death Protein 1) and PD-L1 (Programmed Death-Ligand 1) are two key immune checkpoint proteins that play a crucial role in regulating the body's immune response, particularly in the context of transplantation and cancer immunology. PD-1 is an inhibitory receptor expressed on the surface of T cells, while PD-L1 is a ligand that can bind to PD-1, leading to the suppression of T cell activity and the evasion of the immune system by cancer cells or transplanted tissues.
Prednisone: Prednisone is a synthetic glucocorticoid medication used to treat a wide range of inflammatory and autoimmune conditions. It acts as an immunosuppressant, reducing the body's immune response and inflammation, making it a crucial drug in the context of transplantation and cancer immunology.
Psychoneuroimmunology: Psychoneuroimmunology is the study of how psychological processes, the nervous system, and the immune system interact and affect each other. It explores the impact of mental states, such as stress or depression, on physical health by examining immune responses.
Regulatory T cells (Treg): Regulatory T cells are a subset of T lymphocytes that play a critical role in maintaining immune system balance by suppressing excessive immune responses and preventing autoimmune diseases. They help to keep the immune system in check by ensuring that it does not overreact to non-harmful antigens, which could lead to tissue damage or autoimmune disorders.
Regulatory T Cells (Tregs): Regulatory T cells, or Tregs, are a specialized subset of T cells that play a crucial role in maintaining immune homeostasis and preventing autoimmune diseases. They are essential for controlling the immune response and promoting tolerance to self-antigens, making them a key component in the context of transplantation and cancer immunology.
T cells: T cells, also known as T lymphocytes, are a type of white blood cell that play a crucial role in the adaptive immune response. They are responsible for cell-mediated immunity, which involves the direct destruction of infected or cancerous cells, as well as the regulation and coordination of the overall immune response.
Tacrolimus: Tacrolimus is an immunosuppressant drug used primarily to prevent organ rejection in transplant recipients. It works by inhibiting the activation and proliferation of T-cells, a critical component of the body's immune response, thereby reducing the risk of rejection in organ transplant patients. Tacrolimus is also used in the treatment of certain skin conditions, such as atopic dermatitis, due to its anti-inflammatory properties.
Transforming Growth Factor-Beta (TGF-β): Transforming Growth Factor-Beta (TGF-β) is a multifunctional cytokine that plays a crucial role in various biological processes, including cell growth, differentiation, and immune regulation. It is a key regulator of cellular homeostasis and has been extensively studied in the contexts of transplantation and cancer immunology.
Transfusion reactions: Transfusion reactions are adverse responses that occur when a patient receives blood products that are incompatible with their own blood type. These reactions can lead to serious complications, such as hemolysis, shock, and even death. Understanding these reactions is crucial for ensuring safe blood transfusions and managing organ transplantation, where immune responses can also be triggered by foreign tissues.
Tumor Microenvironment: The tumor microenvironment refers to the complex and dynamic cellular and non-cellular components that surround and interact with cancer cells within a tumor. This intricate network plays a crucial role in tumor development, progression, and response to treatment in the context of both transplantation and cancer immunology.
Tumor-Associated Antigens (TAAs): Tumor-associated antigens (TAAs) are proteins or other molecules that are present on the surface of cancer cells but are either absent or present at much lower levels on normal, healthy cells. These unique antigens can be recognized by the body's immune system, making them potential targets for cancer immunotherapy.
Tumor-Infiltrating Lymphocytes (TILs): Tumor-infiltrating lymphocytes (TILs) are a type of immune cells that have migrated into a tumor and can recognize and target cancer cells. They play a crucial role in the body's immune response against cancer, making them an important factor in both transplantation and cancer immunology.
Tumor-Specific Antigens (TSAs): Tumor-specific antigens (TSAs) are proteins or molecules that are uniquely expressed or present on the surface of cancer cells, but not on normal, healthy cells. These TSAs serve as targets for the immune system to recognize and attack the cancer cells, making them a crucial component in cancer immunology and transplantation immunology.
Xenograft: A xenograft is a type of tissue or organ transplant where the donor and recipient are of different species. This is a common technique used in the field of transplantation and cancer immunology to study immune responses and develop new therapies.