Transplantation and Tumor immunology

Lecture Notes on Transplantation & Tumor Immunology

Transplantation

• Types of Transplantation

  • Autologous Graft, Syngeneic Graft, Allogeneic Graft, Xenogeneic Graft

• Clinical Phases of Rejection

  • Hyperacute, Accelerated, Acute, Chronic

• Laboratory Tests

  • ABO Blood Typing, Tissue Typing, Lymphotoxicity Test, Mixed Leukocyte Reaction, Crossmatching

• Graft-vs-host Disease

  • Occurs when immunocompetent tissue is transplanted into an immunocompromised host

• Classification of Transplants

  • Based on nature of organs and anatomical site

Types of Transplantation

• Autograft

  • Transfer within the same individual, no immune response

• Isograft

  • Transfer between genetically identical individuals, always successful

• Allograft

  • Transfer between non-identical individuals, frequently unsuccessful

• Xenograft

  • Transfer between different species, frequently unsuccessful

Clinical Phases of Rejection

• Hyperacute Rejection

  • Immediate reaction due to pre-existing antibodies

• Accelerated Rejection

• Acute Rejection

  • Cell-mediated immune response in mismatched transplants

• Chronic Rejection

  • Humoral and cellular mechanisms causing slow rejection

Laboratory Tests

• Various tests like ABO Blood Typing and Tissue Typing are conducted to assess compatibility.

Graft-vs-host Disease

• Occurs when immunocompetent tissue is transplanted into an immunocompromised host.

• Can lead to severe symptoms and even fatality.

Classification of Transplants

• Based on the nature of organs and anatomical site.

Tumor Immunology

• Enzymes, Hormones, Proteins, Carbohydrates as Tumor Markers

• Blood Group Antigen Related Markers

• Specific Antigens like Prostate Specific Antigen, Oncofetal Antigen

• Oncogenes and Viral Biomarkers

Tumor Immunology Overview

• Study of the immune system's interaction with cancer cells.

• Differentiates between benign and malignant tumors based on growth and invasiveness.

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Host Immune Response to Tumor

• Immune Editing

  • Tumor cells develop genetic variants resistant to immune defenses.

  • Tumor cells escape immune surveillance by suppressing immunogenicity.

• Immune Surveillance

  • Body monitors tumors and cancerous cells to destroy them before clinical manifestation.

Cancer

• Multigene disease due to mutational and epigenetic changes.

• Involves alteration of proto-oncogenes, tumor suppressor genes, and DNA repair genes.

• Genetic alterations lead to disturbances in molecular pathways regulating cell growth and metastasis.

• Tumor markers are used for detection, targeted therapies, and predicting treatment responses.

Tumor Antigens

• Tumors have antigens recognized as foreign by the immune system.

• Some antibodies are unique to tumor cells, while others are found in normal cells.

Tumor Marker

• Substance produced by a tumor or host in response to a tumor.

• Used to differentiate tumors from normal tissue and detect their presence.

• Ideal tumor marker characteristics include specificity, sensitivity, organ specificity, prognosis correlation, and reliable prediction value.

• Enzymes, hormones, proteins, carbohydrates, blood group antigens, and oncofetal antigens can serve as tumor markers.

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Prostate Specific Antigen (PSA)

• Marker for screening prostate cancer.

• Single chain glycoprotein specific to prostatic tissue.

• Gene encoding PSA located on chromosome 19.

• Serine protease of the kallikrein family.

• Measured using Sandwich Immunoassays.

Oncogenes

• Derived from proto-oncogenes and activated by mutations, translocations, etc.

• Associated with cell proliferation and division.

• Useful as tumor markers in hematologic malignancies and solid tumors.

Breast Cancer Oncogenes

• Her-2/neu (ERBB2)