Immunology: Immune System and Medications

Overview of the Immune System

• The immune system protects the body against foreign invaders.
• It consists of two main branches: the innate and adaptive immune systems.
• The innate immune system offers immediate, non-specific protection.
• The adaptive immune system responds slower but gives specific and lasting immunity.
• Lymphocytes (T cells, B cells, NK cells), macrophages, dendritic cells, and mast cells are essential immune system cells.
• Cytokines are signaling molecules which mediate and regulate immune and inflammatory responses.

Classes of Immunological Medications

• Immunostimulants enhance the immune system's ability to fight disease.
• Immunosuppressants decrease the activity of the immune system.
• Monoclonal antibodies target specific components of the immune system.
• Vaccines induce immunity to specific pathogens.

Immunostimulants

• Immunostimulants boost the activity of the immune system.
• They treat conditions where the immune system is deficient or suppressed.
• Interferons are cytokines that have antiviral, immunomodulatory, and antineoplastic effects.
• They treat viral infections (e.g., hepatitis) and some cancers.
• Interleukins stimulate the growth, differentiation, and activation of immune cells.
• Aldesleukin (IL-2) treats metastatic renal cell carcinoma and melanoma.
• Colony-stimulating factors (CSFs) stimulate the production of blood cells in the bone marrow.
• Filgrastim (G-CSF) and pegfilgrastim prevent neutropenia in cancer patients receiving chemotherapy.

Immunosuppressants

• Immunosuppressants reduce the activity of the immune system.
• They prevent rejection of transplanted organs and treat autoimmune diseases.
• Calcineurin inhibitors (cyclosporine, tacrolimus) inhibit T cell activation by blocking calcineurin, preventing organ rejection, and treating autoimmune disorders.
• Side effects include nephrotoxicity, hypertension, and increased risk of infection.
• mTOR inhibitors (sirolimus, everolimus) inhibit T cell proliferation by blocking mTOR.
• They prevent organ rejection and treat some cancers.
• Side effects include hyperlipidemia, thrombocytopenia, and delayed wound healing.
• Glucocorticoids (prednisone, methylprednisolone) have broad immunosuppressive and anti-inflammatory effects.
• They treat autoimmune diseases and allergic reactions and prevent organ rejection.
• Side effects include hyperglycemia, osteoporosis, and increased risk of infection.
• Antimetabolites (azathioprine, methotrexate) interfere with DNA synthesis, inhibiting cell proliferation.
• They treat autoimmune diseases and prevent organ rejection.
• Side effects include bone marrow suppression, hepatotoxicity, and increased risk of infection.
• Biologic agents, such as TNF-alpha inhibitors and monoclonal antibodies, target specific components of the immune system and treat autoimmune diseases like rheumatoid arthritis and Crohn's disease.

Monoclonal Antibodies

• Monoclonal antibodies (mAbs) are antibodies produced by identical immune cells that are clones of a single parent cell.
• They exhibit monospecificity, binding only to one epitope, which makes them useful for targeting specific cells or proteins.
• They treat various diseases, including cancer, autoimmune disorders, and infectious diseases.
• Naming of monoclonal antibodies typically include the suffix "-mab".
  • The prefix indicates the source of the antibody:
  • "o" indicates mouse
  • "xi" indicates chimeric (part mouse, part human)
  • "zu" indicates humanized (mostly human)
  • "u" indicates fully human
• Examples of monoclonal antibodies:
  • Infliximab (Remicade): targets TNF-alpha, used to treat autoimmune diseases.
  • Rituximab (Rituxan): targets CD20 on B cells, used to treat lymphoma and autoimmune diseases.
  • Trastuzumab (Herceptin): targets HER2/neu, used to treat breast cancer.
  • Adalimumab (Humira): targets TNF-alpha, used to treat autoimmune diseases.
• Monoclonal antibodies can function through various mechanisms, including:
  • Neutralizing the target molecule, preventing it from interacting with its receptor.
  • Inducing cell death through antibody-dependent cell-mediated cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC).
  • Blocking cell signaling pathways.
  • Delivering cytotoxic drugs or radiation directly to cancer cells.
• Infusion reactions are a potential side effect of monoclonal antibody therapy.

Vaccines

• Vaccines induce active immunity to specific pathogens.
• They contain weakened or inactive forms of the pathogen, or components of the pathogen.
• Vaccines stimulate the immune system to produce antibodies and memory cells, providing long-lasting protection.
• Types of vaccines include:
  • Live attenuated vaccines: contain weakened forms of the pathogen.
  • Inactivated vaccines: contain killed pathogens.
  • Subunit vaccines: contain specific components of the pathogen.
  • Toxoid vaccines: contain inactivated toxins produced by the pathogen.
  • mRNA vaccines: contain mRNA that encodes a pathogen protein.
• Common vaccines include:
  • Measles, mumps, and rubella (MMR) vaccine.
  • Varicella (chickenpox) vaccine.
  • Influenza (flu) vaccine.
  • Tetanus, diphtheria, and pertussis (Tdap) vaccine.
  • Human papillomavirus (HPV) vaccine.
  • COVID-19 vaccines (mRNA and others).
• Adverse effects of vaccines are usually mild and may include fever, pain, and redness at the injection site.
• Severe allergic reactions to vaccines are rare.
• Contraindications to vaccination include severe allergic reactions to previous doses or vaccine components.

Nursing Considerations

• Assessment:
  • Assess the patient's immune status, including history of infections, autoimmune diseases, and allergies.
  • Monitor for signs and symptoms of infection, such as fever, cough, and fatigue.
  • Assess for adverse effects of immunological medications, such as infusion reactions and bone marrow suppression.
• Implementation:
  • Administer immunological medications as prescribed, following appropriate protocols.
  • Monitor vital signs during and after administration of medications.
  • Educate patients about the purpose, benefits, and risks of immunological medications.
  • Provide instructions on how to manage side effects and report any unusual symptoms.
• Patient education:
  • The importance of adherence to the prescribed medication regimen.
  • Potential side effects of immunological medications and how to manage them.
  • The importance of avoiding contact with people who have infections.
  • The need for regular monitoring of blood counts and other laboratory tests.
• Evaluation:
  • Evaluate the patient's response to immunological medications based on clinical and laboratory findings.
  • Monitor for resolution of symptoms and improvement in immune function.
  • Assess for adverse effects and adjust the medication regimen as needed.

Key Points

• Immunological medications modulate the immune system, either enhancing or suppressing its activity.
• Each class of immunological medications has specific mechanisms of action, indications, and adverse effects.
• Nursing considerations include assessment of immune status, medication administration, patient education, and evaluation of treatment outcomes.
• Safe and effective use of immunological medications requires careful monitoring and management of potential risks.