Autoimmune Diseases 2

Autoimmune Diseases Overview

Introduction to Autoimmunity

  • Immunology lecture continuation focusing on autoimmune diseases.
  • Previous discussions covered mechanisms of tolerance, education, and self-reactivity checks for B-cells and T-cells.

Common Autoimmune Diseases

  • Multiple Sclerosis (MS): Affects the brain and spinal cord.
  • Systemic Lupus Erythematosus (SLE): Affects multiple organs; systemic autoimmune disease.
  • Rheumatoid Arthritis (RA): Primarily affects joints.

Types of Autoimmune Diseases

  • Organ-Specific Autoimmune Diseases:

    • Target specific organs or glands.
    • Examples include:
    • Autoimmune Hemolytic Anemia: Autoantibodies against red blood cell membranes leading to anemia.
    • Type 1 Diabetes: T-cell mediated destruction of pancreatic beta cells.
    • Pernicious Anemia: Autoantibodies against intrinsic factor affecting B12 absorption.

  • Systemic Autoimmune Diseases:

    • Affect multiple parts of the body.
    • Examples include:
    • SLE: Butterfly rash, kidney dysfunction, arthritis.
    • Graves' Disease and Hashimoto's Thyroiditis, which affect thyroid function.

Specific Autoimmune Diseases

1. Multiple Sclerosis
  • T-cells attack myelin basic proteins in central nervous system (CNS).
  • Characterized by damage to neural tissues and formation of immune complexes.
  • Symptoms include weakness, fatigue, and impaired coordination.
2. Systemic Lupus Erythematosus (SLE)
  • Characterized by a butterfly rash on the face, immune complex formation affecting various organs (but primarily kidneys).
  • Symptoms include:
    • Skin rash
    • Arthritis
    • Fever
    • Kidney dysfunction.
  • Autoantibodies target DNA, histones, and can activate complement pathways.
3. Hashimoto's Thyroiditis
  • Hypo-functioning thyroid, leading to insufficient hormone production.
  • Enlarged thyroid due to immune infiltration; inflammation increases destructiveness.
  • Symptoms include weight gain, fatigue, depression.
4. Graves' Disease
  • Opposite effect of Hashimoto's; characterized by overproduction of thyroid hormones due to autoantibody binding to TSH receptors.
  • Symptoms include weight loss, anxiety, palpitations, and exophthalmos (bulging eyes).

Mechanisms of Autoimmunity

  • Autoimmune diseases can arise from:
    • Genetic predispositions (e.g., specific HLA alleles)
    • Environmental triggers (e.g., infections, stress).
  • Molecular Mimicry: Where infectious agents resemble host antigens, causing misdirected immune responses.

Diagnosis and Treatment

Diagnosis
  • Blood tests for autoantibodies (e.g., presence of anti-TPO antibodies in Hashimoto's).
  • Kidney biopsies and imaging for systemic diseases.
Treatment
  • Immunosuppression via steroids (not ideal due to side effects).
  • Targeted therapies (e.g., TNF-alpha inhibitors) effective for various autoimmune disorders.
  • Personalized medicine still under research; addressing the antigen causing the disease remains complex.
  • Some therapeutic approaches involve re-establishing tolerance via exposure to harmless antigens.

Conclusion

  • Autoimmunity presents intricate challenges that necessitate ongoing research and understanding of complex interactions between genetic and environmental factors.
  • Focus on future lectures regarding vaccines and updates on autoimmune treatments towards mid-semester examinations.