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.