Autoimmunity

• What are autoimmune disorders?

  Disorders where immune responses target self-antigens, damaging organs and tissues.
• How does hypersensitivity differ from autoimmunity?

  Hypersensitivity involves harmless antigens, while autoimmunity involves self-antigens that destroy our own cells.
• What is the etiology of autoimmune disorders?

  A defect in mechanisms underlying self-recognition.
• What does loss of self-tolerance by B and/or T cells mean?

  It means these cells destroy our own cell antigens instead of recognizing them as self.
• What is self-tolerance?

  The ability of the immune system to accept self-antigens without an immune response.
• What happens during the education of lymphocytes?

  Lymphocytes learn to distinguish between self-antigens and foreign antigens.
• What are the two levels of education for lymphocytes?

  1. Central Tolerance

  • Occurs in primary lymphoid organs (thymus and bone marrow)
  • Self-antigens react and are eliminated through apoptosis

  1. Peripheral Tolerance

  • Occurs in secondary lymphoid organs
  • Acts as a filter; loss of self-tolerance can lead to autoimmunity
• What is molecular mimicry in the context of autoimmune disorders?

  It is when bacteria or viral agents have antigens that resemble self-antigens, deceiving the immune system.
• How do hormones influence autoimmune diseases?

  Women are more likely to acquire autoimmune diseases compared to men, possibly due to hormonal differences.
• What role do cryptic antigens play in autoimmune disorders?

  Cryptic antigens can be hidden in tissues, preventing T-cells and B-cells from being educated and leading to immune reactions.
• What is the hallmark feature of rheumatoid arthritis?

  The presence of rheumatoid factors, an anti-IgG immunoglobulin produced by B-cells and plasma cells.
• What distinguishes organ-specific autoimmune diseases from systemic autoimmune diseases?

  • Organ-specific: Lesions and autoantibodies target a single organ (e.g., Grave’s disease, Hashimoto’s thyroiditis).
  • Systemic: Lesions and autoantibodies are not confined to any organ (e.g., rheumatoid arthritis, systemic lupus erythematosus).
• What is the difference between Grave’s disease and Hashimoto’s thyroiditis?

  Grave’s disease causes high levels of thyroid hormones, while Hashimoto’s thyroiditis results in low levels.
• What is the most common manifestation of systemic lupus erythematosus (SLE)?

  The presence of a butterfly rash on the cheeks and forehead.
• What does the term "butterfly rash" refer to in SLE?

  It refers to rashes on the cheekbones and forehead that resemble a butterfly shape.
• What is the purpose of the Fluorescent Antinuclear Antibody test?

  To detect the presence of antinuclear antibodies in a patient's serum.
• What are the different patterns of fluorescence observed in antinuclear antibody tests?

  • Homogenous: Whole nucleus fluoresces evenly.
  • Peripheral: Sharp-ring fluorescence at the nucleus edge.
  • Speckled: Numerous round speckles against a dark background.
  • Nucleolar: Multiple, round fluorescing nucleoli.
  • Anti-centromere antibody: Discrete and speckled pattern.
• What are some diagnostic methods for autoimmune diseases?

  ELISA, Indirect Immunofluorescence, RIA, Immunoblotting, Immunodiffusion, Binding Assays.