Autoimmunity
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Questions and Answers

What are the two primary processes involved in B-cell production of antibodies?

  • Clonal expansion and differentiation
  • Positive selection and apoptosis
  • Negative selection and proliferation
  • Negative selection and positive selection (correct)

    • Which term describes the immune system's ability to tolerate self-tissues?

  • Autoimmunity
  • Desensitization
  • Tolerance (correct)
  • Immunosuppression

    • What is a consequence of the breakdown in self-tolerance?

  • Development of autoimmunity (correct)
  • Increased immune response to infections
  • Enhanced tolerance to allergies
  • Reduction in B-cell activity

    • What can trigger autoimmunity in susceptible individuals?

    <p>Triggering events</p> Signup and view all the answers

    What environmental factor can induce autoimmunity, specifically in relation to drug use?

    <p>Procainamide</p> Signup and view all the answers

    In which gender is Systemic Lupus Erythematosus (SLE) predominantly more prevalent?

    <p>Females</p> Signup and view all the answers

    What concept explains the immune system's attack on self-antigens that are similar to foreign antigens?

    <p>Molecular mimicry</p> Signup and view all the answers

    What biological process can contribute to the development of autoimmunity if it is defective?

    <p>Apoptosis</p> Signup and view all the answers

    Which phase of the cell cycle is characterized by DNA synthesis?

    <p>S phase</p> Signup and view all the answers

    What is the correct sequence of stages in the cell cycle?

    <p>G1, S, G2, M</p> Signup and view all the answers

    What occurs during the anaphase of mitosis?

    <p>Sister chromatids are pulled apart</p> Signup and view all the answers

    What result indicates a negative test in ANA testing during interphase?

    <p>No discernible pattern</p> Signup and view all the answers

    Which autoimmune disease is associated with a homogeneous pattern in ANA testing?

    <p>Systemic Lupus Erythematosus</p> Signup and view all the answers

    In ANA testing, how do nucleoli typically behave in interphase cells with a speckled pattern?

    <p>Nucleoli usually do not stain</p> Signup and view all the answers

    What is indicated by smooth staining of the entire nucleus in interphase cells during ANA testing?

    <p>Homogeneous pattern</p> Signup and view all the answers

    Which pattern in ANA testing is associated with Systemic Sclerosis and Polymyositis?

    <p>Nucleolar pattern</p> Signup and view all the answers

    In metaphase cells displaying a homogeneous pattern, where is the staining observed?

    <p>Smooth staining of the chromosomal region</p> Signup and view all the answers

    What caution should be taken when interpreting the intensity of ANA results?

    <p>Do not confuse intensity with positivity</p> Signup and view all the answers

    How do interphase cells exhibiting a nucleolar pattern typically manifest in ANA testing?

    <p>Staining in the nucleoli only</p> Signup and view all the answers

    Which autoimmune diseases are associated with a speckled pattern in ANA testing?

    <p>Systemic Lupus Erythematosus and Sjogren's syndrome</p> Signup and view all the answers

    What should be avoided to ensure objectivity in ANA interpretation?

    <p>Long observation leading to bias</p> Signup and view all the answers

    What is a key characteristic of autoimmune diseases classified as organ-specific?

    <p>Autoantibodies directed to a specific antigen</p> Signup and view all the answers

    Which autoimmune disease is characterized by antibodies against acetylcholine receptors?

    <p>Myasthenia Gravis</p> Signup and view all the answers

    In autoimmune hemolytic anemia, what do autoantibodies target to initiate hemolysis?

    <p>RBC antigens</p> Signup and view all the answers

    What primarily distinguishes non-organ-specific autoimmune diseases?

    <p>Autoantibodies aimed at a variety of subcellular antigens</p> Signup and view all the answers

    Which immunoglobulin class is considered clinically significant regarding Antinuclear Antibodies (ANAs)?

    <p>IgG</p> Signup and view all the answers

    How many different autoantibodies are estimated to be found in Systemic Lupus Erythematosus (SLE)?

    <p>Over 100</p> Signup and view all the answers

    What type of blood sample is required for detecting Antinuclear Antibodies (ANAs)?

    <p>Clotted whole blood</p> Signup and view all the answers

    What advantage do HEP-2/2000 substrate slides have over rodent substrate slides in detecting autoantibodies?

    <p>More sensitivity in detecting specific autoantibodies</p> Signup and view all the answers

    What is the function of washing the slides after serum incubation in ANA testing?

    <p>To remove unbound antibody</p> Signup and view all the answers

    What type of antigen do HEp-2000 cells express that is relevant in ANA testing?

    <p>SS-A (Ro) antigen</p> Signup and view all the answers

    In ANA testing, what is bound to the substrate during the testing process?

    <p>Serum containing ANAs</p> Signup and view all the answers

    What happens to ANAs in the serum during ANA testing?

    <p>They bind to the cultured cells on the slide</p> Signup and view all the answers

    What is the purpose of using a fluorescent microscope after incubation with FITC-labeled secondary IgG?

    <p>To visualize the binding patterns of ANAs</p> Signup and view all the answers

    What indicates a higher presence of autoantibodies in a serum sample?

    <p>Higher titer</p> Signup and view all the answers

    Which autoantibodies are specifically associated with systemic lupus erythematosus (SLE)?

    <p>Anti-dsDNA</p> Signup and view all the answers

    Which of the following conditions is associated with the nucleolar pattern?

    <p>Systemic sclerosis</p> Signup and view all the answers

    What is the role of dsDNA antigen in the ELISA test for anti-DNA antibodies?

    <p>It is the target for antibody binding</p> Signup and view all the answers

    What pattern is typically associated with systemic lupus erythematosus (SLE)?

    <p>Homogeneous pattern</p> Signup and view all the answers

    Which testing method is used for detecting anti-ENA antibodies?

    <p>ELISA</p> Signup and view all the answers

    What condition is associated with anti-JO-1 antibodies?

    <p>Polymyositis</p> Signup and view all the answers

    What does the presence of anti-ENA antibodies indicate?

    <p>Specific autoimmune condition</p> Signup and view all the answers

    What condition is linked to the centromeric pattern?

    <p>CREST syndrome</p> Signup and view all the answers

    What is a confirmed feature of CREST syndrome?

    <p>Sclerodactyly</p> Signup and view all the answers

    Which autoantibody is associated with Sjogren's syndrome?

    <p>Anti-SSA (RO)</p> Signup and view all the answers

    What does a negative ANA pattern typically indicate regarding further testing?

    <p>No further tests are necessary</p> Signup and view all the answers

    What common testing method is used for both anti-DNA and anti-ENA antibodies?

    <p>ELISA</p> Signup and view all the answers

    What is the typical arrangement of discrete speckles in metaphase mitotic cells?

    <p>Aligned in the chromosomal region</p> Signup and view all the answers

    Which autoimmune diseases are commonly associated with the SS-A/RO pattern?

    <p>Systemic Lupus Erythematosus and Sjogren's Syndrome</p> Signup and view all the answers

    What percentage of samples with anti-SS-A/RO antibodies display the SS-A/RO pattern?

    <p>89%</p> Signup and view all the answers

    How do hyper-expressing interphase cells differ from non-hyperexpressing interphase cells?

    <p>Hyper-expressing cells show stronger nucleolar and speckled staining.</p> Signup and view all the answers

    What is the clinical significance of cytoskeletal antibodies?

    <p>Linked to autoimmune diseases and Mycoplasma pneumoniae infections</p> Signup and view all the answers

    What pattern do mitochondrial antibodies typically display?

    <p>Cytoplasmic pattern</p> Signup and view all the answers

    How are ribosomal antibodies commonly observed in systemic lupus erythematosus (SLE)?

    <p>Seen in approximately 15-20% of cases</p> Signup and view all the answers

    What characterizes mixed patterns in autoimmune testing?

    <p>They can be any combination of patterns</p> Signup and view all the answers

    Why is titering performed on all positive ANAs?

    <p>To determine the amount of antibody present</p> Signup and view all the answers

    What does titering specifically help determine in ANA testing?

    <p>Antibody presence and quantity</p> Signup and view all the answers

    Which organelles are recommended for reporting by ANA guidelines?

    <p>Golgi apparatus, centriole, and mitotic spindle</p> Signup and view all the answers

    What additional feature may be seen in some samples of ribosomal antibodies?

    <p>Prominent nucleolar ANA</p> Signup and view all the answers

    In what percentage of patients with primary biliary cirrhosis are mitochondrial antibodies detected?

    <p>More than 95%</p> Signup and view all the answers

    What staining appearance is typical of ribosomal antibodies in the cytoplasm?

    <p>Fine speckling</p> Signup and view all the answers

    What is a significant preventive measure for SLE patients to ensure heart health?

    <p>Regular exercise</p> Signup and view all the answers

    What percentage of people with lupus survive 10 years?

    <p>85 - 95%</p> Signup and view all the answers

    How does older age at onset generally affect the seriousness of SLE?

    <p>It generally makes it less serious.</p> Signup and view all the answers

    What condition is characterized by dry eyes and dry mouth?

    <p>Sjogren's Syndrome</p> Signup and view all the answers

    What pattern of ANA is commonly associated with Localised Sclerosis?

    <p>Homogeneous</p> Signup and view all the answers

    Which autoantibodies are primarily found in Sjogren's Syndrome?

    <p>SS-A/RO and SS-B/La</p> Signup and view all the answers

    In what ways does Diffuse Systemic Sclerosis typically impact the body?

    <p>Affects skin and internal organs</p> Signup and view all the answers

    What is the clinical association of Raynaud's Phenomenon?

    <p>Sjogren's Syndrome</p> Signup and view all the answers

    Which condition is indicated by inflammation of multiple muscles?

    <p>Polymyositis</p> Signup and view all the answers

    What does CREST stand for in Limited Systemic Sclerosis?

    <p>Calcinosis, Raynaud's, Esophageal dysfunction, Sclerodactyly, Telangiectasia</p> Signup and view all the answers

    Which subtype of Scleroderma primarily affects areas distal to the elbows and knees?

    <p>Limited Systemic Sclerosis</p> Signup and view all the answers

    What is a common clinical feature of Diffuse Systemic Sclerosis?

    <p>Dermatofibrosis</p> Signup and view all the answers

    What distinguishes Limited from Diffuse Systemic Sclerosis?

    <p>Limited affects only the skin, diffuse affects organs</p> Signup and view all the answers

    What is a characteristic symptom of Dermatomyositis?

    <p>Reddish rash</p> Signup and view all the answers

    How has the prognosis for Systemic Lupus Erythematosus (SLE) changed over recent decades?

    <p>It has improved markedly.</p> Signup and view all the answers

    What distinguishes Systemic Rheumatic Diseases from localized conditions?

    <p>They affect various organs and tissues throughout the body.</p> Signup and view all the answers

    What is the typical female to male ratio in cases of Systemic Lupus Erythematosus (SLE)?

    <p>9:1</p> Signup and view all the answers

    Which of the following is a common skin-related symptom of SLE?

    <p>Hair loss</p> Signup and view all the answers

    What is the typical pattern observed in ANA testing for SLE?

    <p>Homogeneous or speckled</p> Signup and view all the answers

    What is the primary goal of treatment for SLE?

    <p>To control symptoms</p> Signup and view all the answers

    Which of the following medications is known to potentially cause Drug-Induced Systemic Lupus Erythematosus?

    <p>Chlorpromazine</p> Signup and view all the answers

    When do symptoms of drug-induced SLE typically occur after starting the medication?

    <p>3-6 months later</p> Signup and view all the answers

    What increases the incidence of SLE over the years in the USA?

    <p>Better diagnosis and awareness</p> Signup and view all the answers

    Which symptom does NOT typically describe SLE?

    <p>Increased hair growth</p> Signup and view all the answers

    What is the reason for screening for osteoporosis in the treatment of SLE?

    <p>To manage side effects of treatments</p> Signup and view all the answers

    Which of the following statements about SLE's ethnic prevalence is true?

    <p>It varies significantly with ethnicity.</p> Signup and view all the answers

    What role does the X-chromosome play in SLE?

    <p>It carries genes related to immunity.</p> Signup and view all the answers

    Which of the following is a serious complication of SLE?

    <p>Lung involvement</p> Signup and view all the answers

    What is a common form of managing mild SLE symptoms?

    <p>Wearing protective clothing and using NSAIDs</p> Signup and view all the answers

    Study Notes

    B-cell Antibody Production and Autoimmunity

    • Two main processes for B-cell production of antibodies: positive selection and negative selection.
    • Tolerance refers to the immune system's ability to tolerate self-tissues, preventing autoimmunity.
    • Breakdown in self-tolerance results in autoimmunity, often marked by autoantibody production.
    • Genetic predisposition significantly contributes to the etiology of autoimmune diseases.
    • HLA-B27 is notably associated with Ankylosing Spondylitis, increasing risk by 90 times.

    Triggers and Factors of Autoimmunity

    • Autoimmunity can be triggered by various events.
    • Environmental factors, such as drug-induced reactions (e.g., procainamide), can provoke autoimmunity.
    • Systemic Lupus Erythematosus (SLE) shows a higher prevalence in females.
    • Defective apoptosis may lead to loss of tolerance, contributing to autoimmune conditions.

    Autoimmune Disease Classification

    • Organ-specific autoimmune diseases involve autoantibodies targeting specific antigens (e.g., Myasthenia Gravis - AChR autoantibodies).
    • Non-organ-specific autoimmune diseases generate autoantibodies against various organelles or subcellular components (e.g., SLE and Rheumatoid Arthritis).
    • Autoantibodies can recognize a diverse range of cellular structures leading to systemic effects.

    Antinuclear Antibodies (ANAs)

    • ANAs bind specifically to the nucleus and can belong to IgG, IgM, or IgA classes.
    • IgG is deemed clinically significant among ANA classes.
    • The incidence of ANAs increases with age and can indicate systemic rheumatologic conditions.
    • ANA tests are useful for diagnosing patients exhibiting relevant symptoms.

    ANA Testing Procedures

    • Blood samples for ANA testing require clotted whole blood collected in red-topped vacutainers.
    • Serum is separated post-centrifugation and tested against substrates coated with cultured cells (e.g., HEp-2, HEp-2000).
    • Positive ANA tests display fluorescent patterns under a microscope, which can vary based on antibody type.

    ANA Patterns and Clinical Significance

    • Homogeneous patterns are associated with SLE and feature smooth nuclear staining in interphase cells.
    • Speckled patterns, indicative of various autoimmune diseases (e.g., SLE, Sjogren's syndrome), show coarse or fine staining in the nucleus.
    • Nucleolar patterns are associated with Systemic Sclerosis, demonstrating staining exclusive to nucleoli.
    • Centromere patterns, often seen in CREST syndrome, show discrete speckling within the nucleus.

    Cytoplasmic Antibodies in Autoimmunity

    • Cytoskeletal, mitochondrial, and ribosomal proteins are notable cytoplasmic antigens in autoimmune diseases.
    • Mitochondrial antibodies are present in over 95% of primary biliary cirrhosis cases.
    • Ribosomal antibodies appear in approximately 15-20% of systemic lupus erythematosus cases, associated with neuropsychiatric symptoms.

    Mixed Patterns in Autoimmune Testing

    • Mixed patterns can show combinations of staining and require careful interpretation and reporting of all observed patterns and titers.
    • Titering is performed on positive ANAs to quantify the antibody levels and support diagnosis.
    • Follow-up tests, including anti-DNA and ENA testing, may be recommended based on pattern analysis.

    Conclusion on ANA Testing

    • Understanding the classification of ANA patterns is crucial for diagnosing autoimmune diseases.
    • Insights into both organ-specific and non-specific autoimmune conditions provide a framework for targeted patient management.
    • Proper interpretive methods and technology in ANA testing enhance diagnostic accuracy and therapeutic approaches in autoimmunity.### Autoantibodies and Testing
    • Follow-on tests for positive ANAs are crucial to clarify unclear staining patterns and confirm conditions like systemic lupus erythematosus (SLE).
    • Negative ANA patterns require no further testing.
    • Anti-DNA antibodies are tested using ELISA, which involves immobilizing double-stranded DNA on a plate to detect IgG antibodies in patient serum.
    • Anti-ENA antibodies are also tested via ELISA, with extractable nuclear antigens (such as RO, LA, Sm, RNP/Sm, Scl 70, and JO-1) immobilized on the plate.
    • Homogeneous and speckled ANA patterns are prominently associated with SLE.

    Systemic Lupus Erythematosus (SLE)

    • SLE presents with diverse symptoms affecting skin, joints, lungs, and kidneys; it's chronic, with remissions and relapses.
    • A notable female-to-male ratio of 9:1; commonly appears in the second or third decade of life.
    • Incidence in the USA increased significantly from 1.0 per 100,000 in 1955 to current rates of 53 to 305 per 100,000, influenced by improved diagnostics.
    • Prevalence varies by ethnicity, with higher rates in Afro-Caribbean individuals (159/100,000).

    Symptoms and Diagnosis

    • Common symptoms include joint pain (arthralgia), skin rashes (butterfly rash), fever, anemia, renal issues, and Raynaud's phenomenon.
    • Diagnosis involves clinical presentation, ANA testing, antibody titration, and possibly follow-up DNA/ENA tests.
    • Specific auto-antibodies like anti-dsDNA and anti-Sm are strongly correlated with SLE.

    Treatment Approaches

    • Treatment focuses on symptom management; aggressive therapy is necessary for severe cases involving organs like kidneys and heart.
    • Options include NSAIDs, corticosteroids, antimalarials (hydroxychloroquine), and cytotoxic drugs.
    • Monitoring for osteoporosis is crucial due to prolonged corticosteroid use.

    Prognosis

    • Prognosis has improved; early treatment positively influences long-term outcomes, with approximately 85-95% survival over ten years.
    • Later-onset SLE is generally less severe than early-onset forms.

    Other Systemic Rheumatic Diseases

    • Systemic rheumatic diseases are characterized by non-organ-specific symptoms.
    • Examples include Sjogren's Syndrome, Scleroderma, and Polymyositis.
    • Sjogren's is characterized by dry eyes and mouth; autoantibodies include SS-A and SS-B.
    • Scleroderma divides into localized and systemic types, with varying clinical implications, generally involving skin and potentially major organ systems.

    Scleroderma Details

    • Limited Scleroderma often presents as CREST syndrome, exhibiting calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia.
    • The centromeric pattern of ANA is prevalent in limited systemic sclerosis.
    • Diffuse Scleroderma affects multiple organ systems and has a higher ANA positivity rate (70-90%).

    Polymyositis and Dermatomyositis

    • Polymyositis affects multiple muscles; Dermatomyositis additionally causes skin inflammation (characterized by a reddish rash).
    • Common symptoms include muscle weakness and soreness, with potential involvement of the heart and GI tract.
    • The JO-1 antibody is frequently found in these conditions.

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    Test your knowledge on B-cell production and the immune response. This quiz covers key concepts such as positive and negative selection, self-tolerance, and the consequences of autoimmunity. Challenge yourself and see how well you understand these vital immunological processes.

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