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Autoimmune Diseases
Dr. Raid Jastania
Autoimmune Diseases• Group of diseases with common pathological
process• Presence of auto-antibody• ?defect in B-cells or T-cells• Genetic and Environmental etiological factors• Result in failure of self-tolerance• The process involve Ag-Ab binding and Ag-Ab
complex formation• Process may lead in complement activation and
inflammation with tissue injury
Autoantibody
• Failure to maintain self-tolerance
• Autoantibody can be formed to:– Nuclear antigen– Cytoplasmic antigen– Cell surface antigen– Proteins and phospholipids
Anti Nuclear Antibody (ANA)
• ANA represent diversity of antibodies that bind to several nuclear antigen– Anti-DNA– Anti-Histone– Antibody to Non-Histone– Antibody to nucleolar antigen
• ANA is usually detected by indirect immunofluorescence
Anti Nuclear Antibody (ANA)
• Patterns of ANA staining:– Homogenous: antibody to chromatin, histone or
DNA– Rim/Peripheral: antibody to DNA– Speckled: antibody to histone (Sm,
ribonucleoprotein RNP, SS-A (Ro), SS-B (La))– Nucleolar pattern
Systemic Lupus Erythematosus
• Autoimmune Disease
• Multi-system disease
• Variable behaviour, unpredictable, remitting relapsing, acute and gradual.
• May involve any organ
• Common: Skin, kidney, serosal membranes, joints, heart.
Systemic Lupus Erythematosus
• ANA (anti-DNA, anti-Sm, anti-phospholipid)
• Prevalence: 1/2500 person
• Female: male 9:1
• 1/700 women
• More common and severe in blacks (1/245)
• Onset: 2nd or 3rd decade
SLE: Criteria for Diagnosis
• Malar Rash• Discoid Rash• Photosensitivity• Oral ulcers• Arthritis• Serositis• Renal disorder
• Neurologic disorder• Hematologic disorder• Immunologic disorder• ANA
SLE
• ANA is sensitive to SLE but not specific• ANA is present in 5-15% of normal people• More specific to SLE are”
– Anti-DNA
– Anti-Sm
• LE bodies (hematoxylin bodies)• Antiphospholipid 40-50% of cases• Antiphospholipid syndrome (lupus anticoagulants)
SLE Atiology
• Genetic factors– 25% concordance in monozygotic twins– Increase risk of disease in family members– SLE and HLA-DQ association– Some SLE patients have deficiency in
complement components
SLE Atiology
• Non-Genetic factors:– Lupus-like syndrome with drug admenistration,
procainamide, hydralazine– Association with sex hormone (more in female)– Trigger by exposure to sun light
SLE Atiology
• Immunologic Factors:– Polyclonal B-cell activation?– Oligoclonal B-cell activation– CD4+ T helper cell activation
SLE: mechanism of tissue injury
• Immune complex disease– Example: deposition of Ag-Ab complex in
glomeruli results in kidney disease
• Type II hypersensitivity:– Hemolysis– Thrombocytopenia
SLE: common clinical manifestations
• Hematologic: anemia, leukopenia, thrombocytopenia
• Arthritis• Skin rash• Fever• Fatigue• Weight loss
• Renal disease• CNS abnormality• Pleuritis• Myalgia• Pericarditis• GI inflammation• Raynaud phenomenon• Peripheral neuropathy
Pathological Findings
• Ag-Ab complex deposition
• Common: kidney, hear, vessels, serosal membranes, and skin
• With the consequences of inflammation and tissue injury
Pathological Findings
• Vessels:– Acute necrotizing vasculitis
• Skin:– Rash, erythema– Cell injury/necrosis of the basal layer of
epidermis, edema, inflammation– Deposition of Ig, complement components
Pathological Findings
• Joints– Inflammation of synuvium, edema, mononuclear cell
infiltrate
• Spleen:– Enlargement with follicular hyperplasia
• Serosa: pleura, peritoneum, pericardium– Serous effusion
– Fibrinous inflammation
– fibrosis
Pathological Findings
• Heart:– Pericarditis, myocarditis
– Valvular lesion: Libman-Sacks endocarditis
– Coronary artery disease
• Kidney– Deposition of complexes in glomeruli
– Lupus nephritis
– Cell injury/necrosis, proliferation of mesangium, endothelium, and epithelium
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