Dr. Samir Ayad
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Part I - SLE
 
Dr. Samir Ayad
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Systemic Lupus Erythematosus(SLE)
Definition:
Autoimmune disease of connective tissue that involves multiple systems.
Incidence:
-1:2500-Sex: females to males (9:1)-Age: 20-40 years at onset (mostly)
 
Dr. Samir Ayad
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Etiology:
(1) Genetic factors:-familial incidence-HLA-DR2 and DR3(2) Immunological factors:-deficiency of suppresor T-cells -hyperactive helper T-cells-abnormal B-cells(3) Drugs-induced (e.g. hydralazine, procainamide)(4) Viral infection(5) Sex hormones(exacerbations in pregnancy)
 
Dr. Samir Ayad
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Mechanism:
(a) Autoimmune disease: antinuclear antibodies(ANAs) against several nuclear antigens (DNA,RNA, nucleoproteins)
react with nuclei of damaged cells (cannot penetrate intact cells)(b) Formation of immune complexesand their deposition in different tissues(c) Activation of complement
inflammatory lesions(
type III hypersensitivity
 
)
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