Autoimmune disese
Lecture ( 12)
Dr.Baha, Hamdi.AL-Amiedie
Ph.D.Microbiology
• Autoimmunity :
• Normally the immune system known its own tissues as self and does not react to them . Rarely, however there is a breakdown in this recognition and the immune system destroy its own tissue a phenomena termed autoimmunity As specificity repertoires that are expressed by both T- and B-Cells are random
it is no surprising that antiself specificites occur , there are mechanism which kill these self - reactive cell , as described earlier , but some escape this surveillance , some autoimmune disease are triggered by microbial antigen which mimic or cross – react with self components.
• Classification of autoimmune disease:
• The organ specific when the specific pathology is confined to particular organ :
• (eg:Hashimotos disease , pernicious anaemia , Addisons disease )
• And when the pathology is not confined to particular organ the disorder were placed under the head non-organ specific .
• systemic lupus erythrematosis, reheumatoid arithritis, dermatomyositis
• Moreover autoimmune disorder may overlap that mean a patient have more than one organ-specific disease & more than one systemic disease
• Based on the clinical experimental studies it has been suggested that autoimmunity may arise
• Due to an immunologic imbalance with excessive B-cell activity &diminished suppressor T-cell activity. This imbalance may occur as a consequence of genetic , viral and environmental mechanisms acting singly or combination .
• Autoimmune diseas can be caused by:
• 1-Microbial antigen cross- reacting with self antigens.
• 2- Cytokine dysregulaion .
• 3-Antigen share B-cell antigens cross react with self molecules.
• 4-foreign antigen activate B-Cells &some of activated cells clones
• produce autoantibody& Cause autoimmune disease
• Genetic factors may afacet the induction of autoimmune disease and this depends on:
• 1-autoimmune within family.
• 2-different genetic factors that select the organ to be affected
• 3-Certain HLA type specificities
• Pathogenesis
• The process of the autoimmune mechanism is pathogenic autoantibody found in the serum, may be of three possibilities:
• 1-The auto antibody itself is responsible for producing the disease
• 2-There is an inflammatory process or a disease which cause a tissue damage & that damage lead to producing of Autoantibody
• 3-There is a factor which produces both the disease &the Autoantibody
• Diagnosis autoimmune disease:
• General signs of autoimmune disease that may have diagnostic value include :
• 1-Elvated serum gamma globuline
• 2-presence of autoantibodies
• 3-Depress levels of serum complement
• 4-lmmune complex in serum
• 5-lesion detected on biopsy (e.glomerular lesions) resulting from deposition of immune complexs.