Autoimmune disease

Autoimmune disease
Lectuer (12)
Dr.Baha,Hamdi.AL-Amiedi
Ph.D.Microbiology


Autoimmune disese
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.
Systemic Lupus Erythematosus (SLE)
a chronic systemic autoimmune disease
Complexes of anti-self antibodies and antigen deposit in, and cause damage to, tissue
1 million sufferers in the U.S.
Strikes women nine times more often than men
symptoms may include butterfly-shaped rash on face, fatigue, headaches
triggered by environmental effects in persons who are genetically susceptible


Butterfly rash of lupus
Damaged kidney (left) caused by immunoglobulin deposits (right)
Rheumatoid Arthritis (RA)
Treatments for autoimmune diseases
current treatments are based on easing disease symptoms
anti-inflammatory drugs to reduce the inflammatory response
cytotoxic drugs to kill immune cells
treatments that block interaction of immune cells – e.g., bind to cytokines, block second signals
replacement of necessary chemical – e.g., injections of insulin for diabetes
changes in diet
exercise
in the future
gene therapy
vaccines to turn off the autoimmune response

How can autoimmune disease produced
This can be done by 3 mechanisms
1-When microbial antigen cross - react with cryptic self epitopes lead to auto reactive T-Cell.
2-antigens sharing B- Cell epitopes cross react with self molecular this break tolerance but by a different mechanism.
3- foreigen antigen (e.g: LPS, E-B virus) cause direct B cell stimulation and some of the clones of these cells produce autoantibodies.







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