Auto immune diaseases

BY
VANA JAGAN MOHAN RAO M.S.Pharm, MED.CHEM
NIPER-KOLKATA
Asst.Professor, MIPER-KURNOOL
Email: jaganvana6@gmail.com

Autoimmunity
• Autoimmunity literally means “protection against
self”;
• In practice it leads to “injury to self.”
Auto or Self antigens
– Antigens present in ones own cells.
– Altered by the action of bacteria, viruses,
chemicals or drugs as a non-self.
Auto antibody
– Altered cell (Auto Ag) - elicits the productions
of Antibody.

Auto Immunity
 Immune response of auto Ab against
self Ag.
 Humoral or cell mediated immune
response against the constitutes of the
body’s own tissues.
 There are more than 80 different kinds
of diseases caused by autoimmunity.

AUTOIMMUNE DISEASES
• Normally, the immune system does not attack
the self.
• However, there is a large group of autoimmune
diseases in which the immune system attack
self-cells.
• Autoimmune diseases is a group of disorders in
which tissue injury is caused by humoral (auto-
antibodies) or cell mediated immune response
(auto-reactive T cells) to self antigens.
• The attack can be directed either against a very
specific tissue or to a large No. of tissues.
• Once started, it is hard to stop.

CAUSES OF AUTOIMMUNE DISEASES
1. Sequestered or Hidden antigens
• Ag in the secluded places - are not accessible to the
immune system.
• E.g. Lens Ag, Sperm Ag & Thyroglubulin.
2. Neo antigens
Altered or Modified Antigens – by physical
(irradiation), chemical (drugs) or microbial agents
( intracellular viruses).
3. Cessation of Tolerance
It may result when tolerance to the self-Ag is
abrogated.

4. Cross reacting Antigens
• A foreign Ag which resembles self Ag.
• Many species share organ specific Ags.
• E.g. Ag of Human brain & Ag of sheep brain,
Streptococcal M protein & Heart muscles,
Nephritogenic strains of Streptococci Ags &
Renal glomeruli shares similar epitopes.
5. Loss of Immunoregulation
• Loss of Self tolerance - caused by over
activity or lowered activity of T and B- cells.

CLASSIFICATION OF AUTOIMMUNE DISEASES
• It is classified into 3 groups:
1. Haemolytic autoimmune diseases.
2. Localised autoimmune diseases.
3. Systemic autoimmune diseases.
Haemolytic autoimmune diseases
- Clinical disorder due to destructions of blood
components.
- Auto Ab are formed against one’s own RBCs,
Platelets or Leucocytes.
- E.g. Haemolytic anaemia, Leucopenia,
Thrombocytopenia.

Localised autoimmune diseases or
Organ specific autoimmune diseases
- A particular organ is affected due to auto Abs.
- For example:
– Thyroiditis (attacks the thyroid).
– Multiple sclerosis (attacks myelin coating of
nerve axons).
– Myasthenia gravis (attacks nerve-muscle
junction).
– Juvenile diabetes or Type I DM
(attacks insulin-producing cells).

Systemic autoimmune diseases or
Non-organ specific autoimmune diseases
• Immune complexes accumulate in many tissues and
cause inflammation and damage.
• Affects many organs or the whole body.
- For example:
– Systemic Lupus Erythematosus (anti-nuclear
Ab.): Harms kidneys, heart, brain, lungs, skin…
– Rheumatoid Arthritis (anti-IgG antibodies):
Joints, hearts, lungs, nervous system.
– Rheumatic fever: cross-reaction between
antibodies to streptococcus and auto-antibodies.

AUTOIMMUNE HEMOLYTIC ANEMIA
• Lysis of RBC is due to the production of
autoantibodies against the RBC-antigens.
• RBC half life= 21 days, Ha. Anaemia <7days
• Caused by infections or Drug therapy [Penicillin,
Anti-hypertensive agent results in destruction of
RBCs].
• Antibody mediated autoimmune diseases.
• 2 classes of autoantibodies involved are:
• IgM.
• IgG.

THROMBOCYTOPENIA
• Characterized by low platelet count due to the
production of antiplatelet Ab. (IgG).
 Mechanism
• An interaction of Ab with bound drug or new
Ag. causes intravascular agglutination of
platelets & can be eliminated by phagocytic
cells.
• Antibody mediated autoimmune diseases.

THYROTOXICOSIS OR GRAVE’S DISEASE
• The Ab (IgG) is directed against the receptor for
thyroid stimulatory hormone (TSH).
• This Ab is called as Long acting thyroid (LATS)
stimulator or thyroid stimulating Ab (TSab).
• Primary causes: Stimulation of Thyroid gland to
secrete more TH (Hyperthyroidism) resulting in
Exophthalmus , bulging eyes & Goitre.

Graves’ disease (anti-thyroid stimulating
hormone; anti-TSH)
In Graves’ disease,
the antibodies do not
destroy the thyroid but
act as if they are TSH
(i.e., they bind and
activate the TSH
receptor)

SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)
• It is a skin disease due to the production of
antinuclear factor (ANF) or antinuclear auto
Ab.
• ANF reacts with the breakdown products of
nuclei in the normal aging of cells & form
immune complexes which cause the tissue
damage.
• In these patients, LE cell (a mature
neutrophil) appears in blood & bone marrow.
– Function – Phagocytosis in the presence of ANF.

CHARACTERISTICS OF SLE
• Appearance of blood red spots over the bridge of
nose & cheeks. The lesions take the shape of a
butterfly.
• Connective tissues of the skin, kidney, heart.
Spleen & blood vessels are severely damaged
resulting in joint pain, fever & anemia.
• Glomerulonephritis due to deposition of immune
complex in the glomerulus region.
• It is a systemic disease affecting the whole body

RHEUMATOID ARTHRITIS
• It is a chronic systemic disease of the joints.
• Caused by the auto Antibody of IgM type,
called as rheumatoid factors.
Characteristics:
• The synovial fluid of these patients contain
increased No. of T-cells & macrophages.
• Marked by inflammatory changes in the
synovial membrane & by atrophy of bones.
• In later stage, deformity & ankylosis
develops.

DIAGNOSIS OF AUTO IMMUNE DISEASE
• Clinical symptoms.
• Confirmed by detecting the auto Ab in the
serum of the patients.
• Autoantibodies are demonstrated by
immunoflurescent Ab test,
haemagglutination, Complement fixation,
immunodiffusion, Radio immuno assay, etc.

TREATMENT
• Some autoimmune diseases are treated with
medications that alleviate specific symptoms.
• Haemolytic anaemia: Treated with Vit B12 .
• Throtoxicosis: Treated with antithyroid drugs.
• Myasthenia Gravis: Choline estrase inhibitors.
• Rhemotoid Arthritis: Anti-inflammatory drugs.

Auto immune diaseases

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