Immune System

Assalamualaikum, & hi readers !!!okay,today i would to share a little bit about immune system. Did you ever heard before about this?Yes or no?if no let me explained to you about this information.Immune system is part of our body defens from the virus or bacteria or the other disease.


Homeostatic imbalances of immunity;
a) Immunodeficiency
A medical condition in which your body does not have the normal ability to resist infection.
• Congenital or acquired condition that impairs the function of immune cells or production of certain molecules (phagocytes or complement system).
 • Causes immune cells to behave abnormally.
• Eg: SCID and AIDS.
 
SCID
– Severe combined immunodeficiency syndromes.
 – Genetic defects that produce a marked deficit of B and T cells.
 – Also abnormalities in interleukin receptors.
 – Children afflicted have little or no protection against disease-causing organisms.
 – Fatal if untreated, usually treatment from bone marrow transplants.

• SCID = bubble baby disease.
• Result of an immune system so highly compromised that it is considered almost absent.
• Victims are extremely vulnerable to infectious diseases.
 • David Vetter become famous for living in a sterile environment.

AIDS
-AIDS is caused by the human immunodeficiency virus (HIV) .
- HIV virus transmitted in body secretions : blood, semen, vaginal secretions,
Infected mothers can also transmit to her fetus.
- Commonly enters body via blood transfusions or bloodcontaminated needles and during sexual intercourse.

SYMPHTOMS OF AIDS

Characterized by
 • Severe weight loss.
 • Night sweat.
 •Swollen lymph nodes.
 • Increase frequent opportunistic infections:
  – Pneumonia (Pneumocystis pneumonia).
  – Kaposi’s sarcoma (cancer of blood vessels Symptoms of AIDS may not appear 5 – 10 years after
   being infected with HIV


b)Autoimmune diseases
Produced by failure of the immune system to recognize and tolerate self-antigens.
 – Immune system loses its ability to distinguish friend (self) from foe (foreign antigens).
 – Then arise an overactive immune response of the body against substances and tissues normally      present in the body.
 – In other words, the body attacks its own cells.
 – This may be restricted to certain organs or involve a particular tissue in different places.

   





 c) Hypersensitivities
Abnormal immune responses to antigens.
 – Result when immune system damage tissues as it fights off a threat that is harmless to body (such as pollen and animal dander).
 – People rarely die but just feel uncomfortable.
 – Different types of hypersensitivities reactions distinguished by:
 • Time course.
 • Involvement of antibodies or T cells.


2 major forms :
a) immediate hypersensitivity.
 – caused by abnormal B lymphocyte (antibodies) response to an allergen to produce symptoms within seconds/minutes.
 – What most of us call allergies reaction.
 – Reaction begin within seconds after contact with allergen and last about half an hour.
– Allergen: antigen that causes an allergy reaction.

 b). Delayed/subacute hypersensitivity.
 – caused by T cell response that produces symptoms between 24 and 72 hours.
– T cells take longer to appear (1-3 days).
 – Inflammation and tissue damage result from action of macrophage or cytotoxic T cells.
 – Example: allergic contact dermatitis which follow skin contact with some metals, cosmetics and deodorant chemicals.