AUTOIMMUNE DISEASES.

GOOD AFTERNOON  BOYS.
MARK YOUR ATTENDANCE FIRST.

Today we will achieve the following LEARNING OUTCOMES:-
Students will be able to -

1. Define Autoimmunity.

2. Analyse the various types of Autoimmune diseases caused in Human body.

3. Understand its basic cause , symptoms & treatment involved in it .

4. Understand how it is different from ALLERGY.



GENERAL INSTRUCTIONS :

1. Write all the notes in your register.

2. I have shared two video links along with this blog . Kindly watch it before you read the blog.

3. Some extra information is given in this blog that will help you with NEET preparations . 

4. Read NCERT for the topic covered here .


5. Ask your doubts 



LET'S BEGIN !!

Autoimmunity : Sometimes it may also happen that the immune system of the body goes off the track and starts behaving against the ‘own body’ or ‘self’. This leads to a variety of diseases known as autoimmune diseases. This type of diseases depends on which type of ‘self-antigen’ is involved. When the cells acting as antigens in the same body, they are called autoantigens. The nature of autoimmune diseases depends on the autoantigens involved. For example, if the autoantigens are RBC then the body destroys its own RBC, resulting in chronic anaemia; if the autoantigens are muscle cells then it results in the destruction of its own muscles resulting in severe weakness (myasthenia gravis); if the autoantigens are liver cells, then it results in chronic hepatitis, etc. Other autoimmune diseases are insulin-dependent diabetes, Addison’s disease, ulcerative colitis and rheumatoid arthritis.

CAUSES OF AUTOIMMUNITY IN OUR BODY 

Several mechanisms of failure have been postulated. Chemical, physical, or biological agents may alter self components so that lymphocytes that normally recognize them as safe would then react to them as foreign. Infectious agents may also produce antigens so similar to those on healthy cells that lymphocytes or antibodies would react to both kinds indiscriminately. (This phenomenon is known as cross-reaction.) Self antigens (such as those found in the lens of the eye) that normally do not come into contact with circulating immune agents may, through tissue infection or injury, be brought into contact with them, triggering a response. Suppressor T cells, lymphocytes that restrain the action of antibody-producing B lymphocytes, may somehow cease functioning. There is also evidence that there may be a genetic predisposition to specific autoimmune diseases. The higher incidence of autoimmune disease in women may indicate a sex-linked or hormonal influence. Although the ultimate cause of autoimmune diseases may not be known, the development and course of many autoimmune diseases is now better understood.

MECHANISM OF HOW AUTOIMMUNITY CELLS WORKS:

Autoimmune attacks follow a variety of routes. In one route, circulating antibodies bind to cells and either assist in destroying them or interfere with their functions. In another route, antibody-antigen combinations circulate in the blood and lymph systems, lodge in various tissues, and cause cell destruction. In yet another route, cell-killing lymphocytes launch a direct attack on healthy tissues.

AUTOIMMUNE DISEASES ARE DIVIDED INTO TWO CLASSES :-

are divided into two classes: organ-specific and systemic. An organ-specific disease is one in which an immune response is directed toward antigens in a single organ. Examples are Addison disease, in which autoantibodies attack the adrenal cortex, and myasthenia gravis, in which they attack neuromuscular cells. In systemic diseases the immune system attacks self antigens in several organs. Systemic lupus erythematosus, for example, is characterized by inflammation of the skin, joints, and kidneys, among other organs.

WHAT ARE THE SYMPTOMS?

The symptoms of autoimmune disease vary between types, but the common indicators are fatigue, fever, general malaise (feeling ill), joint pain and skin rash. Symptoms worsen during flare-ups and reduce during remission.

The common and most noticeable signs of type 1 diabetes are:

• Increased thirst (polydipsia)
• Frequent/increased urination (polyuria)
• Extreme tiredness (fatigue)
• Sudden or unexplained weight loss

These signs are often referred to as the 4Ts of type 1 diabetes – Toilet, Thirsty, Tired and Thinner – to help make them easier to remember.

TREATMENTS INVOLVED 

 treatment of autoimmune diseases centres on alleviating symptoms such as inflammation. In organ-specific disorders, attempts are made to correct the specific defect. Drugs that suppress the production of antibodies must be used carefully to avoid lowering the body’s resistance to infection.

Ways of achieving this include:

• Living a healthy lifestyle – e.g. eating a balanced and healthy diet, exercising regularly, reducing stress and getting plenty of rest
• Medication – including pain relievers, anti-inflammatory drugs (if joints are affected) and immunosuppressive medication
• Avoiding any known causes of flare-ups
• Physical therapy
• Hormone replacement, if necessary
• Blood transfusions, in cases where blood is affected

SOME COMMON AUTOIMMUNE DISEASES ARE DISCUSSED BELOW :-

Immuno deficiencies

(1) Severe Combined Immuno deficiency (SCID) : Sometimes new born children are without T-cells and B-cells. These children are highly susceptible to various infections. The most serious disorder of this type is a congenital disease known as severe combined immuno deficiency (SCID) in which both B-cells and T-cells are not present in the body. Such children are highly susceptible even to minor infections. In developed countries like U.S.A. such children are kept alive by keeping them in germ-free environments called isolation suits.

Autoimmune Disorders

S.No.	Disorder	Symptoms	Antibodies Against
1.	Glomerulonephritis	Lower back pain	Kidney cell antigens that resemble Strep bacteria antigens
2.	Grave disease	Restilessness,    Weight loss,irritability, Increased heart rate  and Blood pressure	Thyroid gland antigens near thyroid stimulating hormone receptor, causing overactivity
3.	Juvenile diabetes	Thirst, hunger, weakness, emaciation	Pancreatic beta cells
4.	Hemolytic anemia	Fatigue and weakness	Red blood cells
5.	Myasthenia gravis	Muscle weakness	Receptors for nerve messages on skeletal muscle
6.	Pernicious anemia	Fatigue and weakness	Binding site for vitamin B on cells lining stomach
7.	Rheumatic fever	Weakness, shortness of breath	Heart cell antigens that resemble Strep bacteria antigens
8.	Rheumatoid arthritis	Joint pain and deformity	Cells lining joints
9.	Scleroderma	Thick, hard, pigmented skin patches	Connective tissue cells
10.	Systemaic lupus erythamtosus	Red rash on face, prolonged fever, weakness, kidney damage	DNA, neurons, blood cells
	Ulcerative colitis	Lower abdominal pain	Colon cells

Similarities Between Allergies and Autoimmunity

The main similarities between the two are as follows:

• Both symptom results in a general feeling of fatigue and sickness.
• Itching is a common symptom of both allergies and autoimmune diseases.
• Both the allergies and autoimmune diseases cause some sort of redness or swelling, due to the higher immune response.

Differences Between Allergies and Autoimmune Disease

The main difference between autoimmune diseases and allergies are summarised in the table as follows:

Allergies	Autoimmune Disease
A condition in which the immune system reacts abnormally to a foreign substance.	An autoimmune disease is a condition in which the immune system mistakenly attacks healthy cells and tissues of the body.
The allergies are mainly caused by an external trigger such as pollens, certain foods, medicines, insects, animals, etc.	Autoimmune diseases are the results of an internal trigger to the body’s own cell.
Examples include skin allergy, sinusitis, asthma, watery eyes, sneezing, itchy nose and eyes.	Examples include type 1 diabetes, multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, etc.

THAT'S ALL FOR TODAY 

I WILL MEET YOU TOMORROW ACCORDING TO DAY 4 TIME TABLE .

NO HOMEWORK.