Every country needs a defense system so that it can defend its
territory.Like wise,Human body needs a defense system to protect it from various
bacteria,Viruses,Fungi,Microbes etc.The natural defense system which a human
body has is called Immune System.In this article, we will see about the immune
system particularly Overactive immune system and the methods to slow it.
Immune system constantly looks for bacteria,viruses and fights
it, if it detects any external pathogens.Blood is a fluid in the human body
which is responsible for carrying Oxygen and nutrients. to the cells and carries
the waste materials away from the cells. There are three type of blood cells
namely:
-
Red blood Cells(RBC) or Erythrocytes
-
White Blood Cells(WBC) or Leukocytes
-
Platelets or Thrombocytes
Blood accounts for 7 percent of the whole human body weight. An
average adult has a blood volume of 5 litres.Erythrocytes consists of 45 percent
volume,Platelets consists of 54.3 percent volume and leukocytes consists of only
0.7 percent volume.Out of these,WBC or White Blood Cells is responsible for the
immune system.One microliter of blood contains 4000-11000 leukocytes. It is the
leukocytes which attacks foreign organisms and protects the human body. If
leukocytes are produced more,then that results in a type of Cancer Called
Leukemia which usually starts from the bone marrow.
WBC’s are stored in Lymphoid organs. Thymus and Bone Marrow are
the primary Lymphoid organs. They generate lymphocytes from immature progenitor
cells.Lymph nodes and Spleen are secondary Lymphoid organs. Thymus is a gland
situated below the neck and inbetween the lungs. Spleen is situated on the upper
side of left abdomen.The spleen contains specialized compartments where immune
cells gather and work, and serves as a meeting point where immune defenses
confront antigens.Clumps of lymphoid tissue are found in many parts of the body,
especially in the linings of the digestive tract and the airways and
lungs—territories that serve as gateways to the body.
Bone Marrow is responsible for the creation of T Cells and the
production of B Cells.B cells joins the Circulatory system and search for
pathogens whereas T cells first go to Thymus,produce more T Cells,then join the
Circulatory system and then search for Pathogens.Spleen produces antibodies in
its white pulp and removes the bacteria through blood circulation and lymph node
circulation.
All leukocytes have a nuclei in their cells. RBC’s and
platelets do not have nuclei.Leukocytes are classified by their structure into
two categories namely:
It is also classified according to the Cell division into two
categories namely:
-
Myeloid cells
-
Lymphoid Cells
The above two categories can be further divided into five main
types namely:
Lympocytes are further classified into
The number of leukocytes present in the blood is often an
indicator of the disease.If the count of WBC is increased above the upper
limit,then that condition is called leukocytosis. If the count of WBC is
decreased below the lower limit,then that condition is called leukopenia. This
indicates a weakened immune system. Increase in WBC is normal when it fights the
pathogens. Decreased count is dangerous to the body.
Neutrophil is 10-12 micrometer and it is responsible for
fighting bacteria and fungi. It has multilobed nucleus. Granules are pink and
its lifetime is 6 hours to few days.
Eosinophil is 10-12 micrometer and it is responsible for
fighting larger parasites. The nucleus is bilobed. Granules are pink to orange
and its lifetime is 8-12 days.
Basophil is 12-15 micrometer and it releases for histamine
responses. Its nucleus is bilobed or trilobed, large blue granules and its life
span is from few hours to few days.
Small lymphocytes are 7-8 micrometer and large lymphocytes are
12-15 micrometer.It has a eccentric nucleus which is deeply staining, granules
are NK-cells and cytotoxic (CD8+) T-cells.It’s lifetime is years for memory
cells whereas weeks for else.It mainly deals with virus infected and tumour
cells.
Monocyte is 15-30 micrometer. It s main target is the
tissues.Its nucleus is kidney shaped and granules are none. Its life span is
from hours to days.
In leukopenia, usually the white blood cell reduced is the
neutrophil.In this case,it is called neutropenia or granulocytopenia. If the WBC
that is reduced is lymphocytes then that condition is called lymphocytopenia or
lymphopenia.
Immune System
Human body naturally has immune system. When a baby is born,
the immune system naturally goes to the child through breast milk. As the baby
grows into an adult,it's immune system is developed well and hence it is less
prone to diseases. When a pathogen enters, the first layer,the skin fights
against it. If it crosses it ,then the second layer of immune system which is
the Acquired immune system takes control and fights the pathogen. The antibodies
are produced against the pathogen and it is kept in memory. If the same type of
pathogen comes again,it fights efficiently as it has a copy already. For
example,chicken pox comes only once. When it first comes the necessary
antibodies are produced. So it halts effectively when it comes second time.This
is called immunity. The body has already acquired immunity to that disease.
Immunodeficiency
Immunodeficiency occurs due to the collapse of immune system.
Immune system naturally starts to collapse when we reach 50 years of age. Others
reasons include Obesity,alcohol,drugs,malnutrition. AIDS is an example of
Immunodeficiency. Its full form is Acquired Immuno Deficiency Syndrome. In this
case, the AIDS virus completely destroys the WBC of blood and the immune system
of the body is broken and the virus takes control of the immune system and hence
result in death.
Immune System disorders are classified into four types namely:
Immunodeficiency disorder
Immunodeficiency disorder may be Innate or acquired. In
autoimmune disorder, the human body's immune system attacks its own defence
mechanism and tissues as if it were foreign organisms.In allergic disorder, the
immune system overreacts to the antigen.Cancer results in the replication of
cells. Immunodeficiencies can affect B lymphocytes, T lymphocytes, or
phagocytes.
IgA deficiency is a most common primary immunodeficiency
disorder. IgA is a immunoglobulin that is found in the body fluids particularly
Saliva.People with this deficiency tend to attract more cold as the antibodies
are not produced effectively.
Antibodies belong to a family of large molecules known as
immunoglobulins.
Different types play different roles in the immune defense
strategy.
• Immunoglobulin G, or IgG, works efficiently to coat microbes,
speeding their uptake by other cells in the immune system.
• IgM is very effective at killing bacteria.
• IgE, whose natural job is to protect against parasitic
infections, is the villain responsible for the symptoms of allergy.
• IgD remains attached to B cells and plays a key role in
initiating early B-cell response.
Immunodeficiencies are caused by medication also. For Example,
Chemotherapy treatment not only kills cancer cells but also kills naturally,fast
growing healthy cells which results in the breakdown of Immune system.
AutoImmune Disorder
Lupus is an example for autoimmune disorder. Patient feels
muscle and joint pain and also inflammation. Scleroderma is a disease which
results in the inflammation,damage of skin,joints is an autoimmune disorder.
Allergic Disorder
Asthma is a breathing ,respiratory disorder caused by allergic
disorder. Due to this disorder, the breathing tubes are narrowed and swollen so
that the person cannot breathe properly.Drug allergies are also of the category
of allergic disorder. For example,Pencillin is a drug not suitable for everyone.
Cancer
Leukemia is a cancer of the immune system
Vaccines
In Vaccination, the virus is injected into the body in mild
quantity and the body starts producing its antibodies and naturally develops
resistance for that virus. If we want a vaccine to be produced for Snake bite,
Then that snake is made available to bite a horse and checks the antibodies
produced by the horse immune system.Then that antibodies are taken with which
the new vaccine for human body is prepared. First they check the vaccine by
putting it on to rats and check the reaction.If scientists are satisfied that
there is no negative reaction,then it is slowly tried with human beings.
Virus
Viruses enter human body and attach it to the surface of the
cell.Then it
-
insert their genetic material in the form of RNA or DNA into
the host cell
-
Replicate within the host cell
-
Take over the functions of the host cell
Examples:
HIV, Avian Flu, the Flu, Colds,Herpes, HPV, Chicken Pox, Small
Pox,
Measles, Mumps, West Nile, Malaria, Rabies
Bacteria
They work by entering the human body,breaks the tissues for
food and releases toxin which are harmful to the body. Examples: Streptococcus,
diphtheria,botulism, anthrax, gonorrhea, syphilis,Chlamydia.
Layers of Defence
1. First line of defense
• Skin
Dead skin cells provide first level barrier
Secretions
• Mucous
• Saliva
• Tears
• Sweat
They contain enzymes to break down bacterial cell walls. They
wash away pathogens.
• Cilia
• In nose and throat
• Keep pathogens from getting into lungs
Stomach acid
• Low pH destroys many pathogens.
2.Second line of defense
Inflammatory response
Reaction to injury, infection
• Redness, swelling, heat
• Phagocytosis
–white blood cells “eat” invading agent
• Destroys toxic agents
Fever
• Kills some pathogens
• Increases metabolic rate
–Produce more white blood cells
•Increased heart rate
• Pumps white cells to infection site faster
Interferons
• Proteins that destroy viruses
Real Defence
• In blood stream and lymphatic system(body fluids), B cells
grow, divide rapidly
and produce:
– Plasma cells
– Memory cells
Plasma cells
• It makes and release antibodies,recognize and bind to
antigen.The antigen and the antibody gets engulfed and destroyed by phagocytes.
Memory B cells can remember antigen,can produce more antibodies
quickly if exposed again and Plasma B cells make more
antibodies quickly.
Helper T-cell
• Help B-cells make antibodies by passing along information
about pathogen
• Divides to become other types of T-Cells
Killer T-cell
– stored in tonsils, lymph nodes
– travel to infected site
– kill cells that have been infected by pathogen
Suppressor T-Cells
When invader is totally destroyed, suppresses further immune
activity.
Antigens are on the surface of macrophage.T Cell binds to the
activated macrophage.T cell,activated by macrophage,becomes a helper T Cell .
Then Helper T cell activates killer T cells and B cells.Killer T cells bind to
infected cells,disrupting their cell membrane and destroys them.
Inadequate defense
Inadequate defense against pathogens can result from genetic
causes, acquired causes
(foremost acquired immunodeficiency syndrome –AIDS— by HIV) or
from escape strategies developed by pathogens during their co-evolution with
humans.
Primary Immunodeficiency Diseases
The majority of primary immunodeficiencies are rare diseases,
that are instructive for the
contribution of individual parts of the human immune system to
overall defense.
Depending on the genes concerned, the following functions may
be impaired:
• T- and B cell function: severe combined immunodeficiency
(SCID)
• global or partial B cell response
• phagocytosis
• complement functions
In addition, the immune system is affected in a number of more
complex syndromes.
Autoimmune diseases are frequently categorized as either organ
specific or systemic.
Organ specific diseases include:
• diabetes mellitus type 1
• Graves' disease
• Hashimoto's thyroiditis
• multiple sclerosis
Diabetes mellitus type 1
It is a autoimmune disease produced due to the lack of
production of Insulin.
Type 1 diabetes signs and symptoms include:
Graves Disease is an autoimmune disease that occurs due to the
overproduction of Thyroid hormone.
Common signs and symptoms of Graves' disease include:
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Anxiety and irritability
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A fine tremor of your hands or fingers
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Heat sensitivity and an increase in perspiration or warm, moist
skin
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Weight loss, despite normal eating habits
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Enlargement of your thyroid gland (goiter)
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Change in menstrual cycles
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Erectile dysfunction or reduced libido
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Frequent bowel movements
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Bulging eyes (Graves' ophthalmopathy)
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Fatigue
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Thick, red skin usually on the shins or tops of the feet
(Graves' dermopathy)
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Rapid or irregular heartbeat (palpitations)
Examples for systemic autoimmune diseases are:
• rheumatoid arthritis
• systemic lupus erythematodes
• systemic sclerosis (scleroderma)
• polymyositis and dermatomyositis
Genetic Engineering
Genetic engineering allows scientists to pluck genes—segments
of the hereditary material, DNA—from one type of organism and combine them with
genes of a second organism. In this way relatively simple organisms such as
bacteria or yeast can be induced to make quantities of human proteins, including
hormones such as insulin as well as lymphokines and monokines. They can also
manufacture proteins from infectious agents, such as the hepatitis virus or HIV,
for use in vaccines.
CD8+ T-cell
A cytotoxic T cell (also known as TC, cytotoxic T lymphocyte,
CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or killer T cell) is a T
lymphocyte .It is a type of White Blood Cell.It kills cells that are
cancerous,affected by viruses or other natural ways. T-Cell Receptors also known
as TCR, can recognize antigen. Antigens are capable of stimulating immune
response. It is produced by cancer cells or the cells affected by
viruses.Inside a cell,antigens are bound to class I MHC molecule. If the TCR is
specific to that antigen,then it binds with the class I MHC molecule and the
T-cell destroys the cell. For the TCR to bind with class I MHC molecule , it
must be accompanied by a glycoprotein called CD8. Hence they are called CD8+ T
cells.
Phagocytes are large white cells that can swallow and digest
microbes and other foreign particles. Monocytes are phagocytes that circulate in
the blood.When monocytes migrate into tissues,they develop into
macrophages.Specialized types of macrophages can be found in many organs,
including lungs,kidneys, brain, and liver. Macrophages act as Scavengers. They
remove the worn out cells. They also produce monokines which are vital to
produce immune response.Granulocytes are another kind of immune cell. They
contain granules filled with chemicals which destroy pathogens.Some of these
chemicals, such as histamine, also contribute to inflammation and allergy
We can boost the immune system by
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Eating healthy food
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No Alcohol
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Not Smoking
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Not putting weight
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Doing Exercise regularly
OverActive Immune System
It is a process by which our own immune system attacks our own
tissues and cells resulting in the self destruction of our human body.Causes for
OverActive Immune system are :
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Dis-proportion of WBC
-
Stress
-
Hormonal changes
-
Genetic changes
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UV rays,
-
Unhealthy diet
-
Enzyme abnormalities
Problems of OverActive Immune System include:
Arthritis is a disorder that affects joints. Patients with
arthritis feels joint pain and stiffness. Other symptoms may include
redness,swelling. One form of Arthritis is Rheumatoid Arthritis. It is a
autoimmune disorder. It often affects the hand and feet.
Inflammatory Bowel Disease is the inflammation of Colon and
small intestine.
Psoriasis is an autoimmune disease characterized by abnormal
skin which is usually red and itchy in nature.
Fibromyalgia is a medical condition often characterized by
widespread pain of the body.Symptoms include frequent tiredness,memory problems
and sleep disorder.It is frequently associated with depression,anxiety and
Posttraumatic stress disorder.
Myasthenia gravis is a condition where antibodies bind to
nerves and make them unable to stimulate muscles properly.
Vasculitis is a condition where the immune system attacks and
damages blood vessels It is a autoimmune diseases.
Multiple Sclerosis
In this disease, the antibodies attacks nerve cells. It is a
autoimmune Psychiatric disorder.
Diabetes
In this disease, the antibodies attacks pancreatic cells.T
lymphocytes cells that destroy insulin-producing cells in the pancreas cause
Type 1 diabetes
Treatment
Some of the most common type of treatments for overactive
immune systems are immunosuppressants, chemotherapy and corticosteroids.
Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen and
naproxen can be used.
Immunosuppressive drugs can be classified into two groups:
-
glucocorticoids
-
cytostatics
Glucocorticoids, such as prednisone, dexamethasone, and
hydrocortisone are used to suppress various allergic, inflammatory, and
autoimmune disorders.
Cytostatics inhibit cell division. Purine analogs such as
azathioprine, fluorouracil, methotrexate and mercaptopurine are most frequently
administered because it destroys T-Cells.
Natural treatment can also be done. Before going with natural
treatment,always do what Doctors advice to do. Use natural boosters such as Aloe
Vera,Grapefruit seed Extract,Olive Oil,Garlic. Make a balance with work and
life. Sleep healthy for 8 hours.Drink plenty of water.Eat raw
vegetables.Exercise regularly.
People of all genders, races, and ages can be affected by
autoimmune diseases, but some people are at larger risk of developing an
autoimmune disease. An individual’s chance of developing an autoimmune disease
is elevated if the following factors are present:
Gender:
Women are more likely to be affected by autoimmune disease than
male. Researches found that women have 75% more chance than Men to get this
disease. The facts are not clear but the female hormones make it for them to be
more vulnerable.
Age:
Most autoimmune diseases affect young and middle aged
individuals. Each autoimmune disease is different,and disorders such as
rheumatoid arthritis are found more commonly in elderly people.
Ethnicity:
People who are African American, American Indian, or Latino
ethnic groups are more likely than Caucasians to develop autoimmune diseases.
Family history of autoimmune disorders:
Numerous studies have shown that the tendency to develop
autoimmune disorders can be genetic. If a family member has an autoimmune
disorder, others within that family have increased chances of getting the same
disorder.
Exposure to environmental agents:
There is some evidence that exposure to certain things in an
individual’s immediate environment may increase their risk of developing an
autoimmune disease. For example, research shows that exposure to some
medications (for example,procainamide or hydrolyzine) and certain metals
(mercury,gold, or silver) may be associated with the development of specific
autoimmune disorders. Even though the scientific evidence relating environmental
exposure to the onset of autoimmune disorders is not entirely conclusive,
researchers are still working to find out how environmental exposures may play a
role.
Important Words
antibodies—molecules (also called immunoglobulins) produced by
a B cell in response to an antigen. When an antibody attaches to an antigen, it
helps the body destroy or inactivate the antigen.
B cells—small white blood cells crucial to the immune defenses.
Also know as B lymphocytes, they come from bone marrow and develop into blood
cells called plasma cells, which are the source of antibodies.
bacteria—microscopic organisms composed of a single cell. Some
cause disease.
bone marrow—soft tissue located in the cavities of the bones.
Bone marrow is the source of all blood cells.
enzyme—a protein produced by living cells that promotes the
chemical processes of life without itself being altered.
fungi—members of a class of relatively primitive vegetable
organisms. They include mushrooms, yeasts, rusts,molds, and smuts.
granules—membrane-bound organelles within cells where proteins
are stored before secretion.
granulocytes—phagocytic white blood cells filled with granules
organisms.Neutrophils, eosinophils, basophils, and mast cells are examples of
granulocytes.
helper T cells (Th cells)—a subset of T cells that carry the
CD4 surface marker and are essential for turning on antibody
production,activating cytotoxic T cells, and initiating many other immune
functions.
HIV (human immunodeficiency virus)—the virus that causes AIDS.
immune response—reaction of the immune system to foreign
substances.
immunoglobulins—a family of large protein molecules, also known
as antibodies, produced by B cells.
immunosuppressive—capable of reducing immune responses.
Inflammatory-response— redness, warmth,and swelling produced in
response to infection, as the result of increased blood flow and an influx of
immune cells and secretions.
leukocytes—all white blood cells.
lymph—a transparent, slightly yellow fluid that carries
lymphocytes, bathes the body tissues, and drains into the lymphatic vessels.
lymph nodes—small bean-shaped organs of the immune system,
distributed widely throughout the body and linked by lymphatic vessels. Lymph
nodes are garrisons of B, T, and other immune cells.
lymphatic vessels—a bodywide network of channels, similar to
the blood vessels,which transport lymph to the immune organs and into the
bloodstream.
lymphocytes—small white blood cells produced in the lymphoid
organs and paramount in the immune defenses.B cells and T cells are lymphocytes.
lymphoid organs—the organs of the immune system, where
lymphocytes develop and congregate. They include the bone marrow, thymus, lymph
nodes,spleen, and various other clusters of lymphoid tissue. Blood vessels and
lymphatic vessels are also lymphoid organs.
lymphokines—powerful chemical substances secreted by
lymphocytes.These molecules help direct and regulate the immune responses.
memory cells—a subset of T cells and B cells that have been
exposed to antigens and can then respond more readily when the immune system
encounters those same antigens again.
microbes—microscopic living organisms, including bacteria,
viruses, fungi, and protozoa.
microorganisms—microscopic organisms, including bacteria,
virus, fungi, plants, and parasites.
molecule—the smallest amount of a specific chemical substance.
Large molecules such as proteins, fats, carbohydrates, and nucleic acids are the
building blocks of a cell, and a gene determines how each molecule is produced.
monocytes—large phagocytic white blood cells which, when
entering tissue, develop into macrophages.
neutrophil—white blood cell that is an abundant and important
phagocyte. organisms—individual living things.
parasites—plants or animals that live, grow, and feed on or
within another living organism.
passive immunity—immunity resulting from the transfer of
antibodies or antiserum produced by another individual.
pathogen—a disease-causing organism.
phagocytes—large white blood cells that contribute to the
immune defenses by ingesting microbes or other cells and foreign particles.
phagocytosis—process by which one cell engulfs another cell or
large particle.
plasma cells—large antibody-producing cells that develop from B
cells.
platelet—cellular fragment critical for blood clotting and
sealing off wounds.
T cells—small white blood cells (also known as T lymphocytes)
that recognize antigen fragments bound to cell surfaces by specialized
antibody-like receptors. “T” stands for thymus, where T cells acquire their
receptors.
thymus—a primary lymphoid organ, high in the chest, where T
lymphocytes proliferate and mature.
tissues—groups of similar cells joined to perform the same
function.
vaccines—preparations that stimulate an immune response that
can prevent an infection or create resistance to an infection. They do not cause
disease.
viruses—microorganisms composed of a piece of genetic
material—RNA or DNA— surrounded by a protein coat. Viruses can reproduce only in
living cells.
natural killer (NK) cells—large granule containing lymphocytes
that recognize and kill cells lacking self antigens. Their target recognition
molecules are different from T cells.
Antibiotics
A compound or substance that kills or slows down the growth of
bacteria. Antibiotics are not effective against viral infections.
Autoimmune
A medical condition characterized by an overactive immune
system which attacks the body, mistaking normal tissues in the body for harmful
substances.
Cancer
A class of disease in which a group of cells display
uncontrolled growth and invasion that intrudes upon and destroys adjacent
tissues. Cancers sometimes spread to other locations in the body. This term is
normally used to describe malignant tumours.
Complete Blood Count
A complete blood count (CBC), also known as full blood count
(FBC) or blood panel, is a test that gives information about the cells in a
patient's blood. It is used to evaluate overall health and detect a wide range
of disorders, including anaemia and infection.
Immune System
The system that protects the body from foreign substances,
cells, and infections.
Inflammation
A local response to injury that is characterised by redness,
heat, pain, swelling, and often loss of function.
Lymph Nodes
Are small glands composed of white blood cells called
lymphocytes. Lymphocytes play a critical role in the immune system by destroying
infectious agents (such as viruses and bacteria) and producing antibodies.
Malnutrition
A condition that results from taking an unbalanced diet in
which certain nutrients are lacking, in excess, or in the wrong proportions.
Immunity
A condition in which the animal's immune system has been primed
and is able to protect the body from a disease-causing agent such as a virus or
bacteria.
