IMMUNE DISORDERS

THE IMMUNE SYSTEM

• The immune system is composed of many interdependent cell types that collectively protect the body from bacterial, parasitic, fungal, viral infections and from the growth of tumor cells. • Many of these cell types have

specialized functions.

THE IMMUNE SYSTEM

THE ORGANS OF THE IMMUNE SYSTEM

• Bone Marrow

• The bone marrow produces B cells, natural killer cells, granulocytes and immature thymocytes, in addition to red blood cells and platelets.

Thymus

• The function of the thymus is to produce mature T cells

Spleen

• The spleen is an immunologic filter of the blood. • It is made up of B cells, T cells,

macrophages, dendritic cells, natural killer cells and red blood cells.

LYMPH NODES

• The lymph nodes function as an immunologic filter for the bodily fluid known as lymph. • Lymph nodes are found

throughout the body.

• Composed mostly of T cells, B cells, dendritic cells and macrophages, the nodes drain fluid from most of our tissues.• Antigens are filtered out of the

lymph in the lymph node before returning the lymph to the circulation.

The Cells of the Immune System

T-Cells

• T lymphocytes are usually divided into two major subsets that are functionally and phenotypically different. • The T helper subset, also called the

CD4+ T cell, is a pertinent coordinator of immune regulation.

• The main function of the T helper cell is to augment or potentiate immune responses by the secretion of specialized factors that activate other white blood cells to fight off infection.

• Another important type of T cell is called the T killer/suppressor subset or CD8+ T cell. • These cells are important in

directly killing certain tumor cells, viral-infected cells and sometimes parasites.

• The CD8+ T cells are also important in down-regulation of immune responses. • Both types of T cells can be found

throughout the body.

Natural Killer Cells • They function as effector cells that

directly kill certain tumours such as melanomas, lymphomas and viral-infected cells, most notably herpes and cytomegalovirus-infected cells. • NK cells, unlike the CD8+ (killer) T cells,

kill their targets without a prior "conference" in the lymphoid organs.

B Cells • The major function of B lymphocytes

is the production of antibodies in response to foreign proteins of bacteria, viruses, and tumor cells.• Antibodies are specialized proteins

that specifically recognize and bind to one particular protein.

Granulocytes or Polymorphonuclear (PMN) Leukocytes

• Granulocytes are composed of three cell types identified as neutrophils, eosinophils and basophils, based on their staining characteristics with certain dyes.

• These cells are predominantly important in the removal of bacteria and parasites from the body. • They engulf these foreign bodies

and degrade them using their powerful enzymes.

Macrophages • Macrophages are important in the

regulation of immune responses. • They are often referred to as

scavengers or antigen-presenting cells (APC) because they pick up and ingest foreign materials and present these antigens to other cells of the immune system such as T cells and B cells.

• This is one of the important first steps in the initiation of an immune response.• Stimulated macrophages exhibit

increased levels of phagocytosis and are also secretory

• The dendritic cells are more efficient apcs than macrophages.• These cells are usually found in the

structural compartment of the lymphoid organs such as the thymus, lymph nodes and spleen.

• They are also found in the bloodstream and other tissues of the body.• It is believed that they capture

antigen or bring it to the lymphoid organs where an immune response is initiated

IMMUNE DISORDERS

An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways:

• By the component of the immune system affected• By whether the immune system is

overactive or underactive• By whether the condition is

congenital or acquired

In over-active immune response:•Allergies •Asthma •Anaphylaxis •Autoimmune diseases

List of autoimmune disorders

• Lupus• Scleroderma• Certain types of hemolytic

anemia• Vasculitis• Type one diabetes• Graves disease

• Rheumatoid arthritis• Multiple sclerosis• Good pasture’s syndrome• Pernicious anemia• Some types of myopathy

Types of Immune symptom

• Immune deficiency • Reduced immune response • Allergic reaction• Anaphylaxis• Antibiotic failure • Allergic skin reaction • Allergic inflammation

IMMUNODEFICIENCIES

• Primary immune deficiency diseases are those caused by inherited genetic mutations. • Secondary or acquired immune

deficiencies are caused by something outside the body such as a virus or immune suppressing drugs

PRIMARY IMMUNE DEFICIENCIES

• Severe combined immunodeficiency (SCID)• DiGeorge syndrome• Hyperimmunoglobulin E syndrome (also

known as Job’s Syndrome)• Common variable immunodeficiency (CVID):

B-cell levels are normal in circulation but with decreased production of IgG throughout the years

• Chronic granulomatous disease (CGD): a deficiency in NADPH oxidase enzyme, which causes failure to generate oxygen radicals.• Classical recurrent infection from

catalase positive bacteria and fungi.• Wiskott-Aldrich syndrome (WAS)

• Autoimmune lymphoproliferative syndrome (ALPS)• Hyper IgM syndrome : X-linked

disorder that causes a deficiency in the production of CD4.• This increases the production and

release of IgM into circulation. • Increased susceptibility to

extracellular bacteria and opportunistic infections.

• Leukocyte adhesion deficiency (LAD)• NF-κB Essential Modifier (NEMO)

Mutations• Selective immunoglobulin A deficiency :

the most common defect of the humoral immunity, characterized by a deficiency of IgA. Produces repeating sino-pulmonary and gastrointestinal infections.

• X-linked agammaglobulinemia (XLA; also known as Bruton type agammaglobulinemia): characterized by a deficiency in tyrosine kinase enzyme that blocks B-cell maturation in the bone marrow.

• X-linked lymphoproliferative disease (XLP)• Ataxia-telangiectasia

• Secondary immune deficiencies• AIDS

COMMOM IMMUNE DISORDERSALLERGIES• An allergy is an abnormal immune reaction to

a harmless antigen.• Seasonal allergy• Mastocytosis• Perennial allergy• Anaphylaxis• Food allergy• Allergic rhinitis• Atopic dermatitis

ALLERGIES AND ASTHMA

• Anaphylaxis is a serious allergic reaction that is rapid in onset and may cause death.• It typically results in a number of

symptoms including an itchy rash, throat swelling, and low blood pressure.• Common causes include insect

bites/stings, foods, and medications.

• Anaphylaxis is caused by the release of mediators from certain types of white blood cells triggered either by immunologic or non-immunologic mechanisms.

• The primary treatment is injection of epinephrine, with other measures being complementary.

FOOD ALLERGY• A food allergy is an adverse

immune response to a food protein.

• Allergic responses include dermatitis, gastrointestinal and respiratory distress, including such life-threatening anaphylactic responses as biphasic anaphylaxis and vasodilation

• Treatment consists of either immunotherapy (desensitisation)

• Avoids all forms of contact with the allergic food.

• Anti -IgE antibody (omalizumab, or Xolair) and specific oral tolerance induction (SOTI)

• Carry an injectable form of epinephrine such as an EpiPen

• Wear some form of medical alert jewellery

ALLERGIC RHINITIS

• Allergic rhinitis is an allergic inflammation of the nasal airways.

• It occurs when an allergen inhaled by an individual with a sensitized immune system, allergen triggers the production of the antibody immunoglobulin E (IgE), which binds to mast cells and basophils containing histamine

• When caused by pollens of any plants, it is called "pollinosis", and if specifically caused by grass pollens, it is known as "hay fever".

ATOPIC DERMATITIS

• Atopic dermatitis is an inflammatory, chronically relapsing, non-contagious and pruritic (itchy) skin disorder.

• The skin of a patient with atopic dermatitis reacts abnormally and easily to irritants, food, and environmental allergens and becomes red, flaky and very itchy.

• It also becomes vulnerable to surface infections caused by bacteria.

• The skin on the flexural surfaces of the joints are the most commonly affected regions in people

• It tends to be more frequent on the hands and feet, on the ankles, wrists, face, neck and upper chest. • Atopic dermatitis can also affect

the skin around the eyes, including the eyelids.

Causes

• Epidermal Barrier Dysfunction

• Allergy

• Microwave radiation

• Food allergy

• Histamine intolerance

URTICARIA

• Urticaria commonly referred to as hives, is a kind of skin rash notable for pale red, raised, itchy bumps. • Hives are frequently caused by

allergic reactions; however, there are many non-allergic causes.

Autoimmune Diseases

• In response to an unknown trigger, the immune system may begin producing antibodies that instead of fighting infections, attack the body's own tissues.• Treatment for autoimmune diseases

generally focuses on reducing immune system activity.

Autoimmune diseases include:

• Rheumatoid arthritis is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks flexible (synovial) joints.

• The process involves an inflammatory response of synovium secondary to swelling (hyperplasia) of synovial cells, excess synovial fluid, and the development of fibrous tissue (pannus) in the synovium.

• The immune system produces antibodies that attach to the linings of joints.• Immune system cells then attack

the joints, causing inflammation, swelling, and pain.

• If untreated, rheumatoid arthritis causes permanent joint damage. • Treatments for rheumatoid

arthritis can include various oral or injectable medications that reduce immune system overactivity

Systemic lupus erythematosus (lupus)

• People with lupus develop autoimmune antibodies that can attach to tissues throughout the body.

• The joints, lungs, blood cells, nerves, and kidneys are commonly affected in lupus.

• Treatment often requires daily oral prednisone, a steroid that reduces immune system function.

Inflammatory bowel disease (IBD)

• The immune system attacks the lining of the intestines, causing episodes of diarrhea, rectal bleeding, urgent bowel movements, abdominal pain, fever, and weight loss.

• Ulcerative colitis and Crohn's disease are the two major forms of IBD. Oral and injected immune-suppressing medicines can treat IBD.

Multiple sclerosis (MS).• The immune system attacks nerve

cells, causing symptoms that can include pain, blindness, weakness, poor coordination, and muscle spasms. • Various medicines that suppress the

immune system can be used to treat multiple sclerosis.

SCLERODERMA

• Scleroderma is a chronic systemic autoimmune disease (primarily of the skin) characterized by fibrosis, vascular alterations, and autoantibodies. There are two major forms

Limited systemic sclerosis/scleroderma

• Involves cutaneous manifestations that mainly affect the hands, arms, and face.• It was previously called CREST

syndrome Calcinosis, Raynaud's phenomenon, Esophageal dysfunction, Sclerodactyly, and Telangiectasias

Diffuse systemic sclerosis/scleroderma

• Is rapidly progressing and affects a large area of the skin and one or more internal organs, frequently the kidneys, esophagus, heart, and lungs. • . There are no treatments for

scleroderma

Goodpasture’s syndrome

• Or anti-glomerular basement antibody disease in which antibodies attack the lungs and kidneys, leading to bleeding from the lungs and to kidney failure.

• It may quickly result in permanent lung and kidney damage, often leading to death.• It is treated with immunosuppressant

drugs such as corticosteroids and cyclophosphamide, and with plasmapheresis, in which the antibodies are removed from the blood.

• The specific target of the immune attack is the GBM antigen, which is found in the lungs and kidneys. • The antigen is a component of the

non-collagenous 1 (NC1) domain of the alpha-3 chain of type IV collagen in the glomerular basement membrane.• Good pasture's syndrome is a type II

hypersensitivity reaction

Type 1 diabetes mellitus

• Immune system antibodies attack and destroy insulin-producing cells in the pancreas.• By young adulthood, people with

type 1 diabetes require insulin injections to survive.

Guillain-Barre syndrome.•

The immune system attacks the nerves controlling muscles in the legs and sometimes the arms and upper body.• Filtering the blood with a procedure

called plasmapheresis is the main treatment for Guillain-Barre syndrome.

Psoriasis.

• In psoriasis, overactive immune system blood cells called T-cells collect in the skin.• The immune system activity

stimulates skin cells to reproduce rapidly, producing silvery, scaly plaques on the skin.

Graves' disease

• The immune system produces antibodies that stimulate the thyroid gland to release excess amounts of thyroid hormone into the blood (hyperthyroidism).

• Symptoms of Graves' disease can include bulging eyes,weight loss, nervousness, irritability, rapid heart rate, weakness, and brittle hair.

• Destruction or removal of the thyroid gland, using medicines or surgery, is usually required to treat Graves' disease

Hashimoto's thyroiditis

• Antibodies produced by the immune system attack the thyroid gland, slowly destroying the cells that produce thyroid hormone. Low levels of thyroid hormone develop (hypothyroidism), usually over months to years.

• Symptoms include fatigue, constipation, weight gain, depression, dry skin, and sensitivity to cold. Taking a daily oral synthetic thyroid hormone pill restores normal body functions.

• Myasthenia gravis. Antibodies bind to nerves and make them unable to stimulate muscles properly. Weakness that gets worse with activity is the main symptom of myasthenia gravis. Mestinon (pyridostigmine) is the main medicine used to treat myasthenia gravis.

Vasculitis• The immune system attacks and

damages blood vessels. • Vasculitis can affect any organ, so

symptoms vary widely and can occur almost anywhere in the body. • Treatment includes reducing immune

system activity, usually with prednisone or another corticosteroid.

• Hemolytic anemia (or haemolytic anaemia) is a form of anemia due to hemolysis either in intravascular hemolysiis or extravascular. • Treatment depends on the cause and

nature of the breakdown.

PERNICIOUS ANEMIA

• Or Biermer's anemia, Addison's anemia, or Addison–Biermer anemia is one of types of megaloblastic anemias.• It is caused by loss of gastric parietal

cells which are responsible, in part, for the secretion of intrinsic factor.

IMMUNE DEFICIENCY DISEASES

• The immune system may be suppressed by medications or illness. • Immune deficiency can also be

present from birth as a genetic disorder (primary immune deficiency).• Immune deficiency diseases result in

higher vulnerability to infections

Severe combined immune deficiency (SCID).

• A genetic condition causing severe impairment in multiple areas of the immune system. • Babies with SCID die from overwhelming

infections, usually before reaching age 1. • Bone marrow transplant can cure some

cases of SCID.

Common variable immune deficiency (CVID)

• Due to a genetic defect, the immune system produces too few antibodies to effectively fight infections.• Children with CVID typically have frequent

infections of the ears, lungs, nose, eyes, and other organs. • Treatment includes replacing the missing

antibodies with regular injections of antibodies, immunoglobulins.

Human immunodeficiency virus / acquired immune deficiency syndrome (HIV/AIDS).

• HIV infects and destroys immune system cells that normally fight infections. • As the number of immune system cells

declines, a person's vulnerability to infections rises steadily.

Drug-induced immune deficiency

• Medicines that suppress the immune system result in an increased chance of infection. • People taking immune-suppressing

drugs for long periods require careful monitoring to detect and treat any infections that occur.

Graft versus host syndrome.

• After bone marrow transplant, the donor's immune system cells may attack the tissues of the person receiving the transplant.• Prednisone and other immune-

suppressing medicines are used to prevent excessive organ damage caused by the donor's immune cells.