Clinical Aspects Immunity

Full Urticaria Cure

Full Urticaria Cure

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Hypersensitivity is a harmful overreaction of the immune system, commonly known as allergy. In cases of allergy, a person is more sensitive to a particular antigen than the average individual. Common allergens are pollen, animal dander, dust, and foods, but there are many more. A seasonal allergy to inhaled pollens is commonly called "hay fever." Responses may include itching, redness or tearing of the eyes (conjunctivitis), skin rash, asthma, runny nose (rhinitis), sneezing, urticaria (hives), and angioedema, a reaction similar to hives but involving deeper layers of tissue.

An anaphylactic reaction is a severe generalized allergic response that can lead rapidly to death as a result of shock and respiratory distress. It must be treated by immediate administration of epinephrine (adrenaline), maintenance of open airways, and antihistamines. Common causes of anaphylaxis are drugs, especially penicillin and other antibiotics, vaccines, diagnostic chemicals, foods, and insect venom.

A delayed hypersensitivity reaction involves T cells and takes at least 12 hours to develop. A common example is the reaction to contact with plant irritants such as those of poison ivy and poison oak.

The term immunodeficiency refers to any failure in the immune system. This may be congenital (present at birth) or acquired and may involve any components of the system. The deficiency may vary in severity but is always evidenced by an increased susceptibility to disease.

AIDS is acquired by infection with HIV, which attacks certain T cells. These cells have a specific surface attachment site, the CD4 receptor, for the virus. HIV is spread by sexual contact, use of contaminated needles, blood transfusions, and passage from an infected mother to a fetus. It leaves the host susceptible to opportunistic infections such as pneumonia caused by the protozoon Pneumocystis carinii; thrush, a fungal infection of the mouth caused by Candida albicans; and infection with Cryptosporidium, a protozoon that causes cramps and diarrhea. It also predisposes to Kaposi sarcoma, a once-rare form of skin cancer. It may also induce autoimmunity or attack the nervous system.

AIDS is diagnosed and followed by CD4+ T lymphocyte counts, which measure the number of cells that have the HIV receptor. A count of less than 200/pL of blood signifies severe immunodeficiency. Antibody levels to HIV and direct viral counts in the blood are also used to track the course of the disease. At present there is no vaccine or cure for AIDS, but some drugs can delay progress of the disease.

A disease that results from an immune response to one's own tissues is classified as an autoimmune disorder. The cause may be a failure in the immune system or a reaction to body cells that have been slightly altered by mutation or disease. The list of diseases that are believed to be caused, at least in part, by autoim-munity is long. Some, such as systemic lupus erythematosus (SLE), systemic sclerosis (scleroderma), and Sjögren syndrome, affect tissues in multiple systems. Others target more specific organs or systems. Examples are pernicious anemia, rheumatoid arthritis, Graves disease (of the thyroid), myasthenia gravis (a muscle disease), fibromyalgia syndrome (a musculoskeletal disorder), rheumatic heart disease, and glomerulonephritis (a kidney disease). These diseases are discussed in more detail in other chapters.

adrenal

Key Clinical Terms adrenal

DISORDERS

V

AIDS

Failure of the immune system caused by infection with HIV (human

immunodeficiency virus). The virus infects certain T cells and thus

interferes with immunity.

allergen

A substance that causes an allergic response

AL-er-jen

allergy_

Hypersensitivity

AL-er-je

anaphylactic reaction

An exaggerated allergic reaction to a foreign substance (root phylaxis

an-a-f i-LAK-tik

means "protection"). It may lead to death caused by circulatory col-

lapse, and respiratory distress if untreated. Also called anaphylaxis.

anemia

A deficiency in the amount of hemoglobin in the blood; may result

a-NE-me-a

from blood loss, malnutrition, a hereditary defect, environmental fac-

tors, and other causes

angioedema

A localized edema with large hives (wheals) similar to urticaria but

an-je-o-e-DE-ma

involving deeper layers of the skin and subcutaneous tissue

aplastic anemia

Anemia caused by bone marrow failure resulting in deficient blood

a-PLAS-tik

cell production, especially of red cells; pancytopenia

autoimmune disorder

A condition in which the immune system produces antibodies

against an individual's own tissues (prefix auto means "self")

Cooley anemia

A form of thalassemia (hereditary anemia) in which the B (beta)

chain of hemoglobin is abnormal

delayed hypersensitivity

An allergic reaction involving T cells that takes at least 12 hours to

reaction

develop. Examples are various types of contact dermatitis, such as

poison ivy or poison oak; the tuberculin reaction (test for TB); and

rejections of transplanted tissue.

disseminated

Widespread formation of clots in the microscopic vessels; may be fol-

intravascular

lowed by bleeding as a result of depletion of clotting factors

coagulation (DIC)

ecchym_osis

A collection of blood under the skin caused by leakage from small

ek-i-MO-sis

vessels (root chym means "juice")

hemolysis

The rupture of red blood cells and the release of hemoglobin (adjec-

he-MOL-i-sis

tive, hemolytic)

hemo_philia_

A hereditary blood disease caused by lack of a clotting factor and re-

he-mo-FIL-e-a

sulting in abnormal bleeding

HIV

The virus that causes AIDS; human immunodeficiency virus

Hodgkin disease

A neoplastic disease of unknown cause that involves the lymph

nodes, spleen, liver, and other tissues; characterized by the presence

of giant Reed-Sternberg cells

Disorders, continued

hypersensitivity

An immunologic reaction to a substance that is harmless to most

people; allergy

immunodeficiency

A congenital or acquired failure of the immune system to protect

im-U-nô-de -FISH-en-se

against disease

intrinsic factor

A substance produced in the stomach that aids in the absorption of

vitamin B12, necessary for the manufacture of red blood cells. Lack of

intrinsic factor causes pernicious anemia.

Kaposi sarcoma

Cancerous lesion of the skin and other tissues, seen most often in

KAP-ô-së

patients with AIDS

leukemia

Malignant overgrowth of immature white blood cells; may be chronic

lû-KE-më-a

or acute; may affect bone marrow (myelogenous leukemia) or lym

phoid tissue (lymphocytic leukemia)

lymphadenopathy_

Any disease of the lymph nodes

lim-fad-e-NOP-a-the

lymph_oma

Any neoplastic disease of lymphoid tissue, such as Burkitt disease,

lim-FO-ma

Hodgkin disease, and others

m_ultipl_e myeloma

A tumor of the blood-forming tissue in bone marrow

mi -e-LO-ma

non-Hodgkin

A widespread malignant disease of lymph nodes that involves lym-

lymphoma (NHL)

phocytes. It differs from Hodgkin disease in the absence of giant

Reed-Sternberg cells (see Fig. 10-8).

Philadelphia

An abnormal chromosome found in the cells of most individuals with

chromosome (Ph)

chronic granulocytic (myelogenous) leukemia

pernicious anemia

Anemia caused by failure of the stomach to produce intrinsic factor, a

per-NISH-us

substance needed for the absorption of vitamin B12. This vitamin is

required for the formation of erythrocytes.

petechiae

Pinpoint, flat, purplish-red spots caused by bleeding within the skin

pe-TE-ke-e

or mucous membrane (singular, petechia)

purpur_a

A condition characterized by hemorrhages into the skin, mucous

PUR-pU-ra

membranes, internal organs, and other tissues (from Greek word

meaning "purple"). Thrombocytopenic purpura is caused by a defi-

ciency of platelets.

sidero_blastic anemia

Anemia caused by inability to use available iron to manufacture he-

sid-e-ro-BLAS-tik

moglobin. The excess iron precipitates in normoblasts (developing

red blood cells).

Sjögren syndrome

An autoimmune disease involving dysfunction of the exocrine glands

SHO-gren

and affecting secretion of tears, saliva, and other body fluids. Defi-

ciency leads to dry mouth, tooth decay, corneal damage, eye infec-

tions, and difficulty in swallowing.

Disorders, continued

sickle cell anemia

A hereditary anemia caused by the presence of abnormal hemoglobin. Red blood cells become sickle-shaped and interfere with normal blood flow to the tissues (see Fig. 10-7). Most common in black populations of West African descent.

splenomegaly sple-no-MEG-a-le

Enlargement of the spleen

systemic lupus er_ythematosu_s_

LU-pus er-i-the-ma-TO-sus

Inflammatory disease of connective tissue affecting the skin and multiple organs. Patients are sensitive to light and may show a red butterfly-shaped rash over the nose and cheeks.

systemic sclerosis

A diffuse disease of connective tissue that may involve any system causing inflammation, degeneration, and fibrosis. Also called sclero-derma because it causes thickening of the skin.

thalasse_mia_

thal-a-SE-me-a

A group of hereditary anemias mostly found in populations of Mediterranean descent (the name comes from the Greek word for "sea").

thrombocy_to_pen_ia_

throm-bo-si-to-PE-ne-a

A deficiency of thrombocytes (platelets) in the blood

urticaria_

ur-ti-KAR-e-a

A skin reaction consisting of round, raised eruptions (wheals) with itching; hives

DIAGNOSIS AND TREATMENT

adrenaline a-DREN-a-lin

See epinephrine

CD4+ T lymphocyte count

A count of the T cells that have the CD4 receptors for the AIDS virus (HIV). A count of less than 200/|lL of blood signifies severe immunodeficiency.

epinephrine ep-i-NEF-rin

A powerful stimulant produced by the adrenal gland and sympathetic nervous system. Activates the cardiovascular, respiratory, and other systems needed to meet stress. Used as a drug to treat severe allergic reactions and shock. Also called adrenaline.

reticulo_cy_te c_ounts re-TIK-u-l o-si t

Blood counts of reticulocytes, a type of immature red blood cell; reticulocyte counts are useful in diagnosis to indicate the rate of erythrocyte formation.

Reed-Sternberg cells

Giant cells that are characteristic of Hodgkin disease. They usually have two large nuclei and are surrounded by a halo.

Ma-QR-ta

Supplementary Terms

NORMAL STRUCTURE AND FUNCTION

aggl_utinati_on a-glu-ti-NA-shun

The clumping of cells or particles in the presence of specific antibodies

bilirub_in bil-i-RU-bin

A pigment derived from the breakdown of hemoglobin. It is eliminated by the liver in bile.

complement

COM-ple-ment

A group of plasma enzymes that interacts with antibodies

corpuscle KOR-pus-l

A small mass or body. A blood corpuscle is a blood cell.

gamma globulin

The fraction of the blood plasma that contains antibodies

h_emo_poietic stem cell he-mo-poy-e-tik

A primitive bone marrow cell that gives rise to all varieties of blood cells

heparin

HEP-a-rin

A substance found throughout the body that inhibits blood coagulation; an anticoagulant

megakaryocyte meg-a-KAR-e-o-si t

A large bone marrow cell that fragments to release platelets

plasmin

PLAZ-min

An enzyme that dissolves clots; also called fibrinolysin

thrombin

THROM-bin

The enzyme derived from prothrombin that converts fibrinogen to fibrin

SYMPTOMS AND CONDITIONS

agranul_ocy_tosis_

a-gran-u-lo-si -TO-sis

A condition involving decrease in the number of granulocytes in the blood; also called granulocytopenia

erythro_cy_tosi_s e-rith-ro-si-TO-sis

Increase in the number of red cells in the blood; may be normal, such as to compensate for life at high altitudes, or abnormal, such as in cases of pulmonary or cardiac disease

Fanco_ni s_yndrome fan-KO-ne

Congenital aplastic anemia that appears between birth and 10 years of age; may be hereditary or caused by damage before birth, as by a virus

graft-versus-host reaction (GVHR)

An immunologic reaction of transplanted lymphocytes against tissues of the host; a common complication of bone marrow transplantation.

hairy cell leukemia

A form of leukemia in which cells have filaments, making them look "hairy"

h_ematoma he-ma-TO-ma

A localized collection of blood, usually clotted, caused by a break in a blood vessel

hemolytic disease of the newborn (HDN)

Disease that results from incompatibility between the blood of a mother and her fetus, usually involving Rh factor. An Rh-negative mother produces antibody to an Rh-positive fetus that, in later preg-

Symptoms and Conditions, continued nancies, will destroy the red cells of an Rh-positive fetus. The problem is usually avoided by treating the mother with antibodies to remove the Rh antigen; erythroblastosis fetalis hemosiderosis A condition involving the deposition of an iron-containing pigment he-mo-sid-er-O-sis (hemosiderin) mainly in the liver and the spleen. The pigment comes from hemoglobin released from disintegrated red blood cells.

idiopathic thrombo- A clotting disorder caused by destruction of platelets that usually fol-

cytopenic purpura (ITP) lows a viral illness. Causes petechiae and hemorrhages into the skin and mucous membranes.

infectious mononucleosis An acute infectious disease caused by Epstein-Barr virus (EBV). Char-mon-O-nu-kle-O-sis acterized by fever, weakness, lymphadenopathy, hepatosplenomegaly, and atypical lymphocytes (resembling monocytes).

lymphocytosis An increase in the number of circulating lymphocytes myelofibrosis Condition in which bone marrow is replaced with fibrous tissue mi -e-lo-fi -BRO-sis neutropenia A decrease in the number of neutrophils with increased susceptibility nu-trô-PE-nê-a to infection. Causes include drugs, irradiation, and infection. May be a side effect of treatment for malignancy.

pancytopenia A decrease in all cells of the blood, as in aplastic anemia pan-si-to-PE-ne-a polycythemia Any condition in which there is a relative increase in the percent of red pol-e-si -THE-me-a blood cells in whole blood. May result from excessive production of red cells because of lack of oxygen, as caused by high altitudes, breathing obstruction, heart failure, or certain forms of poisoning. Apparent poly-cythemia results from concentration of the blood, as in dehydration.

polycythemia vera A condition in which overactive bone marrow produces too many red pol-e-si -THE-me-a VE-ra blood cells. These interfere with circulation and promote thrombosis and hemorrhage. Treated by blood removal. Also called erythremia, Vaquez-Osler disease.

septicem ia Presence of microorganisms in the blood sep-ti-SE-me-a spherocytic anemia Hereditary anemia in which red blood cells are round instead of disk-

sfer-o-SIT-ik shaped and rupture (hemolyze) excessively thrombotic thrombo- An often-fatal disorder in which multiple clots form in blood vessels cytopenic purpura (TTP)

von Willebrand disease A hereditary bleeding disease caused by lack of von Willebrand factor, a substance necessary for blood clotting

DIAGNOSIS (see also Displays 10-2 and 10-3)

Bence Jones protein A protein that appears in the urine of patients with multiple myeloma

Diagnosis, continued

Coombs test

A test for detection of antibodies to red blood cells such as appear in

cases of autoimmune hemolytic anemias

electrophoresis

Separation of particles in a liquid by application of an electrical field;

e-lek-tro-fo-RE-sis

used to separate components of blood.

ELISA

Enzyme-linked immunosorbent assay. A highly sensitive immuno

logic test used to diagnose HIV infection, hepatitis, and Lyme dis-

ease, among others.

monoclonal antibody

A pure antibody produced in the laboratory; used for diagnosis and

mon-O-KLO-nal

treatment

pH

A scale that measures the relative acidity or alkalinity of a solution.

Represents the amount of hydrogen ion in the solution.

Schilling test

Test used to determine absorption of vitamin B12 by measuring excre-

SHIL-ing

tion of radioactive B12 in the urine. Used to distinguish pernicious

from nutritional anemia.

s_ero_conversion

The appearance of antibodies in the serum in response to a disease or

se-ro-con-VER-zhun

an immunization

Western blot assay

A very sensitive test used to detect small amounts of antibodies in the

blood

Wright stain

A commonly used blood stain. Figure 10-1 shows blood cells stained

with Wright stain.

TREATMENT

anticoa_gulan_t

An agent that prevents or delays blood coagulation

an-ti-ko-AG-U-lant

antihistamine_

A drug that counteracts the effects of histamine and is used to treat

an-ti-HIS-ta-men

allergic reactions

apheresis

A procedure in which blood is withdrawn, a portion is separated and

af-e-RE-sis

retained, and the remainder is returned to the donor. Apheresis may

be used as a suffix with a root meaning the fraction retained, such as

plasmapheresis, leukapheresis.

autologo_us blood

A person's own blood. May be donated in advance of surgery and

aw-TOL-o-gus

transfused if needed.

cryo_pre_cipitate_

A sediment obtained by cooling. The fraction obtained by freezing

kri -o-pre-SIP-i-tat

blood plasma contains clotting factors.

desensitizatio_n

Treatment of allergy by small injections of the offending allergen. This

de-sen-si-ti-ZA-shun

causes an increase of antibody to destroy the antigen rapidly on contact.

h_omolog_ous blood

Blood from animals of the same species, such as human blood used

ho-MOL-o-gus

for transfusion from one person to another. Blood used for transfu-

sions must be compatible with the blood of the recipient.

immun_os_uppression

Depression of the immune response. May be correlated with disease

im-u-no-su-PRESH-un

but also may be induced therapeutically to prevent rejection in cases

of tissue transplantation.

pro_tea_se_ inhibitor

An anti-HIV drug that acts by inhibiting an enzyme the virus needs

PRO-te_-a_s

to multiply

DISPLAY 10-3 Coagulation Tests

TEST

ABBREVIATION

DESCRIPTION

activated partial thromboplastin time

APPT

measures time required for clot formation; used to evaluate clotting factors

bleeding time

BT

measures capacity of platelets to stop bleeding after a standard skin incision

partial thromboplastin time

PTT

evaluates clotting factors; similar to APPT, but less sensitive

prothrombin time

PT, Pro Time

indirectly measures prothrombin; Quick test

thrombin time (thrombin clotting time)

TT (TCT)

measures how quickly a clot forms

ABBREVIATIONS

Ab

Antibody

ITP

Idiopathic thrombocytopenic purpura

Ag

Antigen

lytes

Electrolytes

AIDS

Acquired immunodeficiency syndrome

MCH

Mean corpuscular hemoglobin

ALL

Acute lymphoblastic (lymphocytic)

MCHC

Mean corpuscular hemoglobin

leukemia

concentration

AML

Acute myeloblastic (myelogenous)

MCV

Mean corpuscular volume

leukemia

mEq

Milliequivalent

APPT

Activated partial thromboplastin time

NHL

Non-Hodgkin lymphoma

BT

Bleeding time

PCV

Packed cell volume

CBC

Complete blood count

pH

Scale for measuring hydrogen ion

CLL

Chronic lymphocytic leukemia

concentration (acidity)

CML

Chronic myelogenous leukemia

Ph

Philadelphia chromosome

crit

Hematocrit

PMN

Polymorphonuclear (neutrophil)

DIC

Disseminated intravascular coagulation

poly

Neutrophil

Diff

Differential count

polymorph

Neutrophil

EBV

Epstein-Barr virus

PT

Pro time; prothrombin time

ELISA

Enzyme-linked immunosorbent assay

PTT

Partial thromboplastin time

EPO

Erythropoietin

RBC

Red blood cell; red blood cell count

ESR

Erythrocyte sedimentation rate

seg

Neutrophil

FFP

Fresh frozen plasma

SLE

Systemic lupus erythematosus

Hb, Hgb

Hemoglobin

T(C)T

Thrombin (clotting) time

HDN

Hemolytic disease of the newborn

TTP

Thrombotic thrombocytopenic

Ht, Hct

Hematocrit

purpura

HIV

Human immunodeficiency virus

vWF

Von Willebrand factor

IF

Intrinsic factor

WBC

White blood cell; white blood (cell)

Ig

Immunoglobulin

count

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    What aspects are aspects in the medical terminology?
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