Understanding Pathophysiology: Chapter 8 Infection And Defects In Mechanisms Of Defense

an excessive or inappropriate response of the immune system to a sensitizing antigen. Hypersensitivity is an altered immunologic response to an antigen that results in disease or damage to the individual. It is not a reduced immune response or a response to an infectious agent. Antigenic desensitization is performed to decrease hypersensitivity.

Alloimmune. Alloimmunity can be observed during immunologic reactions against transfusions, transplanted tissue, or the fetus during pregnancy. Autoimmunity is a disturbance in the immunologic tolerance of self-antigens. The most rapid and severe immediate hypersensitivity reaction is anaphylaxis. An allergic response occurs related to exposure to an allergen.

delayed hypersensitivity. The response to poison ivy is a delayed hypersensitivity because it takes up to 72 hours to develop. Anaphylaxis is immediate. Serum sickness-type reactions are caused by the formation of immune complexes in the blood and their subsequent generalized deposition in target tissues. Poison ivy is not a viral disease.

anaphylaxis. Anaphylaxis occurs within minutes of reexposure to the antigen and can be either systemic (generalized) or cutaneous (localized). Immunodeficiency is a decrease in the immune response. Autoimmunity is a disturbance in the immunologic tolerance of self-antigens. Tissue-specific reaction is an autoimmune reaction.

anaphylaxis. The most rapid and severe immediate hypersensitivity type I reaction is anaphylaxis. Urticaria, or hives, is a dermal (skin) manifestation of allergic reactions. Hives and urticaria are similar responses. ADCC is a mechanism that involves natural killer (NK) cells. Antibodies on the target cell are recognized by Fc receptors on the NK cells, which release toxic substances that destroy the target cell.

IV. Type IV reactions are mediated by T lymphocytes and do not involve antibodies. All the remaining options are associated with antibody responses.

Arthus reaction. The Arthus reaction is a model of localized or cutaneous reactions. Serum sickness-type reactions are caused by the formation of immune complexes in the blood and their subsequent generalized deposition in target tissues. Typically affected tissues are the blood vessels, joints, and kidneys. Raynaud phenomenon is a condition caused by the temperature-dependent deposition of immune complexes in the capillary beds of the peripheral circulation. Antibody-dependent cytotoxicity is a type II form.

serum sickness. Immune-complex disease can be a systemic reaction, such as serum sickness, and related to type III reactions. Bronchial asthma is not an immune-complex-mediated disease and is related to type I reactions. Neither contact dermatitis nor rheumatoid arthritis is related to type III reactions.

autoimmunity. SLE is the most common, complex, and serious of the autoimmune disorders. SLE is not identified as alloimmune, homoimmune, or alleimmune.

Autoantibodies. The presence of autoantibodies is a diagnostic criterion for SLE. Diagnostic criterion for SLE would include positive LE. Neither antiherpes nor anti-CMV antibodies are associated with a diagnosis SLE.

Photosensitivity. Photosensitivity is one of the 11 common clinical findings in SLE. Gastrointestinal ulcers are not a finding in SLE. Proteinuria is a symptom of SLE. A rash on the face is a symptom, but not a rash on the body.

25% Odds dictate that children will share one haplotype with half their siblings and either no haplotypes or both haplotypes with a quarter of their siblings. Thus, the chance of finding a match among siblings is much higher (25%) than the general population.

A and B. Type O individuals have both anti-A and anti-B antibodies but not O.

Rh antigen. Blood transfusions must also be matched for the Rh antigen. Blood transfusions do not need to be matched to HLA, immunoglobulins, or platelet compatibility.

A-AB. A person with type A blood also has circulating antibodies to the B carbohydrate antigen. If this person receives blood from a type AB or B individual, a severe transfusion reaction occurs, and the transfused erythrocytes are destroyed by agglutination or complement-mediated lysis. Type A can receive type A blood. Type B and type AB can receive type O.

alive, but less infectious. Attenuated vaccines are alive, but less infectious. Attenuated vaccines are not mutated or highly infectious. Inactive infers the virus is killed.

gram-negative bacteria. Endotoxins are produced by gram-negative bacteria. They are not produced by gram-positive bacteria or any type of fungi

Exotoxin. Exotoxins are enzymes that can damage the plasma membranes of host cells or can inactivate enzymes critical to protein synthesis, and endotoxins activate the inflammatory response and produce fever. Endotoxins released by blood-borne bacteria cause the release of vasoactive enzymes that increase the permeability of blood vessels. Hemolysis is the breakdown of red cells. Septicemia is the growth of bacteria in the blood.

Gram-negative bacteria. Symptoms of gram-negative septic shock are produced by endotoxins. Once in the blood, endotoxins cause the release of vasoactive peptides and cytokines that affect blood vessels, producing vasodilation, which reduces blood pressure, causes decreased oxygen delivery, and produces subsequent cardiovascular shock. Gram-positive bacteria nor fungi do not produce endotoxins and thus do not manifest in shock. Viruses do not produce symptoms of shock.

replicate their genetic material inside host cells. Virus replication depends totally on the ability of the virus to infect a permissive host cell, a cell that cannot resist viral invasion and replication. Viruses contain both DNA and RNA, are incapable of independent reproduction, and cannot be killed by antimicrobials.

are commonly opportunistic. Diseases caused by fungi are called mycoses. Mycoses are common and can be opportunistic and occur with other infections but are not treatable with penicillin.

attenuated viruses. Viral vaccines contain live viruses that are weakened (attenuated). Viral vaccines do not contain active viruses, killed viruses, or toxins.

dead bacteria. Vaccines are biological preparations of weakened or dead pathogens that when administered stimulate production of antibodies or cellular immunity against the pathogen without causing disease. Vaccines are not fully active bacteria, nor are they synthetic or toxins

mutation. Antibiotic resistance is usually a result of genetic mutations that can be transmitted directly to neighboring microorganisms by plasmid exchange. Antibiotic resistance is not a result of proliferation, attenuation, or specialization.

Recurrent infections. The clinical hallmark of immunodeficiency is a propensity to unusual or recurrent severe infections. The type of infection usually reflects the immune system defect. Neither anemia, autoantibody production, nor hypersensitivity is a manifestation of immunodeficiency.

T-lymphocyte deficiency. DiGeorge syndrome results in greatly decreased T cell numbers and function and is evidenced by abnormal development of facial features that are controlled by the same embryonic pouches; these include low-set ears, fish-shaped mouth, and other altered features. B-lymphocyte deficiency is not manifested by these symptoms. Neither combined immunologic deficiency nor complement deficiency is manifested by these symptoms.

CD4+ T-helper. The major immunologic finding in AIDS is the striking decrease in the number of CD4+ T cells. The change occurs in CD4 cells, not CD8. Neither CDC nor CDC 10 is a type of cell.

HIV is a retrovirus. AIDS is an acquired dysfunction of the immune system caused by a retrovirus (HIV) that infects and destroys CD4+ lymphocytes (T-helper cells). HIV infection begins when a virion binds to CD4, not a B cell. Infection requires a host cell receptor. The cell remains dormant but does not die.

Antiretroviral therapy (ART). The current regimen for treatment of HIV infection is a combination of drugs, termed antiretroviral therapy (ART). The remaining options are individual components of the ART treatment format.

invade and multiply in the host. Infectivity is the ability of the pathogen to invade and multiply in the host. Communication is the ability to spread from one individual to others and cause disease. Immunogenicity is the ability of pathogens to induce an immune response. Damaging tissues is the pathogen's mechanism of action.

Causes disease. Virulence is the capacity of a pathogen to cause severe disease—for example, measles virus is of low virulence; rabies virus is highly virulent. Communication is the ability to spread from one individual to others and cause disease. Immunogenicity is the ability of pathogens to induce an immune response. Damaging tissues is the pathogen's mechanism of action.

genetic defect. A primary (congenital) immune deficiency is caused by a genetic defect. A primary (congenital) immune deficiency is not a response to an immunization, an adverse response to a medication, or due to renal failure.

The baby is Rh positive Hemolytic disease of the newborn was most commonly caused by IgG anti-D alloantibody produced by Rh-negative mothers against erythrocytes of their Rh-positive fetuses. This disorder is not due to the mother's exposure to measles, the father's exposure to Agent Orange, or the baby's prematurity.

Anemia Lymphopenia The patient is experiencing type II hypersensitivity when experiencing anemia and lymphopenia. Seizures, facial rash, and photosensitivity are not associated with type II hypersensitivity reactions.