Porth Chapter 15

Question 1

Classification of Immunodeficiency States: Primary

Answer 1

(congenital or inherited)​

Question 2

Classification of Immunodeficiency States: Secondary

Answer 2

(acquired later in life)​

Malnutrition​

Infection (e.g., acquired immunodeficiency syndrome [AIDS])​

Neoplastic disease (e.g., lymphoma)​

Immunosuppressive therapy (e.g., corticosteroids or transplant rejection medications)​

Question 3

Results of Alterations of the Immune System

Answer 3

Immunodeficiency states​

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Allergic or hypersensitivity reactions​

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Transplantation rejection​

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Autoimmune disorders

Question 4

Four Major Categories of Immune Mechanisms

Answer 4

Humoral or antibody-mediated immunity (B lymphocytes)​

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Cell-mediated immunity (T lymphocytes)​

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The complement system​

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Phagocytosis (neutrophils and macrophages)

Question 5

Humoral Immunodeficiencies

Answer 5

B-cell function and immunoglobulin or antibody production are involved.​

Defects in humoral immunity increase the risk of recurrent pyrogenic infections.​

Humoral immunity usually is not as important in defending against intracellular bacteria (mycobacteria), fungi, and protozoa.​

Viruses are usually handled normally, except for the enteroviruses that cause gastrointestinal infections.

Question 6

Primary Humoral Immunodeficiency Disorders

Answer 6

Genetic disorders of the B lymphocytes​

Approximately 70% of primary immunodeficiencies ​

Immunoglobulin production depends on the following: ​

The differentiation of stem cells to mature B lymphocytes ​

The generation of immunoglobulin-producing plasma cells ​

Can interrupt the production of one or all of the immunoglobulins

Question 7

Combined T-Cell and B-Cell Immunodeficiencies

Answer 7

Severe combined immunodeficiency​

X-linked SCIDs​

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Ataxia–telangiectasia​

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Wiskott-Aldrich syndrome

Question 8

Disorders of the Complement System

Answer 8

Primary​

Most inherited as autosomal recessive traits and can involve one or more complement components​

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Secondary​

Can occur in persons with functionally normal complement systems because of rapid activation and turnover or reduced synthesis of complement components​

Hereditary angioneurotic edema and loss of regulation

Question 9

The Phagocytic System

Answer 9

Definition: composed primarily of polymorphonuclear leukocytes and mononuclear phagocytes​

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Action of these cells:​

Migrate to the site of infection​

Aggregate around the affected tissue​

Envelope the invading microorganisms ​

Generate microbicidal substances to kill the ingested pathogens

Question 10

Dysfunction of the Phagocytic System

Answer 10

A defect in phagocytic functions or a reduction in the absolute number of available cells disrupts the system. ​

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Susceptible to ​

Candida species. ​

filamentous fungi. ​

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Chronic granulomatous disease (CGD)

Question 11

Adaptive Immunity

Answer 11

Development of response to the antigen​

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Specific humoral and cellular recognition​

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Memory cells

Question 12

Hypersensitivity Disorders

Answer 12

Definition​

Excessive or inappropriate activation of the immune system​

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Types​

Type I, IgE-mediated disorders​

Type II, antibody-mediated disorders​

Type III, complement-mediated immune disorders​

Type IV, T-cell–mediated disorders

Question 13

Types of IgE-Mediated Allergic Reactions

Answer 13

Atopic Disorders​

Heredity predisposition and production of a local reaction to IgE antibodies produced in response to common environmental agents​

Urticaria (hives), allergic rhinitis (hay fever), atopic dermatitis, food allergies, some forms of asthma​

Nonatopic Disorders​

Lack the genetic component and organ specificity of the atopic disorders

Question 14

Phases of Type I Hypersensitivity Reactions

Answer 14

Primary or Initial-phase Response​

Vasodilation​

Vascular leakage​

Smooth muscle contraction​

Secondary or Late-phase Response ​

More intense infiltration of tissues with eosinophils and other acute and chronic inflammatory cells ​

Tissue destruction in the form of epithelial cell damage

Question 15

Type II (Cytotoxic) Hypersensitivity Reactions

Answer 15

Action​

Mediated by IgG or IgM antibodies directed against target antigens on the surface of cells or other tissue components ​

Endogenous antigens: present on the membranes of body cells​

Exogenous antigens: absorbed on the membrane surface
Examples​

Mismatched blood transfusion reactions​

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Hemolytic disease of the newborn​

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Certain drug reactions

Question 16

Type III, Immune Complex Allergic Disorders

Answer 16

Mediated by the formation of insoluble antigen–antibody complexes that activate the complement pathway​

Activation of the complement pathway by the immune complex generates chemotactic and vasoactive mediators that cause tissue damage by​

alterations in blood flow.​

increased vascular permeability.​

destructive action of inflammatory cells.
Immune complexes formed in the circulation produce damage when in contact with the vessel lining or are deposited in tissues.​

They elicit an inflammatory response by activating the complement pathway. ​

Leading to chemotactic recruitment of neutrophils and other inflammatory cells​

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Responsible for the vasculitis seen in certain autoimmune diseases
Systemic immune complex disorders​

Serum sickness​

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Localized immune complex reactions ​

Arthus reaction

Question 17

Type IV Hypersensitivity Reactions

Answer 17

Cell-Mediated Immune Response​

The principal mechanism of response to a variety of microorganisms, including intracellular pathogens and extracellular agents​

Can lead to cell death and tissue injury in response to chemical antigens or self-antigens​

Basic Types​

Direct cell-mediated cytoxicity​

Hepatitis ​

Delayed-type hypersensitivity​

Allergic contact dermatitis ​

Hypersensitivity pneumonitis

Question 18

Routes of Exposure to Latex

Answer 18

Cutaneous​

Mucous membrane​

Most severe reactions resulted from contact with the mouth, vagina, urethra, or rectum​

Inhalation​

Internal tissue​

Intravascular routes​

Reaction types​

Type I versus type IV

Question 19

Histocompatibility Complex

Answer 19

Major histocompatibility complex ​

Set of molecules displayed on cell surfaces​

Lymphocyte recognition​

Antigen presentation​

Controls the immune response through recognition of “self” and “nonself”

Question 20

Allogeneic

Answer 20

The donor and recipient are related or unrelated but share similar HLA types.

Question 21

Syngeneic

Answer 21

The donor and recipient are identical twins.

Question 22

Autologous

Answer 22

The donor and recipient are the same person.

Question 23

Stem Cell Transplantation

Answer 23

Many primary immunodeficiency disorders traced to deficiency in stem cells can be cured with allogeneic stem cell transplantation from an unaffected donor.​

SCIDs, Wiskott-Aldrich syndrome, and chronic granulomatous disease​

Stem cells can repopulate the bone marrow and reestablish hematopoiesis.​

To be effective, the bone marrow cells of the host are destroyed by myeloablative doses of chemotherapy.

Question 24

Mechanisms Postulated to Explain the Tolerant State

Answer 24

Self-tolerance ​

Central tolerance ​

The elimination of self-reactive T cells and B cells in the central lymphoid organs (i.e., the thymus for T cells and the bone marrow for B cells)​

Peripheral tolerance​

Derives from the deletion or inactivation of autoreactive T cells or B cells that escaped elimination in the central lymphoid organs

Question 25

Hyperacute Reaction

Answer 25

Occurs almost immediately after transplantation. ​

Produced by existing recipient antibodies to graft antigens initiating a type III, Arthus-type hypersensitivity reaction

Question 26

Acute Rejection

Answer 26

Occurs within first few months after transplantation with signs of organ failure; may occur months or years after immunosuppression has been terminated​

T lymphocytes respond to antigens in the graft tissue

Question 27

Chronic Host-Versus-Graft Rejection

Answer 27

Occurs over a prolonged period​

Manifests with dense intimal fibrosis of blood vessels of the transplanted organ​

The actual mechanism is unclear but may include release of cytokines that stimulate fibrosis.

Question 28

Basic Requirements Necessary for GVHD

Answer 28

The transplant must have a functional cellular immune component.​

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The recipient tissue must bear antigens foreign to the donor tissue.​

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The recipient immunity must be compromised to the point that it cannot destroy the transplanted cells.

Question 29

Autoimmune Diseases

Answer 29

Systemic lupus erythematosus (SLE) ​

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Autoimmune hemolytic anemia (AIHA)​

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Pemphigus vulgaris ​

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Hashimoto thyroiditis

Question 30

Mechanisms of Autoimmune Disease

Answer 30

Heredity and gender​

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Failure of self-tolerance​

Disorders in MHC–antigen complex/receptor interactions​

Molecular mimicry ​

Superantigens

Question 31

Criteria for Determining an Autoimmune Disorder

Answer 31

Evidence of an autoimmune reaction​

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Determination that the immunologic findings are not secondary to another condition​

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The lack of other identified causes for the disorder