Immunologic Disorders Practice Flashcards

These vocabulary flashcards cover the overview of immunologic disorders, including body defenses, TORCH testing, specific pathogens like Rubella and Toxoplasma, and diagnostic methods like Immunohistochemistry.

Host

The individual that harbors the disease.

Immunocompromised individuals

Individuals with a higher rate of microbial exposure compared to the general population.

First line of defense

The barrier where a microorganism must penetrate the skin or mucous membrane.

Second line of defense

Body defense consisting of phagocytosis alone or with complement activation, highly effective in bacterial immunity.

Third line of defense

The stage of defense involving antibody and cell-mediated responses (T cells) that do not become activated for several days.

IgM

The antibody produced in significant quantities after the first exposure to an infectious agent; positive levels in adults or newborns indicate an active infection.

TORCH

An acronym for traditional infectious disease laboratory testing encompassing Toxoplasma, Other (viruses), Rubella, CMV, and Herpes.

Toxoplasma gondii

The organism that causes toxoplasmosis, commonly found in cat feces.

Congenital toxoplasmosis

A form of toxoplasmosis that can result in CNS malformation or prenatal mortality.

Positive IgG antibodies to T. gondii

Serologic indication of a prior infection in adults and newborns.

Rubella

An infection caused by an enveloped, single-stranded RNA virus from the Togaviridae family, transmitted through respiratory secretions.

Congenital Rubella Syndrome (CRS)

A condition resulting from rubella infection during pregnancy that can cause fetal death; indicated by positive IgM in a neonate.

Anamnestic antibody response

A 4 fold titer increase between acute and convalescent specimens.

Cytomegalovirus (CMV)

A herpes virus that is a major cause of congenital viral infections and produce subclinical infections that can be reactivated.

Immediate early antigens

CMV antigens that appear within 1 hour of cellular infection.

Late antigens

CMV antigens that appear within 72 hours of infection.

Antibody-dependent cell-mediated cytotoxicity (ADCC)

A defense mechanism against large parasites involving IgG or IgE antibodies.

Eosinophils

Phagocytic cells that serve as effector cells for type I reactions during parasitic infections.

Histoplasma capsulatum

A fungal disease evaluated through fungal culture and serologic testing of H and M proteins.

Varicella-zoster virus (VZV)

The herpesvirus responsible for causing chickenpox and shingles.

Human herpesvirus-6 (HHV-6)

A recently identified virus whose primary target of infection is T cells.

Rickettsial Diseases

Diseases caused by obligate intracellular organisms that possess cell walls.

Mycoplasma spp.

Obligate intracellular organisms that lack cell walls.

Immunohistochemistry (IHC)

A technique used for the detection of viruses (such as HSV-1, HSV-2, VZV, EBV, CMV) in tissue samples, most widely used at the protein level in dermatologic diagnostics.

Direct IHC method

An immunohistochemistry method that utilizes only one layer of antibody.

Indirect IHC method

An immunohistochemistry method that utilizes two layers of antibodies.

Chromogens

Substances oxidized by horseradish peroxidase or alkaline phosphatase to produce a red or brown color in IHC.

Polymer based IHC

A method providing higher specificity and sensitivity for viral antigens in tissues using enzyme-labeled dextran and allowing for double staining.