Patho Ch 19 Quiz

During pregnancy, IgG antibodies are able to cross the placenta from the mother to the fetus, providing passive immunity to the infant. IgG is the only immunoglobulin that is capable of crossing the placenta, while IgM, IgD, and IgE antibodies do not have this ability. Therefore, IgG is the correct answer.

Type I hypersensitivity reactions, also known as immediate hypersensitivity reactions, are caused by the release of histamine and other mediators from mast cells and basophils. These reactions occur within minutes of exposure to an allergen and are characterized by symptoms like hives, itching, sneezing, and wheezing. IgE antibodies play a crucial role in type I hypersensitivity reactions by binding to mast cells and basophils, leading to their activation and subsequent release of inflammatory mediators. This type of reaction is commonly associated with allergies, such as hay fever, asthma, and anaphylaxis.

Anaphylactic reaction refers to a severe and immediate immune response triggered by certain antigens. This reaction is characterized by symptoms such as itching, hives, skin erythema (redness), bronchospasm (constriction of the airways), and respiratory distress. It occurs within minutes of exposure to the antigen and can be life-threatening if not treated promptly.

DiGeorge Syndrome is a genetic disorder that results in the partial or complete failure of development of the thymus and parathyroid glands. This leads to a weakened immune system and can cause various health problems, including immunodeficiency. Therefore, DiGeorge Syndrome is the correct answer for the given question.

Selective IgA deficiency is a condition characterized by low levels or absence of immunoglobulin A (IgA) in the blood. IgA is an antibody that plays a crucial role in the immune system's defense against infections in the mucous membranes, such as those in the respiratory and gastrointestinal tracts. Selective IgA deficiency can make individuals more susceptible to recurrent infections, particularly in these areas. It is the most common primary immunodeficiency disorder and is usually asymptomatic, but some individuals may experience symptoms such as respiratory or gastrointestinal infections, allergies, or autoimmune disorders.

Type IV hypersensitivity reaction is a delayed hypersensitivity reaction mediated by T-cells. It is characterized by the activation of T-cells upon exposure to an antigen, leading to the recruitment and activation of inflammatory cells such as macrophages and cytotoxic T-cells. This type of reaction is involved in various immune-mediated disorders such as contact dermatitis, tuberculin skin test reactions, and graft rejection. Unlike other types of hypersensitivity reactions, type IV reactions do not involve antibodies but rather the direct involvement of T-cells in the immune response.

Hyper-IgM syndrome is characterized by low levels of IgG and IgA, and high concentrations of IgM. This condition is caused by a genetic mutation that affects the ability of B cells to switch from producing IgM to other types of antibodies, such as IgG and IgA. As a result, individuals with Hyper-IgM syndrome have a weakened immune system and are more susceptible to infections.

Ataxia-telangiectasia is considered a CIDS because it is characterized by low T-cell function. This syndrome is associated with other disorders and is caused by diverse genetic factors. Pierre-Robin syndrome, Angelman syndrome, and Adair-Dighton syndrome are not classified as CIDS because they do not exhibit low T-cell function.

The immune system typically responds to invaders in our bodies, but sometimes it can overreact and cause tissue injury and disease. This overreaction is known as a hypersensitivity reaction.

Type II hypersensitivity reaction is characterized by the binding of antibodies (IgG or IgM) to antigens on the surface of cells or tissues. This leads to activation of the complement system and recruitment of immune cells, causing damage to the affected cells or tissues. Examples of type II hypersensitivity reactions include autoimmune hemolytic anemia, transfusion reactions, and some drug-induced immune reactions.

Type III hypersensitivity reaction is characterized by the formation of immune complexes that deposit in tissues, leading to inflammation and tissue damage. This reaction occurs when there is an excess of soluble antigens and antibodies in the bloodstream. The immune complexes can activate complement proteins, leading to an inflammatory response. This type of reaction is associated with autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis.

Secondary immunodeficiency refers to a weakened immune system that is acquired later in life, as opposed to being inherited. This can be caused by various factors such as infections, certain medications, chemotherapy, malnutrition, or chronic diseases like HIV/AIDS. Unlike primary immunodeficiency disorders, which are genetic and present from birth, secondary immunodeficiency can develop at any age. It is characterized by a decrease in immune function, making individuals more susceptible to infections and other health complications.

Adenosine deaminase deficiencies and T-cell cytokine receptor mutations can cause severe combined immunodeficiency disease. Severe combined immunodeficiency disease (SCID) is a group of rare genetic disorders characterized by a severely compromised immune system. Adenosine deaminase (ADA) deficiencies result in the accumulation of toxic metabolites that damage lymphocytes, leading to a lack of functional immune cells. T-cell cytokine receptor mutations can also impair the development and function of T-cells, which are crucial for immune responses. Both of these genetic abnormalities can result in SCID and its associated immunodeficiency.

Immunoglobulin G subclass deficiency refers to a condition where there is a decrease in one or more IgG subgroups. This means that the body is unable to produce or properly function with certain types of IgG antibodies, which are important for immune system function. This deficiency can lead to an increased susceptibility to infections, as the body is unable to effectively fight off pathogens.

DiGeorge syndrome is a disease that involves primary cell-mediated disorders of the immune system. It is characterized by the absence or underdevelopment of the thymus, which is responsible for the maturation of T-cells, a type of white blood cell involved in cell-mediated immunity. Without a functional thymus, individuals with DiGeorge syndrome have impaired cell-mediated immune responses, making them more susceptible to severe infections. Therefore, this disease fits the description of a primary cell-mediated disorder of the immune system.

X-linked agammaglobulinemia is a primary immunodeficiency disorder characterized by the absence or very low levels of immunoglobulins, particularly immunoglobulin G (IgG), in the serum. This condition is caused by a mutation in the Bruton's tyrosine kinase (BTK) gene, which is essential for B-cell development and maturation. As a result, individuals with X-linked agammaglobulinemia have impaired B-cell function and are unable to produce normal levels of immunoglobulins. This leads to a significant deficiency in antibody-mediated immune responses, making them susceptible to recurrent infections, particularly of the respiratory tract.

Interferon-beta 1a drugs are not known to produce hypogammaglobulinemia. The other options listed, such as phenytoin, corticosteroids, carbamazepine, and disease modifying antirheumatic drugs, have been associated with drug-induced secondary hypogammaglobulinemia.

A single mutation in any gene that influences major histocompatibility antigens can cause combined immunodeficiency syndrome. Major histocompatibility antigens play a crucial role in the immune system by presenting antigens to T cells and triggering an immune response. If there is a mutation in any gene that influences these antigens, it can lead to defects in both B and T lymphocytes, resulting in the impairment of both humoral and cell-mediated immunity.

Common variable immunodeficiency is characterized by a failure of B cells to differentiate into plasma cells, resulting in decreased production of immunoglobulins. This leads to a deficiency in antibodies, making individuals more susceptible to infections. Other immunodeficiencies listed in the options may have different mechanisms or manifestations, but only common variable immunodeficiency specifically involves a block in terminal differentiation of B cells to plasma cells.

Wiskott-Aldrich syndrome is a primary immunodeficiency disorder characterized by a triad of symptoms including eczema, thrombocytopenia (low platelet count), and recurrent infections. It is caused by a mutation in the WAS gene, which leads to defective immune cell function. Individuals with Wiskott-Aldrich syndrome are susceptible to infections caused by encapsulated microorganisms, such as Streptococcus pneumoniae and Haemophilus influenzae, due to impaired antibody production and defective immune response. This susceptibility to infections caused by encapsulated microorganisms is a characteristic feature of Wiskott-Aldrich syndrome.

Transient hypogammaglobulinemia of infancy is a condition characterized by a temporary decrease in the levels of certain antibodies (immunoglobulins) in the blood. This can lead to repeated bouts of upper respiratory and middle ear infections, as the immune system is not able to effectively fight off infections. However, this condition typically resolves on its own as the child grows older and their immune system matures. Therefore, it is the most appropriate explanation for the given symptoms of repeated infections.

Ataxia-telangiectasia is a genetic disorder that affects multiple systems in the body, including the immune system. It is characterized by a decrease in the ratio of CD4+ helper T cells to CD8+ suppressor T cells, as well as lymphopenia. These abnormalities in T cell subsets can lead to immune dysfunction and increased susceptibility to infections. Therefore, Ataxia-telangiectasia is the most likely explanation for the given presentation.