Ch. 12 Congenital and Acquired Immunodeficiencies Practice Flashcards

Vocabulary flashcards covering primary (congenital) and secondary (acquired) immunodeficiencies, including mechanisms of defect, functional deficiencies, and HIV/AIDS clinical phases.

Chronic granulomatous disease

A condition characterized by defective production of oxygen species of phagocytes and mutations in genes encoding the phagocyte oxidase complex, such as $phox-91$ (cytochrome \text{ } b_{558} \text{ } \text{̑} \text{ } subunit).

Leukocyte adhesion deficiency type 1

A disorder caused by mutations in the gene coding the $\beta$ chain (CD18) of $\beta_2$ integrins, resulting in defective leukocyte adhesion to endothelial cells and migration into tissues.

Leukocyte adhesion deficiency type 2

A defect in leukocyte rolling and migration caused by mutations in the gene encoding GDP-fucose transporter-1, leading to decreased expression of ligands for endothelial E- and P-selectins.

Chediak-Higashi syndrome

A condition involving defective vesicle fusion and lysosomal function in neutrophils, macrophages, and other cells due to mutations in the gene encoding LYST.

Toll-like receptor signaling defects

Recurrent infections caused by mutations in genes encoding TLR3 and MyD88, which compromise NF-\text{̑} B activation and type I interferon production.

C3 deficiency

A complement deficiency resulting in impaired opsonization, chemotaxis, cell lysis, and clearance of immune complexes, which may lead to severe or fatal infections.

Reticular dysgenesis

A general failure of immunity and susceptibility to infections caused by a defect in the stem cell that affects the maturation of leukocytes.

X-linked SCID

A condition with markedly decreased T cells and reduced serum Ig caused by cytokine receptor common \text{̓} chain gene mutations, leading to lack of IL-7 signals.

Autosomal recessive SCID (ADA/PNP)

A progressive disease in T and B cells where the deficiency of adenosine deaminase (ADA) or purine nucleoside phosphorylase (PNP) leads to the accumulation of toxic metabolites in lymphocytes.

RAG gene mutations

Mutations in RAG genes involved in VDJ recombination that result in markedly decreased T and B cells and reduced serum Ig.

DiGeorge syndrome

Decreased T cells caused by the anomalous development of the 3rd and 4th branchial pouches, leading to thymic hypoplasia.

X-linked hyper-IgM syndrome

A deficiency caused by mutations in the CD40 ligand, leading to defects in helper T cell-dependent B cell and macrophage activation.

Selective Ig deficiency

Reduced or absent production of specific immunoglobulin isotypes caused by mutations in Ig genes or unknown mutations.

Common variable immunodeficiency

A condition with reduced immunoglobulins and susceptibility to bacterial infections due to mutations in receptors for B cell growth factors or costimulators.

Bare lymphocyte syndrome

Defective Class II MHC expression resulting in impaired $CD4^+$ T cell development and activation, caused by mutations in genes encoding transcription factors for MHC CII.

TCR complex expression or signaling defects

Decreased T cells or abnormal ratios of $CD4^+$ and $CD8^+$ subsets caused by mutations or deletions in genes encoding CD3 proteins or ZAP-70.

X-linked lymphoproliferative syndrome

Uncontrolled EBV-induced B cell proliferation and CTL activation caused by mutations in the gene encoding SAP (signaling lymphocyte-activation molecule-associated protein).

Wiskott-Aldrich syndrome

An X-linked disorder involving small, dysfunctional platelets and abnormal bleeding caused by mutations in a gene that encodes a protein binding cytoskeletal components in hematopoietic cells.

Hemophagocytic lymphohistiocytosis

Condition involving impaired CTL and NK cell killing function and uncontrolled macrophage activation, often caused by mutations in the perforin gene.

Acquired Immunodeficiency (HIV-1/HIV-2)

Depletion and functional inhibition of $CD4^+$ T cells; features an extremely high mutation rate due to error-prone reverse transcription and downregulation of MHC CI expression.

Kaposi sarcoma

A common type of cancer in AIDS patients involving a tumor of small blood vessels caused by a herpesvirus.

Antiretroviral therapy (ART)

Treatment that blocks the activity of viral reverse transcriptase, protease, and integrase enzymes; it lowers viral load but does not completely eradicate the HIV infection.

Acute HIV syndrome

The clinical phase of HIV characterized by primary infection, wide dissemination of virus, and seeding of lymphoid organs.

Clinical latency (HIV)

The clinical phase of HIV infection where viral replication is partially controlled by the immune system, but infection remains established in lymphoid tissues.

Anti-p24 antibody

One of the specific immune responses generated by the host against HIV peptides.