Immune deficiencies Flashcards Preview

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Flashcards in Immune deficiencies Deck (14):
1

X-linked (Bruton's) agammaglobulinemia

Defect: x-linked recessive (increased in boys) defect in BTK a tyrosine kinase gene (no B cell maturation)

Presentation: recurrent bacterial infections after 6 mo (decreased maternal IgG) as a result of opsonization defect

Findings: normal pro-B, decreased maturation, decreased number of B cells, decreased immunoglobulins of all classes

2

Selective IgA deficiency

Defect: unknown, most common immunodeficiency

Presentation: majority a symptomatic. Can see sinopulmonary infections, GI infections, autoimmune disease. Anaphylaxis to IgA containing blood products

Findings: IgA < 7 mg/dl with normal IgG, IgM, and IgG vaccine tigers. False positive b-hCG tests due to presence of heterophile antibody

3

Common variable immunodeficiency (CVID)

Defect in b-cell maturation (many causes)

Can be acquired in 20s-30s: increased risk of autoimmune disease, lymphoma, sinopulmonary infections

Normal number of B cells; decreased plasma cells, immunoglobulin (low serum IgG)

4

Thymic aplasia (DiGeorge syndrome)

22q11 deletion; failure to develop 3rd and 4th pharyngeal pouches

Tetany (hypocalcemia), recurrent viral/fungal infections (T-cell deficiency), congenital heart and great vessel defects

Thymus and parathyroids fail to develop: leading to decreased T cells, decreased PTH, decreased calcium; absent thymic shadow on CXR

5

IL-12 receptor deficiency

Decreased Th1 response

Disseminated mycobacterial infections

Decreased IFngamma

6

Hyper-IgE syndrome

Th1 cells fail to produce IFNgamma leading to inability of neutrophils to respond to chemo tactic stimuli

FATED: course Facies, cold (non inflamed) staph Abscesses, retained primary Teeth, increased IgE, Derrmatologic problems (eczema)

Increased IgE

7

Chronic mucocutaneous candiasis

T cell dysfunction

Candida albicans infections of skin and mucous membranes

8

Severe combined immunodeficiency

Several types: defective IL-2 receptor (most common x-linked), adenosine deaminase deficiency

Failure to thrive, chronic diarrhea, thrush. Recurrent bacterial, viral, fungal infections. Absence of thymic shadow, germinal centers on lymph node biopsy and B cells on peripheral blood smear

Treatment: bone marrow transplant (no allograft rejection)

Findings: decreased T cell recombinant excision circles (TRECs)

9

Ataxia-telangiectasia

Defects in ATM gene, which codes for DNA repair enzymes

Cerebellar defects (ataxia), spider angioma (telangiectasia), IgA deficiency

Increased AFP

10

Hyper IgM syndrome

Most commonly defective CD40L on helper T cells = inability to class switch

Severe pyogenic infections early in life

Increased IgM, severely decreased other classes

11

Wiskott-Aldrich syndrome

X-linked in WAS gene on X chromosome: T cells unable to reorganize actin cytoskeleton

Thrombocytopenic purpura
Infections
Eczema

Increased IgE, IgA; decreased IgM
Thrombocytopenia

12

Leukocyte adhesion deficiency (type I)

Defect in LFA-1 integrin (CD18) protein on phagocytes

Recurrent bacterial infections, absent pus formation, delayed separation of umbilical cord

Neutrophilia

13

Chediak-Higashi syndrome

Autosomal recessive; defect in lysosomal trafficking regulator gene (LYST). Micro tubule dysfunction in phagosome lysosome function

Recurrent pyogenic infections by staph and strep; partial albinism, peripheral neuropathy

Giant granules in neutrophils

14

Chronic granulomatous disease

Lack of NADPH oxidase: decreased reactive oxygen species and absent respiratory burst in neutrophils

Increased susceptibility to catalase-positive organisms

Abnormal DHR flow cytometry test. Nitro blue tetrazolium dye reduction test no longer preferred

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