Immune deficiencies

Question 1

X-linked (Bruton’s) agammaglobulinemia

Answer 1

• x-linked recessive
• defect in BTK a tyrosine kinase gener –> NO B CELL MATURATION
• recurrent bacterial infections after 6 months (mothers matenral IgG decreases)
• normal pro - B but decrease in overall B cells
• decrease in all IG’s

Question 2

Selective IgA deficiency

Answer 2

• most common primary immunodeficiency
• majority asymptomatic
• can see sinopulmonary infections
• autoimmune disease
• anaphylaxis to IgA-containing blood products
• IgA< 7 mg/dl
• normal IgG, IgM and IgG vaccine titres
• false + for b-HCG
• more isotype swittching to IgE – increased atopy

Question 3

Common variable immunodeficiency

Answer 3

• defect in B-cell maturation
• can be acquired in 20-30’s
• increased risk for autoimmune diesel, lymphoma, sinopulmonary infections
• normal number of B cells
• decreased plasma cells and immunoglobulin

Question 4

Thymic aplasia (digeorges syndrome/velocardiofacial syndrome)

Answer 4

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

• tetany due to hypocalcemia
• recurrent viral/fungal infections (t-cell deficiency)
• congenital heart and great vessel defects
• thymus and parathyroids fail to develop
• decreased T cells, PTH, Ca2+
• absent thymic shadow on CXR

Question 5

IL-12 receptor deficency

Answer 5

• decreased TH1 response( induces differentiation of t cells to TH1. IL-12 is released by macrophages)
• dissemnated mycobacterial infections
• decreased IFN gamma

Question 6

Hyper-IgE syndrome (Job’s syndrom)

Answer 6

• Th1 cells fail to produce IFN gamma
• inability of neutrophils to respond to chemotactic stimuli
• increased IgE
• staph abscesses
• retained primary teeth
• dermatologic problems (eczema)

Question 7

Chronic mucocutanes candidiasis

Answer 7

t- cell dysfunction

-candida albicans infections

Question 8

Severe combined immunodeficiency

Answer 8

• several types:
• defected IL-2 receptor
• x linked
• adenosine deaminase deficiency

failure to thrive

• chronic diarrhea, thrush, recurrent viral, bacterial fungal and protozoal infections. abscence of thymic shadow germinal centers and b cells
• treatment is bone marror transplant
• decreased t cell recombinant excision circles TRECS
• no t cells

recall IL-2 STIMULATES growth of T cells

Question 9

Ataxia-telangiectasia

Answer 9

• defects in the ATM gene which codes for DNA repair enzymes
• cerebellar defects
• spider angionmas
• IgA deficiency
• increased AFP

Question 10

Hyper IgM- syndrome

Answer 10

• CD40L on helpter t cells defective, thus can’t bind to B cells and no class switching =(
• sever pyogenic infection early in life
• increase IgM
• decreased IgG. IgA and IgE

Question 11

Wiskott- aldrich syndrome

Answer 11

• xlinked
• WAGE gene on X chromosome problem
• t cells unable to reoganize actin cytoskeleton
• thrombocytopenic purpura
• infections
• eczema
• increased IgE and IgA
• decreased IgM

Question 12

Leukocyte adehesion deficiency (type 1)

Answer 12

Defect in LFA-1 integrin CD18 protein on phagocytes

• recurrent bacterial infections, absent pus formation, delayed separation of umbilical cord
• neutophilia

Question 13

Chediak-Higashi syndrome

Answer 13

• autosomal recessive
• defect in lysosomal trafficing regulator gene LYST
• microtubule dysfunction in phagosomelysosome fusion
• recurrent pyogenc infections by staph and strep, partial albinisms, peripheral neurapathy
• giant granules in neutrophils

Question 14

Chronic granulomatous disease

Answer 14

Lack of NADPH oxidase

• decreased ROS and absent respiratyo burst in neutrophils
• susceptability to catalase positive organisms like staph,e coli and aspergillus
• abnomral dihyrohodamine DHF flow cytometry test
• ntrioblue terezolium dye reduction test no longer preferred