Immunodeficiencies

Question 1

Bacteria

Answer 1

No T cells: sepsis
No B cells: encapsulated
No granulocytes: staphy, Burkholderia cepacia, Serratia, Nocardia
No complement:

Question 2

Virus

Answer 2

No T cells: CMV, EBV, VZV, chronic
No B cells: Enteroviral encephaitis, poliovirus
No granulocytes: NA
No complement: NA

Question 3

Fungi/parasites

Answer 3

No T cells: Candida, PCP
No B cells: GI giardiasis (no IgA)
No granulocytes: Candida, aspergillus
No complement: NA

Question 4

X linked Bruton’s agamma

Answer 4

X linked, defect in BTK, no B cell maturation
Recurrent bacterial after 6 months
Normal proB, reduced maturation, reduced # of B cells, reduced immunoglobin of all casses

Question 5

Selective IgA deficiency

Answer 5

Unknown, Most common primary immunodeficiency

Majority asyptomatic, can see sinopulmonary infections, GI infection, autoimmune disease

Anaphylaxis to IgA containing blood products

IgA<7mg/dl with normal IgG, IgM, IgG vaccine
False positive beta HCG because of presecen of heterophile antibodies

Question 6

Common variable immunodeficiency

Answer 6

B cell disorder
Defect in B cell maturation; many cuases

Can be acquired in 20s-30s
Increased risk of autoimmune disease, lymphoma, sinopulmonary infection

Finding: normal number of B cells, but reduced plasma cells, and immunoglobulins

Question 7

Thymic aplasia (DiGoeroge)

Answer 7

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 parathyroid fail to develop
Reduced T cells, low PTH, low Ca2+.

Absent thymic shadow on CXR

Question 8

IL 12 receptor deficiency

Answer 8

Reduced Th1 response

Disseminated mycobacterial infection

Reduced IFNgamma

Question 9

Hyper IgE syndrome (Job’s syndrome)

Answer 9

TH1 cells fail to produce IFNgamma: inability of neutrophils to respond to chemotatic stimuli

FATED: coarse Facies, cold staphy Abscesses, retained primary Teeth, increased IgE, Dermatologic problems (eczema).

Increased IgE

Question 10

Chronic mucocutanous candidiasis

Answer 10

T cell dysfunction

Candida albican infections of skin and mucous membrane.

Question 11

SCID

Answer 11

B and T cell disorder
Severe types: defective IL2 receptor (most common, X linked), adenosinedeaminase deficiency

FTT, chronic diarrhea, trust, recurrent viral, bacterial, fungal infection, and protozoal infection

Finding: reduced T cell recombination excision circles,
Absence of thymic shadow, GC (LN bx), and B cells (peripheral blood smear)

Treatment: BM transplant

Question 12

Ataxia telangiectasia

Answer 12

B and T cell disorder
Defects in ATM gene, which codes for DNA repair

Triad: cerebellar defect (ataxia), spider angiomas (telangiectasia), IgA deficiency

Finding: increased AFP

Question 13

Hyper IgM syndrome

Answer 13

B and T cell disorder
Most commonly defective CD40L on helper T cells
Inability to class switch

Severe pyrogenic infectiosn early in life

Increased IgM, low low IgG, IgA, IgE

Question 14

Wiskott Aldrich syndrome

Answer 14

B and T cell disorder
X linked, WAS gene on X chromosome
T cells unable to reorganize action cytoskeleton

Triad (TIE): throbocytopenia purpura, infections, eczema

Increased IgE, IgA, but low IgM
Thrombocytopenia

Question 15

Leukocyte adhesion deficiency Type I

Answer 15

Phagocyte dysfunction
Defect in LFA-1 integrin (CD18) on phagocytes

Recurrent bacterial infection, absent puss formation, delayed separation of umbilical cord

Neutropenia

Question 16

Chediak-Higashi syndrome

Answer 16

Phagocyte dysfunction
Autosomal recessive
Defect in LYST, microtubule dysfunciton in phagosome-lysosome funsion

Recurrent pyrogenic infections by staphy and strep; partial albinism, peripheral neuropathy

Giant granules in neutrophils

Question 17

CGD

Answer 17

Lack of NADPH oxidase - reduced oxygen species (superoxides), and absent respiratory burst in neutrophils

Increased susceptibility to catalase positive organisms

Abnormal dihydrohodamine (DHR) flow cytometry test.
Nitroblue tetrazolium dye no longer preferred.