PATH - Phagocyte dysfunction

Question 1

Leukocyte adhesion

deficiency (type 1)

Answer 1

autosomal recessive

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

impaired migration and chemotaxis

Recurrent bacterial skin and
mucosal infections, *absent
pus formation, impaired
wound healing, **delayed
separation of umbilical cord
(> 30 days)

*INC neutrophils

*Absence of neutrophils at
infection sites.

Question 2

Chédiak-Higashi syndrome

Answer 2

autosomal recessive

Defect in lysosomal trafficking
regulator gene (*LYST)

Microtubule dysfunction in
phagosome-lysosome fusion

Recurrent pyogenic infections by staphylococci
and streptococci, partial
albinism, peripheral neuropathy, progressive
neurodegeneration, infiltrative
lymphohistiocytosis.

*Giant granules in
granulocytes and platelets

*Pancytopenia

Mild coagulation defects

Question 3

Chronic granulomatous

disease

Answer 3

X-linked recessive most common

Defect of *NADPH oxidase–>DEC reactive oxygen
species (eg, superoxide)
and DEC respiratory burst
in neutrophils

INC susceptibility to Catalase ⊕ organisms

Abnormal dihydrorhodamine
(flow cytometry) test (DEC green fluorescence)

Nitroblue tetrazolium dye
reduction test obsolete.