Leuocycte adhesion, Phagocyte aggregation, CD18 (beta2 integrin) gene
5 mL (min. 0.5 mL) sodium heparin blood preferred, EDTA whole blood accepted
1 mL (min. 0.5 mL) sodium heparin bone marrow aspirate preferred, EDTA bone marrow accepted
Whole blood ship ambient. Protect from extreme temperature with an ice pack. Separate ice pack from specimen.
Bone marrow ship with ice pack. Separate ice pack from specimen.
Leukocyte adhesion deficiency (LAD) is a rare disorder of leukocyte function. LAD has been classified into two major subtypes and rare variants.
LAD type 1 is the more common subtype and is characterized by decreased or absent expression of the CD11/CD18 complex, resulting in an inability of leukocytes to emigrate from the bloodstream to sites of inflammation. Severely affected infants present with delayed umbilical cord detachment, recurrent or progressive non-purulent infections, delayed wound healing and leukocytosis. Flow cytometry can be used to detect normal expression of the CD11/CD18 complex.
LAD type 2 is less common and is a disorder of fucosylation characterized by deficiency of sialyl Lewis X (sLex) and an inability of normal leukocyte rolling function on activated endothelium.
Other “variants” of LAD have been reported and include normal expression, but dysfunctional CD11/CD18; E selectin/CD62E expressed, but cleaved and present only as soluble form; and defective Rap-1 activator CalDAG-GEFI.