Leukocyte Adhesion Deficiency (LAD)



Leukocyte Adhesion Deficiency Type 1 (LAD1) is an autosomal-recessive immunodeficiency disorder. LAD1 occurs due to defects in CD18, a critical protein that makes up the LFA-1 and MAC-1 integrins. Defects in these integrins then impair the ability of leukocytes to stick or adhere to the walls of blood vessels. Ultimately, this failure of adhesion leads to failure of migration, leading to white blood cells getting trapped in the bloodstream. Clinically, this presents as an immunodeficiency with recurrent infections, delayed wound healing without pus formation, and delayed separation of the umbilical cord in infants. 

Key Points

  • Leukocyte Adhesion Deficiency Type 1 (LAD1)
    • Autosomal recessive immunodeficiency
    • Caused by defect in CD18 on leukocytes
      • CD 18 is a core component of the integrins LFA-1 and MAC-1
    • Impaired adhesion and migration of leukocytes
    • Clinical Findings
      • Recurrent skin / mucosal infections
        • Secondary to immunodeficiency
      • Elevated leukocyte count in blood
        • Intact leukocyte production with impaired migration to tissues
      • no pus at infection sites
        • No neutrophils at infection sites due to migration defect
      • Impaired wound healing and tissue clearance
        • Delayed (>30 days) separation of umbilical cord