Leukocyte Adhesion Deficiency (Type 1)

Leukocyte Adhesion Deficiency (Type 1) is a rare genetic disorder that affects the body's immune system, specifically the white blood cells called leukocytes. These cells normally help fight infections by moving to sites of injury or infection. In this condition, the leukocytes cannot properly stick to blood vessel walls and migrate to infected tissues due to a defect in their adhesion molecules. This leads to frequent and severe bacterial infections, especially in the skin and mucous membranes. People with this disorder often have delayed healing of wounds and may have very high white blood cell counts in their blood. The condition primarily impacts the immune system and the body's ability to defend against infections.

Leukocyte Adhesion Deficiency (Type 1) is an autosomal recessive immunodeficiency caused by mutations in the ITGB2 gene encoding the CD18 subunit of β2 integrins. This defect impairs leukocyte adhesion to the endothelium, preventing effective transendothelial migration of neutrophils and other leukocytes to sites of infection. The hallmark is recurrent severe bacterial and fungal infections without pus formation due to defective neutrophil extravasation. Patients present with delayed umbilical cord separation, persistent leukocytosis, and poor wound healing. The disorder leads to impaired innate immune responses and increased susceptibility to infections by organisms such as Staphylococcus aureus and Pseudomonas aeruginosa. It is a primary immunodeficiency with significant morbidity if untreated.