Leukocyte Adhesion

The Leukocyte adhesion is the result of a defect of the adhesion molecules, which leads to disruption of granulocyte and lymphocyte function and recurrent soft tissue infections.

(See also Overview of immune deficiency disorders, and approach to the patient with an immunodeficiency disorder.)

The Leukocyte adhesion is the result of a defect of the adhesion molecules, which leads to disruption of granulocyte and lymphocyte function and recurrent soft tissue infections. (See also Overview of immune deficiency disorders, and approach to the patient with an immunodeficiency disorder.) Leukocyte adhesion deficiency (LAD) is a primary immunodeficiency disease, including phagocytic cell defects. Inheritance occurs as an autosomal recessive. LAD is caused by a lack of adhesive glycoproteins on the surface of white blood cells; these glycoproteins allow the cell exchange, the cell adhesion to the walls of blood vessels and cell movements and interact with complement fragments. The defect impairs the ability of granulocytes (and lymphocytes) to migrate from the intravascular region to participate in cytotoxic reactions and of phagocytosis of bacteria. The disease severity correlated with severity of the defect. Three different types of the syndrome have been identified: LAD 1 (deficient or defective beta-2 integrin family) LAD 2 (missing fucosylated carbohydrate ligands for selectins) LAD 3 (defective activation of all beta-integrins [1, 2 and 3] ). Type 1 is the result of mutations in the integrin beta-2 gene (ITGB2), the CD18 of the beta-2 integrins encoded. Type 2 resulting from mutations in the Glukosediphosphat- (GDP) -fucose transporter gene. Symptoms and signs The symptoms usually begin in infancy. Severely affected infants suffer from recurrent or progressive necrotic, staphylococcal or gram negative bacteria-related infections of soft tissues, periodontitis, poor wound healing, lack of pus formation, leukocytosis and a delayed (> 3 weeks) detachment of the umbilical cord. The number of leukocytes remains high even among the infections. Infection control is becoming increasingly difficult. Less severely affected infants have few serious infections and minor changes in the blood picture. A developmental delay often occurs in type. 2 Diagnostic test on adhesive glycoproteins on the surface of the leukocytes of LAD The diagnosis is carried out by flow cytometry using monoclonal antibodies (eg., Anti-CD11, anti-CD18) through which detected the absence or a significant reduction of adhesive glycoproteins on the surface of leukocytes becomes. Leukocytosis image is just as often, but not specific. Genetic testing of siblings is recommended. Supportive therapy treatment with prophylactic antibiotics and granulocyte transfusions Hematopoietic Stem Cell Transplant Treatment of LAD is in a – often continuous – prophylactic antibiotic therapy (usually trimethoprim / sulfamethoxazole). Also granulocyte transfusions may be useful. Hematopoietic stem cell transplantation is currently the only effective therapy that can lead to healing. Gene therapy, which is examined in recent studies seem promising. In patients with type II correcting the underlying defect should be tried with a fucose supplementation. Patients with mild or moderate disease can to young adulthood survive. Most patients with severe disease die before age 5, unless they are successfully treated with hematopoietic stem cell transplantation.

Health Life Media Team

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