A novel ITGB2 variant with long survival in patients with leukocyte adhesion defect type-I

Abstract

Leukocyte adhesion deficiency is an autosomal recessive primary immunodeficiency that has been divided into three types: LAD1 (beta-2 integrin (CD18) family deficiency/defect), LAD2 (absence of fucosylated carbonhydrate ligands for selectins) and LAD3 (defective activation of all beta integrins). However, recently LAD4 has been described in cystic fibrosis patients, with a defect in integrin activation reported in monocytes. LAD-I is the most common type and prevalence of 1 in 1,000,000 live births. Clinical features of LAD patients are recurrent bacterial and fungal infections, omphalitis with delayed umbilical stump separation, significant leukocytosis especially neutrophilia during infection periods, impaired pus formation, and delayed traumatic or surgical wound healing. Flow cytometry is considered a useful tool for rapid diagnosis of the disease. The study of CD18 and CD11 (a, b, c) expression patterns in peripheral blood leukocytes helps to distinguish different phenotypes of LAD-I. In general, patients with ≥ 2% CD18 expression tend to have a less severe infection and often survive until adulthood, whereas < 2% CD18 expression often results in death in infancy. In this case report, three siblings, 10, 15, and 17 years old, diagnosed with leukocyte adhesion defect type 1 in adolescence age group, are presented.