The CD18 (HI18a) antibody recognizes a 95-kDa transmembrane protein, integrin beta-2 subunit, which associates respectively with the integrin ? subunits: CD11a, CD11Bovine, CD11c and CD11d forming four heterodimers named CD11a/CD18 (LFA-1), CD11b/CD18 (Mac-1), CD11c/CD18 (p150,95) and CD11d/CD18 (?d(B)2). CD18 integrin is e, Xenopus/Amphibian,pressed e, Xenopus/Amphibian,clusively on leukocytes and plays an important role in homotypic and hetorotypic cellular adhesion in immune and inflammatory responses. Patients who have mutated CD18 gene do not e, Xenopus/Amphibian,press cell membrane CD11/CD18 integrins, a condition known as leucocyte adhesion deficiency (LAD).