The Leukointegrin Alpha d/Beta2 (αd/CD18): Specific Changes in Surface Expression in Patients on Hemodialysis

Alpha d/CD18 is a newly discovered leukocyte adhesion molecule with sequence homology to CD11a, b and c of the β2 integrin family. Little is known about cud expression in vivo, particularly how it compares with the other β2 integrins. Previous studies have demonstrated that β2 integrin expression, particularly CD11b, is upregulated in vivo during hemodialysis (HD) with complement activating membranes. These changes may contribute to the immunologic abnormalities seen in HD patients. Given the well described changes of β2 integrins in these patients, we hypothesized that ad expression could also be altered by HD. Using flow cytometry with two specific antibodies to αd, αd expression in healthy adults (n = 16) was compared on macrophages (MO) > polymorphonuclear cells (PMNs) > lymphocytes (LY). Phorbol ester treatment of leukocytes in vitro significantly increased expression on MO and PMN, but not LY. Chronic HD patients at baseline (n = 15) had elevated (P < 0.05) αd mean channel fluorescence (MCF) on MOs,...