A MAJOR ROLE FOR CD62P CD15S INTERACTION IN LEUKOCYTE MARGINATION DURING HEMODIALYSIS/

We investigated expression of several antigens on neutrophils and mono cytes, involved in cell adhesion, from patients hemodialyzed with cell ulosic and polyacrylonitrile membranes. Among the antigens tested only the expression of CD15s and CD11b was significantly increased on neut rophils and monocytes in patients dialyzed with cellulosic membranes. No changes occurred with polyacrylonitrile membranes. Leukocyte counts from patients dialyzed with cuprophane membranes decreased at the sam e time as expression of cellular CD15s increased, resulting in a signi ficant negative correlation at all time points tested. No correlation was found between the drop of monocytes and their expression of CD11b. When CD15s expression increased on neutrophils and monocytes, we obse rved a concomitant increase of CD62P, a specific selectin of activated platelets. When whole blood cells were incubated with complement acti vated serum both antigens increased but not when cells were incubated with hrC5a. We also observed that CD61, a platelet phenotypic antigen, was present on leukocytes incubated with complement activated serum. At the time when platelet-leukocyte coaggregates decreased, CD62P expr ession remained stable on leukocytes, suggesting that both neutrophils and monocytes are able to trap either CD62P shed by activated platele ts or soluble CD62P present in normal human serum. The present study d ocuments a major role of P-selectin (CD62P)isialyl-Lewis x (CD15s) int eraction in the transient leukocyte margination during hemodialysis.