THE CHANGES OF MAC-1 AND L-SELECTIN EXPRESSION ON GRANULOCYTES AND SOLUBLE L-SELECTIN LEVEL DURING HEMODIALYSIS

L-selectin and Mac-1 expressed on leukocytes are critical for leukocyt e adhesion to inflamed endothelium. L-selectin is known to be rapidly shed from the cell surface of granulocytes after activation. In the pr esent study the change of expressions of these adhesion molecules on g ranulocytes were analyzed by flow cytometry, and the serum concentrati on of shed L-selectin (soluble Lr selectin; sL-selectin) was measured by enzyme-linked immunosorbent assay (ELISA) during hemodialysis in pa tients treated with regenerated cellulose membranes (RC group) versus polysulfone membranes (PS group). In the RC group, Mac-1 expression on granulocytes increased significantly at 30 min after the initiation o f hemodialysis (p < 0.05) compared with predialysis values, coinciding with the nadir of dialysis-induced granulocytopenia. Granulocyte L-se lectin expression decreased significantly at 15 min after the initiati on of hemodialysis (p < 0.05) and remained decreased through the cours e of dialysis session, compared with predialysis values. Serum sL-sele ctin level significantly increased at 15 min after the initiation of h emodialysis (p < 0.05), compared with predialysis values. In the PS gr oup, no significant variation in Mac-1 and L-selectin expression on gr anulocytes and serum sL-selectin level were detected. This reciprocal change of Mac-1 and L-selectin on granulocyte cell surface was attribu ted to development of granulocytopenia and subsequent reversal during dialysis with cellulose membranes. In this study, we confirmed the she dding of L-selectin during cellulosic dialysis by ELISA. The increase in sL-selectin, which has potential activity of inhibiting L-selectin- dependent adhesion of granulocyte to endothelium, might be involved in rebound granulocytosis during dialysis with cellulose membranes and i mpairment of the granulocyte function in patients on chronic hemodialy sis.