EFFECTS OF IN-VITRO AND IN-VIVO CYTOKINE TREATMENT, LEUKAPHERESIS ANDIRRADIATION ON THE FUNCTION OF HUMAN NEUTROPHILS - IMPLICATIONS FOR WHITE BLOOD-CELL TRANSFUSION THERAPY

Treatment of human polymorphonuclear leucocytes (PMNL) separated by de nsity sedimentation (DS) from normal donors (PMNL-NL-DS) with interfer on-gamma (IFN-gamma)+granulocyte colony-stimulating factor (G-CSF) les sens the damage caused by isolation and irradiation. We have studied g ranulocyte-macrophage colony-stimulating factor (GM-CSF) in this syste m, as well as the behaviour of PMNL collected by continuous now leucap heresis (CFL) from donors treated with G-CSF (PMNL-GCSF-CFL). After is olation, PRMNLs were treated with IFN-gamma+G-CSF, GM-CSF or IFN-gamma +G-CSF+GM-CSF, irradiated with 0 or 30 Gy and studied after 0 and 20 h in cell culture. All regimens reduced apoptosis of PMNL-NL-DS. Killin g of Candida albicans by 20-h-old PMNL-NL-DS was best preserved by IFN -gamma+G-CSF treatment. A similar pattern of results was obtained for assays of PMNL-NL-DS chemotaxis and superoxide production. There was a consistent trend toward reduced function after irradiation in all ass ays. PMNL-GCSF-CFL less often demonstrated the morphological features of apoptosis, and this was further reduced by cytokine regimens contai ning IFN-gamma+G-CSF. In assays of C. albicans killing and chemotaxis, 20-h-old untreated PMNL-GCSF-CFL performed as well as freshly isolate d PMNL-GCSF-CFL. PMNL-GCSF-CFL showed decay in CD11b (CR3), CD16 (Fc g amma RIII) and CD64 (Fc gamma RI) expression after 20 h in cell cultur e, but treatment with IFN-gamma+G-CSF preserved expression. There was a trend toward reduced function after radiation. Comparison of PMNL-GC SF separated by CFL and DS demonstrated that CFL itself is a strong in ducer of the morphological features of apoptosis. This study shows tha t while separation by CFL and irradiation are damaging to PMNLs, damag e may be reduced by use of cytokines.