EFFECTS OF IMMUNOSUPPRESSIVE DRUGS AND ANTIBIOTICS ON GM-CSF AND G-CSF SECRETION IN-VITRO BY MONOCYTES, T-LYMPHOCYTES AND ENDOTHELIAL-CELLS

We studied the effects of eight antibiotics, cyclosporin and corticost eroids on the in vitro secretion of GM-CSF and G-CSF by monocytes, T l ymphocytes and endothelial cells. The aim was to evaluate a possible m echanism for these drugs in the delay of haemopoietic recovery after h igh-dose chemotherapy or bone marrow transplantation. Corticosteroids were prominent inhibitors of GM-CSF secretion by monocytes and T lymph ocytes, but not by endothelial cells. In contrast, G-CSF secretion by monocytes was unchanged whereas that of endothelial cells was enhanced in the presence of corticosteroids. Cyclosporin efficiently down-regu lated GM-CSF secretion by T lymphocytes and had also a minor effect on CSF secretion by endothelial cells, whereas monocyte secretion was un affected. Stimulated T lymphocytes derived from patients under treatme nt with cyclosporin had impaired capacity to secrete GM-CSF compared t o controls, Among the antibiotics, cephalosporins inhibited GM-CSF sec retion by T lymphocytes, and GM- and G-CSF secretion by endothelial ce lls. Ciprofloxacin and sulphmethoxazole had minor effects on GM-CSF se cretion by T lymphocytes and endothelial cells. No antibiotic signific antly influenced GM-CSF secretion by monocytes.