Occurrence of a monocyte/macrophage colony-stimulating factor in the continuous ambulatory peritoneal dialysis fluids and its chromatographic behaviors and antigenicity compared with human urinary colony-stimulating factor.

Continuous ambulatory peritoneal dialysis (CAPD) fluid from three patients with chronic renal failure exhibited the activity of colony-stimulating factor (CSF) in amounts varying from 5 to 40 units per ml. Like the CSF obtained from normal human urine, the peritoneal CSF predominantly produced monocyte/macrophage colonies in soft-agar culture of mouse bone marrow cells. Semipurified peritoneal CSF showed its isoelectric point at pH 3.6 and 4.9 before and after the treatment with neuraminidase. Under the same conditions, the urinary CSF was focused at pH 3.1 and 4.6. The position of elution of the peritoneal and urinary CSF in ordinary gel-filtration chromatography corresponded to a molecular weight of 62,000 and 117,000, whereas both CSFs exhibited a molecular weight of 28,000 upon gel-filtration in the presence of 6 M guanidine HCl. Furthermore, the two CSFs from the human sources were neutralized by antimouse L cell CSF serum in the same manner. We conclude that the peritoneal CSF is a sialoglycoprotein which is nearly identical with the urinary CSF despite processing of the latter through kidneys.