Increased colony-stimulating activity in the plasma of a patient with lymphoepithelioma metastatic to the liver.

Leukocytosis with predominance of poly morphonuclear leukocytes is not unusual in a variety of primary or metastatic hepatic tumors. However, to date no apparent explanation for this event is available. This paper describes extreme leukocytosis in a 17-year-old black male with lymphoepithelioma after development of metastases to the liver. In order to identify the source of leukocytosis, studies of granulocytic colony-stimulating activity (CSA) of the patient's plasma and leukocyte-conditioned media (LCM) were carried out and compared with normal controls. The assay system consisted of nonadherent marrow cells of hematologically normal individuals and normal mice cultured in semi-solid culture media. In this system, the number of granulocytic colony-forming units (CFU-C) is proportional to the amount of stimulating activity present, and therefore allows for quantitative comparison. The number of colonies produced under the influence of patient's plasma was significantly higher (p less than 0.001) than those obtained from the patient's LCM or from control plasma or LCM. This pattern is the reverse of that seen in normal individuals in whom the major sources of CSA are macrophages and monocytes. It is conceivable that malignant cells are the source of additional CSA.