Quantitative studies of monocyte maturation in patients with malignant melanoma.

Peripheral blood monocytes were cultured from normal volunteers and patients with malignant melanoma in a suspension culture containing 50% autologous plasma. The number of monocytes that matured into macrophages in the normal control population was 8.29 +/- 3.14 X 10(4) cells/ml blood, whereas in patients with malignant melanoma the number of matured monocytes was 3.15 +/- 2.80 X 10(4) cells/ml blood. The low macrophage maturation in patients with malignant melanoma was not found to be associated with any serum factors. Furthermore, from morphological studies done using scanning electron microscopy, there was no apparent difference between macrophages maturing from normal individuals or patients with malignant melanoma. From analysis of this adherent cell population there appears to be an intrinsic defeat in the maturation of monocytes in vitro in the case of patients with malignant melanoma.