Cell culture studies on neurofibromatosis (von Recklinghausen). VI. No increased stimulation of cell proliferation by sera from neurofibromatosis patients.

Abstract

The growth-stimulating activity of sera from 10 patients with von Recklinghausen neurofibromatosis (NF-1) was compared with that of sera from 10 age- and sex-matched healthy donors. Cell cultures derived from peripheral neurofibromas and from skin biopsies of healthy persons were used as indicator cells. Stimulation of 3H-thymidine incorporation increased with the clotting time of the blood samples, reaching a plateau at about 35 h with no decline of activity during the following 48 h. There was no difference between the stimulating activity of sera from the NF-1 patients and that of sera from the healthy donors with either type of indicator cells. This held true when the indicator cells were stimulated during the exponential growth phase or when serum-starved confluent cells were exposed to the various sera. Three NF-1 strains used as indicator cells during this investigation showed a significantly less vigorous response to both types of human sera and to fetal calf serum than the respective control strains. All human sera collected after 42 h clotting time were superior to fetal calf serum with both types of indicator cells.