Neurofibroma-derived fibroblast-stimulating factor in the serum of patients with neurofibromatosis (von Recklinghausen's disease)

The effect of serum from patients with von Recklinghausen's disease [neurofibromatosis (NF)] on the cell growth and DNA synthesis of cultured neurofibroma-derived cells (NF fibroblasts grown from explant cultures of cutaneous neurofibromas from seven NF patients, and Schwann cells from a single-cell-suspension culture of the sample from one of these patients) was examined. Serum from patients with NF, whether autologous or allogeneic, enhanced the growth and 3H-thymidine uptake of NF fibroblasts twice as much as non-NF serum. Further study revealed that a dialysable, low-molecular-weight factor isolated from pooled NF serum was responsible for the stimulation of NF fibroblasts. This factor did not influence the DNA synthesis of either dermal fibroblasts cultured from non-NF patients or of Schwann cells. In contrast, no dialysable fraction of pooled serum from healthy persons exhibited such an NF-fibroblast-stimulating activity.