Mitogenic activities for skin fibroblasts in the sera from untreated scleroderma patients at the early stage.

Mitogenic activities for adult skin fibroblasts in 17 sera from untreated patients with scleroderma at the early stage were studied. Mitogenic activities in 10% test sera were measured by the [3H]-thymidine incorporation assay using confluent fibroblasts; there was no significant difference between scleroderma-affected and normal controls. Growth-stimulatory activities for subconfluent fibroblasts in 10% test sera were measured by increased cell numbers; again, there was no significant difference between scleroderma-affected and normal controls. There have been contradictory reports on growth-stimulatory activities in scleroderma sera; our data do not suggest the presence of a specific mitogen in scleroderma sera.