Serum Levels of Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) in a Group of Patients with Systemic Sclerosis

Abstract

In this report we investigate the behaviour of the serum levels of Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) in the course of Systemic Sclerosis (SS). This cytokine is produced mainly by T and NK cells, and its possible role in the pathogenesis of SS has not been previously described in the literature. Serum GM-CSF levels were assayed in 10 female patients, ageing from 35 to 70, affected by SS. These patients were not suffering from other disorders and were not being treated with steroids or immunosuppressive drug. A solid phase immunoenzymatic method was used to assess the serum levels of GM-CSF. Reference values were previously determined in a control group of 36 healthy women blood donors (19 premenopausal and 17 postmenopausal) (x̄=20.1 ±12.3 pg/ml). All the patients but one showed significantly increased serum levels of GM-CSF (x̄= 120.9 ±125.5 pg/ml). The highest levels were found in the two oldest patients, who also had the longest clinical history of SS, but a clear correlation with age, disease duration or clinical manifestations was not evident, even if the postmenopausal age group patients showed a higher mean value of GM-CSF (x̄= 148.0±144.1 pg/ml) than that found in the premenopausal age group (x̄= 57.7±1.4 pg/ml) (in contrast with the findings in the control group). The absence of other pathogenic conditions in our patients suggests that the increase in serum levels of GM-CSF might be linked to the fibroblast proliferation which is typical of SS. However, our results do not explain the role played by this factor in the fibroblastic proliferation process and an in vitro study is necessary to clarify this aspect.