Evidence of the intracellular cytokines in pheripheral blood mononuclear cells of patients with systemic sclerosis

Background Systemic sclerosis (SSc) is currently considered aTh2 disease. The studies underlying such assumption have been mainly carried out on tissues. At present, no data has addressed this topic in the peripheral blood at a cellular level. Objectives To investigate the activation of Th1 and Th2 cells in the peripheral blood of SSc patients. Methods Peripheral blood mononuclear cells (PBMC) from 15 patients with SSc and 15 sex and age-matched healthy controls were investigated for intracellular IL-2, IL-4, IFN-γ. The assays were carried out on both unstimulated and PMA-activated PBMC incubated in the presence of 1 μg/ml of ionomycin and 10 μg/ml of brefeldin-A. Subsequently, samples were incubated with anti-citokines antibodies and stained cells were analysed on a FACScan flow cytometer. Results In basal conditions (i.e. unstimulated cells), 10 out of the 15 SSc patients versus 1 out of the 15 controls presented a significantly higher percentages (i.e. > m ± 2 SD detected in controls) of IL-2 positive cells; 6 patients and 1 control of IL-4 positive cells and 7 patients and 0 control of IFN-γ positive cells. Six patients presented increased percentages of both IL-2 and IL-4 and IFN-γ (i.e. they had both Th1 and Th2 activation), 4 of IL-2 positive cells and 1 IFN-γ only (isolated Th1 activation). After PMA stimulation 6 patients presented increased percentages of IFN-γ positive cells; 1 of IL-4 and 0 patient of IL-2 positive cells. Conclusion Our study demonstrates that Th1 activation occurs in peripheral blood of SSc patients. The role, if any, of such activation must be investigated.