Peripheral Blood T Lymphocytes from Systemic Sclerosis Patients Show Both Th1 and Th2 Activation

Our objective was to investigate the phenotype of helper T cells in the peripheral blood of patients with systemic sclerosis (SSc). PBMC from 15 patients with SSc and 15 sex- and age-matched controls were investigated for lymphocyte subpopulations (CD3, CD4, CD8, CD19, CD16/CD56, CD3-DR); IL-2, IL-4, and IFN-γ mRNAs; and the relative cytokines in their cytoplasm. The last assay was carried out both in unstimulated and in PMA-activated PBMC. SSc patients presented a higher percentage of activated T cells, CD3+ DR+ (19.7 ± 9.9 vs 5.1 ± 2.5%; P < 0.0001); 12 of them presented IFN-γ mRNA-positive cells; and none IL-2 or IL-4 mRNAs. Under basal conditions, PBMC from six SSc patients contained IL-2, IL-4, and IFN-γ (i.e., they showed both Th1 and Th2 activation), and 1 IFN-γ only. PMA-stimulated PBMC of patients differed from those of controls only in the increased percentage of IFN-γ positive cells (52 ± 12 vs 37 ± 11%; P < 0.01). Our study demonstrates that Th1 activation occurs in the peripheral blood of SSc patients. This evidence must be faced with from both a pathogenetic and a therapeutical point of view.