No abstract

In murine systemic lupus erythematosus (SLE), aberrant regulation of interferon (IFN)-alpha-STAT1 signaling and perturbed homeostasis of CD4FOXP3 regulatory T cells (Tregs) were described. In the present study, STAT1 signaling and circulating Treg subsets were assessed by flow cytometry in 39 SLE patients and their potential association with disease course was examined during long-term follow-up. Levels of STAT1 protein as measured by median fluorescence intensity (MFI) were significantly increased in SLE CD4 T cells when compared with rheumatoid arthritis patients and healthy controls and were positively correlated with disease activity. The highest STAT1 MFI was found in CD45RAFOXP3-activated Treg (aTreg) subset, which demonstrated the highest STAT1 phosphorylation responses among SLE CD4 T cells and significant decrease in proliferation marker Ki-67 expression after IFN-alpha stimulation. Percentage of Ki-67 aTregs was significantly decreased in SLE patients and was negatively correlated with CD4 T cell STAT1 MFI. A subgroup of SLE patients characterized by lower aTreg counts experienced more severe relapsing disease course during 1,000 days of follow-up. Mean CD4 T cell STAT1 MFI in follow-up samples from SLE patients was negatively correlated with mean of follow-up aTreg counts. Our findings indicate that augmented STAT1 signaling may be involved in perturbed aTreg homeostasis, which could represent a possible marker of SLE disease severity.

Activation of the STAT5 signaling pathway up-regulates antiapoptotic protein Bcl2 and drives proliferation of autoreactive conventional CD4 T cells (T). In systemic lupus erythematosus (SLE), an increased T cell Bcl2 content and perturbed homeostasis of CD45RAFOXP3 activated regulatory T cells (aT) were described. We assessed T/T subsets and phosphorylation of STAT5 (pSTAT5) in blood T cells from patients with SLE by using conventional and imaging flow cytometry. Forty-one patients with SLE, 33 healthy controls, and 29 patients with rheumatoid arthritis were included. Long-term monitoring was performed in 39 patients with SLE, which were followed longitudinally for up to 1000 d. Significantly increased Bcl2 protein content in T cells from patients with SLE was associated with IL-7-dependent STAT5 activation, expressed as increased basal levels and nuclear localization of pSTAT5. pSTAT5 levels were significantly increased in the FOXP3 low-expressing CD4 T cell subsets but not in the aT subset, which was significantly decreased in patients with SLE. In contrast to aT, SLE T displayed significantly increased pSTAT5 and Bcl2 levels. Moreover, the percentage of T-expressing proliferation marker Ki-67 was significantly increased in patients with SLE and was positively correlated with CD4 T cell pSTAT5 levels. Finally, a subgroup of patients characterized by an increased T-pSTAT5/aT-pSTAT5 ratio experienced a more aggressive-relapsing disease course and displayed higher time-adjusted cumulative CD4 T cell pSTAT5 levels during follow-up, which were positively correlated with time-adjusted cumulative disease activity. Our results indicate that imbalanced STAT5 phosphorylation, which is related to Bcl2 and Ki-67 expression, may confer survival and proliferative advantage to T over aT and could represent a possible marker of SLE disease severity.

No abstract

The Central European Congress of Rheumatology (CECR) has been organized by seven Central European countries: Austria, Croatia, Czech Republic, Hungary, Poland, Slovakia, and Slovenia. These countries have lots of similarities, but also differences, with respect to rheumatology research. In this paper, based on questionnaires, we wish to demonstrate achievements and difficulties in rheumatology research performed in our region.