Work comparing CVID patients with a cohort of healthy controls showed only minor differences in CD20+CD27+CD43lo–int cell numbers when existing CD27+ B cell deficiencies were taken into account. Further work including absolute cell count measurements and functional assays is required with CVID patients to ascertain what role, if any, this B cell subset plays

in the pathogenesis of this disease. We would like to thank the patients and controls for their time and generosity. We would also like to thank staff members ABT263 of the Clinical Immunology Laboratory for their help in this study. There are no disclosures associated with this work. “
“Systemic sclerosis (SSc) is a chronic disease, with early activation of the immune system. The aim of our work was to address how SSc–mesenchymal stem cells (MSCs), although senescent, might preserve specific immunomodulatory abilities during SSc. MSCs were obtained from 10 SSc

patients and 10 healthy controls (HC). Senescence LDK378 research buy was evaluated by assessing cell cycle, β-galactosidase (β-Gal) activity, p21 and p53 expression; doxorubicin was used as acute senescence stimulus to evaluate their ability to react in stressed conditions. Immunomodulatory abilities were studied co-culturing MSCs with peripheral blood mononuclear cells (PBMCs) and CD4+ cells, in order to establish both their ability to block proliferation in mixed lymphocyte reaction and in regulatory T cells (Tregs) induction. SSc–MSC showed an increase of senescence biomarkers. Eighty per cent of MSCs were in G0–G1 phase, without significant differences between SSc and HC. SSc–MSCs showed an increased positive β-Gal staining and higher p21 transcript level compared to HC cells. After doxorubicin, β-Gal staining increased significantly in SSc–MSCs. On the contrary, doxorubicin abolished

p21 activation and elicited p53 induction both in SSc– and HC–MSCs. Interleukin (IL)-6 and transforming growth factor (TGF)-β-related transcripts and their protein levels were significantly higher in SSc–MSCs. The latter maintained their immunosuppressive effect on lymphocyte proliferation and induced a functionally regulatory phenotype on T cells, Protein kinase N1 increasing surface expression of CD69 and restoring the regulatory function which is impaired in SSc. Increased activation of the IL-6 pathway observed in our cells might represent an adaptive mechanism to senescence, but preserving some specific cellular functions, including immunosuppression. Several studies have shown that mesenchymal stem cells (MSCs) represent an attractive option for new therapeutic biological approaches of autoimmune diseases, due to their plasticity, multi-differentiative potential and immunosuppressive function [1-3].