IL-17-producing double-negative T cells are expanded in the peripheral blood, infiltrate the salivary gland and are partially resistant to corticosteroid therapy in patients with Sjögren's syndrome.

A small CD3+ T-cell population, that lacks both CD4 and CD8 molecules, defined as double negative (DN), is expanded in the peripheral blood of patients with systemic lupus erythematosus, produces IL-17 and accumulates in the kidney during lupus nephritis. Since IL-17 production is enhanced in salivary gland infiltrates of patients with primary Sjögren's syndrome (pSS), we aimed to investigate whether DN T cells may be involved in the pathogenesis of salivary gland damage. Fifteen patients with SS and 15 normal controls (NC) were enrolled. Peripheral blood mononuclear cells were stimulated with anti-CD3 antibody and cultured in presence or absence of dexamethasone (Dex). Phenotypic characterization was performed by flow cytometry in freshly isolated cells and after culture. Minor salivary glands (MSG) from pSS were processed for immunofluorescence staining. Total circulating DN T cells were increased in pSS compared to NC (4.7±0.4% vs 2.6±0.4%). NC and pSS freshly isolated DN T cells produce consistent amounts of IL-17 (67.7±5.6 in NC vs 69.2±3.3 in pSS). Notably, DN T cells were found in the pSS-MSG infiltrate. Dex was able to down-regulate IL-17 in vitro production in NC (29±2.6% vs 15.2±1.9% vs 13±1.6%) and pSS (49±4.8% vs 16±3.8% vs 10.2±0.8%) conventional Th17 cells and in DN T cells of NC (80±2.8% vs 3.8±2.1% vs 4.2±1.8%), but not of pSS (81±1.5% vs 85.4±0.8% vs 86.2±1.7%). DN T cells are expanded in pSS PB, produce IL-17 and infiltrate pSS MSG. In pSS, conventional Th17 cells are inhibited by Dex, but DN T cells appear to be resistant to this effect. Taken together, these data suggest a key role of this T-cell subset in the perpetuation of chronic sialoadenitis and eventually in pSS prognosis.

Analysis of the connection redundancy in functional networks from high-resolution EEG: a preliminary study.

In the present study, we propose a theoretical graph procedure to investigate the communication redundancy in brain networks. By taking into account all the possible paths between pairs of cortical regions, this method captures the network redundancy i.e. a critical resource of the brain enhancing the resilience to neural damages and dysfunctions. As an example for its potential, we apply this procedure to the cortical networks estimated from high-resolution EEG signals in a group of spinal cord injured patients during the attempt of the foot movement. Preliminary results suggest that in the high spectral contents the effects due to the spinal trauma affect the expected redundancy attitude by suppressing mainly the longer alternative pathways between the cortical regions.