ROS as signalling molecules in T cells - Evidence for abnormal redox signalling in the autoimmune disease, rheumatoid arthritis

Reactive oxygen species are recognised as important signalling molecules within cells of the immune system. This is, at least in part, due to the reversible activation of kinases, phosphatases and transcription factors by modification of critical thiol residues. However, in the chronic inflammatory disease rheumatoid arthritis, cells of the immune system are exposed to increased levels of oxidative stress and the T cell becomes refractory to growth and death stimuli. This contributes to the perpetuation of the immune response. As many of the effective therapies used in the treatment of rheumatoid arthritis modulate intracellular redox state, this raises the question of whether increased oxidative stress is causative of T-cell hyporesponsiveness. To address this hypothesis, this review considers the putative sources of ROS involved in normal intracellular signalling in T cells and the evidence in support of abnormal ROS fluxes contributing to T-cell hyporesponsiveness. © W. S. Maney & Son Ltd.

Free radicals and redox signalling in T-cells during chronic inflammation and ageing

During chronic inflammation and ageing, the increase in oxidative stress in both intracellular and extracellular compartments is likely to influence local cell functions. Redox changes alter the T-cell proteome in a quantitative and qualitative manner, and post-translational modifications to surface and cytoplasmic proteins by increased reactive species can influence T-cell function. Previously, we have shown that RA (rheumatoid arthritis) T-cells exhibit reduced ROS (reactive oxygen species) production in response to extracellular stimulation compared with age-matched controls, and basal ROS levels [measured as DCF (2',7'-dichlorofluorescein) fluorescence] are lower in RA T-cells. In contrast, exposing T-cells in vitro to different extracellular redox environments modulates intracellular signalling and enhances cytokine secretion. Together, these data suggest that a complex relationship exists between intra- and extra-cellular redox compartments which contribute to the T-cell phenotype.

Chronic illness in non-heterosexual contexts: an online survey of experiences

In this article we contribute to the expansion of lesbian, gay, bisexual, transgender and queer (LGBTQ) health psychology beyond the confines of sexual health by examining the experiences of lesbian, gay and bisexual people living with non-HIV related chronic illness. Using a (predominantly) qualitative online survey, the perspectives of 190 LGB people with 52 different chronic illnesses from eight countries were collected. The five most commonly reported physical conditions were arthritis, hypertension, diabetes, asthma and chronic fatigue syndrome. Our analysis focuses on four themes within participants’ written comments: (1) ableism within LGBT communities; (2) isolation from LGBT communities and other LGB people living with chronic illness; (3)heteronormativity within sources of information and support and; (4) homophobia from healthcare professionals. We conclude by suggesting that LGBTQ psychology could usefully draw on critical health psychology principles and frameworks to explore non-heterosexual’s lived experiences of chronic illness, and also that there remains a need for specifically targeted support groups and services for LGB people with chronic illnesses.