Duration and dosing of systemic corticosteroids for acute exacerbation of COPD, protocol for a systematic review with meta-analysis of randomized trials and cohort studies.

Purpose: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a leading cause of deterioration in patients with otherwise stably controlled COPD. Treatments of AECOPD often require the use of corticosteroid therapy in conjunction with bronchodilators and antibiotics. However, the duration and dosage of corticosteroids still remain unclear.

B220+ double-negative T cells suppress polyclonal T cell activation by a Fas-independent mechanism that involves inhibition of IL-2 production.

Fas-mediated apoptosis is a key mechanism for elimination of autoreactive T cells, yet loss of function mutations in the Fas signaling pathway does not result in overt T cell-mediated autoimmunity. Furthermore, mice and humans with homozygous Fas(lpr) or Fas ligand(gld) mutations develop significant numbers of B220+ CD4- CD8- double-negative (DN) alphabeta T cells (hereafter referred to as B220+ DN T cells) of poorly understood function. In this study, we show that B220+ DN T cells, whether generated in vitro or isolated from mutant mice, can suppress the ability of activated T cells to proliferate or produce IL-2, IL-10, and IFN-gamma.