Repetitive Pertussis Toxin Promotes Development of Regulatory T Cells and Prevents Central Nervous System Autoimmune Disease

Bacterial and viral infections have long been implicated in pathogenesis and progression of multiple sclerosis (MS). Incidence and severity of its animal model experimental autoimmune encephalomyelitis (EAE) can be enhanced by concomitant administration of pertussis toxin (PTx), the major virulence factor of Bordetella pertussis. Its adjuvant effect at the time of immunization with myelin antigen is attributed to an unspecific activation and facilitated migration of immune cells across the blood brain barrier into the central nervous system (CNS). In order to evaluate whether recurring exposure to bacterial antigen may have a differential effect on development of CNS autoimmunity, we repetitively administered PTx prior to immunization. Mice weekly injected with PTx were largely protected from subsequent EAE induction which was reflected by a decreased proliferation and pro-inflammatory differentiation of myelin-reactive T cells. Splenocytes isolated from EAE-resistant mice predominantly produced IL-10 upon re-stimulation with PTx, while non-specific immune responses were unchanged. Longitudinal analyses revealed that repetitive exposure of mice to PTx gradually elevated serum levels for TGF-β and IL-10 which was associated with an expansion of peripheral CD4+CD25+FoxP3+ regulatory T cells (Treg). Increased frequency of Treg persisted upon immunization and thereafter. Collectively, these data suggest a scenario in which repetitive PTx treatment protects mice from development of CNS autoimmune disease through upregulation of regulatory cytokines and expansion of CD4+CD25+FoxP3+ Treg. Besides its therapeutic implication, this finding suggests that encounter of the immune system with microbial products may not only be part of CNS autoimmune disease pathogenesis but also of its regulation

A Marriage Made in Heaven? Mismatches and Misunderstandings between Worker Centres and Unions

Worker centres, community-based mediating institutions that provide support to low-wage workers in the United States, have grown from five in 1992 to 160 in 2007. With unions increasingly targeting low-wage immigrant workers employed in non-footloose industries for organizing drives, it would seem that worker centres and unions are a match made in heaven. On the ground, however, it has been more of a mismatch. This article examines the underlying sources of the mismatch embodied in the structures, ideologies and cultures of worker centres and unions. Copyright Blackwell Publishing Ltd/London School of Economics 2007.

Cost of detecting malignant lesions by endoscopy in 2741 primary care dyspeptic patients without alarm symptoms.

BACKGROUND & AIMS: Current guidelines recommend empirical, noninvasive approaches to manage dyspeptic patients without alarm symptoms, but concerns about missed lesions persist; the cost savings afforded by noninvasive approaches must be weighed against treatment delays. We investigated the prevalence of malignancies and other serious abnormalities in patients with dyspepsia and the cost of detecting these by endoscopy. METHODS: We studied 2741 primary-care outpatients, 18-70 years in age, who met Rome II criteria for dyspepsia. Patients with alarm features (dysphagia, bleeding, weight loss, etc) were excluded. All patients underwent endoscopy. The cost and diagnostic yield of an early endoscopy strategy in all patients were compared with those of endoscopy limited to age-defined cohorts. Costs were calculated for a low, intermediate, and high cost environment. RESULTS: Endoscopies detected abnormalities in 635 patients (23%). The most common findings were reflux esophagitis with erosions (15%), gastric ulcers (2.7%), and duodenal ulcers (2.3%). The prevalence of upper gastrointestinal malignancy was 0.22%. If all dyspeptic patients 50 years or older underwent endoscopy, 1 esophageal cancer and no gastric cancers would have been missed. If the age threshold for endoscopy were set at 50 years, at a cost of $500/endoscopy, it would cost$82,900 (95% CI, $35,714-$250,000) to detect each case of cancer. CONCLUSIONS: Primary care dyspeptic patients without alarm symptoms rarely have serious underlying conditions at endoscopy. The costs associated with diagnosing an occult malignancy are large, but an age cut-off of 50 years for early endoscopy provides the best assurance that an occult malignancy will not be missed