Early Immunomodulatory Program Triggered by Protolerogenic Bifidobacterium pseudolongum Drives Cardiac Transplant Outcomes.

BACKGROUND: Despite ongoing improvements to regimens preventing allograft rejection, most cardiac and other organ grafts eventually succumb to chronic vasculopathy, interstitial fibrosis, or endothelial changes, and eventually graft failure. The events leading to chronic rejection are still poorly understood and the gut microbiota is a known driving force in immune dysfunction. We previously showed that gut microbiota dysbiosis profoundly influences the outcome of vascularized cardiac allografts and subsequently identified biomarker species associated with these differential graft outcomes. METHODS: In this study, we further detailed the multifaceted immunomodulatory properties of protolerogenic and proinflammatory bacterial species over time, using our clinically relevant model of allogenic heart transplantation. RESULTS: In addition to tracing longitudinal changes in the recipient gut microbiome over time, we observed that Bifidobacterium pseudolongum induced an early anti-inflammatory phenotype within 7 d, whereas Desulfovibrio desulfuricans resulted in a proinflammatory phenotype, defined by alterations in leukocyte distribution and lymph node (LN) structure. Indeed, in vitro results showed that B pseudolongum and D desulfuricans acted directly on primary innate immune cells. However, by 40 d after treatment, these 2 bacterial strains were associated with mixed effects in their impact on LN architecture and immune cell composition and loss of colonization within gut microbiota, despite protection of allografts from inflammation with B pseudolongum treatment. CONCLUSIONS: These dynamic effects suggest a critical role for early microbiota-triggered immunologic events such as innate immune cell engagement, T-cell differentiation, and LN architectural changes in the subsequent modulation of protolerant versus proinflammatory immune responses in organ transplant recipients.

Low-Risk Papillary Thyroid Cancer: Treatment De-Escalation and Cost Implications.

INTRODUCTION: The American Thyroid Association (ATA) updated consensus guidelines in 2015 for radioactive iodine (RAI) and resection for low-risk papillary thyroid cancer. The objective of this study was to describe the evolution of institutional practice patterns and estimate the cost implications of these trends. MATERIALS AND METHODS: Patients with cT1-T2N0 papillary thyroid cancer were identified via an institutional tumor registry. Incidences of total thyroidectomy or RAI were tracked longitudinally using cumulative sum. Real-world costs for RAI and each surgical encounter were adjusted for inflation and standardized to national average costs from National Inpatient Sample cost data. RESULTS: Sixty-one patients met inclusion criteria between 2007 and 2018. Among these, 28 patients underwent total thyroidectomies and received RAI treatments based on criteria pre-dating the 2015 ATA guidelines. Cumulative sum revealed significant decreases in the rate of total thyroidectomy following May 2015 (15.8% versus 59.5%, P = 0.002) and RAI following March 2013 (3.0% versus 32.1%, P = 0.002). There were no locoregional recurrences in either period. The average cost savings attributable to these institutional practice changes was $1580 per patient. CONCLUSIONS: De-escalation in surgical and RAI utilization for low-risk papillary thyroid cancer according to 2015 ATA guidelines is associated with a substantial decrease in real-world costs.

T Regulatory Cells and Priming the Suppressive Tumor Microenvironment.

Treg play a central role in maintenance of self tolerance and homeostasis through suppression of self-reactive T cell populations. In addition to that role, Treg also survey cancers and suppress anti-tumor immune responses. Thus, understanding the unique attributes of Treg-tumor interactions may permit control of this pathologic suppression without interfering with homeostatic self-tolerance. This review will define the unique role of Treg in cancer growth, and the ways by which Treg inhibit a robust anti-tumor immune response. There will be specific focus placed on Treg homing to the tumor microenvironment (TME), TME formation of induced Treg (iTreg), mechanisms of suppression that underpin cancer immune escape, and trophic nonimmunologic effects of Treg on tumor cells.