Ex vivo-expanded human CD19+TIM-1+ regulatory B cells suppress immune responses in vivo and are dependent upon the TIM-1/STAT3 axis.

Regulatory B cells (Breg) are a heterogenous population with immune-modulating functions. The rarity of human IL-10+ Breg makes translational studies difficult. Here we report ex vivo expansion of human B cells with in vivo regulatory function (expBreg). CD154-stimulation of human CD19+ B cells drives >900-fold expansion of IL-10+ B cells that is maintained in culture for 14 days. Whilst expBreg-mediated suppressive function is partially dependent on IL-10 expression, CRISPR-mediated gene deletions demonstrate predominant roles for TIM-1 and CD154. TIM-1 regulates STAT3 signalling and modulates downstream suppressive function. In a clinically relevant humanised mouse model of skin transplantation, expBreg prolongs human allograft survival. Meanwhile, CD19+CD73-CD25+CD71+TIM-1+CD154+ Breg cells are enriched in the peripheral blood of human donors with cutaneous squamous cell carcinoma (SCC). TIM-1+ and pSTAT3+ B cells are also identified in B cell clusters within histological sections of human cutaneous SCC tumours. Our findings thus provide insights on Breg homoeostasis and present possible targets for Breg-related therapies.

Successful Lung Transplantation From Hepatitis C Positive Donor to Seronegative Recipient.

Lung transplantation using RNA+ hepatitis C (HCV+) donors to seronegative recipients is not currently performed due to the very high risk of transmission. Previous reports have shown poor survival when this practice was applied. The emergence of new direct-acting antiviral drugs (DAA) suggests a high chance of sustained virologic response in immunocompetent patients. We report here successful transplantation of lungs from HCV+ donor to HCV- recipient. The recipient was an HCV- patient with chronic lung allograft dysfunction. Viral transmission occurred early posttransplant but excellent clinical outcomes were observed including elimination of HCV after 12 weeks of treatment using DAAs.

Quantification of CD4(+) T Cell Alloreactivity and Its Control by Regulatory T Cells Using Time-Lapse Microscopy and Immune Synapse Detection.

Assays designed to select transplant recipients for immunosuppression withdrawal have met with limited success, perhaps because they measure events downstream of T cell-alloantigen interactions. Using in vitro time-lapse microscopy in a mouse transplant model, we investigated whether transplant outcome would result in changes in the proportion of CD4(+) T cells forming prolonged interactions with donor dendritic cells. By blocking CD4-MHC class II and CD28-B7 interactions, we defined immunologically relevant interactions as those ≥500 s. Using this threshold, T cell-dendritic cell (T-DC) interactions were examined in rejection, tolerance and T cell control mediated by regulatory T cells. The frequency of T-DC contacts ≥500 s increased with T cells from mice during acute rejection and decreased with T cells from mice rendered unresponsive to alloantigen. Regulatory T cells reduced prolonged T-DC contacts. Importantly, this effect was replicated with human polyclonally expanded naturally occurring regulatory T cells, which we have previously shown can control rejection of human tissues in humanized mouse models. Finally, in a proof-of-concept translational context, we were able to visualize differential allogeneic immune synapse formation in polyclonal CD4(+) T cells using high-throughput imaging flow cytometry.

Harnessing regulatory T cells for clinical use in transplantation: the end of the beginning.

Owing to the adverse effects of immunosuppression and an inability to prevent chronic rejection, there is a pressing need for alternative strategies to control alloimmunity. In three decades, regulatory T cells (Tregs) have evolved from a hypothetical mediator of adoptively transferred tolerance to a well-defined population that can be expanded ex vivo and returned safely to patients in clinical trials. Herein, we review the historical developments that have permitted these advances and the current status of clinical trials examining Tregs as a cellular therapy in transplantation. We conclude by discussing the critical unanswered questions that face this field in the coming years.

Outcomes of a natural rubber latex control program in an Ontario teaching hospital.

BACKGROUND: Allergy to natural rubber latex (NRL) has been frequently reported in health care workers. However, there is little published evidence of the outcome of hospital intervention programs to reduce exposure and detect cases of sensitization early. OBJECTIVE: This study assesses the effects of intervention to reduce NRL allergy in an Ontario teaching hospital with approximately 8000 employees. METHODS: A retrospective review assessed annual numbers of employees visiting the occupational health clinic, allergy clinic, or both for manifestations of NRL allergy compared with the timing of introduction of intervention strategies, such as worker education, voluntary medical surveillance, and hospital conversion to low-protein, powder-free NRL gloves. RESULTS: The number of workers identified with NRL allergy rose annually, from 1 in 1988 to 6 in 1993. When worker education and voluntary medical surveillance were introduced in 1994, a further 25 workers were identified. Nonsterile gloves were changed to low-protein, powder-free NRL gloves in 1995: Diagnoses fell to 8 workers that year, and 2 of the 3 nurses who had been off work because of asthma-anaphylaxis were able to return to work with personal avoidance of NRL products. With a change to lower protein, powder-free NRL sterile gloves in 1997, allergy diagnoses fell to 3, and only 1 new case was identified subsequently up to May 1999. No increased glove costs were incurred as a result of consolidated glove purchases. CONCLUSIONS: This program to reduce NRL allergy in employees was effectively achieved without additional glove costs while reducing expenses from time off work and workers' compensation claims.