Patterns of emergency department utilization between transplant and non-transplant centers and impact on clinical outcomes in kidney recipients.

There is a high rate of Emergency Department (ED) utilization in kidney recipients post-transplant; ED visits are associated with readmission rates and lower survival rates. However, utilization within and outside transplant centers may lead to different outcomes. The objective was to analyze ED utilization patterns at transplant and non-transplant centers as well as common etiologies of ED visits and correlation with hospitalization, graft, and patient outcomes. This was a longitudinal, retrospective, single-center cohort study in kidney transplant recipients evaluating ED utilization. Comparator groups were determined by ED location, time from transplant, and disposition/readmission from ED visit. 1,106 kidney recipients were included in the study. ED utilization dropped at the transplant center after the 1st year (P < .001), while remaining at a similar rate at non-transplant centers (0.22 vs 1.06 VPPY). Infection and allograft complications were the most common causes of ED visits. In multivariable Cox modeling, an ED visit due to allograft complication at a non-transplant center >1 year post-transplant was associated with higher risk for graft loss and death (aHR 2.93 and aHR 1.75, P < .0001). The results of this study demonstrate an increased risk of graft loss among patients who utilize non-transplant center emergency departments. Improved communication and coordination between transplant centers and non-transplant centers may contribute to better long-term outcomes.

Optimizing TNFR2 antagonism for immunotherapy with tumor microenvironment specificity.

Most approved cancer immunotherapies lack T-regulatory (Treg) or tumor specificity. TNF receptor 2 (TNFR2) antibody antagonism is emerging as an attractive immunotherapy due to its tumor microenvironment (TME) specificity. Here we show that the human TNFR2 receptor is overexpressed on both human tumor cells and on human tumor-residing Tregs, but negligibly expressed on beneficial T effectors (Teffs). Further, we found widespread, if variable, TNFR2 expression on 788 human tumor cell lines from diverse cancer tissues. These findings provided strong rationale for developing a targeted immunotherapy using a TNFR2 antibody antagonist. We designed a novel, human-directed TNFR2 antibody antagonist and tested it for function using three cell-based TME assays. The antagonist showed TME specificity by killing of TNFR2-expressing tumor cells and Tregs, but sparing Teffs, which proliferated. However, the antagonist shuffled between five isoforms, only one of which showed the desirable function. We designed and tested several new chimeric human versions of the antagonist, finding that the IgG2 isotype functioned better than the IgG1 isotype. To further improve function, we introduced targeted mutations to its amino acid sequence to stabilize the natural variability of the IgG2 isotype's hinge. Altogether, our findings suggest that optimal TNFR2 antagonists are of the human IgG2 isotype, have hinge stabilization, and have wide separation of antibody arms to bind to newly synthesized TNFR2 on rapidly growing tumor cells. Antagonistic antibodies with these characteristics, when bound to TNFR2, can form a nonsignaling cell surface dimer that functions with high TME specificity.