Cytolytic Induction Therapy Improves Clinical Outcomes in African-American Kidney Transplant Recipients

Porcine anti-human lymphocyte immunoglobulin depletes the lymphocyte population to promote successful kidney transplantation

Introduction

Porcine anti-human lymphocyte immunoglobulin (pALG) has been used in kidney transplantation, but its impacts on the lymphocyte cell pool remain unclear.

Methods

We retrospectively analyzed 12 kidney transplant recipients receiving pALG, and additional recipients receiving rabbit anti-human thymocyte immunoglobulin (rATG), basiliximab, or no induction therapy as a comparison group.

Results

pALG showed high binding affinity to peripheral blood mononuclear cells (PBMCs) after administration, immediately depleting blood lymphocytes; an effect that was weaker than rATG but stronger than basiliximab. Single-cell sequencing analysis showed that pALG mainly influenced T cells and innate immune cells (mononuclear phagocytes and neutrophils). By analyzing immune cell subsets, we found that pALG moderately depleted CD4+T cells, CD8+T cells, regulatory T cells, and NKT cells and mildly inhibited dendritic cells. Serum inflammatory cytokines (IL-2, IL-6) were only moderately increased compared with rATG, which might be beneficial in terms of reducing the risk of untoward immune activation. During 3 months of follow-up, we found that all recipients and transplanted kidneys survived and showed good organ function recovery; there were no cases of rejection and a low rate of complications.

Discussion

In conclusion, pALG acts mainly by moderately depleting T cells and is thus a good candidate for induction therapy for kidney transplant recipients. The immunological features of pALG should be exploited for the development of individually-optimized induction therapies based on the needs of the transplant and the immune status of the patient, which is appropriate for non-high-risk recipients.

miR-151-5p alleviates corneal allograft rejection by activating PI3K/AKT signaling pathway and balancing Th17/Treg after corneal transplantation via targeting IL-2Rɑ

Background

Worldwide, corneal transplantation (CT) is the most common type of tissue replacement and the increased rate of corneal graft rejection (CGR) after CT is a critical problem. Corneal endothelium cells (CECs) are often targets of the immune response mediated by graft-attacking effector T cells. However, the molecular mechanism underlying CGR remains poorly understood.

Methods

The differentially expressed microRNAs (miRNAs) and mRNA of graft-fail corneas were measured by transcriptome sequencing (RNA-Seq). real-time quantitative polymerase chain reaction was used to measure gene expression levels. Western blot and immunofluorescence staining were used to measure protein expression levels. Kaplan-Meier survival curves were constructed to assess corneal graft survival. Hematoxylin and eosin staining was used for histopathological examination. CCK-8 and ELISA staining were used to detect cell viability and inflammatory cytokines levels, respectively. Flow cytometry was used to detect cell apoptosis and the population of Treg and Th17. Transwell migration and wound-healing assays were used to measure cell migration.

Results

We identified 453 miRNAs and 4,279 mRNAs aberrant expression in the corneas showing CGR. The differentially expressed miR-151-5p and its potential target gene [interleukin 2 receptor subunit alpha (IL-2Rɑ)] were selected from the RNA-Seq microarrays. The levels of miR-151-5p and IL-2Rɑ were respectively downregulated and upregulated in the CGR. The luciferase activity assay suggested that IL-2Rɑ is a target of miR-151-5p in 293 T cells. In addition, the miR-151-5p inhibitor, si-IL-2Rɑ, and oe-IL-2Rɑ transfection tests in CECs further confirmed that miR-151-5p downregulation and IL-2Rɑ overexpression promoted apoptosis of CECs and inhibited CEC migration, tight junction-related protein ZO-1 and Claudin-5 expression, and PI3K/AKT signaling pathway activity; however, downregulation of IL-2Rɑ abolished the inhibitor effect of miR-151-5p. Similarly, upregulation of miR-151-5p alleviated CGR via activation of the PI3K/AKT signaling pathway and balancing of Th17/Treg, and upregulation of IL-2Rɑ abolished the alleviating effect of miR-151-5p.

Conclusions

Upregulation of miR-151-5p alleviated CGR by activating the PI3K/AKT signaling pathway and balancing Th17/Treg via targeting of IL-2Rɑ, which contributes to improving the results of CT.

Comparison of 10-year graft failure rates after induction with basiliximab or anti-thymocyte globulin in pediatric heart transplant recipients-The influence of race

BACKGROUND/OBJECTIVE

The impact of induction therapy in pediatric heart transplantation has been uncertain. Given the risk of poor outcomes in black pediatric heart transplant recipients, we evaluated the effect on graft survival of ATG and BAS induction in black and non-black pediatric recipients.

METHODS

This was a retrospective analysis of pediatric candidates (aged ≤18 years) who underwent heart transplantation from 2000 to 2016 identified from the UNOS database. Primary outcome was 10-year graft survival.

RESULTS

This study included 654 patients receiving BAS, 2385 patients receiving ATG, and 2425 receiving no induction. Ten-year survival was similar for the following groups: non-black BAS (57%), non-black ATG (66%), and black ATG (51%). The black BAS group had a 10-year graft survival of 39% which was inferior on pairwise comparison to the other groups (all P values < 0.001). On multivariate analysis, ATG was associated with decreased risk of graft failure when compared to no induction (HR 0.86, 95% CI 0.76-0.97, P = 0.011) and had an association approaching statistical significance when compared to BAS induction (0.84, 0.7-1.01, P = 0.069). This association was seen in black recipients in whom ATG was strongly associated with decreased risk of graft failure when compared to either no induction (0.65, 0.5-0.83, P = 0.001) or BAS (0.64, 0.46-0.89, P = 0.008) but was not seen in non-black recipients.

CONCLUSIONS

Black pediatric heart transplant recipients who received ATG induction had an improved long-term graft survival compared to those who received BAS induction or no induction.

Center practice drives variation in choice of US kidney transplant induction therapy: a retrospective analysis of contemporary practice

To assess factors that influence the choice of induction regimen in contemporary kidney transplantation, we examined center-identified, national transplant registry data for 166 776 US recipients (2005-2014). Bilevel hierarchical models were constructed, wherein use of each regimen was compared pairwise with use of interleukin-2 receptor blocking antibodies (IL2rAb). Overall, 82% of patients received induction, including thymoglobulin (TMG, 46%), IL2rAb (22%), alemtuzumab (ALEM, 13%), and other agents (1%). However, proportions of patients receiving induction varied widely across centers (0-100%). Recipients of living donor transplants and self-pay patients were less likely to receive induction treatment. Clinical factors associated with use of TMG or ALEM (vs. IL2rAb) included age, black race, sensitization, retransplant status, nonstandard deceased donor, and delayed graft function. However, these characteristics explained only 10-33% of observed variation. Based on intraclass correlation analysis, "center effect" explained most of the variation in TMG (58%), ALEM (66%), other (51%), and no induction (58%) use. Median odds ratios generated from case-factor adjusted models (7.66-11.19) also supported large differences in the likelihood of induction choices between centers. The wide variation in induction therapy choice across US transplant centers is not dominantly explained by differences in patient or donor characteristics; rather, it reflects center choice and practice.