T follicular helper cells expansion in transplant recipients correlates with graft infiltration and adverse outcomes

Introduction

The process of immunization following vaccination in humans bears similarities to that of immunization with allografts. Whereas vaccination aims to elicit a rapid response, in the transplant recipient, immunosuppressants slow the immunization to alloantigens. The induction of CD4+CXCR5+ T follicular helper (Tfh) cells has been shown to correlate with the success of vaccine immunization.

Method

We studied a cohort of 65 transplant recipients who underwent histological evaluation concurrent with PBMC isolation and follow-up sampling to investigate the phenotypic profiles in the blood and allotissue and analyze their association with clinical events.

Results

The proportion of circulating Tfh cells was heterogeneous over time. Patients in whom this compartment increased had lower CCR7-PD1+CD4+CXCR5+ T cells during follow-up. These patients exhibited more alloreactive CD4+ T cells using HLA-DR-specific tetramers and a greater proportion of detectable circulating plasmablasts than the controls. Examination of baseline biopsies revealed that expansion of the circulating Tfh compartment did not follow prior intragraft leukocyte infiltration. However, multicolor immunofluorescence microscopy of the grafts showed a greater proportion of CXCR5+ T cells than in the controls. CD4+CXCR5+ cells were predominantly PD1+ and were in close contact with B cells in situ. Despite clinical stability at baseline, circulating Tfh expansion was associated with a higher risk of a composite of anti-HLA donor-specific antibodies, rejection, lower graft function, or graft loss.

Conclusion

In otherwise stable patients post-transplant, circulating Tfh expansion can identify ongoing alloreactivity, detectable before allograft injury. Tfh expansion is relevant clinically because it predicts poor graft prognosis. These findings have implications for immune surveillance.

Risk factors and outcomes of persistent post-transplant hypotension among simultaneous pancreas and kidney transplant recipients

BACKGROUND

The risk factors and outcomes associated with post- transplant hypotension after simultaneous pancreas and kidney (SPK) Transplantation are poorly defined.

METHODS

SPK recipients at our center between 2010 and 2021 with functioning pancreas and kidney grafts for >6 months were included. Recipients were then divided into three groups based on active medications for the treatment of hypo-or hypertension at 6-months post-transplant: those with normal blood pressure (NBP) not requiring medication (NBP group), those on antihypertensive medications (HTN group), and those on medications for hypotension (fludrocortisone and/or midodrine) (Hypotensive group).

RESULTS

A total of 306 recipients were included in the study: 54 (18%) in the NBP group, 215 (70%) in the HTN group, and 37 (12%) in the Hypotensive group. On multivariate analysis, the use of T-depleting induction (aHR = 9.64, p = .0001, 95% Cl = 3.12-29.75), pre-transplant use of hypotensive medications (aHR = 4.53, p = .0003, 95% Cl = 1.98-10.38), and longer duration of dialysis (aHR = 1.02, p = .01, 95% Cl = 1.00-1.04) were associated with an increased risk of post-transplant hypotension. Post-transplant hypotension was not associated with an increased risk of death-censored kidney or pancreatic allograft failure, or patient death.

CONCLUSION

Hypotension was common even 6 months post-SPK transplantation. With appropriate management, hypotension was not associated with detrimental graft or patient outcomes.

Clinical relevance of the living kidney donor profile index in Korean kidney transplant recipients

BACKGROUND

The Living Kidney Donor Profile Index (LKDPI) was developed in the United States to predict graft outcomes based on donor characteristics. However, there are significant differences in donor demographics, access to transplantation, proportion of ABO incompatibility, and posttransplant mortality in Asian countries compared with the United States.

METHODS

We evaluated the clinical relevance of the LKDPI score in a Korean kidney transplant cohort by analyzing 1860 patients who underwent kidney transplantation between 2000 and 2019. Patients were divided into three groups according to LKDPI score: <0, 1-19.9, and ≥20.

RESULTS

During a median follow-up of 119 months, 232 recipients (12.5%) experienced death-censored graft loss, and 98 recipients (5.3%) died. High LKDPI scores were significantly associated with increased risk of death-censored graft loss independent of recipient characteristics (LKDPI 1-19.9: HR 1.389, 95% CI 1.036-1.863; LKDPI ≥20: HR 2.121, 95% CI 1.50-2.998). High LKDPI score was also significantly associated with increased risk of biopsy-proven acute rejection and impaired graft renal function. By contrast, overall patient survival rates were comparable among the LKDPI groups.

CONCLUSION

High LKDPI scores were associated with an increased risk of death-censored graft loss, biopsy-proven acute rejection, and impaired graft renal function among a Korean kidney transplant cohort.

Impact of preoperative red blood cell transfusion on long-term mortality of liver transplantation: A retrospective cohort study

Preoperative red blood cell (RBC) transfusion can induce immune modulation and alloimmunization; however, few studies have investigated the effect of preoperative transfusion and hemoglobin levels that need to be corrected before surgery, especially in critically ill patients such as those with end-stage liver disease who undergo liver transplantation (LT). This study aimed to investigate the effects of preoperative RBC transfusion on long-term mortality in LT recipients. A total of 249 patients who underwent LT at a single center between January 2012 and December 2021 were included in this study. The patients were divided into 2 groups: preoperative transfusion and preoperative non-transfusion. Since the baseline characteristics were significantly different between the 2 groups, we performed propensity score matching, including factors such as the Model for End-Stage Liver Disease score and intraoperative RBC transfusion, to exclude possible biases that could affect prognosis. We analyzed the 5-year mortality rate as the primary outcome. The preoperative transfusion group showed a 4.84-fold higher hazard ratio than that in the preoperative non-transfusion group. There were no differences in 30-day mortality, duration of intensive care unit stay, or graft rejection rate between the 2 groups. Preoperative transfusion could influence long-term mortality in LT, and clinicians should pay attention to RBC transfusion before LT unless the patient is hemodynamically unstable. A large-scale randomized controlled trial is needed to determine the possible mechanisms related to preoperative RBC transfusion, long-term mortality, and the level of anemia that should be corrected before surgery.

Predicting Long-term Outcomes in Deceased Donor Kidney Transplant Recipients Using Three Short-term Graft Characteristics

Key Points

Delayed graft function is not an ideal measure of graft function, yet is used to assess risk in kidney transplantation. We propose a model that combines it with two other measures of 90-day graft function to identify recipients at incremental risk of inferior long-term outcomes.

Background

Delayed graft function (DGF) in kidney transplant recipients is used to determine graft prognosis, make organ utilization decisions, and as an important end point in clinical trials. However, DGF is not an ideal measure of graft function. We aimed to develop and validate a model that provides incremental risk assessment for inferior patient and graft outcomes.

Methods

We included adult kidney-only deceased donor transplant recipients from 1996 to 2016. In addition to DGF, two short-term measures were used to assess risk: renal function recovery <100% (attaining half the donor's eGFR) and recipient's 90-day eGFR <30. Recipients were at no, low, moderate, or high risk if they met zero, one, two, or all criteria, respectively. Cox proportional hazard models were used to assess the independent relationship between exposure and death-censored graft failure (DCGF) and mortality.

Results

Of the 792 eligible recipients, 24.5% experienced DGF, 40.5% had renal function recovery <100%, and 6.9% had eGFR <30. Over a median follow-up of 7.3 years, the rate of DCGF was 18.7% and mortality was 25.1%. When compared with recipients at no risk, those at low, moderate, and high risk were noted to have an increase in risk of DCGF (adjusted hazard ratio [aHR], 1.53; 95% confidence interval [CI], 1.03 to 2.27; aHR, 2.84; 95% CI, 1.68 to 4.79; aHR, 15.46; 95% CI, 8.04 to 29.71) and mortality (aHR, 1.16; 95% CI, 0.84 to 1.58; aHR, 1.85; 95% CI, 1.13 to 3.07; aHR, 2.66; 95% CI, 1.19 to 5.97). When using a hierarchical approach, each additional exposure predicted the risk of DCGF better than DGF alone and 100 random bootstrap replications supported the internal validity of the risk model. In an external validation cohort deemed to be at lower risk of DCGF, similar nonsignificant trends were noted.

Conclusion

We propose a risk model that provides an incremental assessment of recipients at higher risk of adverse long-term outcomes than DGF alone. This can help advance the field of risk assessment in transplantation and inform therapeutic decision making in patients at the highest spectrum of inferior outcomes.

Impact of pre-transplant donor specific antibodies detected by Luminex with negative microlymphocytotoxicity assay and flow crossmatch in live-related renal transplant recipients

INTRODUCTION/AIM

The Luminex assay, where beads are coated with a single HLA antigen, has been shown to detect HLA antibodies with more sensitivity and specificity as compared to microlymphocytotoxicity (CDC) assay and flow cross match (FCXM). We report the impact of low Mean Flourescence intensity (MFI) pre-transplant DSA by Luminex with negative CDC and FCXM on acute rejection, graft function, and survival.

METHODS

In this retrospective study between January 2015 to December 2021, 45 recipients had pre-transplant anti-HLA donor-specific antibodies (DSAs) detected by Luminex. Two control groups of 45 patients each matched for age and gender, first with non-DSA HLA antibodies and second with no antibodies by Luminex were selected to compare outcomes with DSA group.

RESULTS

In the DSA group of 45, 22 (48.8%) had class I (MFI mean 4043 ± 1909, range: 1096-7111), 20 (44.4%) class II (MFI mean 3601 ± 2310, range: 1031-9259), and 3 (6.6%) both class I (MFI mean 4746 ± 1922) and class II (MFI mean 3940 ± 2312) antibodies. Acute rejection episodes were reported in 15.6%, DSA group, 17.8% in non-DSA, and 24.4% in no antibody group (p = .538). Death censored graft survival at 1 and 5 years was 98% and 93% in DSA group, 100% and 95% in non-DSA and 93% and 85% in the no antibody group (p = .254).

CONCLUSIONS

Patients with low MFI DSA pre-transplant, with a negative CDC and FCXM under ATG induction, have similar graft outcomes at 1 and 5 years when compared to non-DSA and no antibody groups.

Effects of tacrolimus intrapatient variability and CYP3A5 polymorphism on the outcomes of pediatric kidney transplantation

BACKGROUND

The intrapatient variability (IPV) of tacrolimus (Tac) is associated with the long-term outcome of kidney transplantation. The CYP3A single-nucleotide polymorphism (SNP) may affect the IPV of Tac. We investigated the impact of IPV and genetic polymorphism in pediatric patients who received kidney transplantation.

METHODS

A total of 202 pediatric renal transplant recipients from 2000 to 2016 were analyzed retrospectively. The IPV was calculated between 6 and 12 months after surgery. Among these patients, CYP3A5 polymorphism was analyzed in 67 patients.

RESULTS

The group with high IPV had a significantly higher rate of de novo donor-specific human leukocyte antigen antibodies (dnDSA) development (35.7% vs. 16.7%, p = .003). The high IPV group also had a higher incidence of T-cell-mediated rejection (TCMR; p < .001). The high IPV had no significant influence on Epstein-Barr virus, cytomegalovirus, and BK virus viremia but was associated with the incidence of posttransplant lymphoproliferative disorders (p = .003). Overall, the graft survival rate was inferior in the high IPV group (p < .001). The CYP3A5 SNPs did not significantly affect the IPV of Tac. In the CYP3A5 expressor group, however, the IPV was significantly associated with the TCMR-free survival rate (p < .001).

CONCLUSION

The IPV of Tac had a significant impact on dnDSA development, occurrence of acute TCMR, and graft failure in pediatric patients who received renal transplantation. CYP3A5 expressors with high IPV of Tac showed worse outcomes, while the CYP3A5 polymorphism had no impact on IPV of Tac.

Effects of bisphosphonates on long-term kidney transplantation outcomes

BACKGROUND

Bisphosphonates are administered to post-transplantation patients with mineral and bone disorders; however, the association between bisphosphonate therapy and long-term renal graft survival remains unclear.

METHODS

This nested case-control study investigated the effects of bisphosphonates on long-term graft outcomes after kidney transplantation. We enrolled 3836 kidney transplant recipients treated from April 1979 to June 2016 and matched patients with graft failure to those without (controls). Annual post-transplant bone mineral density assessments were performed and recipients with osteopenia or osteoporosis received bisphosphonate therapy. The associations between bisphosphonate use and long-term graft outcomes and graft survival were analyzed using conditional logistic regression and landmark analyses, respectively.

RESULTS

A landmark analysis demonstrated that death-censored graft survival was significantly higher in bisphosphonate users than in non-users in the entire cohort (log-rank test, P < 0.001). In the nested case-control matched cohort, bisphosphonate users had a significantly reduced risk of graft failure than did non-users (odds ratio = 0.38; 95% confidence interval 0.30-0.48). Bisphosphonate use, increased cumulative duration of bisphosphonate use >1 year and increased cumulative bisphosphonate dose above the first quartile were associated with a reduced risk of graft failure, after adjustments.

CONCLUSIONS

Bisphosphonates may improve long-term graft survival in kidney transplant recipients.

Factors Influencing Long-Term Patient and Allograft Outcomes in Elderly Kidney Transplant Recipients

Introduction

Individuals aged ≥65 years are increasingly prevalent on the waitlist for kidney transplantation, yet evidence on recipient and donor factors that define optimal outcomes in elderly patients after kidney transplantation is scarce.

Methods

We used multivariable Cox regression modeling to determine the factors associated with all-cause death, death with a functioning graft, and overall and death-censored graft survival, using data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) registry.

Results

A total of 802 kidney transplant recipients aged ≥65 years underwent their first transplantation between June 2006 and December 2016. Median age at transplantation was 68 years (interquartile range = 66−69 years). The 1-year and 5-year overall patient and graft survivals (95% confidence interval [CI]) were 95.1 (93.5−96.7) and 79.0 (75.1−82.9), and 92.9 (91.1−94.7) and 75.4 (71.3−79.5), respectively. Factors associated with higher risks of all-cause death included prevalent coronary artery disease (adjusted hazard ratio [95% confidence interval] = 1.47 [1.03–2.11]), cerebrovascular disease (1.99 [1.26–3.16]), increasing graft ischemic time (1.06 per hour [1.03–1.09]), donor age (1.02 per year [1.01–1.03]), delayed graft function (1.64 [1.13−2.39]), and peritoneal dialysis pretransplantation (1.71 [1.17–2.51]).

Conclusion

Prevalent vascular disease and peritoneal dialysis as a pretransplantation dialysis modality are risk factors associated with poorer outcomes in transplant recipients aged ≥65 years. Careful selection and evaluation of potential candidates may improve graft and patient outcomes in older patients.

Selected liver grafts from donation after circulatory death can be safely used for retransplantation - a multicenter retrospective study

Due to the growing number of liver transplantations (LTs), there is an increasing number of patients requiring retransplantation (reLT). Data on the use of grafts from extended criteria donors (ECD), especially donation after circulatory death (DCD), for reLT are lacking. We aimed to assess the outcome of patients undergoing reLT using a DCD graft in the Netherlands between 2001 and July 2018. Propensity score matching was used to match each DCD-reLT with three DBD-reLT cases. Primary outcomes were patient and graft survival. Secondary outcome was the incidence of biliary complications, especially nonanastomotic strictures (NAS). 21 DCD-reLT were compared with 63 matched DBD-reLTs. Donors in the DCD-reLT group had a significantly lower BMI (22.4 vs. 24.7 kg/m² , P-value = 0.02). Comparison of recipient demographics and ischemia times yielded no significant differences. Patient and graft survival rates were comparable between the two groups. However, the occurrence of nonanastomotic strictures after DCD-reLT was significantly higher (38.1% vs. 12.7%, P-value = 0.02). ReLT with DCD grafts does not result in inferior patient and graft survival compared with DBD grafts in selected patients. Therefore, DCD liver grafts should not routinely be declined for patients awaiting reLT.

The Presence of Urinary Renal Progenitor Cells in Stable Kidney Transplant Recipients Anticipates Allograft Deterioration

Long-term kidney transplant outcomes have reached mild improvements recently. Parietal epithelial cells (PECs) are progenitor cells located along the Bowman’s capsule that can be isolated in urine, and display the capability to replace podocytes, but in certain situations cause glomerulosclerosis. In this study, a cohort of stable kidney transplant recipients with 6 months protocol biopsy was divided in two groups depending on the presence (uPEC+; n = 41) or absence (uPEC-; n = 25) of PECs in urine and followed for 2 years. No differences were found between groups at 6 months after transplantation considering clinical variables, alloimmune response, renal function, albuminuria and graft pathology. However, uPEC+ group showed increased podocyturia and a higher rate of proliferating PECs along the Bowman’s capsule, without concomitant enhancement of the CD44 pro-sclerotic activation marker. Accordingly, 2 years follow up evidenced poorer outcomes in the uPEC+ group with worse renal function, increased albuminuria, wider mesangial expansion and more severe IFTA. In summary, chronic allograft damage can progress in certain stable-supposed grafts by podocyte detachment and reactive PECs proliferation, being the uPEC presence a biomarker of this process. This damage-response regenerative process, if sustained in time, might fail in preserve the allograft function and histology. Our study raises new prospects to overcome current limits on long-term allograft results.

Renal transplant outcomes in primary FSGS compared with other recipients and risk factors for recurrence: A national review of the Irish Transplant Registry

INTRODUCTION

Primary focal segmental glomerular sclerosis (p-FSGS) is commonly complicated by recurrence (r-FSGS) post-transplantation. Our objective was to describe Irish outcomes for transplantation after end-stage renal disease (ESRD) due to p-FSGS, specifically rates of, and treatments for, r-FSGS.

PATIENTS AND METHODS

Irish patients with biopsy-proven FSGS were identified from the Irish National Kidney Transplant database (1982-2015). Medical record review was performed to identify predictors of r-FSGS and treatments for r-FSGS. Transplant outcomes were compared to outcomes in all renal transplants performed during the same time period using registry data. Demographic and clinical predictors of r-FSGS were identified. Statistical analysis was performed using Stata (version 13, College Station, TX, USA).

RESULTS

Thirty-eight transplant recipients had biopsy-proven p-FSGS, 16 received a second transplant. A total of 3846 transplants formed the comparator group. r-FSGS complicated 60.5% (23/38) of first transplants. Eighty-six percent (10/12) of patients with previous r-FSGS developed recurrent disease after further transplantation. Patients with p-FSGS receiving a first renal transplant had higher rate of graft failure than those with another cause of ESRD (HR 1.9, 95% CI 1.152-3.139). Sixteen patients received immunotherapy for r-FSGS; 12 (86%) had at least partial response, but two (14%) developed significant complications.

DISCUSSION

We demonstrate high rates of r-FSGS and describe modest success from with treatments for r-FSGS.

Correlation of acute tubular injury in reperfusion biopsy with renal transplant outcomes

Acute tubular injury (ATI) is common at reperfusion, but its relationship to graft outcomes is unclear. Prior studies lack standardization of morphological assessments and included elements of acute and chronic tubular injury. This study aimed to evaluate the impact of ATI on graft outcomes. Reperfusion biopsies from 2004 to 2009 were retrospectively reviewed. ATI was assessed by a new standardized scoring system. We also assessed chronic injury (CI) by the Banff criteria. Outcomes evaluated included glomerular filtration rate (GFR) at 1 and 5 years and delayed graft function (DGF), acute rejection (AR), graft and patient survival. ATI did not correlate with DGF, AR, graft or overall survival. Mild-moderate ATI was not predictive of GFR post-transplant. Moderate-severe CI was associated with lower GFR at 5 years with a mean difference of -7.14 mL/min/1.73 m(2) (P=.04) and overall survival (HR 2.44, P=.01). Other predictors of graft function included donor age, DGF, and AR. Histologic criteria of ATI at implantation in the absence of donor demographics or clinical information do not provide sufficient predictability in outcomes after transplantation. On the other hand, histologic assessment of CI correlates with GFR and overall survival.

The role of donor-specific HLA alloantibodies in liver transplantation

The impact of donor-specific HLA alloantibodies (DSA) on short- and long-term liver transplant outcome is not clearly defined. While it is clear that not all levels of allosensitization produce overt clinical injury, and that liver allografts possess some degree of alloantibody resistance, alloantibody-mediated adverse consequences are increasingly being recognized. To better define the current state of this topic, we assembled experts to provide insights, explore controversies and develop recommendations for future research on the consequences of DSA in liver transplantation. This article summarizes the proceedings of this inaugural meeting. Several insights emerged. Acute antibody-mediated rejection (AMR), although rarely diagnosed, is increasingly understood to overlap with T cell-mediated rejection. Isolated liver allograft recipients are at increased risk of early allograft immunologic injury when preformed DSA are high titer and persist posttransplantation. Persons who undergo simultaneous liver-kidney transplantation are at risk of renal AMR when Class II DSA persist posttransplantation. Other under-appreciated DSA associations include ductopenia and fibrosis, plasma cell hepatitis, biliary strictures and accelerated fibrosis associated with recurrent liver disease. Standardized DSA testing and diagnostic criteria for both acute and chronic AMR are needed to distil existing associations into etiological processes in order to develop responsive therapeutic strategies.

Class II alloantibody and mortality in simultaneous liver-kidney transplantation

Hyperacute kidney rejection is unusual in crossmatch positive recipients of simultaneous liver-kidney transplants (SLKT). However, recent data suggest that these patients remain at risk for antibody-mediated kidney rejection. To further investigate the risk associated with donor-specific alloantibodies (DSA) in SLKT, we studied 86 consecutive SLKT patients with an available pre-SLKT serum sample. Serum samples were analyzed in a blinded fashion for HLA DSA using single antigen beads (median florescence intensity≥2,000=positive). Post-SLKT samples were analyzed when available (76%). Thirty patients had preformed DSA, and nine developed de novo DSA. Preformed class I DSA did not change the risk of rejection, patient or allograft survival. In contrast, preformed class II DSA was associated with a markedly increased risk of renal antibody mediated rejection (AMR) (p=0.006), liver allograft rejection (p=0.002), patient death (p=0.02), liver allograft loss (p=0.02) and renal allograft loss (p=0.045). Multivariable modeling showed class II DSA (preformed or de novo) to be an independent predictor of patient death (HR=2.2; p=0.043) and liver allograft loss (HR=2.2; p=0.044). These data warrant reconsideration of the approach to DSA in SLKT.