Risk Factors for Acute Rejection After Deceased Donor Kidney Transplantation in China

Suspicious of Acute Kidney Graft Rejection: Tacrolimus Pharmacokinetics Under Methylprednisolone Therapy

BACKGROUND

Acute rejection remains one of the main complications in the first months after transplantation and may influence long-term outcomes. Tacrolimus has proven its usefulness in solid organ transplants and its monitoring through the application of pharmacokinetic concepts to optimize individual drug therapy.

OBJECTIVE

This research proposes to evaluate the tacrolimus pharmacokinetic parameters in patients suspected of acute kidney graft rejection under methylprednisolone pulse therapy.

METHODS

Eleven adult tacrolimus-treated renal recipients were selected from a prospective, single-arm, single-center cohort study, with suspicion of acute rejection although in use of methylprednisolone pulses therapy. They were followed up for three months posttransplantation, being tacrolimus trough serum concentrations determined using a chemiluminescent magnetic immunoassay, and pharmacokinetic parameters were estimated by using a nonlinear mixed-effects model implemented by Monolix 2020R1. A tacrolimus trough serum concentration range of 8 to 12 ng.mL-1 was considered therapeutic.

RESULTS

Six patients showed acute cellular rejection, and two of them in addition had an antibody- mediated rejection. Tacrolimus trough serum concentration was below the reference range in eight patients. Most patients showed a high tacrolimus concentration intrapatient and pharmacokinetic parameters variability.

CONCLUSION

The obtained pharmacokinetics parameters helped in understanding the kidney recipient patients' tacrolimus behavior, assisting in the improvement of individual drug therapy and reducing the risk of acute rejection episodes.

AIM2 as a putative target in acute kidney graft rejection

Acute rejection (AR) is a process triggered via the recognition of grafted organ-derived antigens by the immune system, which could present as a life-threatening condition. In the context of a kidney transplant, despite improvement with immunosuppressive therapies, AR maintains a significant incidence of 10%, and currently available drugs generally act in similar and canonical pathways of lymphocyte activation. This prompted the research for different approaches to identify potential novel targets that could improve therapeutic interventions. Here, we conducted a transcriptome analysis comparing groups of acute rejection (including T cell-mediated rejection and antibody-mediated rejection) to stable grafts that included differentially expressed genes, transcription factor and kinase enrichment, and Gene Set Enrichment Analysis. These analyses revealed inflammasome enhancement in rejected grafts and AIM2 as a potential component linked to acute rejection, presenting a positive correlation to T-cell activation and a negative correlation to oxidative phosphorylation metabolism. Also, the AIM2 expression showed a global accuracy in discerning acute rejection grafts (area under the curve (AUC) = 0.755 and 0.894, p < 0.0001), and meta-analysis comprising different studies indicated a considerable enhancement of AIM2 in rejection (standardized mean difference (SMD) = 1.45, [CI 95%, 1.18 to 1.71]), especially for T cell-mediated rejection (TCMR) (SMD = 2.01, [CI 95%, 1.58 to 2.45]). These findings could guide future studies of AIM2 as either an adjuvant target for immunosuppression or a potential biomarker for acute rejection and graft survival.

Association Between Regulatory Emotional Self-Efficacy and Immunosuppressive Medication Adherence in Renal Transplant Recipients:Does Medication Belief Act as a Mediator?

Background: Few studies have investigated the association between regulatory emotional self-efficacy (RESE) and immunosuppressive medication adherence or the mechanisms underlying this relationship. Considering that previous evidence of immunosuppressive medication adherence depended on the level of immunosuppressive medication beliefs, a model of multiple mediation was tested in which immunosuppressive medication beliefs acted as mediators of the relationship between RESE and immunosuppressive medication adherence. Methods: A retrospective cross-sectional study was performed in 293 renal transplant patients during outpatient follow-ups from November 2019 to February 2020 in China. All participants completed a general demographic questionnaire, the Chinese version of the RESE, the Beliefs about Medication Questionnaire, and the Basel Assessment of Adherence with Immunosuppressive Medication Scale (BAASIS). Spearson correlation analysis was carried out to identify the correlation between RESE and immunosuppressive medication adherence. Binary logistic regression analysis was performed to confirm factors associated with immunosuppressive medication adherence in renal transplant recipients. Mediating effect analysis was used to explore the internal interaction between RESE and immunosuppressive medication adherence. Results: A total of 293 renal transplant patients were recruited, including 111 women and 182 men with a mean age of 42.5 years (SD = 10.0). A total of 23.21% of patients exhibited immunosuppressive medication none-adherence behavior, and 12.97% reported altering the prescribed amount of immunosuppressive medication without physician permission, which was most popular behavior among patients. The mean RESE score was 45.78 ± 6.12; the positive (POS) score was the highest, and the anger-irritation (ANG) score was the lowest. The correlation analysis results showed that RESE (r = -0.642, p < 0.01) and immunosuppressive medication beliefs (r = -0.534, p < 0.01) were significantly associated with immunosuppressive medication adherence. Binary logistic regression analysis indicated that marital status, fertility status, rejection, immunosuppressive medication beliefs, and RESE were found to be independent predictors of immunosuppressive medication adherence [R 2 = 0.803, p < 0.05]. The results of the mediating effect analysis showed that immunosuppressive medication necessity had a partial mediating effect, RESE directly and indirectly affected immunosuppressive medication adherence via immunosuppressive medication necessity, and immunosuppressive medication concerns were not a mediator between RESE and immunosuppressive medication adherence. Conclusion: The levels of immunosuppressive medication adherence in renal transplant patients need to be improved in China. Marital status, fertility status, rejection, immunosuppressive medication beliefs, and RESE were major factors affecting immunosuppressive medication adherence. RESE could affect immunosuppressive medication adherence indirectly through immunosuppressive medication necessity.

Analysis of Factors Influencing Kidney Function of Recipients After Renal Transplantation in Southwestern China: A Retrospective Study

Background: Factors influencing the kidney function of patients after renal transplantation include both recipient-related factors and donor-related factors. To gain a better understanding of these factors and to improve clinical decision-making, we performed a retrospective study of southwestern Chinese people receiving kidney transplantation.

Methods: In this retrospective analysis, a total of 2,462 recipients receiving allogeneic kidney transplantation in West China Hospital of Sichuan University from December 13, 2008 to January 10, 2018 were included. Data on recipient and donor characteristics were extracted from the Transplant Center Database and stratified by discrete time points after kidney transplantation. Univariate and multivariate logistic regression analyses were carried out on the study variables, and kidney function of postoperative patients was monitored using cystatin C (CysC) as the outcome indicator.

Results: From the univariate analysis, several factors showed statistically significant short-term impact on kidney function based on CysC after kidney transplantation, including age, ethnicity, body mass index (BMI), and HLA A-B-DR-DQ loci mismatch. Gender of recipients and gender-consistency between donors and recipients revealed both short-term and long-term influence. Younger donors had significantly better medium-and-long-term influence on kidney function. From the multivariate logistic regression analysis, recipient gender, ethnicity, BMI, and donor age were independent factors affecting postoperative CysC recovery at discrete time points.

Conclusion: Several factors of recipients related to renal function after kidney transplantation, such as gender, ethnicity, BMI and donor's age should be paid more attention to. Moreover, female and non-Han recipients decreased the risk of poor outcome during postoperative kidney function recovery while large BMI of recipients and higher donor age increased the risk. It is useful to predict the postoperative renal function earlier according to corresponding factors, and improve the patient's quality of life.

The Aquaporin3 Promoter Polymorphism -1431 A/G is Associated with Acute Graft Rejection and Cytomegalovirus Infection in Kidney Recipients Due to Altered Immune Cell Migration

Major complications after kidney transplantation are graft rejection and cytomegalovirus (CMV) infection, which are related to T-cell function, which depends on aquaporin 3 (AQP3) expression. The impact of the AQP3 A(−1431)G promoter polymorphism in kidney transplant recipients was unelucidated and we explored the effect of AQP3 polymorphism on immune cell function and its association with graft rejection and CMV infection in 237 adult patients within 12 months after transplantation. AQP3 promoter polymorphism was molecular and functional characterized. Kaplan–Meier plots evaluated the relationship between genotypes and the incidence of CMV infection and graft rejection. AQP3 A(−1431)G A-allele was associated with enhanced immune cell migration and AQP3 expression in T-cells. The incidences of rejection were 45.4% for the A-allele and 27.1% for G-allele carriers (p = 0.005) and the A-allele was a strong risk factor (hazard ratio (HR): 1.95; 95% CI: 1.216 to 3.127; p = 0.006). The incidences for CMV infection were 21% for A-allele and 35% for G-allele carriers (p = 0.013) and G-allele was an independent risk factor (p = 0.023), with a doubled risk for CMV infection (HR: 1.9; 95% CI: 1.154 to 3.128; p = 0.012). Hence, A-allele confers more resistance against CMV infection, but susceptibility to graft rejection mediated by T-cells. Thus, AQP3-genotype adapted management of immunosuppression and antiviral prophylaxis after kidney transplantation seems prudent.

Gene polymorphisms and risk of acute renal graft rejection: A field synopsis of meta-analyses and genome-wide association studies

In the present study we systematically re-analyzed results from meta-analyses and genome-wide association studies (GWASs) to assess the credibility of genetic associations with acute rejection risk in renal transplantation. A comprehensive literature search was performed on PubMed, Web of Knowledge, Cochrane library, and Open Grey up to July 2019. Methodological quality of systematic meta-analyses was assessed by the AMSTAR tool. Credibility of genetic associations was assessed by employing the Venice criteria and two Bayesian statistical approaches, the false positive report probability (FPRP) and the Bayesian false discovery probability (BFDP). Sixteen systematic meta-analyses, with a moderate-high quality score (median AMSTAR score: 9, range: 6-11) and 1 GWAS fulfilled the inclusion criteria. Overall, our systematic re-analysis has identified 9 polymorphic variants in 8 genes (ACE, CD28, CTLA-4, CYP3A5, IFNG, TNF-α, PTPRO and CCDC67) as potential risk factors for acute renal graft rejection. At the pre-specified prior probability of 0.001, the 2 SNPs identified by the GWAS (rs7976329 and rs10765602) showed no evidence of noteworthiness under FPRP or BFDP, indicating the possibility of false-positive associations. After applying the Venice criteria in combination with FPRP and BFDP to results from systematic meta-analyses, TT/AT vs AA of IFNG +874 T/A reached moderate epidemiological credibility, while weak evidence of association was found for all the other genetic comparisons. Well-designed GWASs and large replication studies with updated meta-analyses are still needed to identify reliable genetic predictors of acute renal graft rejection.

[Application of immunosuppressants in patients with autosomal dominant polycystic kidney disease after kidney transplantation]

OBJECTIVE

To investigate the optimal dose range of immunosuppressants in patients with autosomal dominant polycystic kidney disease (ADPKD) after renal transplantation.

METHODS

A cohort of 68 patients with ADPKD who received their first renal transplantation between March, 2000 and January, 2018 in our institute were retrospectively analyzed, with 68 non-ADPKD renal transplant recipients matched for gender, age and date of transplant as the control group. We analyzed the differences in patient and renal survival rates, postoperative complications and concentrations of immunosuppressive agents between the two groups at different time points within 1 year after kidney transplantation. The concentrations of the immunosuppressants were also compared between the ADPKD patients with urinary tract infections (UTI) and those without UTI after the transplantation.

RESULTS

The recipients with ADPKD and the control recipients showed no significantly difference in the overall 1-, 5-, and 10- year patient survival rates (96.6% vs 96.0%, 94.1% vs 93.9%, and 90.6% vs 93.9%, respectively; P > 0.05), 1-, 5-, and 10-year graft survival rates (95.2% vs 96.0%, 90.8% vs 87.2%, and 79.0% vs 82.3%, respectively; P > 0.05), or the incidences of other post- transplant complications including acute rejection, gastrointestinal symptoms, cardiovascular events, pneumonia, and neoplasms (P > 0.05). The plasma concentrations of both tacrolimus and mycophenolate mofetil (MPA) in ADPKD group were significantly lower than those in the control group at 9 months after operation (P < 0.05). The incidence of UTI was significantly higher in ADPKD patients than in the control group (P < 0.05). In patients with ADPKD, those with UTI after transplantation had a significantly higher MPA plasma concentration (P < 0.05).

CONCLUSIONS

In patients with ADPKD after renal transplant, a higher dose of MPA is associated with a increased risk of UTI, and their plasma concentrations of immunosuppressants for long-term maintenance of immunosuppression regimen can be lower than those in other kidney transplantation recipients.

Long-Term Follow-up Results of Renal Transplantation in Pediatric Patients With Focal Segmental Glomerulosclerosis: A Single-Center Experience

INTRODUCTION AND AIM

Focal segmental glomerulosclerosis (FSGS) is a common cause of end-stage renal disease in children. We analyzed the long-term outcome of pediatric patients with FSGS undergoing renal transplantation. The objective of the study is to report the experience of a single center and determine the incidence of recurrence, rejection, graft loss, and related risk factors.

MATERIALS AND METHOD

This retrospective cohort study was performed between 1991 and 2018. Thirty patients with a pathologic diagnosis of primary FSGS were included in the study. The patients were diagnosed with FSGS according to histologic features in biopsies.

RESULTS

Twenty-one of the donors were deceased (70%) and 9 were alive (30%). FSGS recurred in only 2 patients. Graft loss occurred in 6 patients (20%). The causes of graft loss were chronic rejection in 4 patients and acute rejection in 2. Our graft survival rate was 100% at 1 year, 91% at 5 years, 80% at 10 years, 70% at 15 years, and 42% at 20 years. Five- and 10-year graft survival rates were 83% and 83% in living donors and 94% and 79% in deceased donors, respectively. According to Kaplan-Meier analysis, there was no statistically significant difference in terms of graft survival between living and deceased donors.

CONCLUSION

This study, with its contribution to literature in terms of long follow-up of FSGS patients from childhood to adulthood, is important. However, further studies are required.