The effect of periodontitis on recipient outcomes after kidney transplantation

Recent several reports have demonstrated that periodontitis is prevalent and adversely affects the survival in patients with chronic kidney disease (CKD) or end-stage kidney disease. However, its impact on transplant outcomes remains uncertain. Methods: This retrospective cohort study included 136 and 167 patients, respectively, who underwent living donor kidney transplantation (KT) at Seoul National University Hospital from July 2012 to August 2016 and Korea University Hospital from April 2008 to October 2018. We divided patients into three groups according to stages of periodontitis based on a new classification system. Results: Patients with severe periodontitis were older, had a higher prevalence of diabetes, a higher body mass index and C-reactive protein level, a lower cardiac output, and were more likely to be smokers, indicating its association with chronic systemic inflammation. After KT, stage IV periodontitis was independently associated with a lower incidence of acute T cell-mediated rejection, suggesting the possible effect of periodontitis on immune function. However, 1-year and 3-year estimated glomerular filtration rates were not different. Among the KT recipients followed up more than 3 years, new-onset cardiovascular disease occurred in nine patients, and coronary artery disease occurred more frequently in patients with stage IV periodontitis. However, diabetes was the independent predictor of new-onset coronary artery disease in multivariate logistic regression analysis. Conclusion: Our findings showed that periodontitis might be an important player in determining posttransplant outcomes in recipients. Further interventional trials to test whether treating periodontitis could modify transplant outcome are needed.

Human B1 Cells are the Main Blood Group A-Specific B Cells That Have a Moderate Correlation With Anti-A Antibody Titer

BACKGROUND: Anti-carbohydrate antibody responses, including those of anti-blood group ABO antibodies, are yet to be thoroughly studied in humans. Because anti-ABO antibody-mediated rejection is a key hurdle in ABO-incompatible transplantation, it is important to understand the cellular mechanism of anti-ABO responses. We aimed to identify the main human B cell subsets that produce anti-ABO antibodies by analyzing the correlation between B cell subsets and anti-ABO antibody titers. METHODS: Blood group A-binding B cells were analyzed in peritoneal fluid and peripheral blood samples from 43 patients undergoing peritoneal dialysis and 18 healthy volunteers with blood group B or O. The correlation between each blood group A-specific B cell subset and anti-A antibody titer was then analyzed using Pearson's correlation analysis. RESULTS: Blood group A-binding B cells were enriched in CD27⁺CD43⁺CD1c− B1, CD5⁺ B1, CD11b⁺ B1, and CD27⁺CD43⁺CD1c+ marginal zone-B1 cells in peripheral blood. Blood group A-specific B1 cells (P=0.029 and R=0.356 for IgM; P=0.049 and R=0.325 for IgG) and marginal zone-B1 cells (P=0.011 and R=0.410 for IgM) were positively correlated with anti-A antibody titer. Further analysis of peritoneal B cells confirmed B1 cell enrichment in the peritoneal cavity but showed no difference in blood group A-specific B1 cell enrichment between the peritoneal cavity and peripheral blood. CONCLUSIONS: Human B1 cells are the key blood group A-specific B cells that have a moderate correlation with anti-A antibody titer and therefore constitute a potential therapeutic target for successful ABO-incompatible transplantation.

Formulation of the Scope and Key Questions of the Guideline Recommendations for Immunosuppressive Treatment in Kidney Transplantation

BACKGROUND: Although a growing number of guidelines and clinical researches are available for immunosuppressive treatment of post-transplantation, there is no clinical practice guideline for the care of kidney transplant recipients in Korea. Selection of a researchable question is the most important step in conducting qualified guideline development. Thus, we aimed to formulate key questions for Korean guideline to aid clinical decision-making for immunosuppressive treatment. METHODS: Based on previous published guidelines review, a first survey was constructed with 29 questions in the range of immunosuppressive treatments. The experts were asked to rate the clinical importance of the question using a 5-point Likert scale. The questions reached 60% or more from the first survey and additional new questions were included in the second survey. In analyzing the responses to items rated on the 9-point scale, consensus agreement on each question was defined as 75% or more of experts rating 7 to 9. RESULTS: In the first survey, 50 experts were included. Among the 29 questions, 27 were derived to get 60% or more importance and 3 new questions were additionally identified. Through the second survey, 9 questions were selected that experts reached consensus on 75% and over of the options. Finally, we developed key questions using PICO (patient, intervention, comparison, and outcome) methodology. CONCLUSION: The experts reached a high level of consensus on many of key questions in the survey. Final key questions provide direction for developing clinical practice guideline in the immunosuppressive treatment of transplantation.

Outcomes of the surgical management of encapsulating peritoneal sclerosis: A case series from a single center in Korea

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is a rare but near-fatal complication of peritoneal dialysis (PD). Despite the high mortality rate of EPS, the surgical treatment strategy of severe EPS is yet to be established.METHODS: We retrospectively analyzed outcomes of patients with EPS who underwent enterolysis for intractable EPS at Seoul National University Hospital between 2001 and 2018. EPS was diagnosed based on the clinical symptoms and radiological findings of abdominal computed tomography (CT). CT scans were scored according to an EPS scoring system that assessed peritoneal thickening and calcification as well as bowel thickening, tethering, loculation, and dilatation.RESULTS: Thirteen patients (nine males and four females; age, 48 [29–63] years) underwent enterolysis for severe EPS. PD duration (11 [6–21] years) was not associated with survival. Two patients were newly diagnosed with EPS following kidney transplantation. Five patients died of infectious complications immediately after the surgery. Eight patients survived after the first surgery; however, five of them underwent reoperation but died of persistent infection, fistula formation, or adhesive bowel obstruction. Four young (< 60 years) male patients with relatively low CT scan scores (< 13) survived for > 2 years after the first surgery. Median survival duration from EPS diagnosis was 22 (1.3–184) months and that from the first surgery was 9 (0.3–153) months.CONCLUSION: The high mortality rate of EPS suggests the importance of appropriate surgical intervention in young symptomatic male EPS patients with relatively low CT scan scores.

Proposal of a Selective Prophylaxis Strategy Based on Risk Factors to Prevent Early and Late Pneumocystis jirovecii Pneumonia after Renal Transplantation / 대한이식학회지

BACKGROUND: Currently, trimethoprim-sulfamethoxazole is used for Pneumocystis jirovecii pneumonia (PJP) prophylaxis, but it is associated with frequent adverse effects. This study evaluated the efficacy and safety of the current protocol and proposes an individualized risk-based prophylaxis protocol. METHODS: The PJP incidence and risk factors during the first 6 months (early PJP) and afterwards (late PJP) was assessed in renal transplant recipients with (prophylaxis group) and without (no-prophylaxis group) 6-month PJP prophylaxis. RESULTS: In 578 patients, there were 39 cases of PJP during a median follow-up of 51 months. Renal adverse events were encountered frequently during trimethoprim-sulfamethoxazole prophylaxis, leading to premature discontinuation. Patients without the prophylaxis had a significantly higher incidence of early PJP (n=27, 6.6%) compared to patients with the prophylaxis (n=0). The incidence of late PJP was 2.2%, without between-group differences. The factors associated with early PJP were preoperative desensitization and acute rejection within 1 month, whereas late PJP was associated with age, deceased donor transplant, and acute rejection requiring antithymocyte globulin treatment. CONCLUSIONS: Based on the simulation results of several risk-based scenarios, the authors recommend universal prophylaxis up to 6 months post-transplant and extended selective prophylaxis in patients aged ≥57 years and those with a transplant from deceased donors.

Association of Foxp3 Polymorphism With Allograft Outcome in Kidney Transplantation

BACKGROUND: Forkhead box P3 (Foxp3) is the most reliable marker for regulatory T cells, which play an important role in maintaining renal allograft tolerance. Recently, Foxp3 polymorphisms have been reported to be associated with graft outcome in kidney transplantation. We analyzed the association of Foxp3 polymorphisms with renal allograft outcome. METHODS: Foxp3 polymorphisms (rs3761548 A/C, rs2280883 C/T, rs5902434 del/ATT, and rs2232365 A/G) were tested by PCR with sequence-specific primers (PCR-SSP) in 231 adult kidney transplantation recipients from 1996-2004 at Seoul National University Hospital. RESULTS: Patients with the rs3761548 CC genotype showed better graft survival than those with the AC or AA genotype (log rank test, P=0.03). Patients with the rs3761548 CC genotype also showed a lower rate of recurrence of the original glomerular disease than those with the AC or AA genotype (P=0.01). The frequency of acute rejection (AR) in patients with the rs2280883 TT genotype was lower than that in patients with the rs2280883 CT or CC genotype (26.9% vs 53.3%, P=0.038). Patients with the rs2280883 TT genotype also showed better graft survival than those with the CT or CC genotype (P=0.03). CONCLUSIONS: Foxp3 rs3761548 CC and rs2280883 TT genotypes were associated with superior graft outcome of kidney transplantation. Further studies involving a larger number of patients are needed.

The Need for New Donor Stratification to Predict Graft Survival in Deceased Donor Kidney Transplantation

PURPOSE: The aim of this study was to determine whether stratification of deceased donors by the United Network for Organ Sharing (UNOS) criteria negatively impacts graft survival. MATERIALS AND METHODS: We retrospectively reviewed deceased donor and recipient pretransplant variables of kidney transplantations that occurred between February 1995 and December 2009. We compared clinical outcomes between standard criteria donors (SCDs) and expanded criteria donors (ECDs). RESULTS: The deceased donors consisted of 369 patients. A total of 494 transplant recipients were enrolled in this study. Mean age was 41.7±11.4 year (range 18–69) and 273 patients (55.4%) were male. Mean duration of follow-up was 8.8±4.9 years. The recipients from ECD kidneys were 63 patients (12.8%). The overall mean cold ischemia time was 5.7±3.2 hours. Estimated glomerular filtration rate at 1, 2, and 3 years after transplantation were significantly lower in ECD transplants (1 year, 62.2±17.6 vs. 51.0±16.4, p0.05), although patient survival was lower in ECDs than SCDs (Log rank test, p=0.011). CONCLUSION: Our data demonstrate that stratification by the UNOS criteria does not predict graft survival. In order to expand the donor pool, new criteria for standard/expanded donors need to be modified by regional differences.

Current Perspectives on Emerging CAR-Treg Cell Therapy: Based on Treg Cell Therapy in Clinical Trials and the Recent Approval of CAR-T Cell Therapy / 대한이식학회지

Regulatory T cells (Treg) naturally rein in immune attacks, and they can inhibit rejection of transplanted organs and even reverse the progression of autoimmune diseases in mice. The initial safety trials of Treg against graft-versus-host disease (GVHD) provided evidence that the adoptive transfer of Treg is safe and capable of limiting disease progression. Supported by such evidence, numerous clinical trials have been actively investigating the efficacy of Treg targeting autoimmune diseases, type I diabetes, and organ transplant rejection, including kidney and liver. The limited quantity of Treg cells harvested from peripheral blood and subsequent in vitro culture have posed a great challenge to large-scale clinical application of Treg; nevertheless, the concept of CAR (chimeric antigen receptor)-Treg has emerged as a potential resolution to the problem. Recently, two CAR-T therapies, tisagenlecleucel and axicabtagene ciloleucel, were approved by the US FDA for the treatment of refractory or recurrent acute lymhoblastic leukemia. This approval could serve as a guideline for the production protocols for other genetically engineered T cells for clinical use as well. The phase I and II clinical trials of these agents has demonstrated that genetically engineered and antigen-targeting T cells are safe and efficacious in humans. In conclusion, both the promising results of Treg cell therapy from the clinical studies and the recent FDA approval of CAR-T therapies are paving the way for CAR-Treg therapy in clinical use.

Effect of Simultaneous Nephrectomy on Perioperative Blood Pressure and Graft Outcome in Renal Transplant Recipients with Autosomal Dominant Polycystic Kidney Disease / 대한이식학회지

BACKGROUND: For various reasons, kidney transplant recipients with autosomal dominant polycystic kidney disease (ADPKD) often undergo native nephrectomy in preparation for the transplantation. Simultaneous nephrectomy can result in hypotensive events perioperatively and affect transplant outcome adversely. Our aim was to evaluate the effect of simultaneous native nephrectomy (SNx) on perioperative blood pressure and graft outcome compared to non-nephrectomy (NNx) in renal transplant recipients with ADPKD. METHODS: Data regarding renal function and blood pressure were collected from 42 renal transplant recipients with ADPKD. The primary outcome was graft function over 1 year post-transplant. The secondary outcomes were patient and graft survival, postoperative hypotensive events, and blood pressure control. We compared units of anti-hypertensive medication used by transplanted ADPKD patients in the SNx and NNx groups. RESULTS: Patients with SNx during kidney transplantation showed similar rates of patient and graft survival and renal function. Although they had significantly more hypotensive events during the perioperative period (69.2% vs. 37.5% in NNx, P=0.045), no harmful influence on renal function was observed. No difference in mean blood pressure during the 1-year post-transplant period was observed between the two groups; however, the SNx group required fewer units of anti-hypertensive medication. CONCLUSIONS: SNx is a relatively safe procedure. Graft outcome in the SNx group was not inferior to that of the NNx group, and patients with SNx can have well-controlled blood pressure.

Current progress in ABO-incompatible kidney transplantation

ABO-incompatible kidney transplantation (ABOi KT) was introduced to expand the donor pool and minimize shortage of kidneys for transplantation. Because improved outcomes of ABOi KT were reported in Japan in the early 2000s, the number of ABOi KTs has been increasing worldwide. In addition, a better understanding of immune pathogenesis and subsequent aggressive immunosuppression has helped to make effective desensitization protocols. Current strategies of ABOi KT consist of pretransplant antibody removal using plasmapheresis or immunoadsorption to prevent hyperacute rejection and potent maintenance immunosuppression, such as tacrolimus and mycophenolate mofetil, to inhibit antibody-mediated rejection. Recent outcomes of ABOi KT are comparable with ABO-compatible KT. However, there are still many problems to be resolved. Very high anti-ABO antibody producers are difficult to desensitize. In addition, ABOi KT is associated with an increased risk of infection and possibly malignancy due to aggressive immunosuppression. Optimization of desensitization and patient-tailored immunosuppression protocols are needed to achieve better outcomes of ABOi KT. This review provides an overview of the history, immune mechanism, immunosuppressive protocol, outcomes, current obstacles, and future perspectives in ABOi KT.

A Successful Bilateral Lung Transplantation in a Patient with High Panel Reactive Antibody and Positive Cross Matching

A 44-year-old pregnant female patient gave stillbirth while being treated for pneumonia. She developed acute respiratory failure, which resulted in mechanical ventilator support. Diagnostic lung biopsy revealed a cryptogenic organizing pneumonia. The patient's condition deteriorated and a venous-venous extracorporeal membrane oxygenation was placed. She was listed for lung transplantation. Because of her worsening condition lung transplantation was performed despite positive cross matching result. She was treated with rituximab, intravenous immunoglobulin, and plasmapheresis and recovered without event. There is no sign of rejection at the time of last follow-up.

Cell Therapy in Kidney Transplantation / 대한이식학회지

Current immunosuppressants have nonspecific immuosuppressive effects, and are not helpful for tolerance induction. Consequently, transplant patients cannot discontinue using them, and their nonspecific immunosuppressive effects result in many side effects, including infection and malignancy. However, most of cellular immunotherapy can have donor antigen-specific immunsuppressive effects. Therefore, cell therapy could be an alternative or adjunctive to nonspecific immunosuppressants. Polyclonal or antigen-specific Foxp3+ regulatory T cells have been actively tried for prevention of acute rejection, treatment of chronic rejection, or tolerance induction in clinical trials. Regulatory macrophages are also under clinical trials for kidney transplant patients. IL-10-secreting type 1 regulatory T cells and donor- or recipient-derived tolerogenic dendritic cells will also be used for immunoregulation in clinical trials of kidney transplantation. These cells have antigen-specific immunoregulatory effects. Mesenchymal stromal cells (MSCs) have good proliferative capacity and immunosuppressive actions independently of major histocompatibility complex; therefore, even third-party MSCs can be stored and used for many patients. Cell therapy using various immunoregulatory cells is now promising for not only reducing side effects of nonspecific immunosuppressants but also induction of immune tolerance, and is expected to contribute to better outcomes in transplant patients.

Impact of Combined Acute Rejection on BK Virus-Associated Nephropathy in Kidney Transplantation

BK virus-associated nephropathy (BKVAN) is one of the major causes of allograft dysfunction in kidney transplant (KT) patients. We compared BKVAN combined with acute rejection (BKVAN/AR) with BKVAN alone in KT patients. We retrospectively analyzed biopsy-proven BKVAN in KT patients from 2000 to 2011 at Seoul National University Hospital. Among 414 biopsies from 951 patients, biopsy-proven BKVAN was found in 14 patients. Nine patients had BKVAN alone, while 5 patients had both BKVAN and acute cellular rejection. BKVAN in the BKVAN alone group was detected later than in BKVAN/AR group (21.77 vs 6.39 months after transplantation, P=0.03). Serum creatinine at diagnosis was similar (2.09 vs 2.00 mg/dL). Histological grade was more advanced in the BKVAN/AR group (P=0.034). Serum load of BKV, dose of immunosuppressants, and tacrolimus level showed a higher tendency in the BKVAN alone group; however it was not statistically significant. After anti-rejection therapy, immunosuppression was reduced in the BKVAN/AR group. Renal functional deterioration over 1 yr after BKVAN diagnosis was similar between the two groups (P=0.665). These findings suggest that the prognosis of BKVAN/AR after anti-rejection therapy followed by anti-BKV therapy might be similar to that of BKVAN alone after anti-BKV therapy.

The Impact of ABCB1 Gene Polymorphism on Steroid Responsiveness in Acute Rejection in Kidney Transplantation / 대한이식학회지

BACKGROUND: Steroid pulse therapy has been used for patients with acute rejection after kidney transplantation. The ABCB1 gene codes for P-glycoprotein, a transporter that is involved in the metabolism of steroids. However, the role of ABCB1 polymorphisms has not been investigated in patients with acute rejection after kidney transplantation. METHODS: Among 763 patients that received kidney or simultaneous pancreas-kidney transplantation at Seoul National University Hospital between May 1996 and July 2009, 684 patients agreed to genetic sampling for polymorphisms. Acute rejection was defined as biopsy-proven, acute cellular rejection with increased serum creatinine, or in the context of delayed or slow graft function. Steroid-resistance was defined as no improvement in serum creatinine, need for additional OKT3 or ATG treatment, or repeated acute rejection within 30 days. Three polymorphisms of ABCB1 gene (C1236T, C3435T, G2677T/A) were assessed. RESULTS: C allele frequency of C3435T was 59.3% and of C1236T 40.1%. Patients who were steroid-resistant (n=37) had higher serum creatinine at kidney biopsy compared to those who were steroid-sensitive (n=49, P<0.001). The frequency of ABCB1 gene polymorphisms (C1236T and C3435T) did not differ significantly between patients who were steroid-sensitive and those who were resistant. An association with G2677T/A could not be analyzed due to a high failure rate of genotyping. CONCLUSIONS: ABCB1 gene polymorphisms (C1236T and C3435T) were not associated with steroid resistance in patients with acute cellular rejection after kidney transplantation.

The Role of Macrophages in Transplant Rejection / 대한이식학회지

Macrophage accumulation has been recognized as a feature of allograft rejection, however, the role of macrophages in rejection remains underappreciated. Macrophages are present within graft tissues throughout the lifespan of the graft, including acute rejection episodes. Recent advances in macrophage biology have demonstrated that different types of macrophages in grafts serve a range of functions, including promotion or attenuation of inflammation, participation in innate and adaptive immune responses, and mediation of tissue injury, fibrosis, and tissue repair. Macrophages contribute to both the innate and acquired arms of the alloimmune response, and, thus, may be involved in all aspects of acute and chronic allograft rejection. Macrophages are also involved in hyperacute and acute vascular rejection of xenografts. A deeper understanding of how macrophages accumulate within grafts and of the factors that control differentiation and function of these cells could lead to identification of novel therapeutic targets in transplantation.

ABO Incompatible Kidney Transplantation / 대한신장학회지

No abstract available.

Erratum to "Assessment of Deceased Donor Kidneys Using a Donor Scoring System" by Bang K, et al. (Yonsei Med J 2010;51:870-876)

No abstract available.

Erratum to "Assessment of Deceased Donor Kidneys Using a Donor Scoring System" by Bang K, et al. (Yonsei Med J 2010;51:870-876)

No abstract available.

Early Vascular Access Blood Flow as a Predictor of Long-term Vascular Access Patency in Incident Hemodialysis Patients

The long-term clinical benefits of vascular access blood flow (VABF) measurements in hemodialysis (HD) patients have been controversial. We evaluated whether early VABF may predict long-term vascular access (VA) patency in incident HD patients. We enrolled 57 patients, of whom 27 were starting HD with arteriovenous fistulas (AVFs) and 30 with arteriovenous grafts (AVGs). The patients' VABF was measured monthly with the ultrasound dilution technique over the course of the first six months after the VA operation. During the 20.4-month observational period, a total of 40 VA events in 23 patients were documented. The new VA events included 13 cases of stenosis and 10 thrombotic events. The lowest quartile of average early VABF was related to the new VA events. After adjusting for covariates such as gender, age, hypertension, diabetes, VA type, hemoglobin levels, body mass index, parathyroid hormone, and calcium-phosphorus product levels, the hazard ratio of VABF (defined as <853 mL/min in AVF or <830 mL/min in AVG) to incident VA was 3.077 (95% confidence interval, 1.127-8.395; P=0.028). There were no significant relationships between early VABF parameters and VA thrombosis. It is concluded that early VABF may predict long-term VA patency, particularly VA stenosis.

Improvement in Erythropoieis-stimulating Agent-induced Pure Red-cell Aplasia by Introduction of Darbepoetin-alpha When the Anti-erythropoietin Antibody Titer Declines Spontaneously

Anti-erythropoietin antibodies usually cross-react with all kinds of recombinant erythropoietins; therefore, erythropoiesis-stimulating agent (ESA)-induced pure red-cell aplasia (PRCA) is not rescued by different ESAs. Here, we present a case of ESA-induced PRCA in a 36-yr-old woman with chronic kidney disease, whose anemic condition improved following reintroduction of darbepoetin-alpha. The patient developed progressive, severe anemia after the use of erythropoietin-alpha. As the anemia did not improve after the administration of either other erythropoietin-alpha products or erythropoietin-beta, all ESAs were discontinued. Oxymetholone therapy failed to improve the transfusion-dependent anemia and a rechallenge with ESAs continuously failed to obtain a sustained response. However, her anemia improved following reintroduction of darbepoetin-alpha at 3 yr after the initial diagnosis. Interestingly, anti-erythropoietin antibodies were still detectable, although their concentration was too low for titration. In conclusion, darbepoetin-alpha can improve ESA-induced PRCA when the anti-erythropoietin antibody titer declines and its neutralizing capacity is lost.