Corrigendum: Pre-transplant crossmatch-negative donor-specific anti-HLA antibody predicts acute antibody-mediated rejection but not long-term outcomes in kidney transplantation: an analysis of the Korean Organ Transplantation Registry.

[This corrects the article DOI: 10.3389/fimmu.2024.1420351.].

Comparisons of clinical outcomes between hypertensive and normotensive living kidney donors: a prospective, multicenter nationwide cohort study.

Background: Living kidney donors with hypertension are potential candidates for solving the donor shortages in renal transplantation. However, the safety of donors with hypertension after nephrectomy has not been sufficiently confirmed. Methods: A total of 642 hypertensive and 4,848 normotensive living kidney donors who were enrolled in the Korean Organ Transplantation Registry between May 2014 and December 2020 were included in this study. The study endpoints were a decreased estimated glomerular filtration rate (eGFR) and proteinuria. Results: In the entire cohort, donors with hypertension had a lower eGFR before nephrectomy in comparison to normotensive donors which remained lower after kidney transplantation. The incidence of proteinuria in hypertensive donors increased during follow-up. In propensity score-matched analysis, the risk of eGFR being <60 mL/min/1.73 m2 (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.50-1.19) or <45 mL/min/1.73 m2 (HR, 0.50; 95% CI, 0.06-4.03) was not significantly increased in donors with hypertension. However, hypertensive donors were found to have a significantly higher risk of proteinuria than normotensive donors (HR, 2.28; 95% CI, 1.05-4.94). Similar findings were also observed in the analysis of the entire cohort, indicating that hypertensive donors had a significantly higher risk of proteinuria (adjusted HR, 1.77; 95% CI, 1.10-2.85), without a substantial increase in the risk of decreased renal function. Conclusion: The risk of proteinuria after donation was substantially increased in donors with hypertension. These findings underscore the need for careful monitoring of proteinuria in hypertensive donors following donation.

Impact of Blood Pressure on Allograft Function and Survival in Kidney Transplant Recipients.

The optimal target blood pressure for kidney transplant (KT) patients remains unclear. We included 808 KT patients from the KNOW-KT as a discovery set, and 1,294 KT patients from the KOTRY as a validation set. The main exposures were baseline systolic blood pressure (SBP) at 1 year after KT and time-varying SBP. Patients were classified into five groups: SBP <110; 110-119; 120-129; 130-139; and ≥140 mmHg. SBP trajectories were classified into decreasing, stable, and increasing groups. Primary outcome was composite kidney outcome of ≥50% decrease in eGFR or death-censored graft loss. Compared with the 110-119 mmHg group, both the lowest (adjusted hazard ratio [aHR], 2.43) and the highest SBP (aHR, 2.25) were associated with a higher risk of composite kidney outcome. In time-varying model, also the lowest (aHR, 3.02) and the highest SBP (aHR, 3.60) were associated with a higher risk. In the trajectory model, an increasing SBP trajectory was associated with a higher risk than a stable SBP trajectory (aHR, 2.26). This associations were consistent in the validation set. In conclusion, SBP ≥140 mmHg and an increasing SBP trajectory were associated with a higher risk of allograft dysfunction and failure in KT patients.

Impact of Arterial Calcification on Cardiovascular and Renal Outcomes in Kidney Transplant Patients.

Introduction: Coronary artery calcification score (CACS) and abdominal aortic calcification score (AACS) are both well-established markers of vascular stiffness, and previous studies have shown that a higher CACS is a risk factor for chronic kidney disease (CKD) progression. However, the impact of pretransplant CACS and AACS on cardiovascular and renal outcomes in kidney transplant patients has not been established. Methods: We included 944 kidney transplant recipients from the KoreaN cohort study for Outcome in patients With Kidney Transplantation (KNOW-KT) cohort and categorized them into three groups (low, medium, and high) according to baseline CACS (0, 0 < and ≤100, >100) and AACS (0, 1-4, >4). The low (0), medium (0 < and ≤ 100), and high (>100) CACS groups each consisted of 462, 213, and 225 patients, respectively. Similarly, the low (0), medium (1-4), and high (>4) AACS groups included 638, 159, and 147 patients, respectively. The primary outcome was the occurrence of cardiovascular events. The secondary outcomes were all-cause mortality and composite kidney outcomes, which comprised of >50% decline in the estimated glomerular filtration rate and graft loss. Cox regression analysis was used to investigate the association between baseline CACS/AACS and outcomes. Results: The high CACS group (N = 462) faced a significantly higher risk for cardiovascular outcomes (adjusted hazard ratio [aHR], 5.97; 95% confidence interval [CI], 2.01-17.7) and all-cause mortality (aHR, 2.74; 95% CI, 1.27-5.92) compared to the low CACS group (N = 225). Similarly, the high AACS group (N = 638) had an elevated risk for cardiovascular outcomes (aHR, 2.38; 95% CI, 1.16-4.88). Furthermore, the addition of CACS to prediction models improved prediction indices for cardiovascular outcomes. However, the risk of renal outcomes did not differ among CACS or AACS groups. Conclusion: Pretransplant arterial calcification, characterized by high CACS or AACS, is an independent risk factor for cardiovascular outcomes and mortality in kidney transplant patients.

Arterial calcification, accumulation of calcium in the arterial walls, vascular stiffness, and loss of elasticity of blood vessels can contribute to the development of cardiovascular diseases. Patients with chronic kidney disease and those undergoing dialysis have a considerably increased risk of vascular calcification. Even after kidney transplantation when kidney function has been restored, the prevalence of vascular calcification and subsequent cardiovascular disease remains high. Coronary artery calcification score and abdominal aortic calcification score are both well-established markers of vascular calcification. However, the impact of pretransplant vascular calcification scores on cardiovascular and renal outcomes in kidney transplant patients has not been established. When we analyzed 944 Korean kidney transplant patients, both vascular calcification scores were significantly associated with cardiovascular outcomes after kidney transplantation, but were not associated with renal outcomes. We also demonstrated that the addition of coronary artery calcification scores led to a modest improvement in the prediction performance for kidney transplant outcomes. Our findings suggest a potential role of pretransplant screening of coronary calcification scores and aortic calcification scores in risk stratification for post-kidney transplant outcomes.

Unilateral testicular tuberculosis in a kidney transplant recipient: a case report.

Tuberculosis (TB) of the genitourinary system is a rare form of extrapulmonary TB. Testicular TB is particularly uncommon among kidney transplantation (KT) recipients. Diagnosing testicular TB is challenging due to the nonspecific nature of clinical presentations and ambiguous imaging results. In this report, we describe a case involving a 36-year-old male KT recipient who presented with left scrotal pain. He had undergone a living donor KT 8 years prior and was receiving tacrolimus, mycophenolate mofetil, and prednisolone. Laboratory tests revealed anemia, leukocytosis, and elevated inflammatory markers. Computed tomography showed left scrotal wall thickening and enlargement, suggestive of a left testicular abscess. We discontinued mycophenolate mofetil and administered intravenous antibiotics. Additionally, we performed an incision and drainage of the abscess. However, there was no improvement in his clinical course. Consequently, we performed a radical left orchiectomy. The biopsy revealed extensive chronic granulomatous inflammation with caseous necrosis, consistent with tuberculous orchiepididymitis. A quadruple anti-TB regimen was administered, leading to an improvement in the patient's condition. To the best of our knowledge, this is the first reported case of testicular TB without other organ involvement in KT recipients. Including testicular TB in the differential diagnosis of testicular infections and masses is necessary to avoid unnecessary surgical procedures.

Coexistence of double seropositivity for MPO antibody and anti-GBM antibody in ANCA-associated vasculitis concurrent with multiple myeloma: A case report.

RATIONALE: Immune-mediated vasculitis with 2 or more autoantibodies, for example, anti-proteinase-3, combined with anti-myeloperoxidase (MPO) or anti-glomerular basement membrane (GBM) antibodies, is extremely unusual. Furthermore, the coexistence of autoimmune vasculitis and hematological malignancies is uncommon. Herein, we describe a case of double-seropositive anti-neutrophil cytoplasmic antibody (ANCA) vasculitis with multiple myeloma. PATIENT CONCERNS: A 79-year-old Asian man presented with persistent leg edema and kidney dysfunction. His kidney function rapidly decreased, and serologic test results showed higher titers of the anti-MPO antibody (54.7 IU/mL) and anti-GBM antibodies (>200 IU/mL). Additionally, the clinical features showed the possibility of monoclonal gammopathy with anemia and hyperglobulinemia. We performed kidney and bone marrow biopsy. Serum protein electrophoresis and immunofixation revealed no significant differences, but the results of the bone marrow smear were compatible with those of myeloma with 15% plasmacytosis. However, kidney biopsy showed diffuse crescentic glomerulonephritis without deposition of the immune complex or kappa/lambda chain. DIAGNOSES AND INTERVENTIONS: Finally, the patient was diagnosed with double-seropositive ANCA-associated glomerulonephritis and multiple myeloma. Given the patient's performance status, we initiated low-dose steroid pulse therapy, followed by conservative management. OUTCOMES: While the pulmonary lesions showed improvement, the kidney function did not regain its previous state, prompting the initiation of kidney replacement therapy by hemodialysis. There has been a decrease in the levels of anti-GBM and anti-MPO antibodies since the initial diagnosis. LESSONS: This case elucidates the complex interplay between ANCA-associated glomerulonephritis and hematologic malignancy and emphasizes the need for a nuanced treatment strategy considering its multifaceted clinical presentation.

Pre-transplant crossmatch-negative donor-specific anti-HLA antibody predicts acute antibody-mediated rejection but not long-term outcomes in kidney transplantation: an analysis of the Korean Organ Transplantation Registry.

Background: Pre-transplant donor-specific anti-human leukocyte antigen antibody (HLA-DSA) is a recognized risk factor for acute antibody-mediated rejection (ABMR) and allograft failure. However, the clinical relevance of pre-transplant crossmatch (XM)-negative HLA-DSA remains unclear. Methods: We investigated the effect of XM-negative HLA-DSA on post-transplant clinical outcomes using data from the Korean Organ Transplantation Registry (KOTRY). This study included 2019 living donor kidney transplant recipients from 40 transplant centers in South Korea: 237 with HLA-DSA and 1782 without HLA-DSA. Results: ABMR developed more frequently in patients with HLA-DSA than in those without (5.5% vs. 1.5%, p<0.0001). Multivariable analysis identified HLA-DSA as a significant risk factor for ABMR (odds ratio = 3.912, 95% confidence interval = 1.831-8.360; p<0.0001). Furthermore, the presence of multiple HLA-DSAs, carrying both class I and II HLA-DSAs, or having strong HLA-DSA were associated with an increased incidence of ABMR. However, HLA-DSA did not affect long-term clinical outcomes, such as allograft function and allograft survival, patient survival, and infection-free survival. Conclusion: Pre-transplant XM-negative HLA-DSA increased the risk of ABMR but did not affect long-term allograft outcomes. HLA-incompatible kidney transplantation in the context of XM-negative HLA-DSA appears to be feasible with careful monitoring and ensuring appropriate management of any occurrence of ABMR. Furthermore, considering the characteristics of pre-transplant XM-negative HLA-DSA, the development of a more detailed and standardized desensitization protocol is warranted.

A novel allocation scheme for deceased donor kidneys to balance equity and utility.

Background: Patients with sensitization and blood type O experience increased waiting times for deceased-donor kidney transplantation (DDKT). While allocation benefits are needed to resolve inequity in DDKT opportunity, whether DDKT has comparable outcomes in this disadvantaged population requires further study. This study assessed these outcomes and developed a new allocation system that balances equity and utility. Methods: Patients from national and hospital cohorts from two centers in Korea were categorized as B1 to B4 (according to panel reactive antibody [PRA] positivity and ABO blood type) and A1 to A4 (based on the maximal PRA% and blood type), respectively. Competing risk and Cox regression analyses were performed to assess the effects of PRA and blood type on graft failure and mortality, respectively. Based on DDKT opportunities and posttransplant outcomes, a new scoring system for kidney allocation was developed. Results: The national and hospital cohorts included 3,311 and 819 patients, respectively, who underwent DDKT. Despite the disparities in DDKT opportunities, the graft failure rates and mortality did not differ among the different PRA and blood type groups. Furthermore, posttransplantation outcomes did not differ according to the categories with different DDKT opportunities. A new scoring system to provide additional points to disadvantaged populations was developed based on the hazard ratios for DDKT. Conclusion: A new allocation approach based on PRA and ABO blood types offers benefits to disadvantaged patients with fewer DDKT opportunities and could enhance equity without sacrificing utility in Korea, which has a long waiting time for DDKT.

Molecular incompatibility between pig CD200 and human CD200 receptor in in vitro xenogeneic immune responses.

Overexpression of human CD200 (hCD200) in porcine endothelial cells (PECs) has been reported to suppress xenogeneic immune responses of human macrophages against porcine endothelial cells. The current study aimed to address whether the above-mentioned beneficial effect of hCD200 is mediated by overcoming the molecular incompatibility between porcine CD200 (pCD200) and hCD200 receptor or simply by increasing the expression levels of CD200 without any molecular incompatibility across the two species. We overexpressed hCD200 or pCD200 using lentiviral vectors with V5 marker in porcine endothelial cells and compared their suppressive activity against U937-derived human macrophage-like cells (hMCs) and primary macrophages. In xenogeneic coculture of porcine endothelial cells and human macrophage-like cells or macrophages, hCD200-porcine endothelial cells suppressed phagocytosis and cytotoxicity of human macrophages to a greater extent than pCD200-porcine endothelial cells. Secretion of tumor necrosis factor-α, interleukin-1ß, and monocyte chemoattractant protein-1 from human macrophages and expression of M1 phenotypes (inducible nitric oxide synthase, dectin-1, and CD86) were also suppressed by hCD200 to a greater extent than pCD200. Furthermore, in signal transduction downstream of CD200 receptor, hCD200 induced Dok2 phosphorylation and suppressed IκB phosphorylation to a greater extent than pCD200. The above data supported the possibility of a significant molecular incompatibility between pCD200 and human CD200 receptor, suggesting that the beneficial effects of hCD200 overexpression in porcine endothelial cells could be mediated by overcoming the molecular incompatibility across the species barrier rather than by simple overexpression effects of CD200.

Liver Transplantation from Brain-Dead Donors with Hepatitis B or C in South Korea: A 2014-2020 Korean Organ Transplantation Registry Data Analysis.

BACKGROUND According to the current guidelines for liver transplantation (LT) of brain-dead donors with hepatitis B or C virus (HBV or HCV) in Korea, grafts from hepatitis B surface antigen (HBsAg)(+) or HCV antibody (anti-HCV)(+) donors must be transplanted only to HBsAg(+) or anti-HCV(+) recipients, respectively. We aimed to determine the current status and outcomes of brain-dead donor LT with HBV or HCV in Korea. MATERIAL AND METHODS This retrospective observational study included all LTs from brain-dead donors in the Korean Organ Transplantation Registry between April 2014 and December 2020. According to donor hepatitis status, 24 HBV(+), 1 HCV(+), and 1010 HBV(-)/HCV(-) donors were included. RESULTS Baseline/final model for end-stage liver disease score (MELD) for HBV(+), HCV(+), and HBV(-)/HCV(-) were 22.4±9.3/27.8±7.8, 16/11, and 33.0±15.4/35.5±7.1, respectively. MELD score of HBV (+) were lower than those of HBV(-)/HCV(-) (P<0.01). Five-year graft and patient survival rates of HBV(+) and HBV(-)/HCV(-) recipients were 81.7%/85.6%, and 76.6%/76.7%, respectively (P=0.73 and P=0.038). One-year graft and patient survival rates of HCV (+) graft recipients were both 100%. CONCLUSIONS No differences in graft and patient survival rates between HBV(+) and HBV(-)/HCV(-) groups were observed. Although accumulating the results of transplants from HBV (+) or HCV(+) grafts to HBV(-) or HCV(-) recipients is not possible owing to domestic regulations, Korea should conditionally permit transplantations from HBV(+) or HCV(+) grafts to HBV(-) or HCV(-) recipients by considering the risks and benefits based on foreign studies. Thereafter, we can accumulate the data from Korea and analyze the outcomes.

Anti-intercellular adhesion molecule 1 monomaintenance therapy induced long-term liver allograft survival without chronic rejection.

Calcineurin inhibitors (CNIs) are essential in liver transplantation (LT); however, their long-term use leads to various adverse effects. The anti-intercellular adhesion molecule (ICAM)-1 monoclonal antibody MD3 is a potential alternative to CNI. Despite its promising results with short-term therapy, overcoming the challenge of chronic rejection remains important. Thus, we aimed to investigate the outcomes of long-term MD3 therapy with monthly MD3 monomaintenance in nonhuman primate LT models. Rhesus macaques underwent major histocompatibility complex-mismatched allogeneic LT. The conventional immunosuppression group (Con-IS, n = 4) received steroid, tacrolimus, and sirolimus by 4 months posttransplantation. The induction MD3 group (IN-MD3, n = 5) received short-term MD3 therapy for 3 months with Con-IS. The maintenance MD3 group (MA-MD3, n = 4) received MD3 for 3 months, monthly doses by 2 years, and then quarterly. The MA-MD3 group exhibited stable liver function without overt infection and had significantly better liver allograft survival than the IN-MD3 group. Development of donor-specific antibody and chronic rejection were suppressed in the MA-MD3 group but not in the IN-MD3 group. Donor-specific T cell responses were attenuated in the MA-MD3 group. In conclusion, MD3 monomaintenance therapy without maintenance CNI provides long-term liver allograft survival by suppressing chronic rejection, offering a potential breakthrough for future human trials.

Interleukin-2/anti-interleukin-2 immune complex attenuates cold ischemia-reperfusion injury after kidney transplantation by increasing renal regulatory T cells.

BACKGROUND: Cold ischemia-reperfusion injury (IRI) is an unavoidable complication of kidney transplantation. We investigated the role of regulatory T cells (Treg) in cold IRI and whether the interleukin (IL)-2/anti-IL-2 antibody complex (IL-2C) can ameliorate cold IRI. METHODS: We developed a cold IRI mouse model using kidney transplantation and analyzed the IL-2C impact on cold IRI in acute, subacute and chronic phases. RESULTS: Treg transfer attenuated cold IRI, while Treg depletion aggravated cold IRI. Next, IL-2C administration prior to IRI mitigated acute renal function decline, renal tissue damage and apoptosis and inhibited infiltration of effector cells into kidneys and pro-inflammatory cytokine expression on day 1 after IRI. On day 7 after IRI, IL-2C promoted renal regeneration and reduced subacute renal damage. Furthermore, on day 28 following IRI, IL-2C inhibited chronic fibrosis. IL-2C decreased reactive oxygen species-mediated injury and improved antioxidant function. When IL-2C was administered following IRI, it also increased renal regeneration with Treg infiltration and suppressed renal fibrosis. In contrast, Treg depletion in the presence of IL-2C eliminated the positive effects of IL-2C on IRI. CONCLUSION: Tregs protect kidneys from cold IRI and IL-2C inhibited cold IRI by increasing the renal Tregs, suggesting a potential of IL-2C in treating cold IRI. KEY POINTS: Interleukin (IL)-2/anti-IL-2 antibody complex attenuated acute renal injury, facilitated subacute renal regeneration and suppressed chronic renal fibrosis after cold ischemia-reperfusion injury (IRI) by increasing the renal Tregs. IL-2/anti-IL-2 antibody complex decreased reactive oxygen species-mediated injury and improved antioxidant function. This study suggests the therapeutic potential of the IL-2/anti-IL-2 antibody complex in kidney transplantation-associated cold IR.

Prevention of Cytomegalovirus Infection in Solid Organ Transplant Recipients: Guidelines by the Korean Society of Infectious Diseases and the Korean Society for Transplantation.

Cytomegalovirus (CMV) is the most important opportunistic viral pathogen in solid organ transplant (SOT) recipients. The Korean guideline for the prevention of CMV infection in SOT recipients was developed jointly by the Korean Society for Infectious Diseases and the Korean Society of Transplantation. CMV serostatus of both donors and recipients should be screened before transplantation to best assess the risk of CMV infection after SOT. Seronegative recipients receiving organs from seropositive donors face the highest risk, followed by seropositive recipients. Either antiviral prophylaxis or preemptive therapy can be used to prevent CMV infection. While both strategies have been demonstrated to prevent CMV infection post-transplant, each has its own advantages and disadvantages. CMV serostatus, transplant organ, other risk factors, and practical issues should be considered for the selection of preventive measures. There is no universal viral load threshold to guide treatment in preemptive therapy. Each institution should define and validate its own threshold. Valganciclovir is the favored agent for both prophylaxis and preemptive therapy. The evaluation of CMV-specific cell-mediated immunity and the monitoring of viral load kinetics are gaining interest, but there was insufficient evidence to issue recommendations. Specific considerations on pediatric transplant recipients are included.

Impact of sensitization and ABO blood types on the opportunity of deceased-donor kidney transplantation with prolonged waiting time.

The waiting time to deceased-donor kidney transplantation (DDKT) is long in Asian countries. We investigated the impact of sensitization and ABO blood type (ABO) on DDKT opportunity using two Korean cohorts: a hospital cohort from two centers and a national database. The impact of panel reactive antibody (PRA) based on the maximal PRA% and ABO on DDKT accessibility was analyzed using a competing risks regression model. In the hospital cohort (n = 4722), 88.2%, 8.7%, and 3.1% of patients belonged to < 80%, 80-99%, and ≥ 99% PRA groups, respectively, and 61.1%, 11.6%, and 27.3% belonged to A or B, AB, and O blood types, respectively. When PRA and ABO were combined, PRA < 80%/A or B and 80 ≤ PRA < 99%/AB had fewer DDKT opportunities (median, 12 years; subdistribution hazard ratio [sHR], 0.71) compared with PRA < 80%/AB (median, 11 years). Also, PRA < 80%/O, 80 ≤ PRA < 99%/A or B, and PRA ≥ 99%/AB had a much lower DDKT opportunity (median, 13 years; sHR, 0.49). Furthermore, 80 ≤ PRA < 99%/O and PRA ≥ 99%/non-AB had the lowest DDKT opportunity (sHR, 0.28). We found similar results in the national cohort (n = 18,974). In conclusion, an integrated priority system for PRA and ABO is needed to reduce the inequity in DDKT opportunities, particularly in areas with prolonged waiting times.

Creatinine-cystatin C ratio and death with a functioning graft in kidney transplant recipients.

Death with a functioning graft is important cause of graft loss after kidney transplantation. However, little is known about factors predicting death with a functioning graft among kidney transplant recipients. In this study, we evaluated the association between post-transplant creatinine-cystatin C ratio and death with a functioning graft in 1592 kidney transplant recipients. We divided the patients into tertiles based on sex-specific creatinine-cystatin C ratio. Among the 1592 recipients, 39.5% were female, and 86.1% underwent living-donor kidney transplantation. The cut-off value for the lowest creatinine-cystatin C ratio tertile was 0.86 in males and 0.73 in females. The lowest tertile had a significantly lower 5-year patient survival rate and was independently associated with death with a functioning graft (adjusted hazard ratio 2.574, 95% confidence interval 1.339-4.950, P < 0.001). Infection was the most common cause of death in the lowest tertile group, accounting for 62% of deaths. A low creatinine-cystatin C ratio was significantly associated with an increased risk of death with a functioning graft after kidney transplantation.

Association of Serum Osteoprotegerin With Vascular Calcification, and Cardiovascular and Graft Outcomes in Kidney Transplant Patients: Results From the KNOW-KT.

BACKGROUND: Vascular calcification and stiffness contribute to increased cardiovascular morbidity in patients with chronic kidney disease. This study investigated associations between serum osteoprotegerin (OPG) levels and vascular calcification or stiffness to assess cardiovascular and graft outcomes in kidney transplant patients. METHODS: The KoreaN cohort study for Outcome in patients With Kidney Transplantation was a prospective multicenter cohort study. Serum OPG levels were measured at baseline and 3 y after transplantation in 1018 patients. Patients were classified into high and low OPG groups according to median serum OPG levels. The median follow-up duration was 93.5 mo. RESULTS: The mean age was 45.8 ±â€…11.7 y and 62.9% were men. Patients with high OPG had significantly higher coronary artery calcium scores, abdominal aortic calcification scores, and brachial-ankle pulse wave velocities than those with lower OPG; these parameters remained significant for 5 y after transplantation. The 3-y OPG levels were lower than baseline values ( P < 0.001) and were positively correlated ( r = 0.42, P < 0.001). Multivariate Cox regression analysis showed that high OPG levels were significantly associated with posttransplant cardiovascular events ( P = 0.008) and death-censored graft loss ( P = 0.004). Similar findings regarding posttransplant cardiovascular events ( P = 0.012) and death-censored graft loss ( P = 0.037) were noted in patients with high OPG at the 3-y follow-up. Mediation analyses revealed that coronary artery calcium scores, abdominal aortic calcification scores, and brachial-ankle pulse wave velocities could act as mediators between serum OPG levels and posttransplant cardiovascular events. CONCLUSIONS: Serum OPG concentration is associated with vascular calcification and stiffness and could be a significant risk factor for cardiovascular outcomes and graft loss in patients undergoing kidney transplantation.

Association of Serum Activin Levels with Allograft Outcomes in Patients with Kidney Transplant: Results from the KNOW-KT.

INTRODUCTION: Serum activin A has been reported to contribute to vascular calcification and kidney fibrosis in chronic kidney disease. We aimed to investigate whether higher serum activin levels were associated with poor allograft outcomes in patients with kidney transplantation (KT). METHODS: A total of 860 KT patients from KNOW-KT (Korean Cohort Study for Outcome in Patients with Kidney Transplantation) were analyzed. We measured serum activin levels pre-KT and 1 year after KT. The primary outcome was the composite of a ≥50% decline in estimated glomerular filtration rate and graft failure. Multivariable cause-specific hazard model was used to analyze association of 1-year activin levels with the primary outcome. The secondary outcome was coronary artery calcification score (CACS) at 5 years after KT. RESULTS: During the median follow-up of 6.7 years, the primary outcome occurred in 109 (12.7%) patients. The serum activin levels at 1 year were significantly lower than those at pre-KT (488.2 ± 247.3 vs. 704.0 ± 349.6). When patients were grouped based on the median activin level at 1 year, the high-activin group had a 1.91-fold higher risk (95% CI, 1.25-2.91) for the primary outcome compared to the low-activin group. A one-standard deviation increase in activin levels as a continuous variable was associated with a 1.36-fold higher risk (95% CI, 1.16-1.60) for the primary outcome. Moreover, high activin levels were significantly associated with 1.56-fold higher CACS (95% CI, 1.12-2.18). CONCLUSION: Post-transplant activin levels were independently associated with allograft functions as well as coronary artery calcification in KT patients.

Kidney Transplantation From Brain-Dead Donors With Hepatitis B or C in South Korea: A 2015 to 2020 Korean Organ Transplantation Registry Data Analysis.

BACKGROUND: According to the current Center for Korean Network for Organ Sharing guidelines for kidney transplantation from brain-dead donors with hepatitis B or C infection, organs from hepatitis B surface antigen-positive (HbsAg+) or anti-hepatitis C virus-positive (HCV+) donors can only be transplanted into HBsAg+ or anti-HCV+ recipients. We aimed to confirm the status and the outcomes of kidney transplantation from brain-dead donors with hepatitis B or C virus in Korea. METHODS: This retrospective study included all kidney transplantations from brain-dead donors in the Korean Organ Transplantation Registry database between January 2015 and June 2020, divided into 3 groups according to donor hepatitis status. Finally, kidney transplantations from 80 HBV+, 12 HCV+, and 2013 HBV-/HCV- donors were included. RESULTS: No statistically significant differences were observed in the recipient characteristics and the transplant outcomes except the waiting time (HBV+ to HBV-/HCV-, P < .001; HCV+ to HBV-/HCV-, P = .10; HBV+ to HCV+P = .95). Five-year graft survival rates of the HBV+, HCV+, and HBV-/HCV- recipients were 95%, 83%, and 85%, respectively (HBV+ to HCV+, P = .22; HCV+ to HBV-/HCV-, P = .81; HBV+ to HBV-/HCV-, P = .02). Five-year patient survival rates of the HBV+, HCV+, and HBV-/HCV- recipients were 95%, 100%, and 76%, respectively (HBV+ to HCV+, P = .61; HCV+ to HBV-/HCV-, P = .13; HBV+ to HBV-/HCV-, P < .001). CONCLUSION: HBV+/HCV+ brain-dead donor kidney transplantation outcomes were comparable to HBV-/HCV-. South Korea should consider conditionally permitting transplantation from HBV+ or HCV+ donors to HBV- or HCV- recipients to accumulate new data and conduct further studies.

Outcomes of ABO-Incompatible Living Donor Kidney Transplantation Compared to Waiting or Deceased Donor Kidney Transplantation.

INTRODUCTION: ABO-incompatible (ABOi) living donor kidney transplantation (LDKT) is considered only for patients who do not have an ABO-compatible (ABOc) LD. Therefore, a clinically practical question is whether to proceed with ABOi LDKT or remain on dialysis while waiting for ABOc deceased donor kidney transplantation (DDKT). However, this issue has not been addressed in Asian countries, where ABOi LDKT programs are more active than DDKT programs. METHODS: A total of 426 patients underwent ABOi-LDKT between 2010 and 2020 at Seoul National University Hospital and Severance Hospital, Korea. We compared outcomes between the ABOi-LDKT and the propensity-matched control groups (waiting-list-only group, n = 1,278; waiting-list-or-ABOc-DDKT group, n = 1,278). RESULTS: The ABOi-LDKT group showed a significantly better patient survival rate than the waiting-list-only group (p = 0.001) and the waiting-list-or-ABOc-DDKT group (p = 0.048). When the ABOi-LDKT group was categorized into a high-titer group (peak anti-ABO titer ≥1:128) and a low-titer group (peak anti-ABO titer ≤1:64), the low-titer group showed better patient survival rates than those of the waiting-list-or-ABOc-DDKT group (p = 0.046) or the waiting-list-only group (p = 0.004). In contrast, the high-titer ABOi-LDKT group showed no significant benefit in patient survival compared to the waiting-list-or-ABOc-DDKT group. Death-censored graft survival in the ABOi-LDKT group was not significantly different from that in the ABOc-DDKT group (p = 0.563). CONCLUSION: The ABOi-LDKT group has better outcomes than the waiting-list-or-ABOc-DDKT group in a country with a long waiting time.

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.