Surgical Outcomes of Ipsilateral Inguinal Hernia After Kidney Transplantation.

OBJECTIVES: We aimed to clarify the clinical features and outcomes of ipsilateral inguinal hernias after kidney transplantation. PATIENTS AND METHODS: Eleven patients diagnosed with inguinal hernia on the ipsilateral side after kidney transplantation between 2011 and 2022 were analyzed. Clinical data were retrospectively reviewed from the medical records. RESULT: Eleven patients were included in the analysis (median age, 68 [range, 28-75] years, male, n = 11). The time from kidney transplantation to hernia surgery was 107 (6-393) months. Eight patients had direct-type inguinal hernias. Three had indirect-type inguinal hernias. Hernia contents included the small intestine (n = 5), transplanted ureter and bladder (n = 2), only bladder (n = 1), transplanted kidney, ureter, and small intestine (n = 1), transplanted kidney and small intestine (n = 1), and transplanted ureter (n = 1). Six patients (55%) were diagnosed with urinary tract obstruction due to inguinal hernia. All hernias were repaired using mesh. The plug method was used in 9 cases. The Lichtenstein method was used in 2 cases. The median operative time was 110 (73-155) minutes, and the median blood loss was 3 (1-85) mL. The median postoperative hospital stay was 4 (2-7) days. In the 6 patients with urinary obstruction, the serum creatinine levels improved (P = .028), and the transplanted urinary tract obstruction disappeared after surgery. There was no recurrence of inguinal hernia. One patient experienced chronic pain in the groin area (Clavien-Dindo grade II) during follow-up. CONCLUSION: Surgical intervention for inguinal hernia after kidney transplantation is safe and effective for preventing worsening of the kidney graft function.

Arteriolar hyalinization at 0-hour biopsy predicts long-term graft function in deceased kidney transplantation.

OBJECTIVES: Regarding the relationship between donor kidney quality and renal graft function after deceased kidney transplantation (KTx) following donation after cardiac death (DCD), the evaluation timing varies depending on the study. Evaluation of histology and changes in long-term renal graft function is limited. METHODS: A retrospective single-center study included 71 recipients who underwent 0-hour biopsy for KTx from DCD. The recipients were divided into two groups to evaluate factors related to renal graft function (study1). The two groups were categorized as stable graft function and poor graft function with the change of estimated glomerular filtration rate (eGFR) after KTx. The recipients were then divided into four groups to assess whether the factors identified in study1 were related to the change in long-term renal graft function (study2). They were categorized as follows: Improved, Stable, Deteriorated, and Primary non-function with the change of eGFR after KTx. RESULTS: In study1, donor age ≥ 50 years (29.5% vs. 65.2%; p = 0.09), banff arteriolar hyalinosis (ah) score (0.66 ± 0.78 vs. 1.2 ± 1.0; p = 0.018), and presence of glomerulosclerosis (43.2% vs. 76.2%; p = 0.017) were significant risk factors for poor long-term graft function. When the recipients were divided into four groups, the severity of ah correlated well with changes in long-term renal function. CONCLUSIONS: We can predict the shift in long-term renal graft function after KTx from DCD according to the severity of ah by 0-hour biopsy.

Immunological risk and complement genetic evaluations in early onset de novo thrombotic microangiopathy after living donor kidney transplantation: A Japanese multicenter registry.

BACKGROUND: Thrombotic microangiopathy (TMA) after kidney transplantation (KTx), particularly early onset de novo (dn) TMA, requires immediate interventions to prevent irreversible organ damage. This multicenter study was performed to investigate the allogeneic clinical factors and complement genetic background of dnTMA after KTx. METHODS: Perioperative dnTMA after KTx within 1 week after KTx were diagnosed based on pathological or/and hematological criteria at each center, and their immunological backgrounds were researched. Twelve aHUS-related gene variants were examined in dnTMA cases. RESULTS: Seventeen recipients (15 donors) were enrolled, and all dnTMA cases were onset within 72-h of KTx, and 16 of 17 cases were ABO incompatible. The implementation rate of pre-transplant plasmaphereses therapies were low, including cases with high titers of anti-A/anti-B antibodies. Examination of aHUS-related gene variants revealed some deletions and variants with minor allele frequency (MAF) in Japan or East Asian genome databases in genes encoding alternative pathways and complement regulatory factors. These variants was positive in 8 cases, 6 of which were positive in both recipient and donor, but only in one graft loss case. CONCLUSIONS: Although some immunological risks were found for dnTMA after KTx, only a few cases developed into TMA. The characteristic variations revealed in the present study may be novel candidates related to dnTMA in Japanese or Asian patients, but not pathogenic variants of aHUS. Future studies on genetic and antigenic factors are needed to identify factors contributing to dnTMA after KTx.

Long-term CMV monitoring and chronic rejection in renal transplant recipients.

Introduction: Cytomegalovirus (CMV) is well established to be an independent risk factor for graft loss after kidney transplantation (KTx). Monitoring for CMV in the chronic phase is not defined in the current guideline. The effects of CMV infection, including asymptomatic CMV viremia, in the chronic phase are unclear. Methods: We performed a single-center retrospective study to investigate incidence of CMV infection in the chronic phase, defined as more than 1 year after KTx. We included 205 patients who received KTx between April 2004 and December 2017. The CMV pp65 antigenemia assays to detect CMV viremia were continuously performed every 1-3 months. Results: The median duration of the follow-up was 80.6 (13.1-172.1) months. Asymptomatic CMV infection and CMV disease were observed in 30.7% and 2.9% in the chronic phase, respectively. We found that 10-20% of patients had CMV infections in each year after KTx which did not change over 10 years. The history of CMV infection in the early phase (within 1 year after KTx) and chronic rejection were significantly associated with CMV viremia in the chronic phase. CMV viremia in the chronic phase was significantly associated with graft loss. Discussion: This is the first study to examine the incidence of CMV viremia for 10 years post KTx. Preventing latent CMV infection may decrease chronic rejection and graft loss after KTx.

Acquisition of Antibody Against Cytomegalovirus After Kidney Transplantation in Seronegative Recipients.

BACKGROUND: Cytomegalovirus (CMV) infection is one of the most important infectious diseases affecting recipients of kidney transplantation (KTx). However, the timing of seroconversion for CMV infection in seronegative recipients remains unclear. We evaluated CMV infections in CMV-seronegative recipients and the time to acquire antibodies against CMV. METHODS: We conducted a retrospective study of 228 recipients who underwent KTx between March 1988 and February 2018 at the Niigata University Hospital. The anti-CMV IgG antibody profile before and after transplantation was analyzed. Oral acyclovir or valganciclovir was used as prophylactic therapy for at least 6 months after transplantation. Cytomegalovirus infection was defined as CMV viremia detected using the CMV pp65 antigenemia assay. RESULTS: In this study, 50 cases (21.9%) were CMV-seronegative recipients. Over a median follow-up period of 126.7 months, 68% (34/50) of CMV-seronegative recipients experienced CMV viremia or overt disease symptoms as the first episode of CMV infection. The median duration from transplant to CMV infection was 69.0 days (range, 22-7426). All the recipients who experienced CMV infections acquired seroconversion. The median duration from KTx to seroconversion was 7.2 months (range, 2.8-252.3). Almost all CMV-seronegative recipients could acquire anti-CMV IgG antibodies within 2.5 years. In seronegative recipients whose donors were seronegative, no CMV viremia was found, and none developed anti-CMV IgG antibodies. CONCLUSIONS: In the clinical practice of CMV-seronegative recipients, we should consider that physicians must closely monitor the occurrence of CMV infection up until 2.5 years after KTx.

Current Status of ABO-incompatible Liver Transplantation.

By 2014, strategies to prevent antibody-mediated rejection (AMR) after ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) were established in Japan and expanded primarily to Asia, where LDLT is now the predominant form of LT owing to the scarcity of brain-dead donors. A desensitization protocol consisting of rituximab (375 mg/m 2 ), plasma pheresis, tacrolimus, and mycophenolate mofetil before LDLT, followed by standard immunosuppression, is currently the best option in terms of safety and efficacy. Rituximab administration is now known not to increase the risk of hepatocellular carcinoma recurrence, and the feasibility of rituximab for LDLT for acute liver failure and the need for desensitization before LDLT in children older than 1 y have been documented. Strategies are needed to distinguish patients at high risk of AMR from those at low risk and to adjust immunosuppression to prevent both AMR and infection. Specific single-nucleotide polymorphisms in genes encoding Fcγ receptors affecting the cytotoxicity of rituximab on B cells could be useful for adjusting immunosuppression levels to decrease infectious complications. Immunological accommodation after ABO-I transplantation could be provided by immune factors in both the grafts and recipients.

Pretransplant BMI Should Be <25 in Japanese Kidney Transplant Recipients: A Single-Center Experience.

BACKGROUND: The aim of this study was to determine the appropriate body mass index (BMI) in Japanese kidney transplant (KTx) recipients. We analyzed the effects of pre- and post-transplant (Tx) obesity on graft and patient survival, perioperative complications, post-transplant diabetes mellitus (PTDM), and cardiovascular disease (CVD) in Japanese KTx recipients. METHODS: This retrospective study included 269 recipients who underwent KTx from 2008 through 2020 at Niigata University Hospital. Obesity was defined as a body mass index (BMI) ≥25 kg/m2. We examined the association between pre- and post-Tx obesity and graft survival, patient survival, the incidence of PTDM and CVD, and perioperative surgical complications. RESULTS: The graft survival rate was lower in the pre-Tx BMI ≥25 kg/m2 group, although there was no significant difference in patient survival. There was no difference in graft and patient survival between the post-Tx BMI ≥25 kg/m2 group and the <25 kg/m2 group. A pre-Tx BMI ≥25 kg/m2 was an independent risk factor for biopsy-proven allograft rejection. New-onset DM after transplantation was significantly more common in the BMI ≥25 kg/m2 group than in the BMI <25 kg/m2 group (36% vs 13%; P = .002). The incidence of CVD was significantly higher in the post-Tx BMI ≥30 kg/m2 group than in the BMI <30 kg/m2 group (50% vs 11%; P = .023). There were no differences in surgical operating time, intraoperative blood loss, or perioperative complications between the obese and non-obese groups. CONCLUSION: Pre-Tx BMI ≥25 kg/m2 may be a risk factor for allograft rejection and graft loss. Post-Tx BMI should be <25 kg/m2 to reduce the risk for PTDM.

Hyporesponsiveness against donor's ABO antigens of renal grafts after ABO-incompatible kidney transplantation.

BACKGROUND: ABO antigens expressed on the red blood cells (RBCs) are not identical to those expressed on the renal endothelial cells. The isohemagglutinin assay employing the RBCs is the gold standard for evaluating anti-ABO antibody (Ab) levels. However, it remains unclear whether the anti-ABO Abs detected by the isohemagglutinin assay after ABO-incompatible (ABOi) kidney transplantations (KTx) that are not associated with antibody-mediated rejection can bind to renal graft endothelial cells. METHODS: Ninety plasma samples were collected from patients with stable graft function after ABO-compatible (ABOc) or ABOi KTx. Anti-ABO Ab titers were examined by both the isohemagglutinin assay and the CD31-ABO microarray, which was developed as a mimic of the ABO antigens expressed on the renal endothelial cells. RESULTS: The antibody titers detected by the isohemagglutinin assay and the CD31-ABO microarray after the ABOc KTx relatively correlated with each other. However, the CD31-ABO microarray results showed low antibody levels against donor blood group antigens after ABOi KTx and did not correlate with the isohemagglutinin assay. In contrast, the antibody levels against non-donor blood group antigens after ABOi KTx were comparable to those after the ABOc KTx. Fourteen patients received graft biopsies, and no antibody-mediated rejection was observed in ABOi KTx recipients, except for two patients who had anti-donor-HLA Abs. CONCLUSION: The present study suggested that the anti-ABO Abs detected by the isohemagglutinin assay after ABOi KTx with stable graft function were hyporeactive to the ABO antigen of graft renal endothelial cells.

[PREGNANCIES IN KIDNEY TRANSPLANT RECIPIENTS, AN ANALYSIS OF 9 CASES].

(Objective) Pregnancy in kidney transplant recipient continues to remain challenging due to a high rate of cesarean section along with preterm delivery, and concern for worsening renal function. This study examined the prognosis and perinatal management of post-transplant pregnancies. (Patients and methods) A total of nine post-transplant recipients at Niigata University Medical and Dental Hospital between 2007 and 2021 were retrospectively examined. (Results) All pregnancies were planned. Calcineurin inhibitors and steroids were continued, and antimetabolites were changed to azathioprine. The mean age at delivery was 33±3.8 years, and the mean time from renal transplantation to delivery was 6.5±3.5 years. Five patients (55.5%) had cesarean sections, while four (44.5%) patients had normal vaginal deliveries. The mean gestational age was 35±3.0 weeks, and the mean birth weight was 2,336±565.4 g. No congenital malformation was observed. The most common reason for early delivery was worsening renal function, seen in six (66.7%) patients. The mean serum creatinine level before pregnancy was 1.11±0.23 mg/dL and then worsened to 1.59±0.37 mg/dL during pregnancy. However, it recovered to 1.14±0.40 mg/dL after delivery. One patient had antibody-mediated rejection with donor specific antibody (DSA) prior to pregnancy, and her renal graft function worsened slightly after delivery. Another patient had a de novo DSA after delivery, which was not detected before pregnancy. (Conclusions) In our hospital, pregnancy in kidney transplant recipients were safe and renal graft function after delivery was relatively stable. Patients may require adjustment of calcineurin inhibitors during pregnancy, and the appearance of DSA after delivery should be noted.

A Novel Method of CD31-Combined ABO Carbohydrate Antigen Microarray Predicts Acute Antibody-Mediated Rejection in ABO-Incompatible Kidney Transplantation.

Isohemagglutinin assays employing red blood cells (RBCs) are the most common assays used to measure antibody titer in ABO-incompatible kidney transplantation (ABOi KTx). However, ABO antigens expressed on RBCs are not identical to those of kidney and antibody titers do not always correlate with clinical outcome. We previously reported that CD31 was the main protein linked to ABO antigens on kidney endothelial cells (KECs), which was different from those on RBCs. We developed a new method to measure antibody titer using a microarray of recombinant CD31 (rCD31) linked to ABO antigens (CD31-ABO microarray). Mass spectrometry analysis suggested that rCD31 and native CD31 purified from human kidney had similar ABO glycan. To confirm clinical use of CD31-ABO microarray, a total of 252 plasma samples including volunteers, hemodialysis patients, and transplant recipients were examined. In transplant recipients, any initial IgG or IgM antibody intensity >30,000 against the donor blood type in the CD31-ABO microarray showed higher sensitivity, specificity, positive predictive value, and negative predictive value of AABMR, compared to isohemagglutinin assays. Use of a CD31-ABO microarray to determine antibody titer specifically against ABO antigens expressed on KECs will contribute to precisely predicting AABMR or preventing over immunosuppression following ABOi KTx.

Endometrial Cancer After Pancreas-After-Kidney Transplantation: A Case Report and Review of the Literature.

BACKGROUND: As the number of long-term survivors after organ transplantation increases, malignancy has become a problem as a late complication. We herein report a case of endometrial cancer during the follow-up of pancreas transplantation after kidney transplantation. CASE PRESENTATION: A 49-year-old woman was diagnosed with endometrial cancer. The patient had developed type 1 diabetes at 8 years old and started insulin treatment, and at 29 years old, she started hemodialysis for diabetic nephropathy. At 31 years old, she received living donor kidney transplantation and withdrew from dialysis. Hypoglycemia unawareness began to occur frequently from around 36 years old, and at 48 years old, the patient underwent deceased donor pancreas transplantation after kidney transplantation and achieved insulin independence. At 49 years old, she was diagnosed with endometrial cancer. Surgical treatment (total abdominal hysterectomy with left salpingo-oophorectomy) was performed. The pathologic diagnosis was confirmed as stage 1A uterine endometrioid carcinoma grade 1. The postoperative course was uneventful. She was discharged from our hospital on postoperative day 8. There has been no evidence of recurrence and/or metastasis of endometrial cancer for 16 months since the surgery. CONCLUSIONS: Carcinogenesis after pancreas transplantation may be a lethal late complication. It is important to carry out regular screening examinations with carcinogenesis in mind.

Incisional Hernia Repaired Using Thigh Muscle Fascia After Kidney Transplantation: A Case Report.

BACKGROUND: Although monofilament mesh-based repair is a safe and effective procedure for incisional hernia (IH) in organ transplant patients, there is no definite evidence of IH treatment for patients with graft rejection and enhanced immunosuppressive therapy. We report a successful case of large IH repair using an autologous thigh muscle fascia sheet in a kidney transplant patient. CASE PRESENTATION: A 69-year-old man had IH from the incision of kidney transplantation, which was performed 6 years ago. He had a large right lower abdominal distension hanging down to the inguinal portion. A computed tomography scan revealed a large IH with a maximum abdominal defect diameter of 15 cm. The hernia sac contained the intestine, colon, and transplanted kidney, which had pulled out along with the retroperitoneum and protruded into the abdominal wall. He had chronic active acute antibody-mediated rejection, which required frequent steroid pulse therapy and additional or adjusted immunosuppressive drugs. After total circumferential exposure of the hernia sac and abdominal fascia, the abdominal wall defect was closed using a horizontal mattress suture. The sutured line was covered with a thigh muscle fascia sheet harvested from the patient's right femur and attached to the closed fascia. He was discharged on postoperative day 13 without any complications, and no IH recurrence was observed 10 months after surgery. CONCLUSIONS: Hernia repair using autologous tissue could be a treatment option for post-transplant IH with a higher risk of infection.

Development of patient­derived tumor organoids and a drug testing model for renal cell carcinoma.

The selection of effective therapeutic agents is critical for improving the survival of patients with renal cell carcinoma (RCC). The aim of the present study was to develop an ex vivo drug testing assay using patient­derived tumor organoid (TO) cultures. For this purpose, surgical tumor specimens were obtained from 20 patients with RCC. TOs were developed ex vivo from freshly resected RCC tumors, and their histopathological and molecular characteristics were evaluated using histological staining and whole­exome sequencing (WES). Using a cell viability assay, the therapeutic efficacy of standard of care tyrosine kinase inhibitors in RCC TOs was determined. It was found that TOs recapitulated the histological features of primary RCC tumors. Using WES, a strong concordance was identified at the genetic level between the primary tumors and their corresponding TOs. Using patient­derived TO models, a prototype of an ex vivo drug testing assay was developed, and it was found that RCC TOs exhibited differential responses to sunitinib, pazopanib, cabozantinib, axitinib and sorafenib treatment. On the whole, although the predictive value of the current assay has to be tested and validated in future clinical studies, the findings of the present study demonstrate a novel approach for ex vivo drug testing in patient­derived TO models, which may have potential for use in the personalized treatment of cancer patients.

A case of bronchiolitis obliterans after living-donor renal transplantation.

We herein report the case of a 20 year-old-man who developed bronchiolitis obliterans after living-donor renal transplantation. The patient presented with dyspnea on exertion and wheezing two years after renal transplantation, and spirometry showed an obstructive pattern. Surgical lung biopsy revealed subepithelial fibrosis that constricted and obstructed the intrabronchiolar space. Based on these findings, the patient was diagnosed with bronchiolitis obliterans. He was prescribed bronchodilators and azithromycin, and he achieved stable respiratory function for two years. The differential diagnosis of respiratory symptoms after renal transplantation includes opportunistic infection and drug-induced lung injury; however, bronchiolitis obliterans should also be considered.

Inguinal Herniation After Living Donor Kidney Transplantation: A Case Report.

A 68-year-old male patient received a living donor kidney transplantation 8 years earlier for end-stage kidney disease secondary to IgA nephropathy. His post-transplantation follow-up had been routinely performed with laboratory examinations, ultrasound, and computed tomography (CT). His kidney graft function had been excellent and stable, as shown by a baseline serum creatinine level of 1.0 mg/dL. At referral, regular follow-up ultrasound and CT showed allograft hydroureteronephrosis. He did not have any complaints, but his physical examination revealed right inguinal bulging that was 3.5 × 3.5 cm. Abdominal enhanced CT revealed transplant allograft hydroureteronephrosis due to ipsilateral herniation of ureteroneocystostomy into the right inguinal canal. His serum creatinine level was slightly elevated (1.1 mg/dL). Then, he underwent an open right inguinal hernia repair. Paraperitoneal allograft hydroureteronephrosis and bladder herniation was confirmed at surgery, and hernioplasty with polypropylene mesh reinforcement was successfully performed. The postoperative course was uneventful. He was discharged on the seventh day after surgery. Six weeks after surgery, CT revealed disappearance of allograft hydroureteronephrosis and no sign of inguinal hernia recurrence with the serum creatinine stable at 1.0 mg/dL. Transplant ureteral obstruction due to inguinal hernia is a rare complication after kidney transplantation. However, transplant ureter or bladder herniation should be considered in the differential diagnosis of graft hydroureteronephrosis for preventing allograft loss.

Kidney function of Japanese children undergoing kidney transplant with preemptive therapy for cytomegalovirus infection.

BACKGROUND: Cytomegalovirus (CMV) infection is one of the major factors that affect morbidity and mortality in kidney transplant (KTx) patients. The rate of CMV seropositivity in children before KTx is lower than that in adults; therefore, pediatric KTx patients have a higher risk of CMV infection. In Japanese pediatric KTx patients, preemptive therapy for CMV infection is a main conventional therapy. This study investigated whether this preemptive treatment would affect kidney function at 2 years post-KTx. METHODS: A total of 163 patients, that is approximately half of the Japanese pediatric KTx patients nationwide, were recruited to participate in our study. We compared the values of the sequential estimated glomerular filtration rate (eGFR) at two years post-KTx and other influencing factors in CMV viremia, CMV disease, and no-infection groups. RESULTS: Cytomegalovirus infection after KTx occurred in 75 patients (46.0%), 38.7% of whom developed CMV disease. The sequential eGFR values post-KTx did not differ significantly between the three groups. CMV infection was not significantly correlated with other factors, other infections (including Epstein-Barr [EB] virus infection), acute rejection (AR), or adverse events. Only prolonged duration of total hospitalization was significantly associated with CMV infection (P = .002). In the multivariate analysis, younger age, CMV infection, and adverse effects were independently significantly related to prolonged total hospitalization. CONCLUSION: Preemptive therapy for CMV infection evidenced by viremia and disease did not significantly influence kidney function in Japanese pediatric KTx patients at two years after the operation.

[PLASMA RENIN ACTIVITY AND ALDOSTERONE IN RENAL TRANSPLANT PATIENTS].

(Background) It has become evident in recent year that aldosterone has a pathogenic role in hypertension, heart failure and renal disease. Elevation of aldosterone occurs in a certain fraction of hemodialysis patients, and the adverse effects of hyperaldosteronism could pose a problem after kidney transplantation. Long-term effects of aldosterone level in renal transplant recipients remain unknown. (Materials and methods) All recipients underwent transplantation between 1996 and 2018 in Niigata university hospital were included in the study. Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were retrospectively analyzed in 210 recipients before and after kidney transplantation. (Results) Sixty percent of recipients had higher PRA than normal upper limit before and after transplantation. The use of angiotensin receptor blocker (ARB) or angiotensin-converting-enzyme inhibitor (ACEI) was significantly more frequent in the patients with hyperreninemia than those without one after transplantation. Sixty percent of recipients had higher PAC than normal upper limit before transplantation and it spontaneously decreased to normal level after transplantation in most of them. There was no significant correlation between PAC and blood pressure, recipient age, and renal graft function after transplantation. We divided the patients into two groups, with and without post-transplant hyperaldosteronemia. The patients with post-transplant hyperaldosteronemia (n=29) had higher diastolic blood pressure and less use of renin-angiotensin-aldosterone system (RAAS) inhibitors than those with normal PAC level. (Conclusions) The use of RAAS inhibitors should be considered in post-transplant hyperaldosteronemia patients to control blood pressure and to save their long-term renal graft and heart function.

A Nationwide Survey of Hepatitis E Virus Infection and Chronic Hepatitis in Heart and Kidney Transplant Recipients in Japan.

BACKGROUND: Recently, chronic hepatitis E has been reported in solid organ transplant (SOT) recipients in European countries. Previously, we clarified the prevalence of hepatitis E virus (HEV) infection in Japanese liver transplant recipients and identified 2 chronic hepatitis E patients infected by blood transfusion. However, the rate of HEV infection in recipients of SOTs other than liver in Japan remains unclear, so we conducted a nationwide survey to clarify the prevalence of chronic HEV infection in Japanese heart and kidney transplant recipients. METHODS: A total of 99 heart and 2526 kidney transplant recipients in 17 hospitals in Japan were examined for the presence of the IgG class of anti-HEV antibodies as well as for serum HEV RNA. RESULTS: The prevalence of anti-HEV IgG among heart and kidney transplant recipients was 7.07% (7/99) and 4.08% (103/2526), respectively. One heart transplant patient (1.01%) and 11 kidney transplant patients (0.44%) were found to be positive for HEV RNA. The HEV isolates from all viremic patients were typed as genotype 3. Four patients developed chronic hepatitis E after transplantation. Three patients were treated with ribavirin; their liver enzymes normalized, and HEV RNA became negative immediately. Sustained virologic response was achieved in all cases. CONCLUSIONS: This is the first nationwide survey of HEV infection in Japanese heart and kidney transplant recipients. The prevalence of anti-HEV IgG and HEV RNA in heart and kidney transplant recipients in Japan was lower than that in European countries. Of note, 42% of viremic transplant patients developed chronic hepatitis.

Analysis of the prevalence of systemic de novo thrombotic microangiopathy after ABO-incompatible kidney transplantation and the associated risk factors.

OBJECTIVES: To analyze the prevalence of systemic de novo thrombotic microangiopathy in ABO-incompatible kidney transplantation and risk factors associated with this condition. METHODS: A total of 201 patients who received living-donor kidney transplantation (114 patients with ABO-identical kidney transplantation and 87 patients with ABO-incompatible kidney transplantation) were retrospectively analyzed. Systemic de novo thrombotic microangiopathy was diagnosed clinically according to the presence of thrombocytopenia with microangiopathic hemolytic anemia and pathological findings of thrombotic microangiopathy. Anti-A and anti-B antibodies were purified from human plasma, and these antibodies' bindings to human kidney were investigated in vitro. RESULTS: ABO-incompatible kidney transplantation was a significant risk factor of systemic de novo thrombotic microangiopathy (odds ratio 55.9, 95% CI 1.8-8.9, P < 0.001) after transplantation. Multivariate logistic regression analysis showed that non-use of mycophenolate mofetil, pretreatment immunoglobulin G antibody titer ≥64-fold and pretransplant immunoglobulin M antibody titer ≥16-fold were significant risk factors for systemic de novo thrombotic microangiopathy in ABO-incompatible kidney transplantation. Microvascular inflammation of 1-h post-transplant biopsy could be observed more frequently in thrombotic microangiopathy patients than in non-thrombotic microangiopathy patients. Anti-A and anti-B antibodies purified from human plasma showed a strong in vitro reaction against human kidney when the antibody titer was ≥16-fold. CONCLUSIONS: Antibody titer should be decreased to ≤16-fold until the day of ABO-incompatible kidney transplantation by desensitization therapy including mycophenolate mofetil. The 1-h biopsy results might help to diagnose systemic de novo thrombotic microangiopathy.