Transcript analysis of uterus transplant cervical biopsies using the Banff Human Organ Transplant panel.

Uterus transplantation is being more widely implemented in clinical practice. Monitoring of rejection is routinely done for cervical biopsies and is dependent on histopathological assessment, as rejections are clinically silent and nonhistological biomarkers are missing. Until this gap is filled, it is important to corroborate the histopathological diagnosis of rejection through independent methods such as gene expression analysis. In this study, we compared our previously published scoring system for grading rejection in uterus transplant cervical biopsies to the gene expression profile in the same biopsy. For this, we used the Banff Human Organ Transplant gene panel to analyze the expression of 788 genes in 75 paraffin-embedded transplant cervical biopsies with a spectrum of histologic findings, as well as in 24 cervical biopsies from healthy controls. We found that gene expression in borderline changes did not differ from normal transplants, whereas the genes with increased expression in mild rejections overlapped with previously published rejection-associated transcripts. Moderate/severe rejection samples showed a gene expression pattern characterized by a mixture of rejection-associated and tissue injury-associated genes and a decrease in epithelial transcripts. In summary, our findings support our proposed scoring system for rejection but argue against the treatment of borderline changes.

The Banff 2022 Kidney Meeting Work Plan: Data-driven refinement of the Banff Classification for renal allografts.

The XVIth Banff Meeting for Allograft Pathology was held in Banff, Alberta, Canada, from September 19 to 23, 2022, as a joint meeting with the Canadian Society of Transplantation. In addition to a key focus on the impact of microvascular inflammation and biopsy-based transcript analysis on the Banff Classification, further sessions were devoted to other aspects of kidney transplant pathology, in particular T cell-mediated rejection, activity and chronicity indices, digital pathology, xenotransplantation, clinical trials, and surrogate endpoints. Although the output of these sessions has not led to any changes in the classification, the key role of Banff Working Groups in phrasing unanswered questions, and coordinating and disseminating results of investigations addressing these unanswered questions was emphasized. This paper summarizes the key Banff Meeting 2022 sessions not covered in the Banff Kidney Meeting 2022 Report paper and also provides an update on other Banff Working Group activities relevant to kidney allografts.

Implementing MyChoice® CDx HRD testing for the Nordics: lessons from 2021 to 2023.

BACKGROUND: Assessment of homologous recombinant deficient (HRD) phenotypes is key for managing Poly (ADP-ribose) polymerase inhibitor (PARPi) treatment. To accommodate the need for a validated HRD platform and enhance targeted treatment of ovarian cancer patients, a Nordic core facility for the myChoice® CDx platform was established in Denmark. MATERIALS AND METHODS: Comparative calculations and statistics are based on information from test requisitions and results (Genome Instability Score [GIS], BRCA status and combined HRD status) obtained from ovarian and breast cancer samples submitted for HRD-testing by myChoice® CDx through the Nordic core facility in the 2-year period. RESULTS: Copenhagen University Hospital received 1,948 requisitions during the 2-year period. Conclusive results were obtained in 89% of the tests, while 7% were inconclusive due to the lack of GIS and 4% were not able to be analysed. Comparing the conclusive HRD status results across countries, Sweden had the highest percentage of HRD positives (38%) compared to Denmark, Norway, and Finland (28-32%). INTERPRETATION: The myChoice® CDx Nordic core facility has been well received among the Nordic countries and provides new insights on the influence of national guidelines on HRD testing. Overall, we experienced an efficient turnaround time and a high fraction of conclusive results. Interestingly, prior somatic BRCA testing is redundant when assessing HRD status through myChoice® CDx test since somatic BRCA screening is already a significant component of the myChoice® CDx test. Thus, it should be considered to omit prior somatic BRCA testing to ensure a rationalised HRD diagnostic flow optimised for clinical use.

Delphi: A Democratic and Cost-Effective Method of Consensus Generation in Transplantation.

The Thrombotic Microangiopathy Banff Working Group (TMA-BWG) was formed in 2015 to survey current practices and develop minimum diagnostic criteria (MDC) for renal transplant TMA (Tx-TMA). To generate consensus among pathologists and nephrologists, the TMA BWG designed a 3-Phase study. Phase I of the study is presented here. Using the Delphi methodology, 23 panelists with >3 years of diagnostic experience with Tx-TMA pathology listed their MDC suggesting light, immunofluorescence, and electron microscopy lesions, clinical and laboratory information, and differential diagnoses. Nine rounds (R) of consensus resulted in MDC validated during two Rs using online evaluation of whole slide digital images of 37 biopsies (28 TMA, 9 non-TMA). Starting with 338 criteria the process resulted in 24 criteria and 8 differential diagnoses including 18 pathologic, 2 clinical, and 4 laboratory criteria. Results show that 3/4 of the panelists agreed on the diagnosis of 3/4 of cases. The process also allowed definition refinement for 4 light and 4 electron microscopy lesions. For the first time in Banff classification, the Delphi methodology was used to generate consensus. The study shows that Delphi is a democratic and cost-effective method allowing rapid consensus generation among numerous physicians dealing with large number of criteria in transplantation.

Thrombotic Microangiopathy in the Renal Allograft: Results of the TMA Banff Working Group Consensus on Pathologic Diagnostic Criteria.

The Banff community summoned the TMA Banff Working Group to develop minimum diagnostic criteria (MDC) and recommendations for renal transplant TMA (Tx-TMA) diagnosis, which currently lacks standardized criteria. Using the Delphi method for consensus generation, 23 nephropathologists (panelists) with >3 years of diagnostic experience with Tx-TMA were asked to list light, immunofluorescence, and electron microscopic, clinical and laboratory criteria and differential diagnoses for Tx-TMA. Delphi was modified to include 2 validations rounds with histological evaluation of whole slide images of 37 transplant biopsies (28 TMA and 9 non-TMA). Starting with 338 criteria in R1, MDC were narrowed down to 24 in R8 generating 18 pathological, 2 clinical, 4 laboratory criteria, and 8 differential diagnoses. The panelists reached a good level of agreement (70%) on 76% of the validated cases. For the first time in Banff classification, Delphi was used to reach consensus on MDC for Tx-TMA. Phase I of the study (pathology phase) will be used as a model for Phase II (nephrology phase) for consensus regarding clinical and laboratory criteria. Eventually in Phase III (consensus of the consensus groups) and the final MDC for Tx-TMA will be reported to the transplantation community.

Corrigendum: Delphi: A Democratic and Cost-Effective Method of Consensus Generation in Transplantation.

[This corrects the article DOI: 10.3389/ti.2023.11589.].

Corrigendum: Thrombotic Microangiopathy in the Renal Allograft: Results of the TMA Banff Working Group Consensus on Pathologic Diagnostic Criteria.

[This corrects the article DOI: 10.3389/ti.2023.11590.].

Endogenous Formaldehyde Is a Hematopoietic Stem Cell Genotoxin and Metabolic Carcinogen.

Endogenous formaldehyde is produced by numerous biochemical pathways fundamental to life, and it can crosslink both DNA and proteins. However, the consequences of its accumulation are unclear. Here we show that endogenous formaldehyde is removed by the enzyme alcohol dehydrogenase 5 (ADH5/GSNOR), and Adh5(-/-) mice therefore accumulate formaldehyde adducts in DNA. The repair of this damage is mediated by FANCD2, a DNA crosslink repair protein. Adh5(-/-)Fancd2(-/-) mice reveal an essential requirement for these protection mechanisms in hematopoietic stem cells (HSCs), leading to their depletion and precipitating bone marrow failure. More widespread formaldehyde-induced DNA damage also causes karyomegaly and dysfunction of hepatocytes and nephrons. Bone marrow transplantation not only rescued hematopoiesis but, surprisingly, also preserved nephron function. Nevertheless, all of these animals eventually developed fatal malignancies. Formaldehyde is therefore an important source of endogenous DNA damage that is counteracted in mammals by a conserved protection mechanism.

Hysterectomy after uterus transplantation and detailed analyses of graft failures.

INTRODUCTION: The first live birth after uterus transplantation occurred in Sweden in 2014. Uterus transplantation has repeatedly, and at many centers worldwide, proven to be a feasible treatment for absolute uterine factor infertility. Hysterectomy in live donors and transplantation are well described in numerous reports. However, there are no reports of hysterectomy in the recipient after uterus transplantation, which will occur at either graft failure, after childbirth, or after numerous failed pregnancy attempts. We present the first report of hysterectomy in recipients after uterus transplantation with detailed analyses of findings in conjunction with graft failures. MATERIAL AND METHODS: An analysis of recipient hysterectomies (n = 10), performed in 2012-2020, was conducted. Data from the international uterus transplantation registry (ISUTx registry) were extracted, and medical records were systematically reviewed, to collect and compile characteristics of recipients and donors, as well as pre-, per-, and postoperative data, including clinical course of graft failures. RESULTS: Hysterectomy in recipients was performed in conjunction with cesarean section (n = 3), 3-6 months after cesarean section (n = 3), or after failed pregnancy attempts (n = 1) or graft failure (n = 3). The durations of anesthesia (2 h 36 min to 7 h 35 min) and hysterectomy surgery (1 h 42 min to 5 h 52 min) ranged widely, with long perioperative interruptions for insertion of ureteral catheters in two cases. Adhesions to the uterus were abundant, the majority being mild. Three uteri that subsequently showed graft failure (hysterectomy at 1, 3, and 8 months post transplantation) showed histological signs of ischemia in biopsies taken 1-week post-transplant and early signs of central hypoperfusion by Doppler ultrasound. In these graft failure explants, there were no epithelial linings in the uterine cavity or in the cervix. The inner uterine wall was severely ischemic and/or necrotic, whereas outer parts were partly viable. There were signs of moderate atherosclerosis of uterine arteries but no rejection. Mild postoperative complications were frequent (6/10), with one supravaginal hematoma requiring surgical drainage. CONCLUSIONS: Hysterectomy after uterus transplantation is a complex and time-consuming procedure, and perioperative ureteral catheters may be helpful. Histopathology of early cervical biopsies showing ischemic signs may indicate subsequent irreversible damage, leading to graft failure.

Uterus transplantation: Histological findings in explants at elective hysterectomy.

Uterus transplantation has enabled women with absolute uterine factor infertility to carry a pregnancy. The first human uterus transplantation trial was initiated in 2013 in Gothenburg, Sweden. It was completed with 7 transplantations with long-term allograft survival and 9 children born from 6 women. In the present study we describe the histopathology of these 7 allografts, which were removed at 22-83 months after transplantation, and compare findings to control cases. Morphological findings in a subset of explants included linear subepithelial inflammation and perivascular stromal inflammation in the cervix, small inflammatory foci in the myometrium, and intimal inflammation in larger arteries. The average number of T cells, B cells, and macrophages was higher in transplants compared to normal controls, but variability was high among transplants. Chronic-active vascular rejection was seen in 2 of 7 transplants, both showed also inflammation in the cervix. Further, the inflammation seen in the cervix reflected the inflammation in the myometrium, suggesting that cervical biopsies are suitable to monitor rejection. However, the degree of inflammation and signs of rejection in explants did not reflect on the possibility to become pregnant in this limited series.

Signaling through tumor necrosis receptor 2 induces stem cell marker in CD133+ regenerating tubular epithelial cells in acute cell-mediated rejection of human renal allografts.

Tumor necrosis factor receptor 2 (TNFR2) is strongly upregulated on renal tubular epithelial cells by acute cell-mediated rejection (ACR. In human kidney organ culture, TNFR2 signaling both upregulates TNFR2 expression and promotes cell cycle entry of tubular epithelial cells. We find significantly more cells express CD133 mRNA and protein, a putative stem cell marker, in allograft biopsy samples with ACR compared to acute tubular injury without rejection or pretransplant "normal kidney" biopsy samples. Of CD133+ cells, ~85% are within injured tubules and ~15% are interstitial. Both populations express stem cell marker TRA-1-60 and TNFR2, but only tubular CD133+ cells express proximal tubular markers megalin and aquaporin-1. TNFR2+ CD133+ cells in tubules express proliferation marker phospho-histone H3S10 (pH3S10 ). Tubular epithelial cells in normal kidney organ cultures respond to TNFR2 signaling by expressing CD133 mRNA and protein, stem cell marker TRA-1-60, and pH3S10 within 3 hours of treatment. This rapid response time suggests that CD133+ cells in regenerating tubules of kidneys undergoing ACR represent proliferating tubular epithelial cells with TNFR2-induced stem cell markers rather than expansion of resident stem cells. Infiltrating host mononuclear cells are a likely source of TNF as these changes are absent in acute tubular injury .

Clinical-pathological correlations in post-transplant thrombotic microangiopathy.

AIMS: Post-transplant thrombotic microangiopathy (TMA) is a rare and clinically challenging finding in renal transplant biopsies. In addition to recurrent atypical haemolytic uraemic syndrome, TMA in renal transplants is associated with various conditions, such as calcineurin inhibitor (CNI) treatment, antibody-mediated rejection (ABMR), viral infections, sepsis, pregnancy, malignancies, and surgery. The therapeutic implications of this diagnosis are considerable. In order to better understand post-transplant TMA and to identify histological or clinical differences between associated causes, we conducted a multicentre retrospective study. METHODS AND RESULTS: Clinical parameters and transplant renal biopsy findings from 81 patients with TMA were analysed. Biopsies from 38 patients were also analysed with electron microscopy. On the basis of clinical-pathological correlation, TMA was attributed to a main aetiology, whenever possible. TMA occurred at a median of 30 days post-transplantation. Systemic features of TMA were present in only 18% of cases. Twenty-two per cent of cases were attributed to CNI and 11% to ABMR. Although other potentially contributing factors were found in 56% of patients, in most cases (63%) no clearly attributable cause of TMA was identified. Histological differences between groups were minimal. The detection of ultrastructural features that are usually associated with ABMR may help to establish ABMR as the cause of TMA. CONCLUSIONS: Although CNI and ABMR appear to be the main contributors to post-transplant TMA, the aetiology of most cases is probably multifactorial, and TMA cannot be unequivocally attributed to a single underlying aetiology. Morphological features of TMA are not discriminating, but electron microscopy may help to identify ABMR-associated TMA.

Risk factors for death in kidney transplant patients: analysis from a large protocol biopsy registry.

BACKGROUND: Identification and quantification of the relevant factors for death can improve patients' individual risk assessment and decision-making. We used a well-documented patient cohort (n = 892) in a renal transplant programme with protocol biopsies to establish multivariable Cox models for risk assessment at 3 and 12 months post-transplantation. METHODS: Patients transplanted between 2000 and 2007 were observed up to 11 years (total observation 5227 patient-years; median 5.9 years). Loss to follow-up was negligible (n = 15). A total of 2251 protocol biopsies and 1214 biopsies for cause were performed. All rejections and clinical borderline rejections in protocol biopsies were treated. RESULTS: Overall 10-year patient survival was 78%, with inferior survival of patients with graft loss and superior survival of patients with living-donor transplantation. Eight factors were common in the models at 3 and 12 months, including age, pre-transplant heart failure and a score of cardiovascular disease and type 2 diabetes, post-transplant urinary tract infection, treatment of rejection, new-onset heart failure, coronary events and malignancies. Additional variables of the model at 3 months included deceased donor transplantation, transplant lymphocele, BK virus nephropathy and severe infections. Graft function and graft loss were significant factors of the model at 12 months. Internal validation and validation with a separate cohort of patients (n = 349) demonstrated good discrimination of the models. CONCLUSIONS: The identified factors indicate the important areas that need special attention in the pre- and post-transplant care of renal transplant patients. On the basis of these models, we provide nomograms as a tool to weigh individual risks that may contribute to decreased survival.

Distinct morphological features of acute tubular injury in renal allografts correlate with clinical outcome.

Acute tubular injury (ATI) is common in renal allografts and is related to inferior long-term allograft function. However, it is unknown which of the morphological features of ATI can predict outcome and how they should be graded. Here, we examine features of ATI systematically in protocol biopsies and biopsies for cause to define the most predictive features. Analyses included 521 protocol biopsies taken at 6 wk, 3 mo, and 6 mo after transplantation and 141 biopsies for cause from 204 patients. Features of ATI included brush border loss, tubular epithelial lucency, flattening, pyknosis, nuclei loss, and luminal debris, each graded semiquantitatively. Additional immunohistochemical stainings were performed for markers of cell injury (neutrophil gelatinase-associated lipocalin), cell death [cleaved caspase-3, fatty acid-coenzyme A ligase 4 (FACL4)], and proliferation (Ki-67). Interobserver reliability was good for pyknosis, flattening, and brush border loss and poor for lucency, nuclei loss, and luminal debris. In protocol biopsies between 6 wk and 6 mo, the degree of ATI remained virtually unchanged. Biopsies for cause had generally higher injury scores. Deceased donor source, delayed graft function, ganciclovir/valganciclovir treatment, and urinary tract infection correlated with ATI. The degree of pyknosis, flattening, and brush border loss correlated best with impaired allograft function. FACL4 expression was observed in areas of ATI. Only patients with Ki-67 expression showed stable or improved allograft function in the longitudinal assessment. Reliable assessment of ATI is possible by semiquantitative grading of tubular epithelial cell brush border loss, flattening, and pyknosis. Examination of Ki-67 expression can help determine the potential for recovery from this damage.

A rolling circle amplification screen for polyomaviruses other than BKPyV in renal transplant recipients confirms high prevalence of urinary JCPyV shedding.

OBJECTIVES: Multiple novel human polyomaviruses (HPyVs) have been discovered in the last few years. These or other, unknown, nephrotropic HPyVs may potentially be shed in urine. METHODS: To search for known and unknown HPyVs we investigated BKPyV-negative urine samples from 105 renal transplant recipients (RTR) by rolling circle amplification (RCA) analysis and quantitative JCPyV PCR. Clinical data was analysed to identify risk factors for urinary polyomavirus shedding. RESULTS: In 10% (11/105) of the urine samples RCA with subsequent sequencing revealed JCPyV, but no other HPyV sequences. Using quantitative JCPyV PCR, 24% (25/105) of the samples tested positive. Overall sensitivities of RCA of 44% (11/25) in detecting JCPyV in JCPyV DNA-positive urine and 67% (10/15) for samples with JCPyV loads >10,000 copies/ml can be assumed. Despite frequent detectable urinary shedding of JCPyV in our cohort, this could not be correlated with clinical risk factors. CONCLUSION: Routine urinary JCPyV monitoring in BKPyV-negative RTR without suspected polyomavirus-associated nephropathy might be of limited diagnostic value. As RCA works in a sequence-independent manner, detection of novel and known polyomaviruses shed in sufficient quantities is feasible. High-level shedding of HPyVs other than BKPyV or JCPyV in the urine of RTR is unlikely to occur.

The significance of histological diagnosis in renal allograft biopsies in 2014.

In 2014, the renal allograft biopsy still represents the best available diagnostic 'gold' standard to assess reasons for allograft dysfunction. However, it is well recognized that histological lesion observed in the biopsy is of limited diagnostic specificity and that the Banff classification as the international diagnostic standard represents mere expert consensus. Here, we review the role of the renal allograft biopsy in different clinical and diagnostic settings. To increase diagnostic accuracy and to compensate for lack of specificity, the interpretation of biopsy pathology needs to be within the clinical context, primarily defined by time post-transplantation and patient-specific risk profile. With this in mind, similar histopathological patterns will lead to different conclusions with regard to diagnosis, disease grading and staging and thus to patient-specific clinical decision-making. Consensus generation for such integrated diagnostic approach, preferably including new molecular tools, represents the next challenge to the transplant community on its way to precision medicine in transplantation.

Analysis of Immunological Biomarkers Associated With Rejection After Uterus Transplantation in Human.

BACKGROUND: Uterus transplantation (UTx) is an emerging therapy for women with uterine infertility. However, critical questions remain with this procedure including the mechanisms involved in graft rejection. METHODS: In this study, we analyzed the immune profile of ectocervical biopsies from 5 patients after UTx before and during their first episode of rejection using RNA sequencing, quantitative polymerase chain reaction, and imaging mass cytometry. RESULTS: We identified 530 upregulated and 207 downregulated genes associated with graft rejection. Enrichment databases revealed abnormalities of skin-associated genes and the immune system, in particular activation of T and B lymphocytes, and macrophages. Imaging mass cytometry confirmed these observations; in cervical biopsies of 3 women, rejection was associated with the presence of B-cell structures linked to tertiary lymphoid structures, and 2 biopsies from 1 woman with severe rejection episodes and poor prognosis of graft function (repeated miscarriage and implantation failures) were associated with an accumulation of HLA-DR- macrophages, producing granzyme B at the surface of the epithelium. CONCLUSIONS: We showed that rejection of a UTx graft was associated with major alterations of immune markers including the involvement of tertiary lymphoid structures, the most organized of which may be a sign of chronic rejection, and with an increase in HLA-DR- macrophages expressing granzyme B in the case of grade 3 rejection episodes according Mölne's classification. We identified potential emerging biomarkers to predict or diagnose graft rejection (Keratin 1 granzyme B, IL1ß). These findings could lead to development of improved strategies for the identification, prevention, and/or treatment of uterus graft rejection.

Reproducibility of Rejection Grading in Uterus Transplantation: A Multicenter Study.

Background: Diagnosis of rejection after uterus transplantation is based on histopathological examination of ectocervical biopsies. Inflammation at the stromal-epithelial interface is the backbone of the histopathological classification proposed by our group in 2017. However, the reproducibility of this grading scheme has not been tested, and it is unclear whether it covers the full morphological spectrum of rejection. Methods: We present a multicenter study in which 5 pathologists from 4 uterus transplantation centers performed 2 rounds of grading on 145 and 48 cervical biopsies, respectively. Three of the centers provided biopsies. Additionally, the presence of perivascular stromal inflammation was recorded. During discussions after the first round, further histological lesions (venous endothelial inflammation and apoptosis) were identified for closer evaluation and added to the panel of lesions to score in the second round. All participants completed a questionnaire to explore current practices in handling and reporting uterus transplant biopsies. Results: Cervical biopsies were commonly performed in all centers to monitor rejection. Intraobserver reproducibility of rejection grading (performed by 1 rater) was excellent, whereas interobserver reproducibility was moderate and did not improve in the second round. Reproducibility of perivascular stromal inflammation was moderate but unsatisfactory for venous endothelial inflammation and apoptosis. All lesions were more frequent in, but not restricted to, biopsies with rejection patterns. Conclusions: Grading of rejection in cervical biopsies is reproducible and applicable to biopsies from different centers. Diagnosis of rejection may be improved by adding further histological lesions to the grading system; however, lesions require rigorous consensus definition.

Difficult-to-Treat Rejections in Kidney Transplant Recipients: Our Experience with Everolimus-Based Quadruple Maintenance Therapy.

All chronic and treatment-resistant acute rejections are "difficult-to-treat" and lead to progressive loss of graft function in kidney transplant recipients (KTR), as no effective treatment exists for such rejections to date. We review our experience with a novel strategy to treat such rejections by adding everolimus as a "rescue" to conventional triple maintenance therapy with prednisolone, mycophenolate mofetil and calcineurin inhibitor. We retrospectively analysed data in 28 KTR who received everolimus-based quadruple therapy at our institution for biopsy-proven chronic active T cell-mediated or antibody-mediated rejection (n = 19) or treatment-resistant acute rejections (n = 9) between 2011-2017. The primary outcome was 5-year death-censored graft survival. Main secondary outcomes were response to treatment defined by stable or improved graft function, 5-year patient survival and discontinuation rate of treatment. The Kaplan-Meier estimate for 5-year death-censored graft survival was 79% in all patients, 90% for patients with chronic active T cell-mediated rejections, 78% for chronic active antibody-mediated rejection and 67% for acute rejections. Response to treatment was achieved in 43% and 5-year patient survival was 94%. Treatment was stopped in 12 (43%) patients due to adverse events. Everolimus-based maintenance quadruple therapy, despite high rate of everolimus discontinuation due to adverse events, may be a valid approach in a subset of kidney transplant recipients with such difficult-to-treat rejections, which otherwise would lead to a high rate of graft loss.

Outcome of Recipient Surgery and 6-Month Follow-Up of the Swedish Live Donor Robotic Uterus Transplantation Trial.

Uterus transplantation has proved to be a feasible treatment for uterine factor infertility. Herein, we report on recipient outcome in the robotic uterus transplantation trial of 2017-2019. The eight recipients had congenital uterine aplasia. The donors were six mothers, one sister, and one family friend. Donor surgery was by robotic-assisted laparoscopy. Recipient surgery was by laparotomy and vascular anastomoses to the external iliacs. The duration (median (ranges)) of recipient surgery, blood loss, measured (left/right) uterine artery blood flow after reperfusion, and length of hospital stay were 5.15 h (4.5-6.6), 300 mL (150-600), 43.5 mL/min (20-125)/37.5 mL/min (10-98), and 6 days (5-9), respectively. Postoperative uterine perfusion evaluated by color Doppler showed open anastomoses but restricted blood distribution in two cases. Repeated cervical biopsies in these two cases initially showed ischemia and, later, necrosis. Endometrial growth was not seen, and hysterectomy was later performed, with pathology showing partly viable myometrium and fibrosis but necrosis towards the cavity. The other six patients acquired regular menstrual cyclicity. Surgery was performed in two patients to correct vaginal stenosis. Reversible rejection episodes were seen in two patients. In conclusion, the rate of viable uterine grafts during the initial 6-months of the present study (75%) leaves room for improvement in the inclusion/exclusion criteria of donors and in surgical techniques. Initial low blood flow may indicate subsequent graft failure.