Can regulatory T cells improve outcomes of sensitised patients after HLA-Ab incompatible renal transplantation: study protocol for the Phase IIa GAMECHANgER-1 trial.

BACKGROUND: Kidney transplantation is the gold-standard treatment for patients with kidney failure. However, one-third of patients awaiting a kidney transplant are highly sensitized to human leukocyte antigens (HLA), resulting in an increased waiting time for a suitable kidney, more acute and chronic rejection, and a shorter graft survival compared to non-highly sensitised patients. Current standard immunosuppression protocols do not adequately suppress memory responses, and so alternative strategies are needed. Autologous polyclonally expanded regulatory T cells (Tregs) have been demonstrated to be safe in transplant settings and could be a potential alternative to modulate memory immune alloresponses. METHODS: The aim of this trial is to determine whether adoptive transfer of autologous Tregs into HLA sensitised patients can suppress memory T and B cell responses against specific HLA antigens. This is a two-part, multi-centre, prospective clinical trial, comprising an observational phase (Part 1) aiming to identify patients with unregulated cellular memory responses to HLA (Pure HLA Proteins) followed by an interventional phase (Part 2). The first 9 patients identified as being eligible in Part 1 will undergo baseline immune monitoring for 2 months to inform statistical analysis of the primary endpoint. Part 2 is an adaptive, open labelled trial based on Simon's two-stage design, with 21 patients receiving Good Manufacturing Practice (GMP)-grade polyclonally expanded Tregs to a dose of 5-10 × 106 cells/kg body weight. The primary EP is suppression of in vitro memory responses for 2 months post-infusion. 12 patients will receive treatment in stage 1 of Part 2, and 9 patients will receive treatment in stage 2 of Part 2 if ≥ 50% patients pass the primary EP in stage 1. DISCUSSION: This is a prospective study aiming to identify patients with unregulated cellular memory responses to Pure HLA Proteins and determine baseline variation in these patterns of response. Part 2 will be an adaptive phase IIa clinical trial with 21 patients receiving a single infusion of GMP-grade polyclonally expanded Tregs in two stages. It remains to be demonstrated that modulating memory alloresponses clinically using Treg therapy is achievable. TRIAL REGISTRATION: EudraCT Number: 2021-001,664-23. REC Number: 21/SC/0253. Trial registration number ISRCTN14582152.

Thrombalexin: Use of a Cytotopic Anticoagulant to Reduce Thrombotic Microangiopathy in a Highly Sensitized Model of Kidney Transplantation.

Early activation of coagulation is an important factor in the initiation of innate immunity, as characterized by thrombotic microangiopathy (TMA). In transplantation, systemic anticoagulation is difficult due to bleeding. A novel "cytotopic" agent, thrombalexin (TLN), combines a cell-membrane-bound (myristoyl tail) anti-thrombin (hirudin-like peptide [HLL]), which can be perfused directly to the donor organ or cells. Thromboelastography was used to measure time to clot formation (r-time) in both rhesus and human blood, comparing TLN versus HLL (without cytotopic tail) versus negative control. Both TLN- and HLL-treated rhesus or human whole blood result in significantly prolonged r-time compared to kaolin controls. Only TLN-treated human endothelial cells and neonatal porcine islets prolonged time to clot formation. Detection of membrane-bound TLN was confirmed by immunohistochemistry and fluorescence activated cell sorter. In vivo, perfusion of a nonhuman primate kidney TLN-supplemented preservation solution in a sensitized model of transplantation demonstrated no evidence of TLN systemically. Histologically, TLN was shown to be present up to 4 days after transplantation. There was no platelet deposition, and TMA severity, as well as microvascular injury scores (glomerulitis + peritubular capillaritis), were less in the TLN-treated animals. Despite promising evidence of localized efficacy, no survival benefit was demonstrated.

The clinical spectrum of de novo donor-specific antibodies in pediatric renal transplant recipients.

The development of donor-specific HLA antibodies (DSA) is associated with worse renal allograft survival in adult patients. This study assessed the natural history of de novo DSA, and its impact on renal function in pediatric renal transplant recipients (RTR). HLA antibodies were measured prospectively using single-antigen-bead assays at 1, 3, 6 and 12 months posttransplant followed by 12-monthly intervals and during episodes of allograft dysfunction. Of 215 patients with HLA antibody monitoring, 75 (35%) developed DSA at median of 0.25 years posttransplant with a high prevalence of Class II (70%) and HLA-DQ (45%) DSA. DSA resolved in 35 (47%) patients and was associated with earlier detection (median, inter-quartile range 0.14, 0.09-0.33 vs. 0.84, 0.15-2.37 years) and lower mean fluorescence intensity (MFI) (2658, 1573-3819 vs. 7820, 5166-11 990). Overall, DSA positive patients had more rapid GFR decline with a 50% reduction in GFR at mean 5.3 (CI: 4.7-5.8) years versus 6.1 (5.7-6.4) years in DSA negative patients (p = 0.02). GFR decreased by a magnitude of 1 mL/min/1.73 m(2) per log10 increase in Class II DSA MFI (p < 0.01). Using Cox regression, independent factors predicting poorer renal allograft outcome were older age at transplant (hazard ratio 1.1, CI: 1.0-1.2 per year), tubulitis (1.5, 1.3-1.8) and microvasculature injury (2.9, 1.4-5.7). In conclusion, pediatric RTR with de novo DSA and microvasculature injury were at risk of allograft failure.

Highly sensitised individuals present a distinct Treg signature compared to unsensitised individuals on haemodialysis.

Introduction: Highly sensitised (HS) patients represent up to 30% of patients on the kidney transplant waiting list. When they are transplanted, they have a high risk of acute/chronic rejection and long-term allograft loss. Regulatory T cells (Tregs) (CD4+CD25hiCD127lo) are T cells involved in the suppression of immune alloresponses. A particular subset, called T follicular regulatory T cells (Tfr, CXCR5+Bcl-6+), is involved in regulating interactions between T effectors and B cells within the germinal centre and can be found in peripheral blood. Therefore, we wanted to identify specific subsets of Tregs in the peripheral blood of HS individuals. Methods: We recruited prospectively healthy volunteers (HV) (n = 9), non-sensitised patients on haemodialysis (HD) (n = 9) and HS individuals, all of whom were on haemodialysis (n = 15). Results: We compared the Treg phenotypes of HV, HD and HS. HS patients had more CD161+ Tregs (p = 0.02) and more CD45RA-CCR7- T effectors (Teffs) (p = 0.04, memory Teffs able to home to the germinal centre) compared to HVs. HS patients had more Bcl-6+ Tregs (p < 0.05), fewer Th1-like Tregs, more Th2-like Tregs (p < 0.001) and more CD161+ (p < 0.05) Tregs compared to HD patients. This population has been described to be highly suppressive. HD had a deficiency in a Th17-like CD161+ effector Treg cluster (cluster iii., CCR6+CCR4+CXCR3- CD39+CD15s+ICOS-CCR7-CD161+) (p < 0.05). Discussion: This is the first study presenting a deep Treg phenotype in HS patients. We confirmed that HS patients had more of a Th17-like CD161+ effector Treg from population III (CD4+CD25hiCD127loCD45RA-) compared to non-sensitised patients on HD. The clinical relevance of this highly suppressive Tregs population remains to be determined in the context of transplantation.

High-grade blunt traumatic rupture of kidney transplant: is conservative management an option?

Road traffic accidents are the most common cause of blunt native kidney injuries. Transplanted kidneys are more exposed to such injuries due to the common positioning in the iliac fossa compared with the relatively protected position of the native kidneys. The small number of cases identified in the literature describe grade II and III transplant kidney injuries that were treated surgically. In our case a grade IV injury was managed conservatively giving the necessary time to appropriately plan the future renal replacement therapy options for the patient.

Ablative and reconstructive robotic-assisted laparoscopic renal surgery.

INTRODUCTION: The increasing role of robotic technology to facilitate surgical procedures has attracted much attention from surgeons and patients alike. In particular, the dramatic increase in the number of laparoscopic radical prostatectomies performed using the da Vinci surgical system has led to interest in using this technology for other procedures. We have evaluated our own experience performing ablative and reconstructive laparoscopic renal surgery using the da Vinci system to determine its potential role. AIMS: To review our experience of robotic-assisted laparoscopic procedures of the upper urinary tract. MATERIALS AND METHODS: Our da Vinci system was installed in June 2004. A prospective database has been maintained concerning all patients and procedures performed from that time. Procedures involving the upper urinary tract were identified and the data was examined. This included patient demographics, operative time, blood loss, hospital stay and patient outcomes. RESULTS: Twenty-six robotic procedures involved the upper urinary tract. Of these, two had to be converted to conventional laparoscopic surgery because of da Vinci mechanical failure. Robotic-assisted procedures included pyeloplasty (n = 15), simple nephrectomy (n = 2), radical nephrectomy (n = 1), nephroureterectomy (n = 2), and live donor nephrectomy (n = 4). The mean operative time was 215 min. The anastomotic time for the pyeloplasties averaged 47 min. The mean blood loss was 75 ml. There were no conversions to open surgery. The complication rate was 8.7%. Postoperative stay averaged 2.9 days. CONCLUSION: The da Vinci surgical system may be safely used to assist in the performance of laparoscopic renal surgery.

Influence of number of retransplants on renal graft outcome.

BACKGROUND: To assess the influence of number of transplants on the renal graft outcome. METHODS: Retrospective analysis of various factors that could influence the outcome of kidney retransplantation in patients receiving more than one allograft between 1993 and 2005 at our center. RESULTS: During the 12-year period (1993-2005), 196 patients received more than one renal transplant. Of these, 163 had two (group 1) and 33 had more than two transplants (group II). In group II, 24 patients had three, eight had four, and one had five consecutive allografts. The control group comprised of 100 randomly selected patients receiving a first graft during the same period. In group I, 53 (32.5%) grafts failed. Eighteen (11.0%) patients died with functioning grafts. In group II, 14 (41.2%) grafts failed while four patients (11.8%) died with functioning grafts. In group I, actuarial graft survival rates at 1, 2, 3, and 4 years were 82.3%, 67.3%, 55.97%, and 42.14%, respectively. In group II, the respective figures were 84.85%, 66.67%, 60.61%, and 51.52%. The difference was not statistically significant (P = .96). In the control group, 1-, 2-, 3-, and 4-year survival rates were 92%, 84, 74%, and 60%, respectively. The difference between the control and study groups was statistically significant (P = .0002). CONCLUSION: Graft survival after retransplantation is relatively inferior when compared to the primary graft but still remains fairly high. Therefore, previous graft failure should not be considered as a relative contraindication for retransplantation.

Telementoring facilitates independent hand-assisted laparoscopic living donor nephrectomy.

Laparoscopic living donor nephrectomy is a major advance but a challenging procedure to learn even after laparoscopic training. It requires significant previous training in both laparoscopic and transplant surgery. Telementoring has been shown to reduce the laparoscopic learning curve in other fields. Of six cases of hand-assisted laparoscopic (HAL) living donor nephrectomy at our institution, an on-site mentor supervised the initial two. We present the subsequent four cases as the first documented examples of telementored HAL live donor nephrectomy. Telelink was established with a Comstation (Zydacron, UK) incorporating a Z360 telementoring codec and four ISDN lines (512 kb/s) with time delay of 500 ms for both audio and video. The remote surgeon in Minnesota (USA) could change independently between the laparoscopic and external views. The operating surgeons were able to look at the mentor and converse with him throughout. There were no adverse events in recipients and graft function was excellent. With regards to the telementored group the mean operative time was 240 minutes, the mean warm ischemic time 189 seconds, the mean estimated blood loss 171 mL, and the mean length of hospital stay 3 days. Telementoring for laparoscopic donor nephrectomy is feasible, effective, and likely to aid independent practice by providing continued supervision and reducing the learning period.

Expanding the Living Donor Pool "Second Act": Laparoscopic Donor Nephrectomy and ABO-Incompatible Kidney Transplantation Improve Donor Recruitment.

BACKGROUND: To safely expand our living donor pool, we recently decided to work on 3 areas: analysis of causes of exclusion of potential donors, the results of which we recently published, introduction of laparoscopic donor nephrectomy (LDN), and ABO-incompatible (ABOi) transplantation. We sought to determine the impact of the new strategy on living donor recruitment and transplantation during over a 10-year period at a single institution. METHODS: From January 2005 to September 2014, we evaluated 131 living donors. Of these, 80 (61%) were genetically related, 51 (39%) unrelated, 119 (91%) ABO compatible (ABOc), 12 ABOi (9%). The analysis was divided into 2 eras: era 1, 2005-2010 (n = 53) included the use of open lumbotomy and acceptance of ABOc only; and era 2, 2011-2014 (n = 78), which saw the introduction of LDN and ABOi transplantation. RESULTS: Forty-five (34%) potential candidates successfully donated, 67 (51%) were excluded, and 19 (15%) were actively undergoing evaluation. Overall, 53 potential donors were evaluated in era 1 (8.8 donors/year), 78 in era 2 (19.5 donors/year). There were fewer excluded donors in era 2 vs era 1 (62% era 1 vs 44% era 2), and living donor kidney transplantation (LDKT) significantly increased in era 2 vs era 1 (3.3/year era 1 vs 7.1/year era 2). The establishment of an ABOi LDKT program led to a 15% increase of evaluations in era 2 (12/78 donors). CONCLUSIONS: LDN along with ABOi LDKT allowed for an improvement in recruitment of living donors and corresponding LDKT.

Graft type for femoro-popliteal bypass surgery.

BACKGROUND: Vascular surgeons construct femoro-popliteal bypass grafts, from the groin to the knee, to save limbs that might otherwise require amputation in patients with severe arterial disease, and to improve walking distance in patients with less severe arterial disease. During the operation, the blocked native artery is bypassed using either a section of the patient's own vein (autologous vein), human umbilical vein (HUV), or an artificial graft e.g. Dacron or polytetrafluoroethylene (PTFE). OBJECTIVES: The objective of this review was to determine the most effective type of graft for femoro-popliteal bypass surgery. SEARCH STRATEGY: The reviewers searched the Cochrane Peripheral Vascular Diseases Group trials register, reference lists of relevant articles, and hand searched proceedings from the British and European Vascular Surgical Societies and the North American Society of Vascular Surgery. They also contacted all major manufacturers of artificial grafts and authors of published trials to enquire about unpublished trials. SELECTION CRITERIA: Randomised trials comparing one type of femoro-popliteal graft with another. DATA COLLECTION AND ANALYSIS: Both reviewers selected trials and assessed trial quality independently. MAIN RESULTS: Nine trials were included with a total of 1334 participants. These investigated a variety of graft types. In one trial of above-knee grafting, primary and secondary patency were significantly better for saphenous vein (73% and 90%, respectively) compared to PTFE (47%, p<0.05 and 47%, p<0.05) and Dacron (54%, p<0.01 and 60%, p<0.01) at four years. Two trials comparing in-situ and reversed saphenous vein grafts to the above- and below-knee popliteal artery revealed no differences in primary patency (64% v 62% respectively), secondary patency (65% v 70%), or survival with intact limb (74% both groups) with five to ten year follow-up. Three trials comparing PTFE with HUV showed significantly better secondary patency rates for HUV, (41% v 73%, p<0.005; 49% v 66%, p<0.05; 22% v 42%,p=0.005) one also showed significantly better primary patency for HUV at five years (32% v 65%, p<0.001). Comparison of PTFE grafts with, and without, a vein cuff found no difference in above-knee grafts. However, primary patency below-knee was higher with a PTFE plus vein cuff bypass (52% v 29%, p=0.03) at two years. REVIEWER'S CONCLUSIONS: There is no clear evidence which type of graft is best for femoro-popliteal grafting. In terms of autologous graft patency, in-situ and reversed vein grafts are equally successful, while HUV performs better than PTFE. A distal vein cuff may improve primary patency for below-knee PTFE femoro-popliteal grafts.

2509 living donor nephrectomies, morbidity and mortality, including the UK introduction of laparoscopic donor surgery.

The worldwide expansion of laparoscopic, at the expense of open, donor nephrectomy (DN) has been driven on the basis of faster convalescence for the donor. However, concerns have been expressed over the safety of the laparoscopic procedure. The UK Transplant National Registry collecting mandatory information on all living kidney donations in the country was analyzed for donations between November 2000 (start of living donor follow-up data reporting) to June 2006 to assess the safety of living DN, after the recent introduction of the laparoscopic procedure in the United Kingdom. Twenty-four transplant units reported data on 2509 donors (601 laparoscopic, 1800 open and 108 [4.3%] unspecified); 46.5% male; mean donor age: 46 years. There was one death 3 months postdischarge and a further five deaths beyond 1 year postdischarge. The mean length of stay was 1.5 days less for the laparoscopic procedure (p < 0.001). The risk of major morbidity for all donors was 4.9% (laparoscopic = 4.5%, open = 5.1%, p = 0.549). The overall rate of any morbidity was 14.3% (laparoscopic = 10.3%, open = 15.7%, p = 0.001). Living donation has remained a safe procedure in the UK during the learning curve of introduction of the laparoscopic procedure. The latter offers measurable advantages to the donor in terms of reduced length of stay and morbidity.

Regression of post-transplant Kaposi's sarcoma using sirolimus.

Kaposi's sarcoma (KS) is a recognised complication following kidney transplantation, but the incidence varies according to the geographical area. Although it is a rare tumour, its incidence increases dramatically after solid-organ transplantation. The immunosuppressive medications reactivate human herpes virus 8, which has been proposed as the offending agent. The usual treatment of KS is to reduce immunosuppression, chemotherapy and radiotherapy. Nevertheless, the mortality still remains considerably high and has been reported between 8 and 14%. Sirolimus (SRL) has properties which may be useful in the management of some posttransplant tumours such as KS. We report a renal transplant patient with KS, who had multiple relapses after radiotherapy but responded well to the change of immunosuppression from cyclosporine to SRL.

Failure to improve outcome in acute mesenteric ischaemia: seven-year review.

OBJECTIVE: To determine whether the prognosis of acute mesenteric ischaemia has changed over the past seven years. DESIGN: Retrospective study. SETTING: Teaching hospital, Scotland. SUBJECTS: 57 patients who presented to this hospital between January 1987 and December 1993 with acute mesenteric ischaemia. MAIN OUTCOME MEASURES: Morbidity, mortality and prognostic features. RESULTS: 46 of the 57 patients died. Only 18(32%) patients were accurately diagnosed before operation or death. Clinical presentation, white cell count, and serum amylase activity were not helpful in the diagnosis. Only 3 patients had mesenteric angiography, and none were given lytic agents or vasodilators. CONCLUSION: Mortality from acute mesenteric ischaemia has not changed during the past two decades and in the absence of an accurate diagnostic test is unlikely to do so.

Gastroenteritis causing critical limb ischaemia.

Six days after admission to hospital with Salmonella gastroenteritis, this patient presented with a critically ischaemic leg, having developed an iliac occlusion, and a subcutaneous Salmonella abscess in the anterior compartment of the leg. Critical limb ischaemia and abscess formation can be added to infective aortic aneurysm as vascular complications of Salmonella gastroenteritis.