Joseph K. Melancon

Outcomes of Kidney Transplantation in HIV-Infected Recipients

BACKGROUND The outcomes of kidney transplantation and immunosuppression in people infected with human immunodeficiency virus (HIV) are incompletely understood. METHODS We undertook a prospective, nonrandomized trial of kidney transplantation in HIV-infected candidates who had CD4+ T-cell counts of at least 200 per cubic millimeter and undetectable plasma HIV type 1 (HIV-1) RNA levels while being treated with a stable antiretroviral regimen. Post-transplantation management was provided in accordance with study protocols that defined prophylaxis against opportunistic infection, indications for biopsy, and acceptable approaches to immunosuppression, management of rejection, and antiretroviral therapy. RESULTS Between November 2003 and June 2009, a total of 150 patients underwent kidney transplantation; survivors were followed for a median period of 1.7 years. Patient survival rates (±SD) at 1 year and 3 years were 94.6±2.0% and 88.2±3.8%, respectively, and the corresponding mean graft-survival rates were 90.4% and 73.7%. In general, these rates fall somewhere between those reported in the national database for older kidney-transplant recipients (≥65 years) and those reported for all kidney-transplant recipients. A multivariate proportional-hazards analysis showed that the risk of graft loss was increased among patients treated for rejection (hazard ratio, 2.8; 95% confidence interval [CI], 1.2 to 6.6; P=0.02) and those receiving antithymocyte globulin induction therapy (hazard ratio, 2.5; 95% CI, 1.1 to 5.6; P=0.03); living-donor transplants were protective (hazard ratio, 0.2; 95% CI, 0.04 to 0.8; P=0.02). A higher-than-expected rejection rate was observed, with 1-year and 3-year estimates of 31% (95% CI, 24 to 40) and 41% (95% CI, 32 to 52), respectively. HIV infection remained well controlled, with stable CD4+ T-cell counts and few HIV-associated complications. CONCLUSIONS In this cohort of carefully selected HIV-infected patients, both patient- and graft-survival rates were high at 1 and 3 years, with no increases in complications associated with HIV infection. The unexpectedly high rejection rates are of serious concern and indicate the need for better immunotherapy. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT00074386.).

Multicenter evaluation of a novel endothelial cell crossmatch test in kidney transplantation.

Background. Despite their clinical importance, clinical routine tests to detect anti-endothelial cell antibodies (AECA) in organ transplantation have not been readily available. This multicenter prospective kidney transplantation trial evaluates the efficacy of a novel endothelial cell crossmatch (ECXM) test to detect donor-reactive AECA associated with kidney allograft rejection. Methods. Pretransplant serum samples from 147 patients were tested for AECA by a novel flow cytometric crossmatch technique (XM-ONE) using peripheral blood endothelial progenitor cells as targets. Patient enrolment was based on acceptance for transplantation determined by donor lymphocyte crossmatch results. Results. Donor-reactive AECA were found in 35 of 147 (24%) patients. A significantly higher proportion of patients with a positive ECXM had rejections (16 of 35, 46%) during the follow-up of at least 3 months compared with those without AECA (13 of 112, 12%; P<0.00005). Both IgG and IgM AECAs were associated with graft rejections. Mean serum creatinine levels were significantly higher in patients with a positive ECXM test at 3 and 6 months posttransplant. Conclusions. XM-ONE is quick, easy to perform on whole blood samples and identifies patients at risk for rejection and reduced graft function not identified by conventional lymphocyte crossmatches.

HLA-specific B cells: II. Application to transplantation

Background. Differences in the antibody response to allogeneic transplantation exist between groups defined by race or gender. These differences may reflect differences in immune competency and/or exposure to alloantigens. We have investigated the frequencies and phenotypes of HLA-specific B cells to address those possibilities. Methods. HLA-specific B cells were identified by staining with HLA tetramers (tet) as described previously and the distribution of CD27 and CD38 among those cells were measured in groups defined by various parameters. Possible correlation between frequencies of HLA-specific B cells and production of HLA-specific antibody after transplantation was also investigated. Results. We found no correlation between the frequencies of CD27+tet+ (33%–44% vs. 34%–36%) or CD38+tet+ (57%–65% vs. 59%–66%) B cells and a previous mismatch for the HLA antigen of the tetramer. However, there was an increase in CD38+tet+ B cells among patients making antibody to the tetramer antigen (67%–72% vs. 53%–56%). Blacks had lower frequencies of CD27+ B cells than did whites (11.8% vs. 28.9%, P=0.003), but had greater increases of these cells among tet+ cells than did whites. There was a higher frequency of tet+ B cells among patients who developed “new” antibody to the HLA antigen (3.9%–8.6%) of the tetramer after transplantation than among those who did not (1.1%–3.7%). Conclusions. The phenotype of HLA-specific B cells reflects current or historic sensitization to HLA and may reflect inherent differences between groups defined by race and/or gender. The frequencies of HLA-specific B cells may predict patients at risk for production of donor-specific antibody after transplantation.

DNA testing for live kidney donors at risk for autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by age-dependent growth of kidney cysts with end-stage renal disease developing in approximately 50% of affected individuals. Living donors from ADPKD families are at risk for developing ADPKD and may be excluded from renal donation if the diagnosis cannot be conclusively ruled out. Radiographic imaging may be adequate to screen for kidney cysts in most at-risk donors but may fail to identify affected individuals younger than 40 years or older individuals from families with mild disease. In this article, we report a strategy that incorporates genetic testing in the evaluation of live kidney donors at risk for ADPKD whose disease status cannot be established with certainty on the basis of imaging studies alone. We show that DNA diagnostics can be used to enhance safe donation for certain living donor candidates at risk for ADPKD.

Microvascular Endothelial Dysfunction and Enhanced Thromboxane and Endothelial Contractility in Patients with HIV

11 BACKGROUND The prevalence of cardiovascular disease is increased with human immunodeficiency virus (HIV) infection, but the mechanism is unclear. We hypothesized that HIV increases microvascular reactive oxygen species, thereby impairing endothelial function and enhancing contractility. 12 METHOD Subcutaneous microarterioles were isolated from gluteal skin biopsies in premenopausal, African American, HIV positive women receiving effective anti-retroviral therapy, but without cardiovascular risk factors except for increased body mass index (n=10) and healthy matched controls (n=10). The arterioles were mounted on myographs, preconstricted and relaxed with acetylcholine for: endothelium-dependent relaxation, endothelium-dependent relaxation factor (nitric oxide synthase-dependent relaxation), endothelium-dependent hyperpolarizing factor (potassium-channel dependent relaxation) and endothelium-independent relaxation (nitroprusside). Contractions were tested to endothelium-dependent contracting factor (acetylcholine contraction with blocked relaxation); phenylephrine, U-46,619 and endothelin-1. Plasma L-arginine and asymmetric dimethylarginine were measured by high performance capillary electrophoresis. 13 RESULTS The micro-arterioles from HIV positive women had significantly (% change in tension; P<0.05) reduced acetylcholine relaxation (-51 ± 6 vs. -78 ± 3%), endothelium-dependent relaxation factor (-28 ± 4 vs. -39 ± 3%), endothelium-dependent hyperpolarizing factor (-17 ± 4 vs. -37 ± 4%) and decreased nitric oxide activity (0.16 ± 0.03 vs. 0.70 ± 0.16 Δ unit) but unchanged nitroprusside relaxation. They had significantly enhanced endothelium-dependent contracting factor (+21 ± 6 vs. +7 ± 2%) and contractions to U-46,619 (+164 ± 10 vs. +117 ± 11%) and endothelin-1(+151 ± 12 vs. +97 ± 9%), but not to phenylephrine. There was enhanced reactive oxygen species with acetylcholine (0.11 ± 0.02 vs. 0.05 ± 0.01 Δ unit; P<0.05) and endothelin-1 (0.31 ± 0.06 vs. 0.10 ± 0.02 Δ unit; P<0.05). Plasma L-arginine: assymetric dimethyl arginine rates was reduced (173 ± 12 vs. 231 ± 6 μmol·μmol-1, P<0.05). 14 CONCLUSION Premenopausal HIV positive womenhad microvascular oxidative stress with severe endothelial dysfunction and reduced nitric oxide and arginine: assymetric dimethylarginine ratio but enhanced endothelial, thromboxane and endothelin contractions. These microvascular changes may herald later cardiovascular disease.

Autotransplantation of Solitary Kidney With Renal Artery Aneurysm Treated With Laparoscopic Nephrectomy and Ex Vivo Repair: A Case Report

INTRODUCTION Renal artery aneurysms (RAA) are extremely rare clinical entities with associated morbidities including hypertension and rupture. Although most RAA can be treated with in vivo repair or endovascular techniques, these may not be possible in patients with complex RAA beyond the renal artery bifurcation. We report a case of RAA in a patient with a solitary kidney that we treated successfully by extracorporeal repair and autotransplantation and the 2-years follow-up. CASE REPORT A 64-year-old woman with a history of right nephrectomy for renal cell carcinoma presented with RAA found on routine computed tomography (CT). Preoperative workup demonstrated a 2.2 × 2.1 × 3-cm aneurysm in the distal left renal artery that was not amendable to in vivo or endovascular repair. The patient underwent a laparoscopic-assisted left nephrectomy, ex vivo renal artery aneurysm repair, and autotransplantation. She did well postoperatively and in clinic follow-up was found to have a creatinine of 1.2 mg/dL at the end of 2 years and stable blood pressure control. DISCUSSION This patient with RAA in her solitary kidney was successfully treated with laparoscopic-assisted nephrectomy, ex vivo repair, and autotransplantation. Her creatinine was stable postoperatively despite absence of a second kidney.

Paired Kidney Donor Exchanges and Antibody Reduction Therapy: Novel Methods to Ameliorate Disparate Access to Living Donor Kidney Transplantation in Ethnic Minorities

BACKGROUND Currently ethnic minority patients comprise 60% of patients listed for kidney transplantation in the US; however, they receive only 55% of deceased donor renal transplants and 25% of living donor renal transplants. Ethnic disparities in access to kidney transplantation result in increased morbidity and mortality for minority patients with end-stage renal disease. Because these patients remain dialysis dependent for longer durations, they are more prone to the development of HLA antibodies that further delay the possibility of receiving a successful kidney transplant. STUDY DESIGN Two to 4 pretransplant and post-transplant plasma exchanges and i.v. immunoglobulin were used to lower donor-specific antibody levels to less than 1:16 dilution; cell lytic therapy was used additionally in some cases. Match pairing by virtual cross-matching was performed to identify the maximal exchange benefit. Sixty candidates for renal transplantation were placed into 4 paired kidney exchanges and/or underwent antibody reduction therapy. RESULTS Sixty living donor renal transplants were performed by paired exchange pools and/or antibody reduction therapy in recipients whose original intended donors had ABO or HLA incompatibilities or both (24 desensitization and 36 paired kidney exchanges). Successful transplants were performed in 38 ethnic minorities, of which 33 were African American. Twenty-two recipients were white. Graft and patient survival was 100% at 6 months; graft function (mean serum creatinine 1.4 g/dL) and acute rejection rates (20%) have been comparable to traditional live donor kidney transplantation. CONCLUSIONS Paired kidney donor exchange pools with antibody reduction therapy can allow successful transplant in difficult to match recipients. This approach can address kidney transplant disparities.

Liver transplantation should be offered to patients with small solitary hepatocellular carcinoma and a positive serum alpha fetoprotein rather than resection

BACKGROUND As debate continues as to what surgical modality should be offered to patients with hepatocellular carcinoma, the authors submit that serum α-fetoprotein (AFP) is an important variable to consider. METHODS Using the Surveillance, Epidemiology and End Results database, patients with solitary tumors within the Milan criteria were further stratified into 2 groups, those who underwent orthotopic liver transplantation (OLT) and those who underwent segmentectomy, lobectomy, or extended lobectomy (resection). Patients were further grouped according to serum AFP status (negative or positive). Relative survival was retrospectively evaluated for 3 years using the log-rank test. RESULTS In the AFP-negative group, resection (n = 165) offered equivalent survival compared with OLT (n = 116); 3-year survival was 73.8% and 81.6%, respectively (P = .245). In the AFP-positive group, 3-year survival for resection (n = 200) was 59%, while survival was 75.3% for OLT (n = 181), which showed a clear survival advantage (P = .001). CONCLUSIONS The results of this study demonstrate that patients with solitary hepatocellular carcinoma lesions within the Milan criteria and AFP-positive status should not undergo resection but rather be offered OLT.