Renal Graft Rejection Research Articles

Abstract 5548: Novel small-molecule delta opioid receptor ligands modeled from naltrindole inhibit the proliferation of human U266 multiple myeloma cells.

Abstract Multiple myeloma is an invasive plasma cell neoplasm that proliferates in the bone marrow, and is responsible for 10% of all hematological malignancies. Naltrindole, synthesized by Portoghese and colleagues (1988) is a synthetic alkaloid derived from naltrexone, and has the pharmacological profile of a selective delta opioid receptor antagonist. Naltrindole also acts as a potent immunosuppressant in the allogeneic mixed lymphocyte reaction and in inhibiting renal graft rejection, and Gaveriaux-Ruff and colleagues (2001) demonstrated that a non-opioid receptor target was involved in the immunosuppressant activity of naltrindole. In a recent report (Mundra et al., J. Pharmacol. Exp. Ther. 342: 273-287, 2012), naltrindole inhibited human multiple myeloma cell proliferation in vitro and in a murine xenograft model in vivo, by interaction with a non-opioid receptor target. In this study, it was discovered that four novel small-molecule delta opioid receptor ligands (DOPs) derived from naltrindole by rational design (see Peng et al., Bioorgan. & Med. Chem. 17: 6442-6450, 2009) competed for specific 3H-naltrindole binding to human U266 multiple myeloma cells. The apparent dissociation constant, KD, of naltrindole binding to intact multiple myeloma cells was 20 μM, and the Bmax was 1.8 nmol/mg protein. Whole cells were incubated with 10 nM 3H-naltrindole in the absence and presence of 500 μM unlabeled naltrindole (to define specific binding), and the ability of the DOP ligands to displace specific naltrindole binding was assayed at room temperature following a 30 min incubation of each DOP compound at 50 μM. DOP 108 inhibited specific naltrindole binding down to 22 ± 6 % of control (78% inhibition of binding); DOP 121 reduced binding to 36 ± 10 % control; DOP 126 inhibited binding to 12 ± 5 % control, and DOP 402 inhibited binding to 16 ± 7 % control. More detailed competition curves will be performed, but it appears that the affinity of the DOP ligands for the naltrindole binding site are similar or higher than naltrindole itself. When U266 multiple myeloma cells were incubated at 37°C for 72 h in the presence of naltrindole or the DOP ligands, each at 50 μM, the number of viable myeloma cells was inhibited to 42 ± 7, 49 ±11, 31 ± 8, 29 ± 8, and 28 ± 9 % of the number of control untreated cells by naltrindole, DOP 108, DOP 121, DOP 126, and DOP 402, respectively, demonstrating that the efficacy of the DOP compounds to inhibit multiple myeloma cell growth was similar or better than naltrindole. This study provides a rationale basis for further evaluation of the DOP compounds as anti-multiple myeloma therapeutic agents. Citation Format: Richard D. Howells, Jyoti Joshi Mundra, Alessandro Howells, Giovanni Howells, Youyi Peng, William Welsh. Novel small-molecule delta opioid receptor ligands modeled from naltrindole inhibit the proliferation of human U266 multiple myeloma cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5548. doi:10.1158/1538-7445.AM2013-5548

Significance of Urine Diagnostic Tests After Renal Transplantation

Background: Validity, reliability and clinical value of classical urinary parameters for transplant monitoring are controversial. Urinary parameters were analyzed regarding cost-effectiveness, frequency of urinary tract infection and prediction of renal graft function and rejection. Methods: Urinary parameters of the first two postoperative weeks of 120 renal transplant patients were retrospectively correlated with the postoperative course. Results: Creatinine levels were significantly different on each postoperative day between the groups with and without rejection. Osmolaluria, diuresis and serum creatinine are equivalent in predicting graft rejection. Osmolaluria is not suitable as a distinguishing criterion between graft rejection and other complications. Measurement of glucosuria has no diagnostic value. Proteinuria has no prognostic relevance regarding rejection, although proteinuria >0.5g/l occurred more often in patients with rejection. Despite antibiotic prophylaxis with co-trimoxazole, 41 of 120 patients (34%) suffered from urinary tract infection (UTI; mostly E. coli) within the first 14 days after transplantation. Conclusions: The measurement of some classical urinary parameters delivers no diagnostic gain. UTIs are frequent despite antibiotic prophylaxis, but the use of urine cultures makes sense only if a (cheaper) semiquantitative test is positive.

Analysis of TNF-β, IL-10, and IL-1 Cluster Gene Polymorphisms and Clinical Risk Factors on Acute Renal Graft Rejection

Introduction: There is growing evidence of the genetic association between certain cytokine and acute renal graft rejection. We sought to investigate the role of recipients’ TNF-β, IL-10, IL-1β and IL-1 receptor antagonist (ra) gene polymorphism as well as other variables such as PRA levels and HLA mismatches in acute renal graft rejection. Methods: TNF-β (+252A/G), IL-10(-592A/C), IL-1β (-511C/T) and IL-1ra (86bp VNTR) gene polymorphisms were determined in 157 renal allograft recipients with and without acute rejection using PCR. TNF-β, IL-10, IL-1β and IL-1ra genotypic variants were investigated for correlation with acute rejection within the first year after renal transplantation. Results: Patients with increased panel-reactive antibody (PRA) levels were predisposed to acute renal graft rejection (P=0.001). After adjusting for all variables of P 10% remained significant risk factor in a multivariate logistic regression analysis (OR=5.897, 95% confidence intervals=1.884-18.456, P=0.002). No significant difference was found between recipients with and without acute rejection regarding TNF β, IL-10, IL-1β and IL-1ra gene polymorphisms. Conclusion: Increased PRA levels have more significant impacts than cytokine gene polymorphisms on the likelihood of developing acute renal graft rejection. We should take necessary pre-transplant and/or post-transplant measures such as plasma exchange or immune adsorption to lower the PRA levels. To identify the actual role of both PRA levels and gene polymorphisms in acute renal graft rejection additional studies with larger sample sizes will be necessary.

Law change increases renal graft rejection, resource use and costs

Law change increases renal graft rejection, resource use and costs

Indoleamine, 2-3 Dioxygenase Activity Could Be an Early Marker of Graft Rejection in Heart Transplantation

BackgroundThe indoleamine, 2-3 dioxygenase (IDO) is an inducible intracellular enzyme with immunosuppressive effects mainly on lymphocyte populations. It has been postulated that indirect determination of IDO serum activity may be a marker of renal graft rejection, but its potential usefulness in heart transplantation (HT) is unknown. MethodsThis longitudinal study included 98 HT patients (83% males) who survived ≥1 year. Mean age was 54.14 ± 11.57 years. Serum IDO activity was analyzed one month after HT by means of high performance liquid chromatography and correlated with the cumulative incidence of acute rejection (AR) during one-year follow-up. AR was defined as biopsy-proven ≥ ISHLT grade 2R rejection or empirically treated non-biopsy-proven rejection. The study sample was divided into two groups: AR group (n = 51), including patients who experienced at least one AR episode during the first year after HT; No-AR group (N = 47), including the remaining patients. ResultsMean serum IDO activity one month after HT was significantly higher (P = .021) in the AR group (3.32 ± 1.56) than in the no-AR group (2.62 ± 1.35). No significant association between serum IDO activity and gender (male: 3.1 ± 1.56, women: 2.43 ± 0.99, P = .092), recipient age (r = −.07, P = .943) or donor age (r = 0.108, P = 0.293) was observed. By means of binary logistic regression, an odds ratio of 1.4 [CI 95%: 1.033-1.876, P = .03] per unit increase of act-IDO was estimated, with no significant modification upon forced adjustment for age and sex. Mean glomerular filtration rate 1 month after HT was 67.01 ± 28.51 mL/min/m2. No significant correlation between this parameter and serum IDO activity was observed (r = .160, P = .117). ConclusionsOur study suggests that serum IDO activity one month after HT might be associated with a higher risk of AR during one-year follow-up. This association seems to be independent of recipient gender, age or renal function.

Expression of MMP-2 and TIMP-1 in Renal Tissue of Patients with Chronic Active Antibody-mediated Renal Graft Rejection

ObjectiveTo investigate the expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metallopropteinase-1 (TIMP-1) in the renal allografts of patients with chronic active antibody-mediated rejection (AMR), and to explore their role in the pathogenesis of AMR.MethodsImmunohistochemistry assay and computer-assisted image analysis were used to detect the expression of MMP-2 and TIMP-1 in the renal allografts with interstitial fibrosis and tubular atrophy (IF/TA) in 46 transplant recipients and 15 normal renal tissue specimens as the controls. The association of the expression level of either MMP-2 or TIMP-1 with the pathological grade of IF/TA in AMR was analyzed.ResultsThe expression of either MMP-2 or TIMP-1 was significantly increased in the renal allografts of the recipients as compared with the normal renal tissue (P < 0.05). MMP-2 expression tended to decrease, while TIMP-1 and serum creatinine increased along with the increase of pathological grade of IF/TA (P < 0.05). In IF/TA groups, the expression of TIMP-1 was positively correlated to serum creatinine level (r = 0.718, P < 0.05).ConclusionsIt is suggested by the results that abnormal expressions of MMP-2 and TIMP-1 might play roles in the development of renal fibrosis in chronic AMR.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1128474926172838

A blood test for acute rejection after renal transplantation? Commentary on “Osteopontin level correlates with acute cellular renal allograft rejection”

DOI of original article: 10.1016/j.jss.2012.0 * Corresponding author. Department of Sur Tel.: þ1 212 844 8570; fax: þ1 212 844 8440. E-mail address: mleitman@chpnet.org (I. 0022-4804/$ e see front matter a 2013 Elsev http://dx.doi.org/10.1016/j.jss.2012.08.056 End-stage renal disease affects over 500,000 patients each year in the United States. Currently, over 92,000 people wait on the kidney transplant list in the United States alone, where approximately 16,000 transplants occur annually [1]. With such a discrepancy between supply and demand, graft survival is critical. Yet, even with advances in transplantation technique and immunosuppression, year one acute rejection rates remain between 10% and 20% [2]. Acute rejection begins subclinically and progression may lead to irreversible organ damage or graft loss. Research has been focused on finding early markers of rejection. Traditionally, renal allografts have been monitored using urinalysis, serum creatinine levels, and renal biopsies. Urinalysis provides a basic substrate to monitor renal function and graft rejection. Proteinuria has long correlated with chronic kidney disease and is also positively associated with rejection. However, proteinuria is indicative of an inflammatory process that has already advanced to irreversible kidney injury. Evidence has emerged that shows a relationship between microproteinuria and rejection, which may prove beneficial in

Differential expression of Neuropeptide Y (NPY) and NPY receptors 1/2 between rat lung and kidney allografts

Recently, our group described a strong leukocytic expression of NPY in the rat. During acute renal graft rejection, we observed a drastical down-regulation of NPY by mononuclear leukocytes accumulating in blood vessels of rat kidneys. Concurrently, the expression of NPY receptors Y1 and Y2 was increased. NPY, a sympathetic co-mediator modulating immune functions, may regulate leukocyte accumulation in graft blood vessels. Lung transplantation is the therapeutic measure of last resort for patients with end-stage lung disease. Compared to kidney transplants, the long-term outcomes of lung grafts are worse. This study addresses the expression of NPY and its receptors in acute rejection of pulmonary grafts. Orthotopic left lung transplantations were performed in the Dark Agouti to Lewis rat strain combination. Animals were sacrificed 4 days after surgery, one day before irreversible graft destruction. Time-matched isografts and untreated organs served as controls. The expression of NPY and its receptors was analyzed by quantitative RT-PCR, Western Blotting, radioimmunoassay and/or immunohistochemistry. Surprisingly, in lung allografts, mononuclear intravascular leukocytes, obtained by vascular perfusion, and intraalveolar leukocytes from bronchoalveolar lavages, abundantly expressed NPY mRNA during acute rejection. In intraalveolar leukocytes, but not in leukocytes isolated from the blood vessels of allografts, we observed an increase in Y1 expression. NPY peptide concentrations in the lung lavage fluids were higher in transplanted allografts compared to control lungs. Our study verifies distinctive organ-specific features of the mononuclear leukocytes in lung allografts. The observed differences between lungs and kidneys may be responsible for the moderate number of leukocytes accumulating in pulmonary graft vessels compared to the massive number in renal grafts. The mechanisms involved in the regulations of the NPY/NPY receptor system are currently under investigation.

Effect of alprostadil on recovery of renal transplant recipients with delayed graft function

Objective To assess the effect of alprostadil on accelerating early recovery of renal transplant patients with delayed graft function.Methods A randomized control clinical trial was designed in renal recipients with delayed graft function(DGF)who were administered with 50μg alprostadil each day after the operation.The effects of alprostadil were compared with the control group which included 14 recipients with DGF to determine the influences of alprostadil on urine,serum creatinine(SCr).Under Doppler ultrasound,the renal blood flow resistance-indexes(RI)were measured.The rates of acute renal graft rejection(AR)were also calculated in both groups,and the 1year patient/graft survival rates were compared between the two groups.Results Urine was significantly higher in alprostadil-treated group than in control group(P ＜ 0.05).On the contrary,SCr and RI were significantly lower in alprostadil-treated group than in control group(P ＜ 0.05).No significant differences were found between the two groups in AR rate(6.25％ vs 7.14％)and the 1-year patient/graft survival rates(P ＞ 0.05).Conclusion The application of alprostadil in renal recipients with DGF had beneficial effects on accelerating recovery of renal graft function. Key words: Renal transplantation; Delayed graft function; Alprostadil

Association studies of Toll‐like receptor gene polymorphisms with allograft survival in renal transplant recipients of North India

Organ transplantation itself inevitably activates the innate immune system by Toll-like receptors (TLRs), potentially leading to allograft rejection and graft failure. We evaluated the possible association of TLR2, TLR3, and TLR9 polymorphisms of donor-recipient pairs and acute rejection in renal transplant patients of North India. TLR2 (-196 to -174 del), TLR3 (c.1377C/T; rs 3775290), and TLR9 (+2848 G/A; rs 352140) were genotyped using DNA samples from 200 donor-recipient pairs of live donor kidney transplantation by applying Restriction Fragment Length Polymorphism (RFLP) methodology. The variant allele frequency of TLR2 (-196 to -174 del) was significantly different between recipients and donors (7.5% vs. 5.0%; p = 0.049; OR = 3.9; 95% CI = 1.01-15.32). However, no significant association for allograft rejection was observed in transplant recipients for TLR3 and TLR9. Interestingly, a low prevalence of AA genotype of TLR9 + 2848 G>A was observed in rejecters when compared with non-rejecters, demonstrating protective association with allograft rejection (OR = 0.30, 95% CI = 0.12-0.88, p = 0.028). An allele in patients was also observed to be associated with higher rejection-free survival (log-rank = 0.044). These TLR gene polymorphisms, upon further evaluation, may be helpful in elucidation of immunobiological mechanisms associated with renal graft rejection.

Role of combination of l‐arginine and α‐tocopherol in renal transplantation ischaemia/reperfusion injury: a randomized controlled experimental study in a rat model

What's known on the subject? and What does the study add? Renal ischaemia/reperfusion (I/R) injury is an inevitable consequence of kidney transplantation. It contributes to delayed graft function (DGF), acute renal failure and graft rejection. The present study investigates for the first time the impact of a combination of L-arginine and alpha tocopherol on the renal ischemia/reperfusion injury in a rodent model of kidney transplantation. We found that concomitant administration of L-arginine and α-tocopherol has a more protective effect and synergistic antioxidant effect on ischaemia/reperfusion injury in transplanted rat kidneys. To investigate the role of L-arginine and α-tocopherol in ischaemia/reperfusion injury in a kidney transplanted rat model. In total, 40 male Sprague-Dawley rats subjected to renal transplantation received FK506 (tacrolimus) to overcome early acute rejection episodes. Animals were divided randomly into four groups (ten rats each). Group I were treated with FK506 (2 mg/kg/bw/day) and served as the control group. Group II were treated with L-arginine 300 mg/kg/bw. Group III were treated with α-tocopherol 30 mg/kg/bw. Group IV were treated with L-arginine and α-tocopherol. Urine and blood samples were taken at 0 (before operation), 2, 7 and 14 days post-transplantation for estimation of urine sodium, creatinine, fractional excretion of sodium, serum creatinine, sodium and blood urea nitrogen. Histological examination and measurement of malondialdehyde in kidney tissues were also performed. Serum creatinine and blood urea nitrogen significantly decreased in L-arginine and α-tocopherol, as well as combination groups, compared to the control group. Malondialdehyde was significantly decreased in the combination group compared to L-arginine and α-tocopherol alone. Histological examination of the control group showed that acute tubular necrosis was markedly decreased in transplanted kidneys treated with a combination of both L-arginine and α-tocopherol. Concomitant administration of l-arginine and α-tocopherol has a more protective effect and synergistic antioxidant effect on ischaemia/reperfusion injury in transplanted rat kidneys.

Successful Treatment of Fibrosing Cholestatic Hepatitis After Liver Transplantation

Background A minority of liver transplant (OLT) recipients with hepatitis C virus (HCV) develop fibrosing cholestatic hepatitis (FCH), a severe form of HCV recurrence associated with early graft failure and death. There are few reports of successful salvage strategies. In this retrospective study, we sought to determine the characteristics and outcomes for patients with FCH at our transplant center. Methods All cases of HCV-positive OLT recipients from July 2007 through July 2010 were reviewed. Patient demographics, donor characteristics, and the post-OLT clinical course were analyzed. Tacrolimus-based immunosuppression was used. FCH was treated by conversion to cyclosporine A (CsA) and aggressive treatment with pegylated interferon (IFN) alpha2A and ribavirin (RBV). Liver biopsies and HCV RNA were obtained frequently per protocol or for cause. Results The rate of FCH during the study period was 13.5% (5/37). Of the 5 patients with FCH (4 males, 4 Caucasian), mean age was 51 (± 4.8) years and the Model for End-Stage Liver Disease (MELD) score at listing was 26.6 (± 10). Three of the 5 received liver and kidney (L/K) transplants (60%); the rate of L/K transplant in non-FCH patients was 12.5%. HCV RNA levels ranged from 5 to 6.69 log IU/mL pre-OLT; none were on anti-HCV therapy at the time of OLT. Mean ischemic time was 385 (± 152) minutes; donor age was 34.4 (± 13.7) years. No CMV infections developed postoperatively. Time to histologic HCV recurrence was 2 (± 2.23) months (range, 1–6); FCH occurred at 2.2 (± 2.2) months. Patients were converted from tacrolimus to CsA and treated with IFN and RBV; 2 were changed to consensus IFN. HCV RNA increased post-OLT in all, but responded to therapy in 4 of 5. None of the L/K recipients experienced renal graft rejection during treatment. Four of 5 had clinical and histologic improvement; 1 progressed to cirrhosis with minimal inflammation. One-year patient survival after OLT in this group was 80%. Liver allograft rejection occurred in 60% at 4.7 (± 5.5) months and was treated by CsA and prednisone dosage adjustments. In this cohort of patients undergoing OLT for HCV, FCH occurred early after OLT but responded to aggressive management with conversion from tacrolimus to CsA and treatment with pegylated IFN or consensus IFN/RBV. There was a higher rate of combined L/K transplants in the FCH group compared with the non-FCH group. Liver allograft rejection occurred in 60% of cases, but responded to treatment in all; no renal graft rejection occurred in the 3 with L/K transplants while on IFN. One-year graft and patient survival was 80%. Conclusion Better survival with FCH is possible with early initiation of IFN/RBV therapy with close monitoring of biopsies and viral load, and conversion from tacrolimus to CsA. Treatment can be performed even in L/K transplantation recipients, although it is associated with a higher incidence of treatable liver allograft rejection.

Functional evaluation of transplanted kidneys in normal function and acute rejection using BOLD MR imaging

In this study, we evaluated a large number of subjects using BOLD MRI to provide more information about oxygen metabolism in the normal function of transplanted kidneys and to distinguish acute graft rejection from normal function kidneys. This study included 122 subjects (20 volunteers, 72 patients with normal functioning transplants, and 21 patients with acute rejection), and 9 patients had normal function grafts received examination while grafts dysfunction occurred within 6 months during the follow-up. The R2 (1/s) values in the cortex and medulla as well as the R2 ratio of the medulla to cortex (R2 ratio of M/C) were recorded. The R2 values of the medulla were higher than those of the cortex in the normal function group and the volunteers which have a steep R2 ratio of M/C. All the R2 values in the acute rejection group were lower than those in the normal function grafts group (P<0.001). Moreover, in the 9 patients as normal function, the R2 values of the cortex and medulla were different from the normal function grafts, which was lower in 5 patients and was higher in the 4 remaining patients. Conversely, the R2 ratios of M/C of the 9 patients were similar to those in the normal function group. BOLD MRI shows that decreased R2 values of the cortex and medulla and R2 ratio of M/C suggest acute renal graft rejection; furthermore, a steep R2 ratio of M/C (>1.1) is an important reason for keeping clinical normal function.

Immunosuppressive regimens containing generic mycophenolate mofetil (Myfenax) in de novo renal transplant recipients – preliminary results of 6-month observation

The aim of the findings presented below is to show the preliminary outcomes of transplantation in patients treated with the generic formulation of mycophenolate mofetil (Myfenax, Teva). Over the past 2 years 34 patients received generic mycophenolate mofetil (Myfenax) after renal transplantation at the Gdansk Transplantology Center. During the same time period another 127 kidney transplantations were performed in our Department and these patients were treated with other formulations of mycophenolate (CellCept, Myfortic or Mycophenolate mofetil Apotex) as a part of the immunosuppressive scheme. Fifteen of the Myfenax patients received a pair of kidneys from the same donor and received original mycophenolate mofetil Cell-Cept. The outcomes of the renal transplants in both groups (Myfenax vs. pair) were good; with satisfactory function of grafts, and no instances of graft loss were reported. There was no difference in the incidence of acute renal graft rejection (AR) in either group. Moderate adverse reactions to immunosupression were observed in both groups. On the other hand, a comparison between the 34 patients with Myfenax and the 127 other patients with other formulations of mycophenolate revealed no differences in the incidence of AR, delayed graft function (DGF), graft loss and death. There were no differences in the incidence of AR, DGF, graft loss and death in patients with Myfenax vs. original CellCept and other formulations of mycophenolate. In order to confirm its complete biological and pharmacokinetic equivalence with the reference medicine, long-term, randomized observations carried out on larger renal transplant patients groups are needed.

Chronic Renal Graft Rejection-associated Bullous Pemphigoid: A Cross-reactive Immune Response?

Rare cases of immune disturbances after solid organ grafting have been described, mainly autoimmune hepatitis, bullous autoimmune skin diseases, and autoimmune cytopaenia. We describe here a patient who developed two similar flares of bullous pemphigoid (BP) in a setting of recurrent chronic renal graft rejection.

IL-17 Promotes Immune Privilege of Corneal Allografts

Corneal allograft rejection has been described as a Th1-mediated process involving IFN-γ production. However, it has been reported that corneal allograft rejection soars in IFN-γ(-/-) mice or mice treated with anti-IFN-γ mAb. Th17 is a recently described IL-17A-producing Th cell population that has been linked to renal and cardiac graft rejection, which was originally thought to be Th1-mediated. We tested the hypothesis that Th17 cells mediate corneal allograft rejection in an IL-17A-dependent fashion and unexpectedly found that depletion of IL-17A increased the incidence of rejection to 90%. We demonstrate that the exacerbated rejection following depletion of IL-17A did not result from a loss of cross-regulation of Th1 cells or exaggerated delayed-type hypersensitivity responses. Instead, inhibition of the Th1 or Th17 cell lineages promoted the emergence of a Th2 cell subset that independently mediated allograft rejection. These findings demonstrate that IL-17A is not required for corneal allograft rejection and may instead contribute to the immune privilege of corneal allografts.

Stability of unused reconstituted bortezomib in original manufacturer vials

BACKGROUND. Bortezomib is a modified dipeptidyl boronic acid analogue used to treat multiple myeloma, mantle cell lymphoma, and, more recently, renal transplantation graft rejection. As per manufacturer recommendations, bortezomib is to be administered within 8 h of preparation or may be stored for up to 8 h in the vial or a syringe following reconstitution. Preserving unused reconstituted bortezomib beyond these 8 h may allow for cost savings. This study aims to examine the stability of unused reconstituted bortezomib when stored at 4°C for up to 15 days. Using an LC-MS/MS assay, the concentration of reconstituted bortezomib was measured at predetermined time points following storage at 4°C in the manufacturer vial. Percent bortezomib remaining at a time point was calculated versus initial bortezomib concentration. The concentrations of bortezomib were found to be 51.93 ng/mL±4.60 after 1 day of storage, 57.40 ng/mL±4.77 after 8 days of storage, and 49.43 ng/mL±2.85 after 15 days of storage. The percent of bortezomib remaining was 110.53% and 95.19% after 8 days and 15 days, respectively. Unused reconstituted bortezomib is stable for up to 15 days stored at 4°C in the original manufacturer vial. Such use of bortezomib may improve cost efficiency by reducing bortezomib waste.

Allogeneic Renal Graft Rejection in a Rat Model: In Vivo MR Imaging of the Homing Trait of Macrophages

To evaluate the feasibility of MR imaging to depict the in vivo recruitment of superparamagnetic iron oxide (SPIO)-labeled macrophages and to aid diagnosis of graft rejection in kidney transplantation. This study was approved by the institution's committee on animal research. Eighteen male Lewis rats received a kidney transplant; 12 had an F344 rat donor and six had a Lewis rat donor. Peritoneal macrophages were harvested from thioglycollate-treated Lewis rats, cultured, and labeled with SPIO. After resuspension of macrophages in a concentration of 1 x 10(7) cells per milliliter of Hanks balanced salt solution, 5 x 10(6) of SPIO-labeled macrophages was administered through the tail vein 2 or 5 days after transplantation in each group. The transplanted kidneys were imaged on a 4.7-T MR imager 24 hours after macrophage administration. The Wilcoxon signed rank test was performed for evaluating the differences between the relative signal intensity (SI) before and after SPIO-labeled macrophage administration. A low-SI zone was predominantly noted in the medulla of the transplanted kidneys, and the relative SI decreased significantly from 1.40 to 0.53 (P < .001) in the allogeneic transplants following SPIO-labeled macrophage administration 5 days after the allogeneic transplantation. In the syngeneic group, the lower-SI zone was not noted in the grafts. At histopathologic examination, the lower-SI zone corresponded to the distribution of the SPIO-labeled macrophages. This study demonstrates that the homing of intravenously administered SPIO-labeled macrophages can be monitored in the allograft rejection model on in vivo MR images.

An Investigation Into the Bias Between Liquid Chromatography–Tandem Mass Spectrometry and an Enzyme Multiplied Immunoassay Technique for the Measurement of Mycophenolic Acid

Mycophenolic acid is now the second most widely used immunosuppressant in solid organ transplantation. Overestimation of mycophenolic acid concentration is a recognized problem of immunoassay, and high-performance liquid chromatography with ultraviolet detection methods have long analysis times and a risk of analyte coelution which may compromise high sample throughput in a clinically meaningful time frame. A novel liquid chromatography-tandem mass spectrometry assay for mycophenolic acid was developed using very small (10 microL) sample volumes and evaluated in comparison with an established immunological assay. The enzyme mediated immunoassay showed a median positive bias compared with liquid chromatography-tandem mass spectrometry of 14.6%. Linear regression analysis showed a significant positive impact of bilirubin (r2 = 0.230) on bias with further increases of r2 to 0.261, 0.286, and 0.294 with the stepwise addition of creatinine, hematocrit, and gamma-glutamyl transpeptidase, respectively. The impact of comedication and transplant type depended on the patient population: analysis of all samples showed opposing effects to analysis of those samples lacking data with biochemical variables above. The liquid chromatography-tandem mass spectrometry method described in this report is capable of measuring mycophenolic acid concentrations in very small sample volumes and in a timely fashion without the significant overestimates characterizing enzyme mediated immunoassay measurements in patients with serologic features characterizing liver or renal graft rejection.

Role of Major Histocompatibility Complex and Ethnicity in Acute Renal Graft Rejection

Background The major histocompatibility complex (MHC) plays a main role in antigen presentation. Class I, II, and III genes form defined “blocks” of conserved DNA sequences (conserved extended haplotypes) that are useful to follow the ancestry of a population. Each variant encodes a specific peptide that determines a particular individual's immune response. In addition, differential expression of HLA antigens in certain physiological and pathological conditions may participate in the pathogenesis of allograft rejection versus tolerance. Objectives The aim of this study was to determine whether the specific HLA ancestry was associated with acute renal graft rejection among the Mexican mestizo population. Materials and Methods We studied 544 Mexican mestizo renal donors and their respective recipients for their serologically determined HLA and based on antigens haplotype assignments. The acute rejection group was compared with the nonrejection group among donors and recipients, correspondingly. Results Frequent Mexican alleles were observed in this study. Moreover, HLA-B*61/-DR*04, HLA-A*35/-DR*06 (Amerindian ancestry), HLA-A*68/-DR*01, HLA-A*28/-B*65/-DR*01 (African ancestry), and HLA-A*33/-B*65 (Caucasian ancestry) in donors were associated with acute renal graft rejection episodes. Conclusion Knowing the ancestry of a donor's HLA molecules may help to individualize immunosuppressive therapy for postransplant surveillance, because they may be more membrane-exposed in parenchymal cells, making them more susceptible of being recognized by the recipient's immune system.