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Ron Shapiro

Publications and source records attributed to Ron Shapiro.

At least 37 records · Page 2Linked to original sources
PubMed2006

Phylogenetic analysis of polyomavirus BK sequences.

Polyomavirus BK (BKV) has emerged as an important pathogen in kidney transplant patients. Existing taxonomic classifications of BKV come from conventional DNA sequence alignments based on limited data derived from the VP1 gene. We have used a phylogenetic whole-genome approach to examine the pattern of diversity and evolutionary relationships between 45 BKV strains isolated from multiple clinical settings. This analysis supports the classification of BKV into six genotypes, of which types V and VI have not been previously recognized. BKV strains hitherto classified as type I are, in fact, quite heterogeneous, and several cluster with our newly defined genotypes V and VI. The sequence information needed for assigning genotypes can be captured by VP1, VP2, VP3, or large T-gene sequencing. The most polymorphic coding region in the viral genome is VP1, but significant variation is also present in the large T-antigen gene, wherein polymorphisms are found in 11.39% of all nucleotide sites, 46.22% of which are cluster specific. Type-specific amino acid changes within the VP1 region are predicted to map to the BC and DE loops. The number of taxonomically informative amino acid changes in the large T antigen exceeds even that of the VP1 region. Viral strains isolated from healthy subjects and from patients with human immunodeficiency virus infection, Wiskott-Aldrich syndrome, and vasculopathy with capillary leak syndrome formed distinct subclusters. However, within the kidney transplant population, BKV strains derived from patients with asymptomatic viruria did not show complete separation from strains associated with allograft nephropathy.

Antigens, Viral, Tumor↗
PubMed2006

Immunosuppressive preconditioning or induction regimens : evidence to date.

The success of solid organ transplantation has been directly related to the development of immunosuppressive drug therapies. Preconditioning or induction therapy was developed to reduce early immunological and nonimmunological renal injury, with the goal of increasing long-term graft survival. However, the routine induction of immunological tolerance to solid organ allograft is currently not achievable because of the morbidity and mortality related to the immunosuppressive regimens themselves. The different therapeutic preconditioning or induction agents and their associated effects on cellular rejection, graft survival outcomes and the need for multiagent post-transplant maintenance therapy are reviewed.

Antilymphocyte Serum↗
PubMed2005

Rituximab (chimeric anti-CD20 antibody) for posttransplant lymphoproliferative disorder after solid organ transplantation in adults: long-term experience from a single center.

BACKGROUND: Occurrence of posttransplant lymphoproliferative disorder (PTLD) after transplantation is known. Drastic reduction or withdrawal of immunosuppression with anti-viral therapy for Ebstein-Barr virus (EBV) is the primary treatment for all PTLD. Many PTLD are B cell in origin have CD20 antigen on the cell surface. Rituximab is a chimeric anti CD20 antibody, which has been used to treat PTLD with variable success. This study aims to report long-term experience with rituximab for PTLD from a single center. METHODS: Seventeen patients (13 male, 4 female, mean age 51.2 years) received rituximab to treat PTLD. Five patients received rituximab with drastic reduction in immunosuppression (primary). Nine patients received rituximab after failure of primary therapy (rescue) and three patients received it after resolution of PTLD (prophylactic). Mean follow-up period was 60 months. RESULTS: Overall 1-, 3-, and 5-year patient survivals were 64.7%, 47.1% and 35.3%, respectively. In the primary group, three patients had complete and one had partial response; however, only two (40%) patients are currently alive. In the rescue group, none of the patients had a complete response, four patients had partial response, and only two (22%) patients are currently alive. In the prophylactic group, two patients died at 28 and 41 months due to recurrence and graft failure, respectively. CONCLUSION: Sixty percent (3 of 5) of patients who received rituximab as primary therapy had complete resolution, and 44% (4 of 9) of patients who received it as rescue therapy had partial response. Overall 5-year patient survival was a disappointing 35%.

Antibodies, Monoclonal↗
PubMed2005

Comorbid conditions in kidney transplantation: association with graft and patient survival.

Although the impact of comorbidity on outcomes in ESRD has been evaluated extensively, its contribution after kidney transplantation has not been well studied. It is believed that comorbidity assessment is critical to the informed interpretation of kidney transplant outcomes. In this study, the Charlson Comorbidity Index was used to assess the comorbid conditions of 715 patients who underwent kidney transplantation at the Starzl Transplant Institute between January 1998 and January 2003. The impact of pretransplantation comorbidity on the development of acute cellular rejection after transplantation and on patient and graft survival was examined. The most common comorbid conditions among our patient population were diabetes (n = 217, 30.3%) and heart failure (n = 85, 11.9%). It was found the number of patients with high comorbidity at the Starzl Transplant Institute has increased significantly over time (P = 0.04). In multivariate adjusted models, high comorbidity was associated with an increased risk for patient death, both in the perioperative period (hazard ratio 3.20, 95% confidence interval 1.32 to 7.78; P = 0.01) and >3 mo after transplantation (hazard ratio 2.63; 95% confidence interval 1.62 to 4.28; P < 0.001). The Charlson Comorbidity Index is a practical tool for the evaluation of comorbidity in the transplant population, which has an increasing burden of comorbid disease. Increased comorbidity affects both perioperative and long-term patient outcomes and carries significant implications not only for the development of individual patient therapeutic strategies but also for the interpretation of patient trials and the development of policies that govern distribution of donor organs.

Adult↗
PubMed2005

Quantitation of DNA of polyomaviruses BK and JC in human kidneys.

BACKGROUND: Renal allograft recipients can be monitored for polyomavirus-associated nephropathy (PVAN) using urine samples. Because virus in urine can be derived from the kidneys, ureter, or urinary bladder, we evaluated whether measurement of intrarenal concentrations of viral DNA might serve as a more reliable monitoring tool. METHODS: Real-time quantitative polymerase chain reaction was used to quantitate DNA of polyomaviruses BK (BKV) and JC (JCV) in renal tissue obtained from various clinical settings. RESULTS: Renal biopsy samples from 28 nonimmunosuppressed patients contained very low viral copy numbers. Minimally higher BKV loads (mean +/- SE, 3.4 +/- 1.7 copies/cell) were observed in 74 renal biopsy samples from renal allograft recipients with BKV viruria. The BKV DNA concentration was approximately 10-fold higher in renal allograft recipients with BKV viruria, but 58 (50.4%) of 115 renal biopsy samples tested negative for BKV DNA, reflecting the focal nature of infection. JCV DNA was found in only 2 renal biopsy samples. CONCLUSIONS: The BKV load is better measured in urine than in tissue, because a urine sample represents material from the entire kidney. An increase in the BKV load is usually not accompanied by a proportional increase in the JCV load, which indicates that these 2 related polyomaviruses are subject to different mechanisms regulating viral replication.

BK Virus↗
PubMed2005

Polyomavirus-associated nephropathy in renal transplantation: interdisciplinary analyses and recommendations.

Polyomavirus-associated nephropathy (PVAN) is an emerging cause of kidney transplant failure affecting 1-10% of patients. As uncertainty exists regarding risk factors, diagnosis, and intervention, an independent panel of experts reviewed the currently available evidence and prepared this report. Most cases of PVAN are elicited by BK virus (BKV) in the context of intense immunosuppression. No specific immunosuppressive drug is exclusively associated with PVAN, but most cases reported to date arise while the patient is on triple immunosuppressive combinations, often comprising tacrolimus and/or mycophenolate mofetil plus corticosteroids. Immunologic control of polyomavirus replication can be achieved by reducing, switching, and/or discontinuing components of the immunosuppressive regimen, but the individual's risk of rejection should be considered. The success rate of this intervention is increased with earlier diagnosis. Therefore, it is recommended that all renal transplant recipients should be screened for BKV replication in the urine: 1) every three months during the first two years posttransplant; 2) when allograft dysfunction is noted; and 3) when allograft biopsy is performed. A positive screening result should be confirmed in <4 weeks and assessed by quantitative assays (e.g. BKV DNA or RNA load in plasma or urine). Definitive diagnosis of PVAN requires allograft biopsy. If PVAN and concurrent acute rejection is diagnosed, antirejection treatment should be considered, coupled with subsequently reducing immunosuppression. The antiviral cidofovir is not approved for PVAN, but investigational use at low doses (0.25-0.33 mg/kg intravenously biweekly) without probenicid should be considered for refractory cases. Retransplantation after renal allograft loss to PVAN remains a treatment option for patients clearing polyomavirus replication.

Humans↗
PubMed2005

Monitoring for polyomavirus BK And JC in urine: comparison of quantitative polymerase chain reaction with urine cytology.

Clinical monitoring for polyomavirus infection is becoming common, but the optimal detection technique remains undefined. We compared the relative efficacy of exfoliative cytology and polymerase chain reaction (PCR) for detecting viruria in 100 urine samples. Definite decoy cells were seen in 8% and probable decoy cells in 5% of specimens. PCR showed BK virus (BKV) DNA in all these and in an additional 18% of samples. Using decoy cells as a marker of polyomavirus viruria cytology has a sensitivity of 41.9% and negative predictive value of 82.8%. The specificity and positive predictive value for viruria (not viral nephropathy) are 100%. False-negative results occurred in samples with suboptimal cellularity, vaginal contamination, and a low viral load. One patient with a false-negative urine cytology developed BKV nephropathy on follow-up. Compared with PCR, urine cytology is a less sensitive technique, which requires morphologically intact cells, and cannot distinguish BKV from JC virus.

BK Virus↗
PubMed2005

EBV-specific memory CD8+ T cell phenotype and function in stable solid organ transplant patients.

Immune responses to EBV in immunosuppressed (IS) solid organ transplant (SOTx) recipients have not been well characterized. Here we evaluate the phenotype and function of EBV-specific CD8+ T cells in peripheral blood isolated from "stable" IS SOTx recipients. The EBV-specific CD8+ T cell memory subset distribution in the peripheral blood of patients was examined by flow cytometric analysis using HLA-A2 tetramers incorporating BMLF1 (lytic), and LMP2 and EBNA3A (latent)-derived peptides, in conjunction with mAbs against the CD45RO, CD45RA, and CD62L markers. The ability of CD8+ T cells to produce IFN-gamma in response to the same EBV-derived peptides was measured by ELISPOT assay. Patients and healthy normal donors exhibited similar anti-EBV CD8+ T cell frequencies and specificities against the EBV epitopes evaluated. When compared to healthy normal donors, an overall significant expansion of the CD8+ T cell "effector memory" (CD45RO+/CD62L-) pool, including that of EBV "latent" (LMP2 and EBNA3A)-specific CD8+ T cells was detected in IS SOTx patients. However, the patients' EBV-specific CD8+ T cells showed decreased IFN-gamma production to the EBV-peptide stimulation. These results indicate that the impairment of EBV-specific CD8+ T cell activity is not due to clonal depletion, but is mainly due to impaired functional activation.

Antigens, Viral↗
PubMed2005

Augmentation of type-1 polarizing ability of monocyte-derived dendritic cells from chronically immunosuppressed organ-transplant recipients.

BACKGROUND: Chronic immunosuppressive (IS) therapy impairs normal T-cell immune surveillance and may predispose to opportunistic infections and malignancies that represent life-threatening complication of solid-organ transplantation (SOTx). Our study was designed to ascertain the impact of chronic in vivo administration of IS on the ability of monocyte-derived dendritic cells (MoDC) to differentiate, mature, and function ex vivo. The potential of these cells to be implemented for DC-based adoptive immunotherapy was also considered. METHODS: MoDCs were propagated by conventional procedures, their phenotype was analyzed by flow cytometry, and their function was assessed by mixed leukocyte reaction, enzyme-linked immunoadsorbent assay, and ELISPOT assays. Nuclear translocation of nuclear factor (NF)-kB was analyzed by electrophoretic mobility shift assay. RESULTS: Circulating DC1s in peripheral blood were reduced in SOTx patients. MoDCs generated from patients displayed higher endocytic activity versus normal DCs, indicating their comparative immaturity. Patients' DCs exposed to pro-inflammatory cytokines (tumor necrosis factor-alpha, interleukin [IL]-1beta, and IL-6) were less able to mature, to stimulate recall antigen (Ag)- or allo-Ag-induced proliferation responses, or to secrete IL-12p70. These deficiencies were associated with a decrease in NF-kB translocation. In contrast, combination of pro-inflammatory cytokines and interferon (IFN)-gamma (a Th1-polarizing factor) augmented patients' DC1-type function and IL-12p70 production by way of an NF-kB-independent mechanism. CONCLUSIONS: Chronic IS restrains DC differentiation, maturation, and function at a transcriptional level; however, type-1 polarizing potential of patients' DC1 can be augmented ex vivo by a two-signal stimulation provided by pro-inflammatory cytokines and IFN-gamma. These results may have implications for DC-based immunotherapy of malignancies in the transplantation setting.

Active Transport, Cell Nucleus↗
PubMed2005

Effect of leflunomide and cidofovir on replication of BK virus in an in vitro culture system.

BACKGROUND: Cidofovir and Leflunomide are used empirically in the treatment of BK virus nephropathy. The aim of this study is to quantify the antiviral activity of these drugs. METHODS: BK virus was grown in a cell-culture system. The rate of viral replication in the presence or absence of the drug being tested was assessed using a quantitative polymerase chain reaction assay. RESULTS: The inhibitory concentration, effective concentration, and selectivity index for Leflunomide are 39.7+/-6.9, 11.3+/-2.8, and 3.8+/-0.8 microg/mL, respectively. For Cidofovir, these indices were, respectively, 63.9+/-17.2, 36.3+/-11.7, and 2.3+/-0.8 microg/mL. CONCLUSIONS: The in vitro activity of Cidofovir and Leflunomide is modest, and the selectivity index is low. There is a need to develop more effective and less toxic anti-BK virus drugs for clinical use.

Antiviral Agents↗
PubMed2005

A comparative study of BK and JC virus infections in organ transplant recipients.

JC virus (JCV) rarely causes kidney disease, whereas BK virus (BKV) is a known cause of viral nephropathy. Existing studies on prevalence of JCV in healthy and transplanted subjects have reported only qualitative detection of viral DNA. We used quantitative PCR (qPCR) to assess JC viral load in transplant recipients and non-immunosuppressed controls, and compared JCV loads to BKV loads. JC viruria was seen in 8/23 (34.7%) controls, 23/103 (22.3%) renal, and 10/44 (22.7%) liver transplant patients. No patient developed JC viremia. BK viruria was seen in 2/23 (8.7%) controls, 36/103 (34.9%) renal, and 7/44 (15.9%) liver transplant patients. BK viremia was seen only in the kidney (8/103 = 7.7%) patients. The mean BKV urinary load was higher in kidney compared to liver patients and controls (4.22E + 07 vs. 2.88E + 05 vs. 4.39E + 02 copies/ml), whereas JC viral load was similar for all three patient groups (1.55E + 06 vs. 2.66E + 06 vs. 2.13E + 06 copies/ml). JCV viral loads were surprisingly high in all patient categories studied, but did not result in viremia or viral nephropathy. Although both BKV and JCV are widely latent in patients accepted for transplantation, concurrent reactivation of both viruses was infrequent. BKV viremia was seen in kidney but not liver recipients. The mechanisms underlying these notable phenomena remain to be investigated.

BK Virus↗
PubMed2005

Kidney transplantation under minimal immunosuppression after pretransplant lymphoid depletion with Thymoglobulin or Campath.

BACKGROUND: Multiple drug immunosuppression has allowed the near elimination of rejection, but without commensurate improvements in longterm graft survival and at the cost of quality of life. We have suggested that transplantation outcomes can be improved by modifying the timing and dosage of immunosuppression to facilitate natural mechanisms of alloengraftment and acquired tolerance. STUDY DESIGN: Two therapeutic principles were applied for kidney transplantation: pretransplant recipient conditioning with antilymphoid antibody preparations (Thymoglobulin [Sangstat] or Campath [ILEX Pharmaceuticals]), and minimal posttransplant immunosuppression with tacrolimus monotherapy including "spaced weaning" of maintenance doses when possible. The results in Thymoglobulin- (n = 101) and Campath-pretreated renal transplantation recipients (n = 90) were compared with those in 152 conventionally immunosuppressed recipients in the immediately preceding era. RESULTS: Spaced weaning was attempted in more than 90% of the kidney transplant recipients after pretreatment with both lymphoid-depleting agents, and is currently in effect in two-thirds of the survivors. Although there was a much higher rate of acute rejection in the Thymoglobulin-pretreated recipients than in either the Campath-pretreated or historic control recipients, patient and graft survival in both lymphoid depletion groups is at least equivalent to that of historic control patients. In the Thymoglobulin-conditioned patients for whom followups are now 24 to 40 months, chronic allograft nephropathy (CAN) progressed at the same rate as in historic control patients. Selected patients on weaning developed donor-specific nonreactivity. CONCLUSIONS: After lymphoid depletion, kidney transplantation can be readily accomplished under minimal immunosuppression with less dependence on late maintenance immunosuppression and a better quality of life. Campath was the more effective agent for pretreatment. Guidelines for spaced weaning need additional refinement.

Analysis of Variance↗
PubMed2005

Serum analysis after transplant nephrectomy reveals restricted antibody specificity patterns against structurally defined HLA class I mismatches.

This study deals with HLA-mismatched kidney transplants that have been removed following rejection. Sera from 27 patients were screened for HLA-specific antibodies by direct complement-dependent lymphocytotoxicity with HLA-typed cell panels. Circulating donor-specific antibodies were detected in 3 cases (11%) before and in 26 cases (97%) after allograft nephrectomy. These findings demonstrate the production of donor-specific antibodies in patients with rejected transplants, but in most cases, they were undetectable before nephrectomy, because the graft had adsorbed them. With an HLAMatchmaker-based serum analysis program, we observed restricted antibody specificity patterns against amino acid triplet-defined epitopes on donor HLA-A,B antigens. Many donor triplets were non-reactive while others were apparently recognized by antibodies. In some patients, the donor triplet specific antibodies persisted for a long time whereas in many other patients, they became undetectable after a few months. The characterization of the antibody specificity profiles of post-allograft nephrectomy sera is clinically useful in defining criteria of HLA mismatch acceptability for sensitized patients awaiting another transplant. It provides also opportunities for determining the relative immunogenicity of mismatched triplets.

Adult↗
PubMed2005

Immunosuppression: evolution in practice and trends, 1993-2003.

Immunosuppression trends for solid organ transplantation have undergone a perceptible shift over the past decade. This period is of interest because it was during this time that the Food and Drug Administration (FDA) expanded the variety of medications to allow for alternatives in immunosuppressive management. An organ-by-organ review of SRTR data identifies several important trends. Antibody induction continues to be used for the majority of kidney (70%), simultaneous pancreas-kidney (SPK, 79%) pancreas after kidney (PAK, 74%), and intestine recipients (74%). It is used for under half of thoracic organ recipients and remains uncommon for liver transplant recipients (20%). The type of antibody preparation utilized has shifted from muromonab-CD3 and horse ATG to rabbit ATG and monoclonal anti-IL-2 receptor antagonists. Calcineurin inhibitors continue to be used for maintenance immunosuppression for most recipients, although there has been a shift from cyclosporine to tacrolimus. A clear transition is apparent in the choice of antimetabolite from azathioprine to mycophenolate mofetil. Although corticosteroids continue to be used as maintenance immunosuppression for most recipients prior to discharge, there is evidence that efforts of steroid avoidance protocols are having an impact across all organs, as slight decreases in their use have been observed.

Graft Rejection↗
PubMed2004

Living-related donor renal transplantation in HIV+ recipients using alemtuzumab preconditioning and steroid-free tacrolimus monotherapy: a single center preliminary experience.

BACKGROUND: End-stage renal disease (ESRD) is an increasing problem in patients infected with the human immunodeficiency virus (HIV). The use of highly active antiretroviral therapy (HAART) has decreased the morbidity associated with HIV and has prompted renewed interest in renal transplantation. METHODS: We performed four cases of deceased donor renal transplantation in HIV+ recipients and three cases where laparoscopic live donor nephrectomy (LLDN) was utilized to obtain the kidney for transplantation into living-related HIV+ recipients. In the four deceased donor cases, conventional tacrolimus-based immunosuppression, without antibody induction was used. In the three living-related cases, the immunosuppressive regimen was based on two principles: recipient pretreatment and minimal posttransplant immunosuppression. Alemtuzumab 30 mg (Campath 1-H) was used for preconditioning followed by low-dose tacrolimus monotherapy. RESULTS: Of the four deceased donor cases, one patient continues to have good graft function, and another is not yet on dialysis but has significant graft dysfunction. Rejection was observed in three patients (75%). Infectious complications occurred in one patient (25%), all non-acquired immunodeficiency syndrome (AIDs) defining. In the three living-related cases, all had good graft function, and none have experienced acute rejection. HIV viral loads remain undetectable. CD4 counts are slowly recovering. No infectious or surgical complications occurred. There were no deaths in either group. CONCLUSIONS: These data suggest that living-related donor renal transplantation with steroid-free tacrolimus monotherapy in a "tolerogenic" regimen can be efficacious. However, long-term follow-up is needed to confirm this observation.

Adult↗