Conversion from tacrolimus-mycophenolate mofetil to tacrolimus-mTOR immunosuppression after kidney-pancreas transplantation reduces the incidence of both BK and CMV viremia.

BACKGROUND: We sought to determine whether conversion from tacrolimus/mycophenolate mofetil (TAC-MMF) into tacrolimus/mTOR inhibitor (TAC-mTOR) immunosuppression would reduce the incidences of BK and CMV viremia after kidney/pancreas (KP) transplantation. METHODS: In this single-center review, the TAC-mTOR cohort (n = 39) was converted at 1 month post-transplant to an mTOR inhibitor and reduced-dose tacrolimus. Outcomes were compared to a cohort of KP recipients (n = 40) maintained on TAC-MMF. RESULTS: At 3 years post-transplant, KP survivals and incidences of kidney/pancreas rejection were equivalent between mTOR and MMF-treated cohorts. (P = ns). BK viremia-free survival was better for the mTOR vs MMF-treated group (P = .004). In multivariate analysis, MMF vs mTOR immunosuppression was an independent risk factor for BK viremia (hazard ratio 12.27, P = .02). Similarly, mTOR-treated recipients displayed better CMV infection-free survival compared to the MMF-treated cohort (P = .01). MMF vs mTOR immunosuppression (hazard ratio 18.77, P = .001) and older recipient age (hazard ratio 1.13 per year, P = .006) were independent risk factors for CMV viremia. Mean estimated GFR and HgbA1c levels were equivalent between groups at 1, 2, and 3 years post-transplantation. CONCLUSION: Conversion from TAC/MMF into TAC/mTOR immunosuppression after KP transplantation reduced the incidences of BK and CMV viremia with an equivalent risk of acute rejection and similar renal/pancreas function.

Disparate rates of acute rejection and donor-specific antibodies among high-immunologic risk renal transplant subgroups receiving antithymocyte globulin induction.

Lymphocyte-depleting induction lowers acute rejection (AR) rates among high-immunologic risk (HIR) renal transplant recipients, including African Americans (AAs), retransplants, and the sensitized. It is unclear whether different HIR subgroups experience similarly low rates of AR. We aimed to describe the incidence of AR and de novo donor-specific antibody (dnDSA) among HIR recipients categorized by age, race, or donor type. All received antithymocyte globulin (ATG) induction and triple maintenance immunosuppression. A total of 464 HIR recipients from 2007 to 2014 were reviewed. AR and dnDSA rates at 1 year for the entire population were 14% and 27%, respectively. AR ranged from 6.7% among living donor (LD) recipients to 30% in younger AA deceased donor (DD) recipients. De novo donor-specific antibody at 1 year ranged from 7% in older non-AA LD recipients to 32% in AAs. AA race remained as an independent risk factor for AR among DD recipients and for dnDSA among all HIR recipients. Development of both AR and dnDSA within the first year was associated with a 54% graft survival at 5 years and was an independent risk factor for graft loss. Despite utilization of recommended immunosuppression for HIR recipients, substantial disparities exist among subgroups, warranting further consideration of individualized immunosuppression in certain HIR subgroups.

Vancomycin nephrotoxicity: A comprehensive clinico-pathological study.

INTRODUCTION: Vancomycin, a commonly prescribed antibiotic particularly in the setting of multi-drug resistant infections, is limited by its nephrotoxicity. Despite its common occurrence, much remains unknown on the clinicopathologic profile as well as the pathogenesis of vancomycin nephrotoxicity. Clinical studies included patients often with severe comorbidities and concomitant polypharmacy confounding the causal pathogenesis. Animal models cannot recapitulate this complex clinical situation. Kidney biopsy was not commonly performed. METHODS: To address this limitation, we studied 36 patients who had renal biopsies for acute kidney injury (AKI) for suspicion of vancomycin nephrotoxicity. Detailed renal biopsy evaluation, meticulous evaluation of clinical profiles, and up-to-date follow-up allowed for a diagnostic categorization of vancomycin nephrotoxicity (VNT) in 25 patients and absence of vancomycin nephrotoxicity (NO-VNT) in 11 patients. For careful comparison of these two groups, we proceeded to compile a clinicopathologic and morphologic profiles characteristic for each group. RESULTS: Patients with VNT had a characteristic clinical profile including a common clinical background, a high serum trough level of vancomycin, a rapidly developed and severe acute kidney injury, and a recovery of renal function often shortly after discontinuation of vancomycin. This clinical course was correlated with characteristic renal biopsy findings including acute tubulointerstitial nephritis of allergic type, frequent granulomatous inflammation, concomitant and pronounced acute tubular necrosis of nephrotoxic type, and vancomycin casts, in the absence of significant tubular atrophy and interstitial fibrosis. This clinico-pathologic profile was different from that of patients with NO-VNT, highlighting its role in the diagnosis, management and pathogenetic exploration of vancomycin nephrotoxicity. CONCLUSION: Vancomycin nephrotoxicity has a distinctive morphologic and clinical profile, which should facilitate diagnosis, guide treatment and prognostication, and confer pathogenetic insights.

Reproducibility and prognostic ability of chronicity parameters in kidney biopsy - Comprehensive evaluation comparing microscopy and artificial intelligence in digital pathology.

INTRODUCTION: Semi-quantitative scoring of various parameters in renal biopsy is accepted as an important tool to assess disease activity and prognostication. There are concerns on the impact of interobserver variability in its prognostic utility, generating a need for computerized quantification. METHODS: We studied 94 patients with renal biopsies, 45 with native diseases and 49 transplant patients with index biopsies for Polyomavirus nephropathy. Chronicity scores were evaluated using two methods. A standard definition diagram was agreed after international consultation and four renal pathologists scored each parameter in a double-blinded manner. Interstitial fibrosis (IF) score was assessed with five different computerized and AI-based algorithms on trichrome and PAS stains. RESULTS: There was strong prognostic correlation with renal function and graft outcome at a median follow-up ranging from 24 to 42 months respectively, independent of moderate concordance for pathologists scores. IF scores with two of the computerized algorithms showed significant correlation with estimated glomerular filtration rate (eGFR) at biopsy but not at the end of follow-up. There was poor concordance for AI based platforms. CONCLUSION: Chronicity scores are robust prognostic tools despite interobserver reproducibility. AI-algorithms have absolute precision but are limited by significant variation when different hardware and software algorithms are used for quantification.

Myoglobin Cast Nephropathy Diagnosed on Renal Biopsy in a Patient Treated for Malarial Infection.

Myoglobin cast nephropathy occurs in cases of acute renal injury in which large amounts of myoglobin accumulate in the renal tubules, presenting as muscle pain, reddish-brown urine, and elevated creatine kinase levels. Our case describes a 60-year-old male who came to the emergency department with fevers, mild abdominal pain, and constitutional symptoms one day after returning to the United States from a trip to Nigeria. Initial workup demonstrated an acute kidney injury and elevated aminotransferase levels and the patient was started onatovaquone-proguanil for possible malaria given a recent diagnosis in Nigeria. Two days later, the patient was found to have rhabdomyolysis, resulting in a renal biopsy that showed myoglobin cast nephropathy. Previous literature has suggested mechanisms for the development of rhabdomyolysis in malarial infection, including inflammatory processes, direct effect of parasite accumulation, and drug-induced toxicity. Our case further implicates antimalarial therapy as a cause of rhabdomyolysis and increases awareness of myoglobin cast nephropathy as a potential complication of malaria.

Renal cortical necrosis following a colonoscopy.

A 76-year old African-American male presented with profound renal failure within 2 weeks after a screening colonoscopy. Polyethylene glycol (PEG) was the sole oral preparatory agent. The significantly elevated lactate dehydrogenase (LDH) and biopsy findings were consistent with acute renal cortical necrosis (RCN). PEG is associated with AKI, but the exact mechanism is uncertain. PEG can be biodegraded to diethylene glycol (DEG), which is a nephrotoxic agent associated with RCN. Three months after presentation, the patient remains hemodialysis dependent.

Polyarteritis Nodosa Associated With Hepatitis C Virus Infection.

Polyarteritis nodosa (PAN) is a rare necrotizing vasculitis that affects medium-sized arteries. The association of hepatitis B virus (HBV)and HIV with PAN is well documented. Although there are documented cases of PAN in patients with hepatitis C virus (HCV) infection, the connection between PAN and HCV is not well established. We report a case of PAN in a patient with HCV infection who failed treatment with interferon.

Donor-specific HLA-DQ antibodies may contribute to poor graft outcome after renal transplantation.

Increasing evidence suggests a detrimental effect of donor-specific antibodies directed against the human leukocyte antigen (HLA)-A, -B, and -DR loci on renal allograft outcomes. Limited data exist on the impact of de novo HLA-DQ antibodies. Over a 3-year period, we prospectively monitored 347 renal transplant recipients without pre-transplant donor-specific antibodies for their development de novo. After 26 months of follow-up, 62 patients developed donor-specific antibodies, of which 48 had a HLA-DQ antibody either alone (33 patients) or in combination with an HLA-A, -B, or -DR antibody (15 patients). Only 14 patients developed a donor-specific HLA-A, -B, or -DR antibody without a HLA-DQ antibody present. Acute rejection occurred in 21% of the HLA-DQ-only patients, insignificant when compared with 11% of patients without donor-specific antibodies. At the last follow-up, the mean serum creatinine and the fraction of patients with proteinuria were significantly higher in those that developed only HLA-DQ than those without antibodies. The 3-year graft survival was significantly worse when HLA-DQ antibodies were combined with non-DQ antibodies (52%) compared with HLA-DQ alone, non-DQ antibodies alone, or no antibodies (92-94%). Thus, our prospective monitoring study found that donor-specific HLA-DQ antibodies were the most common type detected and these antibodies may contribute to inferior graft outcomes. Ongoing surveillance is necessary to determine the long-term outcome of patients developing HLA-DQ donor-specific antibodies.

Association of IgG co-deposition with serum levels of galactose-deficient IgA1 in pediatric IgA nephropathy.

OBJECTIVE: To determine whether the absence of mesangial IgG deposits is associated with the absence of elevated blood levels of galactose-deficient IgA1 (Gd-IgA1) in pediatric patients with IgA nephropathy (IgAN). DESIGN AND METHODS: Serum Gd-IgA1 levels were determined by ELISA using an N-acetylgalactosamine-specific lectin from Helix aspersa. Levels of Gd-IgA1 above the 90th percentile for healthy pediatric controls were considered to be elevated. Renal biopsy samples were examined by immunofluorescence for presence and intensity of staining for IgA, IgG, IgM, C3 and C1q and by light microscopy for histological changes. Findings were graded by a single pathologist (L. Gaber) at UTHSC until 2007 and by NephropathTM (Little Rock, AR, USA) thereafter. Staining for the mesangial deposits was considered negative when intensity was trace or less, and positive at greater intensity. Fisher's exact test was used to determine significance of 2 × 2 tables. RESULTS: Serum samples were obtained from 30 patients with IgAN diagnosed before age 18 years. Male:female ratio was 2.3:1. Twenty were Caucasian and 10 were African-American. Blood was obtained within 3 months of biopsy (incident cases) for 12, while 18 provided blood > 3 months after biopsy (prevalent cases). Serum Gd-IgA1 level was elevated in 23 (77%) of cases and 20 (67%) had a biopsy positive for IgG. Of those 20 patients, 18 (90%) had an elevated serum Gd-IgA1 level, whereas 5 (50%) of patients with biopsies without IgG had a normal serum Gd-IgA1 level (p = 0.026). SUMMARY: In this small study we found a weak association between the absence of IgG in the biopsy and normal serum Gd-IgA1 level.

Anti-Neutrophil Cytoplasmic Antibodies: To Care or Not to Care.

Anti-neutrophil cytoplasmic antibodies (ANCA) associated vasculitis is a disease process with a wide range of presentations, from asymptomatic or minimally symptomatic disease with positive laboratory testing, to florid acute end-organ damage. Consensus has not been established as to the frequency and/or protocol by which ANCA testing should be repeated. We present the case of a 53-year-old woman who initially came to medical attention with persistent dyspnea and pulmonary infiltrates presumed to be due to acute exacerbation of chronic diastolic congestive heart failure. Extensive infectious disease testing was negative, but ANCA testing was positive. However, because antinuclear antibody (ANA) interference in the original sample rendered the test result difficult to interpret, the test was not repeated. The patient presented eight months after the initial hospitalization with acute hypoxemic respiratory failure requiring intubation, with an ANCA titer of 1:1280 with a negative ANA titer, and renal biopsy-proven severe crescentic glomerulonephritis. In the discussion of our case, we review the importance of interpreting ANCA testing in the correct clinical context. The ANCA laboratory testing requires cautious interpretation, and diagnosed ANCA-associated vasculitis (AAV) requires vigilance for prompt and proactive treatment.

Vancomycin-Associated Tubular Casts and Vancomycin Nephrotoxicity.

INTRODUCTION: Vancomycin nephrotoxicity is frequent and may be due to drug-induced acute tubular necrosis (ATN) or tubulointerstitial nephritis (TIN). Vancomycin-associated tubular cast (VTC) was recently described and may represent a novel cause of vancomycin nephrotoxicity. However, much is still unknown about VTC. MATERIALS AND METHODS: Thirty-seven kidney biopsy specimens from patients who were treated with vancomycin and developed acute kidney injury (AKI) were found among a total of 4673 biopsy samples between 2010 and 2019. These biopsy specimens were subjected to light microscopy, immunofluorescence, electron microscopy, and immunolocalization for vancomycin, uromodulin, myoglobin, tubular segment-specific markers, and examined for VTCs. The findings were correlated with the clinical course. RESULTS: VTCs displayed precipitated vancomycin casts in a background of uromodulin; the casts were limited to the distal tubules, and always associated with a background of more diffuse renal injury (ATN or TIN). The diagnosis of vancomycin nephrotoxicity was made in in 28 of 37 patients. VTC was noted in 25 of 28 biopsy samples from patients diagnosed with vancomycin nephrotoxicity and in one of nine biopsy samples from patients without this diagnosis. Vancomycin nephrotoxicity was diagnosed in 25 of 26 patients whose biopsy specimens showed VTC, but in only 3 of 11 patients without VTC in the biopsy samples. CONCLUSIONS: VTC displays a characteristic morphologic profile amenable to ready recognition in biopsy specimens. It results from coprecipitation of vancomycin and uromodulin. It facilitates the biopsy diagnosis of vancomycin nephrotoxicity. It may have a nephrotoxic effect superimposing on and independent from the ATN or interstitial nephritis in the pathogenesis of vancomycin nephrotoxicity.

Prevalence, Characteristics, and Outcomes of Incidental IgA Glomerular Deposits in Donor Kidneys.

INTRODUCTION: Incidental IgA deposits in donor kidneys have unknown sequelae and may predate clinical kidney disease if primed by adverse immunologic or hemodynamic stimuli or may remain dormant. METHODS: The presence of incidental IgA in post-implantation (T0) biopsies from living (LDK) and deceased donor (DDK) kidneys, and its relationship to post-transplant patient and graft outcomes was investigated in an ethnically diverse US population at a large transplant center. RESULTS: Mesangial IgA was present in 20.4% of 802 T0 biopsies; 13.2% and 24.5% of LDK and DDK, respectively. Donors with incidental IgA deposits were more likely to have hypertension and be of Hispanic or Asian origin. Intensity of IgA staining was 1+ (57.3%), 2+ (26.8%), or 3+ (15.8%) of the T0 IgA+ biopsies. Mesangial pathology correlated with higher-intensity IgA staining with less clearance on follow-up (53.8%) versus 79.2% without mesangial pathology. IgA cleared in 91%, 63%, and 40% of follow-up biopsies with 1+, 2+, and 3+ IgA staining, respectively. Early post-transplant rejection and rejection-related graft loss occurred more frequently in IgA+ kidney recipients; however, 5-year kidney function and graft survival were comparable to kidneys without IgA. CONCLUSION: This first and largest report of incidental IgA in T0 biopsies of LDK and DDK in a US ethnically diverse population demonstrated no adverse association between the presence of IgA in donor kidneys and graft or patient survival. Whether IgA in donor kidneys represents latent IgA nephropathy (IgAN) is uncertain; nevertheless, living donors who demonstrate IgA on T0 biopsy deserve careful follow-up.

Donor-related diabetic nephropathy: a comprehensive clinicopathological study.

Knowledge on renal involvement in kidney donors with diabetes, that is, diabetic nephropathy (DN), is limited. During the 7 years (2010-2017), 921 postperfusion biopsies were performed for living donors (14%) or deceased donors (86%). The Renal Pathology Society classification schema for DN (class 0-IV) was used. Biopsies with light microscopic changes of DN (at least class IIa) were selected for study. Eleven biopsies (1.2%) showed DN, all from deceased donors (class IIa in 8, class IIb in 2, and class III in 1 biopsy). The glomerular basement membrane thickness ranged from 439 ± 52 to 725 ± 82 nm. These biopsies also displayed arterionephrosclerosis. They were from 9 deceased donors (fulfilling clinical criteria for acceptance in all, diabetes ;[>6 years] in 8, hypertension in 6, and proteinuria [1+] in all). Follow-up biopsies (5-342 weeks after transplant) showed DN of the same class (7 biopsies), probably progression (1), or progression (3). At follow-up (15-416 weeks), all recipients were alive. One graft was lost at 76 weeks because of progressive DN. The other 10 grafts were functioning, but the serum creatinine reached 2.0 to 2.7 mg/dL in 5 of them. Although diabetes is frequent in kidney donors, donor-related DN is unusual. It is observed only in deceased donors, but the risk factors for its development are not known. Donor-related DN may be stable or progress. Whether it resolves, especially for DN in early phase, remains unknown. It may adversely impact the graft outcome with a magnitude proportional to the severity of the tissue injury in the postperfusion biopsies.

Nephrotoxicity of immune checkpoint inhibitors beyond tubulointerstitial nephritis: single-center experience.

RATIONALE & OBJECTIVE: The approved therapeutic indication for immune checkpoint inhibitors (CPIs) are rapidly expanding including treatment in the adjuvant setting, the immune related toxicities associated with CPI can limit the efficacy of these agents. The literature on the nephrotoxicity of CPI is limited. Here, we present cases of biopsy proven acute tubulointerstitial nephritis (ATIN) and glomerulonephritis (GN) induced by CPIs and discuss potential mechanisms of these adverse effects. STUDY DESIGN, SETTING, & PARTICIPANTS: We retrospectively reviewed all cancer patients from 2008 to 2018 who were treated with a CPI and subsequently underwent a kidney biopsy at The University of Texas MD Anderson Cancer Center. RESULTS: We identified 16 cases diagnosed with advanced solid or hematologic malignancy; 12 patients were male, and the median age was 64 (range 38 to 77 years). The median time to developing acute kidney injury (AKI) from starting CPIs was 14 weeks (range 6-56 weeks). The average time from AKI diagnosis to obtaining renal biopsy was 16 days (range from 1 to 46 days). Fifteen cases occurred post anti-PD-1based therapy. ATIN was the most common pathologic finding on biopsy (14 of 16) and presented in almost all cases as either the major microscopic finding or as a mild form of interstitial inflammation in association with other glomerular pathologies (pauci-immune glomerulonephritis, membranous glomerulonephritis, C3 glomerulonephritis, immunoglobulin A (IgA) nephropathy, or amyloid A (AA) amyloidosis). CPIs were discontinued in 15 out of 16 cases. Steroids and further immunosuppression were used in most cases as indicated for treatment of ATIN and glomerulonephritis (14 of 16), with the majority achieving complete to partial renal recovery. CONCLUSIONS: Our data demonstrate that CPI related AKI occurs relatively late after CPI therapy. Our biopsy data demonstrate that ATIN is the most common pathological finding; however it can frequently co-occur with other glomerular pathologies, which may require immune suppressive therapy beyond corticosteroids. In the lack of predictive blood or urine biomarker, we recommend obtaining kidney biopsy for CPI related AKI.

Risk factors and consequences of delayed graft function in deceased donor renal transplant patients receiving antithymocyte globulin induction.

BACKGROUND: Induction rabbit antithymocyte globulin (rATG) is largely used in renal allograft recipients at risk for delayed graft function (DGF) and immunologic rejection. The purpose of our study was to characterize risk factors and outcomes associated with DGF when it occurs in recipients undergoing routine rATG induction. METHODS: We retrospectively reviewed our experience in a predominantly high-risk population receiving modern immunosuppressive regimens. RESULTS: Of 231 deceased-donor transplants, high-risk characteristics included African American race (68%), retransplants (12%), peak panel reactive antibody of atleast 20% (19%), expanded criteria donor kidney (15%), and cold ischemia time exceeding 24 hr (27%). DGF occurred in 29% of patients. rATG was continued to a dose of 7.3 mg/kg in DGF patients and 5 mg/kg in non-DGF patients (P<0.0001). Risk factors for DGF were recipient body mass index greater than 30 kg/m(2) (odds ratio [OR]=1.5, P=0.02), female donor/male recipient pairings (OR=1.5, P=0.033), sirolimus use (OR=1.7, P=0.003), and donor creatinine more than 1.5 mg/dL (OR=1.6, P=0.016). One-year patient survival (99% non-DGF, 91% DGF; P=0.001) and acute rejection incidence through 36 months (11% non-DGF, 22.4% DGF; P=0.025) differed between groups. DGF patients experienced a higher rejection rate during the second and third years posttransplant. Death-censored graft survival was similar throughout 36 months. CONCLUSION: In kidney transplantation with routine rATG induction, DGF was related to size and gender, donor creatinine, and immunosuppressive protocol. Despite low first-year rejection rates, DGF was associated with inferior patient survival. Importantly, patients with DGF continued to be at risk for rejection beyond the first year. Donor and recipient selection impacts short-term outcomes, and induction alone may not confer a long-term advantage without further modification of baseline therapy.

Ipsilateral placement in double-kidney transplantation.

Ipsilateral placement of double kidneys from marginal donors into older recipients may reduce the stress of the operation on the patient and allow for extension of the utility of older donor kidneys. A separate bench preparation of the kidneys is performed to aid in assessing the quality of the kidneys before placement in the recipient. Multiple renal arteries and proximal calcifications may require extracorporeal anastomosis or multiple anastomoses in the recipient depending on length and size of the renal vessels. In the recipient, the incision should allow complete dissection of the common external and internal iliac arteries. This report provides a detail of the technique used for ipsilateral placement of double kidneys.

BK virus-induced tubulointerstitial nephritis in a child with acute lymphoblastic leukemia.

We report a case of BK virus-induced tubulointerstitial nephritis in a child with acute lymphoblastic leukemia. Primary BK virus infection was exacerbated by chemotherapy-induced immunodeficiency. Careful administration of chemotherapy and anti-viral therapy prevented further damage. This diagnosis should be considered in children who experience renal dysfunction during cancer treatment.

Acute oxalate nephropathy associated with orlistat, a gastrointestinal lipase inhibitor.

Orlistat is an oral inhibitor of gastrointestinal lipase used for weight reduction in obese patients. Although most adverse drug effects manifest in the gastrointestinal tract, this is the first reported case of orlistat-induced acute kidney injury secondary to acute oxalate nephropathy in a white woman with underlying chronic kidney disease. Acute kidney injury was associated temporally with an increased dose of orlistat and the development of increased fat malabsorption (more frequent loose oily stools). Urine sediment showed abundant calcium oxalate crystals and increased 24-hour urine oxalate concentration. Kidney biopsy showed deposition of calcium oxalate crystals within tubular lumens, consistent with acute oxalate nephropathy. Orlistat therapy was discontinued, and oral fluid intake was increased. A second kidney biopsy performed 1 month later to evaluate the slow resolution of kidney failure did not show calcium oxalate crystals within tubules. A steady improvement in renal function subsequently was observed. Results of a repeated 24-hour urine oxalate collection performed 3 weeks later when kidney function had improved were within normal limits.

Expression of transforming growth factor-beta by human islets: impact on islet viability and function.

Transforming growth factor-beta1 (TGF-beta1) is a pleotropic cytokine that promotes angiogenesis and extracellular matrix protein synthesis in addition to its immunosuppressive effects. The purpose of this study is to identify optimal conditions for in vivo expression of TGF-beta1 by human islets to exploit the possible beneficial effects and minimize undesirable side effects. We transduced human islets with adenoviral vectors encoding the active form of Ad-TGF-beta1 or Ad-LacZ to test the effects of TGF-beta1 gene expression on islet in vivo function following their transplantation into a NOD-SCID mouse model. Islets were transduced with multiplicity of infection (MOI) of 20, 10, 5, and 2.5 per islet cell. At a MOI ranging from 2.5 to 20, expression of TGF-beta1 in islet supernatant persisted for 1-2 months and ranged from 153 +/- 5 to 2574 +/- 1299 pg/ml, respectively. Transduction with the lowest MOI (2.5) did not compromise the in vivo production of human C-peptide. We conclude that TGF-beta1 expression in transplanted islets does not compromise viability and that adenoviral transduction with the TGF-beta1 gene has a dose-dependent effect, with larger MOIs being deleterious. The data also indicate that in vitro culture system and the in vivo NOD-SCID model could be used successfully to evaluate the nonimmune effects of gene transduction.