APRIL/BLyS deficient rats prevent donor specific antibody (DSA) production and cell proliferation in rodent kidney transplant model.

APRIL (A proliferation inducing ligand) and BLyS (B Lymphocyte Stimulator) are two critical survival factors for B lymphocytes and plasma cells, the main source of alloantibody. We sought to characterize the specific effects of these cytokines in a kidney transplant model of antibody mediated rejection (AMR). We engineered APRIL-/- and BLyS-/- Lewis rats using CRISPR/Cas9. APRIL-/- and BLyS-/- rats were sensitized with Brown Norway (BN) blood (complete MHC mismatch). Twenty-one days following sensitization, animals were harvested and collected tissues were analyzed using flow cytometry, ELISPOT, and immunohistochemistry. Flow cross match and a 3 day mixed lymphocyte reaction (MLR) was performed to assess donor specific antibody (DSA) production and T-cell proliferation, respectively. Sensitized dual knock out Lewis rats (APRIL-/-/BLyS-/-) underwent kidney transplantation and were sacrificed on day 7 post-transplant. Sensitized BLyS-/- had significant decreases in DSA and cell proliferation compared to WT and APRIL-/- (p<0.02). Additionally, BLyS-/- rats had a significant reduction in IgG secreting cells in splenic marginal zone B lymphocytes, and in cell proliferation when challenged with alloantigen compared to WT and APRIL-/-. Transplanted APRIL-/-/BLyS-/- rodents had significantly less DSA and antibody secreting cells compared to WT (p<0.05); however, this did not translate into a significant difference in AMR seen between groups. In summary, our studies suggest that APRIL and BLyS play a greater role in DSA generation rather than AMR, highlighting the role of cellular pathways that regulate AMR.

Voucher-Based Kidney Donation and Redemption for Future Transplant.

Importance: Policy makers, transplant professionals, and patient organizations agree that there is a need to increase the number of kidney transplants by facilitating living donation. Vouchers for future transplant provide a means of overcoming the chronological incompatibility that occurs when the ideal time for living donation differs from the time at which the intended recipient actually needs a transplant. However, uncertainty remains regarding the actual change in the number of living kidney donors associated with voucher programs and the capability of voucher redemptions to produce timely transplants. Objective: To examine the consequences of voucher-based kidney donation and the capability of voucher redemptions to provide timely kidney allografts. Design, Setting, and Participants: This multicenter cohort study of 79 transplant centers across the US used data from the National Kidney Registry from January 1, 2014, to January 31, 2021, to identify all family vouchers and patterns in downstream kidney-paired donations. The analysis included living kidney donors and recipients participating in the National Kidney Registry family voucher program. Exposures: A voucher was provided to the intended recipient at the time of donation. Vouchers had no cash value and could not be sold, bartered, or transferred to another person. When a voucher was redeemed, a living donation chain was used to return a kidney to the voucher holder. Main Outcomes and Measures: Deidentified demographic and clinical data from each kidney donation were evaluated, including the downstream patterns in kidney-paired donation. Voucher redemptions were separately evaluated and analyzed. Results: Between 2014 and 2021, 250 family voucher-based donations were facilitated. Each donation precipitated a transplant chain with a mean (SD) length of 2.3 (1.6) downstream kidney transplants, facilitating 573 total transplants. Of those, 111 transplants (19.4%) were performed in highly sensitized recipients. Among 250 voucher donors, the median age was 46 years (range, 19-78 years), and 157 donors (62.8%) were female, 241 (96.4%) were White, and 104 (41.6%) had blood type O. Over a 7-year period, the waiting time for those in the National Kidney Registry exchange pool decreased by more than 3 months. Six vouchers were redeemed, and 3 of those redemptions were among individuals with blood type O. The time from voucher redemption to kidney transplant ranged from 36 to 155 days. Conclusions and Relevance: In this study, the family voucher program appeared to mitigate a major disincentive to living kidney donation, namely the reluctance to donate a kidney in the present that could be redeemed in the future if needed. The program facilitated kidney donations that may not otherwise have occurred. All 6 of the redeemed vouchers produced timely kidney transplants, indicating the capability of the voucher program.

Early detection of SARS-CoV-2 and other infections in solid organ transplant recipients and household members using wearable devices.

The increasing global prevalence of SARS-CoV-2 and the resulting COVID-19 disease pandemic pose significant concerns for clinical management of solid organ transplant recipients (SOTR). Wearable devices that can measure physiologic changes in biometrics including heart rate, heart rate variability, body temperature, respiratory, activity (such as steps taken per day) and sleep patterns, and blood oxygen saturation show utility for the early detection of infection before clinical presentation of symptoms. Recent algorithms developed using preliminary wearable datasets show that SARS-CoV-2 is detectable before clinical symptoms in >80% of adults. Early detection of SARS-CoV-2, influenza, and other pathogens in SOTR, and their household members, could facilitate early interventions such as self-isolation and early clinical management of relevant infection(s). Ongoing studies testing the utility of wearable devices such as smartwatches for early detection of SARS-CoV-2 and other infections in the general population are reviewed here, along with the practical challenges to implementing these processes at scale in pediatric and adult SOTR, and their household members. The resources and logistics, including transplant-specific analyses pipelines to account for confounders such as polypharmacy and comorbidities, required in studies of pediatric and adult SOTR for the robust early detection of SARS-CoV-2, and other infections are also reviewed.

Oxidized-ATP Attenuates Kidney Allograft Rejection By Inhibiting T-Cell, B-Cell, and Macrophage Activity.

Background: Extracellular ATP binds to purinergic receptors and promotes inflammatory responses. We tested whether oxidized ATP (oATP), P2X7 receptor antagonist can attenuate acute kidney allograft rejection. Methods: Brown Norway kidney allografts were transplanted into Lewis recipients. Three groups were defined: oATP (n=8), cyclosporine A (n=6), and no treatment (n=8). On day 7, we assessed kidney allograft survival, function, and rejection characteristics. We further determined T-cell, B-cell, and macrophage response to oATP in vivo and in vitro and examined intragraft inflammatory gene transcripts. Results: Kaplan-Meier survival analyses demonstrated significantly better graft survival rates in oATP and CsA groups compared with no treatment (P<0.05). Similarly, serum creatinine (Scr) and BUN levels were significantly lower in oATP and CsA groups (P<0.05). oATP reduced both T cell-mediated rejection and antibody-mediated rejection, inhibited B-cell and T-cell activation, and downregulated intragraft IL-6 mRNA levels (P<0.0001). In vitro, oATP prevented proliferation in mixed lymphocyte reaction assays, and inhibited macrophage P2X7R activity in a dose-dependent manner. Conclusions: Our findings suggest that oATP mitigates kidney allograft rejection by inhibiting T-cell, B-cell, and macrophage activity and indicate a potential role for the purinergic system and oATP in solid organ transplantation.

Alemtuzumab induction for retransplantation after primary transplant with alemtuzumab induction
.

BACKGROUND: Lymphocyte-depleting induction with alemtuzumab (ALEM) or rabbit antithymocyte-globulin (rATG) is commonly used at retransplantation. It is unknown which agent is preferable, particularly when ALEM was used at primary transplant. OBJECTIVE: Evaluate outcomes after ALEM at retransplant following primary transplant with ALEM induction (ALEM-ALEM) as compared to retransplant with rATG (ALEM-rATG). MATERIALS AND METHODS: Single-center, observational cohort study of adult patients receiving kidney or pancreas transplant between January 1, 2001 and December 12, 2016. RESULTS: 45 patients (16 ALEM-ALEM and 29 ALEM-rATG) met inclusion criteria. The ALEM-ALEM group had fewer days between transplants (621.0 ± 821.8 vs. 2,024.4 ± 1,285.8, p = 0.049), lower panel-reactive-antibodies (PRA) prior to transplant 2 (15.7 ± 31.5 vs. 53.2 ± 37.8; p = 0.0003), and more pancreas secondary transplants, although this was not statistically significant (ALEM-ALEM 37.5% vs. ALEM-rATG 10.3%, p = 0.05). The ALEM-ALEM group experienced a significantly higher rate of fungal infection (ALEM-ALEM 46.8% vs. ALEM-rATG 11.3%, p = 0.02). When adjusted in a multivariate model, this trend persisted (HR 3.97, CI 0.95 - 16.5, p = 0.05). A subgroup analysis of patients receiving a kidney for both transplant 1 and 2 to remove the possible confounding effect of pancreas allografts also found incidence of fungal infection at 1 year to be significantly higher in the ALEM-ALEM group (ALEM-ALEM 25% vs. ALEM-rATG 9.3%, p = 0.025). Rejection rates were not different between groups at 1 year (ALEM-ALEM 25% vs. ALEM-rATG 24.2%). Rates of cytomegalovirus (CMV) infection, BK polyomavirus infection, patient and graft survival were also similar. CONCLUSION: Patients with repeat courses of ALEM induction across multiple transplants may have a higher incidence of fungal infection. Future studies are needed to explore this risk, particularly in light of current drug manufacturer allocation practices and potential increased utilization by transplant centers.

Pancreas Retransplant After Pancreas Graft Failure in Simultaneous Pancreas-kidney Transplants Is Associated With Better Kidney Graft Survival.

BACKGROUND: Simultaneous pancreas-kidney (SPK) transplant is usually the best option for the diabetic end-stage renal disease patient. There is limited information about kidney graft outcomes in SPK recipients with isolated pancreas graft failure who do versus do not undergo pancreas retransplantation. METHODS: Patients were divided into 2 groups based on whether they underwent pancreas retransplant (ReTx+) or not (ReTx-). Kidney graft function and survival were the primary endpoints. RESULTS: One hundred and nine patients satisfied our selection criteria, 25 in ReTx+ and 84 in ReTx-. Mean interval from SPK to pancreas failure was significantly shorter in the ReTx+ compared with the ReTx- group, 19.3 ± 36.7 versus 45.7 ± 47.0 months (P = 0.01), respectively. There was no significant difference in kidney graft follow-up post SPK between 2 groups (P = 0.48). At last follow-up, 15 of the 25 (60%) of the repeat pancreas graft had failed, with a mean graft survival among these failed pancreas graft of 2.6 ± 2.7 years, ranging from 0 to 8.1 years. Uncensored kidney graft failure was significantly lower in the ReTx+ group compared with the ReTx- group, 44% versus 67% (P = 0.04). Death-censored kidney graft failure was also lower in the ReTx+ group, 24% versus 48% (P = 0.04). The difference in patient survival did not reach statistical significance. In adjusted Cox regression analysis, rejection as a cause of pancreas failure was associated with increased risk of death-censored kidney graft failure, and pancreas retransplantation was associated with decreased risk of kidney graft failure. A similar pattern was seen after 1:1 matching for the interval between SPK and pancreas graft failure. CONCLUSIONS: Even though ReTx+ patients accept the risks associated with repeat pancreas surgery, providers should consider this option in suitable otherwise healthy patients.

Donor-Specific Antibodies in the Absence of Rejection Are Not a Risk Factor for Allograft Failure.

INTRODUCTION: Donor-specific antibodies (DSAs) are considered an important risk factor for graft injury and failure. However, there is limited information on long-term outcomes for kidney transplant recipients with positive DSAs in the absence of rejection on biopsy. METHODS: We evaluated all patients at the University of Wisconsin who underwent a kidney allograft biopsy between January 1, 2013, and December 31, 2016. All patients with clinical indication or protocol biopsies that were negative for acute rejection and lacked significant acute pathological features were included in the study and divided into 2 groups based on DSAs at the time of biopsy. There were a total of 1102 kidney biopsies during the study period of which 587 fulfilled our selection criteria (DSA+, n = 192, and DSA-, n = 395). The incidence of subsequent rejection and death-censored graft failure (DCGF) were outcomes of interest. RESULTS: There was no difference in acute (i + t + v + c4d + ptc + g = 0 in both groups) or chronic (ci + ct + cv + cg = 2.4 ± 2.2 vs. 2.7 ± 2.4; cg = 0.12 ± 0.48 vs. 0.13 ± 0.48) Banff scores in the index biopsy. Patients were followed for a mean of 33.1 ± 16.8 months. Kaplan-Meier analyses demonstrated a higher incidence of DCGF in DSA- group (n = 83) but this was not observed for subsequent rejection (n = 76). In multivariate Cox regression analyses, the interval from transplant to biopsy, de novo DSA, and younger age remained independently associated with increased risk of subsequent rejection. Notably, there was no association between subsequent rejection or DSA (pretransplant, de novo, persistant, Class I/II, MFIsum, or MFImax) and graft failure. CONCLUSION: This study suggests that in the absence of biopsy-proven rejection and acute inflammation, human leukocyte antigen (HLA) DSAs are not associated with increased risk of graft failure.

Renal autotransplantation results in pain resolution after left renal vein transposition.

Left renal vein transposition is often the preferred treatment of nutcracker syndrome. However, pain returns in some patients despite surgery. One solution to this problem is renal autotransplantation. Here we report our initial results of renal autotransplantation in patients with persistent flank pain despite a previous left renal vein transposition. We used the University of Wisconsin loin pain hematuria syndrome test as a diagnostic maneuver to determine who may benefit from renal autotransplantation; this procedure subsequently resulted in complete pain resolution in all three patients. All patients underwent successful renal autotransplantation and remain pain free. These cases support the test as a diagnostic maneuver to determine which patients may benefit from renal autotransplantation.

The Abdominal Transplant Surgery Workforce: Current state and future trends.

Transplant surgical workforce concerns have arisen in the last 5 years as reflected in challenges securing job opportunities for new fellows. The present survey was designed by the ASTS Membership and Workforce Committee to describe the current practice characteristics of transplant centers in order to estimate changes in the workforce. The survey questionnaire requested information about the transplant programs, the transplant surgeons involved in the program, and the estimated changes in the staffing of the program over the next 3 years. Seventy-one transplant centers responded from a total of 235 identified and queried (30.2% response rate), with median responding centers per UNOS region of 7 (IQR 4.5-8.5). The recruitment outlook for the next 3 years forecasts a positive inflow of surgeons at a 2:1 rate (incoming:leaving). The new female transplant workforce within the responding cohort has increased from 3.7% in 1980 to 18.4% in 2010. Currently, 13.1% of practicing US transplant surgeons in this survey are female which is higher than many other surgical specialties. This report represents the most up-to-date view into the abdominal transplant surgical workforce. The positive job recruitment outlook for transplant surgeons and the narrowing gender gap are new findings from this study.

Safety, pharmacokinetics, and pharmacodynamic activity of obinutuzumab, a type 2 anti-CD20 monoclonal antibody for the desensitization of candidates for renal transplant.

The limited effectiveness of rituximab plus intravenous immunoglobulin (IVIG) in desensitization may be due to incomplete B cell depletion. Obinutuzumab is a type 2 anti-CD20 antibody that induces increased B cell depletion relative to rituximab and may therefore be more effective for desensitization. This open-label phase 1b study assessed the safety, pharmacokinetics, and pharmacodynamics of obinutuzumab in highly sensitized patients with end-stage renal disease. Patients received 1 (day 1, n = 5) or 2 (days 1 and 15; n = 20) infusions of 1000-mg obinutuzumab followed by 2 doses of IVIG on days 22 and 43. Eleven patients received additional obinutuzumab doses at the time of transplant and/or at week 24. The median follow-up duration was 9.4 months. Obinutuzumab was well tolerated, and most adverse events were grade 1-2 in severity. There were 11 serious adverse events (SAEs) in 9 patients (36%); 10 of these SAEs were infections and 4 occurred after kidney transplant. Obinutuzumab plus IVIG resulted in profound peripheral B cell depletion and appeared to reduce B cells in retroperitoneal lymph nodes. Reductions in anti-HLA antibodies, number of unacceptable antigens, and the calculated panel reactive antibody score as centrally assessed using single-antigen bead assay were limited and not clinically meaningful for most patients (NCT02586051).

Significant Reduction of Murine Renal Ischemia-Reperfusion Cell Death Using the Immediate-Acting PrC-210 Reactive Oxygen Species Scavenger.

BACKGROUND: Ischemia-reperfusion (IR) injury remains a significant problem for all solid organ transplants; thus, an important unmet need in transplantation is the prevention of IR injury. PrC-210 has demonstrated superior prevention of reactive oxygen species damage in several preclinical studies as a free radical scavenger. Here, we describe its profound efficacy in suppressing IR injury in a murine model of kidney IR injury. METHODS: C57/B6 mice underwent laparotomy with the left renal pedicle occluded for 30 minutes to induce IR injury. Right nephrectomy was performed at the time of surgery. Mice received a single systemic dose of the PrC-210, PrC-211, or PrC-252 aminothiols 20 minutes before IR injury. Twenty-four hours following IR injury, blood and kidney tissue were collected for analysis. Kidney caspase-3 level (a marker of cell death), direct histological analysis of kidneys, and serum blood urea nitrogen (BUN) were measured in animals to assess reactive oxygen species scavenger protective efficacies. RESULTS: A single systemic PrC-210 dose 20 minutes before IR injury resulted in significant reductions in (1) IR-induced kidney caspase level (P < 0.0001); caspase was reduced to levels not significantly different than control caspase levels seen in unperturbed kidneys, (2) IR-induced renal tubular injury scores (P < 0.0001); brush border loss and tubular dilation were markedly reduced, and (3) serum BUN compared with control IR injury kidneys (P < 0.0001). The ranked protective efficacies of PrC-210 > PrC-211 >> PrC-252 paralleled previous radioprotection studies of the molecules. CONCLUSIONS: A single PrC-210 dose, minutes before the IR insult, profoundly reduced caspase, renal tubular injury, and serum BUN in mice exposed to standard kidney IR injury. These findings support further development of the PrC-210 molecule to suppress or prevent IR injury in organ transplant and other IR injury settings.

Suppression of Active HIV-1 Infection in CD34+ Hematopoietic Humanized NSG Mice by a Combination of Combined Antiretroviral Therapy and CCR5 Targeting Drugs.

Significant progress has been made in the diagnostics and treatment of AIDS since the discovery of the human immunodeficiency virus type 1 (HIV-1) in 1983. The remarkable effectiveness of combined antiretroviral therapy (cART) is evidenced by mortality reduction, control of peripheral blood viral load, and in a nearly normal quality of HIV patients' lives. Remaining obstacles in treatment and cure are drug toxicities and side effects, viral resistance, persistence of HIV-1 reservoirs on termination of cART treatment, the cost of lifelong antiretroviral therapy, and the stigma associated with taking antiretroviral drugs. As determined by plasma viral RNA and peripheral blood mononuclear cells (PBMC) proviral DNA, we show improved suppression of productive HIV infection in human CD34+ hematopoietic stem cell-engrafted NOD (nonobese diabetic)-SCID (severe combined immunodeficiency)-il2rg-/- (NSG) mice by combined treatment with cART and CCR5 targeting drugs, compared with cART alone, as well as an increased preservation of human CD4+ T cells (defined as CD45+ CD3+ CD4+ cells) and CD4+/CD8+ cell ratios in infected mice. The data also suggest a possible reduction in viral reservoirs. Our data confirm that this animal model is suitable for detection of productive HIV infection, replication, and establishment of viral reservoirs. The data also provide proof of principle for the utility of combining CCR5 targeting drugs, maraviroc and rapamycin, with traditional cART to improve control of viremia and reduce viral reservoirs. This study thus serves as a model for future HIV-1 studies that could lead to the clinical development of new generations of antiretroviral drugs.

APRIL/BLyS Blockade Reduces Donor-specific Antibodies in Allosensitized Mice.

BACKGROUND: Highly sensitized candidates on the transplant waitlist remain a significant challenge, as current desensitization protocols have variable success rates of donor-specific antibody (DSA) reduction. Therefore, improved therapies are needed. A proliferation-inducing ligand (APRIL) and B-lymphocyte stimulator (BLyS) are critical survival factors for B-lymphocytes and plasma cells, which are the primary sources of alloantibody production. We examined the effect of APRIL/BLyS blockade on DSA in a murine kidney transplant model as a possible novel desensitization strategy. METHODS: C57BL/6 mice were sensitized with intraperitoneal (IP) injections of 2 × 10 BALB/c splenocytes. Twenty-one days following sensitization, animals were treated with 100 µg of BLyS blockade (B-cell activating factor receptor-immunoglobulin) or APRIL/BLyS blockade (transmembrane activator and calcium modulator and cyclophilin ligand interactor-immunoglobulin), administered thrice weekly for an additional 21 days. Animals were then euthanized or randomized to kidney transplant with Control Ig, BLyS blockade, or APRIL/BLyS blockade. Animals were euthanized 7 days posttransplant. B-lymphocytes and DSA of BLyS blockade only or APRIL/BLyS blockade-treated mice were assessed by flow cytometry, immunohistochemistry, and enzyme-linked immunospot. RESULTS: APRIL/BLyS inhibition resulted in a significant reduction of DSA by flow crossmatch compared with controls (P < 0.01). APRIL/BLyS blockade also significantly depleted IgM- and IgG-secreting cells and B-lymphocyte populations compared to controls (P < 0.0001). APRIL/BLyS blockade in transplanted mice also resulted in decreased B-lymphocyte populations; however, no difference in rejection rates were seen between groups. CONCLUSIONS: APRIL/BLyS blockade with transmembrane activator and calcium modulator and cyclophilin ligand interactor-immunoglobulin significantly depleted B-lymphocytes and reduced DSA in this sensitized murine model. APRIL/BLyS inhibition may be a clinically useful desensitization strategy for sensitized transplant candidates.

Desensitization and treatment with APRIL/BLyS blockade in rodent kidney transplant model.

Alloantibody represents a significant barrier in kidney transplant through the sensitization of patients prior to transplant through antibody mediated rejection (ABMR). APRIL BLyS are critical survival factors for mature B lymphocytes plasma cells, the primary source of alloantibody. We examined the effect of APRIL/BLyS blockade via TACI-Ig (Transmembrane activator calcium modulator cyclophilin lig interactor-Immunoglobulin) in a preclinical rodent model as treatment for both desensitization ABMR. Lewis rats were sensitized with Brown Norway (BN) blood for 21 days. Following sensitization, animals were then sacrificed or romized into kidney transplant (G4, sensitized transplant control); desensitization with TACI-Ig followed by kidney transplant (G5, sensitized + pre-transplant TACI-Ig); kidney transplant with post-transplant TACI-Ig for 21 days (G6, sensitized + post-transplant TACI-Ig); desensitization with TACI-Ig followed by kidney transplant post-transplant TACI-Ig for 21 days (G7, sensitized + pre- post-transplant TACI-Ig). Animals were sacrificed on day 21 post-transplant tissues were analyzed using flow cytometry, IHC, ELISPOT, RT-PCR. Sensitized animals treated with APRIL/BLyS blockade demonstrated a significant decrease in marginal zone non-switched B lymphocyte populations (p<0.01). Antibody secreting cells were also significantly reduced in the sensitized APRIL/BLyS blockade treated group. Post-transplant APRIL/BLyS blockade treated animals were found to have significantly less C4d deposition less ABMR as defined by Banff classification when compared to groups receiving APRIL/BLyS blockade before transplant or both before after transplant (p<0.0001). The finding of worse ABMR in groups receiving APRIL/BLyS blockade before both before after transplant may indicate that B lymphocyte depletion in this setting also resulted in regulatory lymphocyte depletion resulting in a worse rejection. Data presented here demonstrates that the targeting of APRIL BLyS can significantly deplete mature B lymphocytes, antibody secreting cells, effectively decrease ABMR when given post-transplant in a sensitized animal model.

Outcomes of Pancreas Transplant Recipients With De Novo Donor-specific Antibodies.

BACKGROUND: Development of de novo donor-specific antibodies (dnDSA) has detrimental effects on graft survival in several types of solid organ transplants. However, limited information exists about the effect of dnDSA on pancreas transplant graft survival. METHODS: We report our experience with pancreas recipients transplanted between January 01, 2005, and August 31, 2017. RESULTS: We identified 541 pancreas transplant recipients, of which 121 developed dnDSA and 420 did not. Thirty-two percent developed dnDSA against HLA class I antigens, 56% developed against class II antigens, and 12% developed against both. Fifty-two percent of the patients in the dnDSA+ and 24% in the dnDSA- group underwent pancreas biopsy, mainly due to a rise in pancreatic enzymes. Rejection was found in 42% of the dnDSA+ group, and 20% of the dnDSA- group(P < 0.001). There were 36% uncensored graft failures in the dnDSA+ group and 17% uncensored failures in the dnDSA- group (P < 0.001). A similar trend was seen in death-censored graft failure between the groups. In univariate Cox regression analyses, male sex, older age, and recipients of simultaneous pancreas and kidney transplant were found to be protective for death-censored graft failure; multiple transplants, dnDSA, requirement for pancreas biopsy and presence of pancreas rejection were associated with increased risk of graft failure. In multivariate analysis, only older age and dnDSA were significantly associated with death-censored graft failure. CONCLUSIONS: Our findings suggest that dnDSA in pancreas transplant recipients are associated with increased rates of rejection and graft failure. Timely detection of dnDSA through regular screening and early treatment of pancreas rejection may ultimately improve graft outcomes.

Clinical Significance of Microvascular Inflammation in the Absence of Anti-HLA DSA in Kidney Transplantation.

BACKGROUND: Limited information exists about outcomes of HLA donor-specific antibody (DSA) negative (DSA-) microvascular inflammation (MVI). METHODS: We report our experience with 25 DSA- patients with MVI compared to 155 DSA+ patients who met Banff 2013 criteria for antibody-mediated rejection (AMR). We also compared outcomes to 228 DSA+ patients whose biopsies were negative for rejection and served as a negative control. RESULTS: There were no significant differences in the baseline characteristics between the DSA- MVI and DSA+ AMR groups. At the time of diagnosis, both groups had similar graft function. The DSA- group had higher MVI scores but lower C4d scores. At last follow-up, renal function was similar between the groups. There were 12 (48%) graft failures in the DSA- group and 59 (38%) graft failures in the DSA+ group, which was not statistically different. Similar results were found after matching for the MVI scores, C4d, and treatment between 2 groups. We also found similar outcomes between DSA- and DSA+ patients when only including those who would have met Banff 2017 criteria for AMR. In univariate Cox regression analyses, estimated glomerular filtration rate at time of biopsy, glomerulitis, rituximab, diabetes, v score, allograft glomerulopathy, fibrous intimal thickening, tubular atrophy, and interstitial fibrosis scores were associated with graft failure. In multivariate analysis, only estimated glomerular filtration rate was protective. Both groups had significantly worse outcomes than the DSA+-negative controls without AMR. CONCLUSIONS: Our findings suggest that outcomes and response to treatment with HLA DSA- MVI patients are similarly poor to those with DSA+ MVI patients, supporting a critical role for MVI in the diagnosis of AMR.

Disparate effects of cytotoxic chemotherapy on the antiviral activity of antiretroviral therapy: implications for treatments of HIV-infected cancer patients.

BACKGROUND: Cancer is a leading cause of death in HIV-infected patients in the era of combination antiretroviral therapy (cART). Yet, there are no specific guidelines for the combined use of cART and chemotherapy in HIV-infected cancer patients. The cellular enzyme thymidylate synthase (TS) catalyses the conversion of dUMP to TMP, which is converted to TDP and ultimately to TTP, a building block in DNA synthesis. TS inhibitors are recommended in some cancers, particularly non-small cell lung cancer (NSCLC). Because TS inhibitors modulate intracellular concentrations of endogenous 2'-deoxynucleotides, we hypothesized that TS inhibitors could impact the anti-HIV activity of nucleoside analogue reverse transcriptase inhibitors (NRTIs). METHODS: We evaluated gemcitabine and pemetrexed, two approved TS inhibitors, on the anti-HIV activities of NRTIs in infectivity assays using peripheral blood mononuclear cells (PBMCs) and in humanized mice. RESULTS: Gemcitabine enhanced the anti-HIV activities of tenofovir, abacavir and emtricitabine (FTC) in PBMCs. In contrast, pemetrexed had no effect on tenofovir, enhanced abacavir and, unexpectedly, decreased FTC and lamivudine (3TC) activities. Pemetrexed inhibitory effects on FTC and 3TC may be due to lower concentrations of active metabolites (FTCtp and 3TCtp) relative to their competing endogenous nucleotide (dCTP), as shown by decreases in FTCtp/dCTP ratios. Gemcitabine enhanced tenofovir while pemetrexed abrogated FTC antiviral activity in humanized mice. CONCLUSIONS: Chemotherapy with TS inhibitors can have opposing effects on cART, potentially impacting control of HIV and thereby development of viral resistance and size of the reservoir in HIV-infected cancer patients. Combinations of cART and chemotherapy should be carefully selected.

Impact of High-Dose Acyclovir Cytomegalovirus Prophylaxis Failure in Abdominal Solid Organ Transplant Recipients.

STUDY OBJECTIVE: To evaluate the clinical course and long-term impact of high-dose acyclovir (HD-A, 800 mg 4 times/day) cytomegalovirus (CMV) prophylaxis failure in a CMV-seropositive abdominal solid organ transplant population. DESIGN: Retrospective cohort study. SETTING: Tertiary academic medical center. PATIENTS: A total of 691 adults who received solid organ transplants between January 1, 2008, and June 30, 2013, without lymphocyte-depleting induction and were prescribed 3 months of HD-A prophylaxis at the time of hospital discharge. Of those patients, 54 experienced prophylaxis failure, defined as CMV detected via molecular diagnostics or on biopsy while receiving HD-A (prophylaxis failure group), and 637 did not (comparator group). MEASUREMENTS AND MAIN RESULTS: Mean ± SD time to failure was 64 ± 23 days; 98% (53/54 patients) was attributable to viremia diagnosed via positive polymerase chain reaction (PCR). Of these 53 patients, 34% (18 patients) were below the quantifiable range when detected. Median initial and peak CMV PCR for quantifiable readings were 1531 IU/ml (interquartile range [IQR] less than 250-2947) and 4442 IU/ml (IQR less than 250-32,500); 19 (36%) had a single detectable CMV PCR. Treatment was required in 56% (30/54 patients), with a median duration of 63 days; 40% (12 patients) were treated with valganciclovir alone, and the remainder received intravenous ganciclovir. CMV disease resulted in hospitalization in 28% (15 patients). Immunosuppression was modified in 52% (28 patients). The rate of CMV recurrence after 100 days was significantly higher in the prophylaxis failure group (59% vs 13%, p<0.0001). Higher rates of rejection; higher rates of 1-, 3-, and 5-year graft failure; and higher rates of 1-, 3-, and 5-year mortality were noted in the prophylaxis failure group on univariate analysis (43% vs 30%, p=0.045; 8%, 17%, and 34% vs 4%, 12%, and 17%, p=0.006; and 6%, 17%, and 26% vs 1%, 6%, and 10%, p=0.003, respectively). Multivariate analysis demonstrated an increased risk of graft failure in the prophylaxis failure group (hazard ratio [HR] 1.76, 95% confidence interval [CI] 1-3.1, p=0.0499) and a trend to increased mortality (HR 1.6, 95% CI 0.83-3.1, p=0.16). CONCLUSION: Prophylaxis failure with HD-A was mostly limited to mild viremia; however, it was associated with significantly reduced long-term graft survival, likely reflecting the negative impact of CMV viremia.