Matthew H. Levine

Helios Expression Is a Marker of T Cell Activation and Proliferation

Foxp3+ T-regulatory cells (Tregs) normally serve to attenuate immune responses and are key to maintenance of immune homeostasis. Over the past decade, Treg cells have become a major focus of research for many groups, and various functional subsets have been characterized. Recently, the Ikaros family member, Helios, was reported as a marker to discriminate naturally occurring, thymic-derived Tregs from those peripherally induced from naïve CD4+ T cells. We investigated Helios expression in murine and human T cells under resting or activating conditions, using well-characterized molecules of naïve/effector/memory phenotypes, as well as a set of Treg-associated markers. We found that Helios-negative T cells are enriched for naïve T cell phenotypes and vice versa. Moreover, Helios can be induced during T cell activation and proliferation, but regresses in the same cells under resting conditions. We demonstrated comparable findings using human and murine CD4+Foxp3+ Tregs, as well as in CD4+ and CD8+ T cells. Since Helios expression is associated with T cell activation and cellular division, regardless of the cell subset involved, it does not appear suitable as a marker to distinguish natural and induced Treg cells.

Trial of Transplantation of HCV-Infected Kidneys into Uninfected Recipients

An open-label pilot trial involving 10 patients shows that hepatitis C virus genotype 1–infected kidneys transplanted into HCV-negative recipients, followed by direct-acting antiviral therapy, can result in excellent allograft function with cure of HCV infection.

Differing Effects of Rapamycin or Calcineurin Inhibitor on T‐Regulatory Cells in Pediatric Liver and Kidney Transplant Recipients

In a cross‐sectional study, we assessed effects of calcineurin inhibitor (CNI) or rapamycin on T‐regulatory (Treg) cells from children with stable liver (n = 53) or kidney (n = 9) allografts several years posttransplant. We analyzed Treg number, phenotype, suppressive function, and methylation at the Treg‐specific demethylation region (TSDR) using Tregs and peripheral blood mononuclear cells. Forty‐eight patients received CNI (39 as monotherapy) and 12 patients received rapamycin (9 as monotherapy). Treg numbers diminished over time on either regimen, but reached significance only with CNI (r =−0.424, p = 0.017). CNI levels inversely correlated with Treg number (r =−0.371, p = 0.026), and positively correlated with CD127+ expression by Tregs (r = 0.437, p = 0.023). Patients with CNI levels >3.6 ng/mL had weaker Treg function than those with levels <3.6 ng/mL, whereas rapamycin therapy positively correlated with Treg numbers (r = 0.628, p = 0.029) and their expression of CTLA4 (r = 0.726, p = 0.041). Overall, CTLA4 expression, TSDR demethylation and an absence of CD127 were important for Treg suppressive function. We conclude that rapamycin has beneficial effects on Treg biology, whereas long‐term and high dose CNI use may impair Treg number, function and phenotype, potentially acting as a barrier to attaining host hyporesponsiveness to an allograft.

Risk of End‐Stage Renal Disease Among Liver Transplant Recipients With Pretransplant Renal Dysfunction

Guidelines recommend restricting simultaneous liver–kidney (SLK) transplant to candidates with prolonged dialysis or estimated glomerular filtration rate (eGFR) <30 mL/min/1.73m2 for 90 days. However, few studies exist to support the latter recommendation. Using Scientific Registry of Transplant Recipients and Medicare dialysis data, we assembled a cohort of 4997 liver transplant recipients from February 27, 2002–January 1, 2008. Serial eGFRs were calculated from serum creatinines submitted with MELD reports. We categorized recipients by eGFR patterns in the 90 days pretransplant: Group 1 (eGFR always >30), Group 2 (eGFR fluctuated), Group 3 (eGFR always <30) and Group 4 (short‐term dialysis). For Group 2, we characterized fluctuations in renal function using time‐weighted mean eGFR. Among liver‐alone recipients in Group 3, the rate of end‐stage renal disease (ESRD) by 3 years was 31%, versus <10% for other groups (p < 0.001). In multivariable Cox regression, eGFR Group, diabetes (HR 2.65, p < 0.001) and black race (HR 1.83, p = 0.02) were associated with ESRD. Among liver‐alone recipients in Group 2, only diabetics with time‐weighted mean eGFR <30 had a substantial ESRD risk (25.6%). In summary, among liver transplant candidates not on prolonged dialysis, SLK should be considered for those whose eGFR is always <30 and diabetic candidates whose weighted mean eGFR is <30 for 90 days.

Wait List Death and Survival Benefit of Kidney Transplantation Among Nonrenal Transplant Recipients

The disparity between the number of patients waiting for kidney transplantation and the limited supply of kidney allografts has renewed interest in the benefit from kidney transplantation experienced by different groups. This study evaluated kidney transplant survival benefit in prior nonrenal transplant recipients (kidney after liver, KALi; lung, KALu; heart, KAH) compared to primary isolated (KA1) or repeat isolated kidney (KA2) transplant. Multivariable Cox regression models were fit using UNOS data for patients wait listed and transplanted from 1995 to 2008. Compared to KA1, the risk of death on the wait list was lower for KA2 (p < 0.001;HR = 0.84;CI = 0.81–0.88), but substantially higher for KALu (p < 0.001; HR = 3.80;CI = 3.08–4.69), KAH (p < 0.001; HR = 1.92; CI = 1.66–2.22), and KALi (p < 0.001; HR = 2.69; CI = 2.46–2.95). Following kidney transplant, patient survival was greatest for KA1, similar among KA2, KALi, KAH, and inferior for KALu. Compared to the entire wait list, renal transplantation was associated with a survival benefit among all groups except KALu (p = 0.017; HR = 1.61; CI = 1.09–2.38), where posttransplant survival was inferior to the wait list population. Recipients of KA1 kidney transplantation have the greatest posttransplant survival and compared to the overall kidney wait list, the greatest survival benefit.

Improving Organ Utilization to Help Overcome the Tragedies of the Opioid Epidemic.

Death rates from drug overdoses have nearly doubled since 2003, with over 47 000 deaths in 2014. This is largely attributable to the opioid epidemic. If the unfortunate deaths of otherwise healthy people have yielded an increase in organ donors, then this might serve as perhaps the only comforting factor among this tragic and unnecessary loss of life. In this viewpoint, we present data from the Organ Procurement and Transplantation Network (OPTN) that show how the greatest relative increases in the mechanism of death among deceased donors from 2003 to 2014 were drug overdoses. Unfortunately, despite the absolute increase in the number of donors who died from a drug overdose, the mean organ yield was significantly lower than in other categories, in part due to concerns about disease transmission. In this paper, we present data on the changes in donation from donors with a drug overdose as a result of the opioid epidemic and discuss the need to educate transplant candidates and their physicians about the low risk of disease transmission compared to the greater risk of dying on a transplant waitlist.

New Solutions to Reduce Discard of Kidneys Donated for Transplantation

Kidney transplantation is a cost-saving treatment that extends the lives of patients with ESRD. Unfortunately, the kidney transplant waiting list has ballooned to over 100,000 Americans. Across large areas of the United States, many kidney transplant candidates spend over 5 years waiting and often die before undergoing transplantation. However, more than 2500 kidneys (>17% of the total recovered from deceased donors) were discarded in 2013, despite evidence that many of these kidneys would provide a survival benefit to wait-listed patients. Transplant leaders have focused attention on transplant center report cards as a likely cause for this discard problem, although that focus is too narrow. In this review, we examine the risks associated with accepting various categories of donated kidneys, including discarded kidneys, compared with the risk of remaining on dialysis. With the goal of improving access to kidney transplant, we describe feasible proposals to increase acceptance of currently discarded organs.

Early Rehospitalization After Kidney Transplantation: Assessing Preventability and Prognosis

Early rehospitalization after kidney transplantation (KT) is common and may predict future adverse outcomes. Previous studies using claims data have been limited in identifying preventable rehospitalizations. We assembled a cohort of 753 adults at our institution undergoing KT from January 1, 2003 to December 31, 2007. Two physicians independently reviewed medical records of 237 patients (32%) with early rehospitalization and identified (1) primary reason for and (2) preventability of rehospitalization. Mortality and graft failure were ascertained through linkage to the Scientific Registry of Transplant Recipients. Leading reasons for rehospitalization included surgical complications (15%), rejection (14%), volume shifts (11%) and systemic and surgical wound infections (11% and 2.5%). Reviewer agreement on primary reason (85% of cases) was strong (kappa = 0.78). Only 19 rehospitalizations (8%) met preventability criteria. Using logistic regression, weekend discharge (odds ratio [OR] 1.59, p = 0.01), waitlist time (OR 1.10, p = 0.04) and longer initial length of stay (OR 1.42, p = 0.03) were associated with early rehospitalization. Using Cox regression, early rehospitalization was associated with mortality (hazard ratio [HR] 1.55; p = 0.03) but not graft loss (HR 1.33; p = 0.09). Early rehospitalization has diverse causes and presents challenges as a quality metric after KT. These results should be validated prospectively at multiple centers to identify vulnerable patients and modifiable processes‐of‐care.

Increased Early Graft Failure in Right-Sided Living Donor Nephrectomy

Background. Laparoscopic donor nephrectomy (LDN) is well established; however, there is concern about early graft loss because of technical issues with right-sided LDN. Prior studies on the subject were mostly single centered and not powered to detect clinically significant differences in allograft failure. Method. We conducted a retrospective cohort study of recipients of live donor kidney transplants using national registry data. The primary endpoint was 90-day allograft failure. Multivariable logistic regression analyses were stratified as overall live donor transplantation, transplantation after LDN, and transplantation after open donor nephrectomy (ODN). Results. Between 2001 and 2006, a total of 2555 right LDNs, 25,387 left LDNs, 2496 right ODNs, and 5552 left ODNs were performed. For the entire cohort compared with ODN, LDN was not associated with early allograft loss (odds ratio [OR]=0.94, P=0.4); however, right-sided nephrectomy increased the risk of allograft loss (OR=1.49, P<0.01). When stratified by procedure type, right LDN (OR=1.58, P<0.01) and right ODN (OR=1.38, P=0.02) demonstrated an association with increased risk of graft failure compared with the left side. The observed risk of allograft failure with right-sided LDN was 3.8% vs. 2.5% with left-sided LDN. Conclusion. Right-sided donor nephrectomy is associated with a small increased risk of allograft failure regardless of open or laparoscopic approach. However, the low observed risk of allograft failure with right-sided nephrectomy suggests that recovering the right kidney is a reasonable option for donors with contraindications for donating the left kidney.

Class-Specific Histone/Protein Deacetylase Inhibition Protects Against Renal Ischemia Reperfusion Injury and Fibrosis Formation

Renal ischemia‐reperfusion injury (IRI) is a common cause of renal dysfunction and renal failure. Histone/protein deacetylases (HDACs) regulate gene accessibility and higher order protein structures and may alter cellular responses to a variety of stresses. We investigated whether use of pan‐ and class‐specific HDAC inhibitors (HDACi) could improve IRI tolerance in the kidney. Using a model of unilateral renal IRI, we investigated early renal function after IRI, and calculated fibrosis after IRI using an automated scoring system. We found that pan‐HDAC inhibition using trichostatin (TSA) yielded significant renal functional benefit at 24–96 hours (p < 0.001). Treated mice developed significantly less fibrosis at 30 days (p < 0.0004). Class I HDAC inhibition with MS‐275 yielded similar effects. Protection from fibrosis formation was also noted in a cold ischemia transplant model (p < 0.008) with a trend toward improved cold ischemic survival in TSA‐treated mice. These effects were not accompanied by induction of typical ischemic tolerance pathways or by priming of heat shock protein expression. In fact, heat shock protein 70 deletion or overexpression did not alter renal ischemia tolerance. Micro‐RNA 21, known to be enhanced in vitro in renal tubular cells that survive stress, was enhanced by treatment with HDACi, pointing to possible mechanism.