CD4+ T cell immunity is dependent on an intrinsic stem-like program.

CD4+ T cells are central to various immune responses, but the molecular programs that drive and maintain CD4+ T cell immunity are not entirely clear. Here we identify a stem-like program that governs the CD4+ T cell response in transplantation models. Single-cell-transcriptomic analysis revealed that naive alloantigen-specific CD4+ T cells develop into TCF1hi effector precursor (TEP) cells and TCF1-CXCR6+ effectors in transplant recipients. The TCF1-CXCR6+CD4+ effectors lose proliferation capacity and do not reject allografts upon adoptive transfer into secondary hosts. By contrast, the TCF1hiCD4+ TEP cells have dual features of self-renewal and effector differentiation potential, and allograft rejection depends on continuous replenishment of TCF1-CXCR6+ effectors from TCF1hiCD4+ TEP cells. Mechanistically, TCF1 sustains the CD4+ TEP cell population, whereas the transcription factor IRF4 and the glycolytic enzyme LDHA govern the effector differentiation potential of CD4+ TEP cells. Deletion of IRF4 or LDHA in T cells induces transplant acceptance. These findings unravel a stem-like program that controls the self-renewal capacity and effector differentiation potential of CD4+ TEP cells and have implications for T cell-related immunotherapies.

Long-Term Follow-Up of Renal Transplant Recipients Treated With IVIG for De Novo Donor-Specific Antibodies.

BACKGROUND: Renal allograft survival is negatively affected by the development of de novo posttransplant donor-specific antibodies (dnDSA). We sought to determine whether treatment with intravenous immunoglobulin (IVIG) could remove or reduce the intensity of dnDSA. METHODS: A single-center study of 12 recipients with dnDSA and stable function who received IVIG 1 g/kg monthly for 6 months were compared with a contemporaneous cohort of 24 recipients with dnDSA who did not receive IVIG. RESULTS: The median time to first dnDSA was 6 months (interquartile range [IQR], 1-12), and follow-up was 83 months (IQR, 58-94) posttransplant. Resolution of dnDSA occurred in 27% of IVIG vs 46% of control recipients (P = .48). Fifty-eight percent of recipients in both cohorts demonstrated a reduction in the intensity of the dominant DSA at last follow-up (P =1.0). A reduction in the number of dnDSAs occurred in 58% vs 62% of the IVIG and control cohorts, respectively (P = .81). Post-dnDSA, acute rejection occurred in 8% of the IVIG vs 42% in the control group (P = .06). Forty-two percent of IVIG-treated vs 49% of control recipients had a deterioration in function from first dnDSA until most recent follow-up (P = .81). Actuarial graft survivals were equivalent between groups. CONCLUSIONS: IVIG treatment of dnDSA in recipients with stable graft function had no impact on DSA clearance or MFI reduction, but this outcome may also be owing to sample size. Larger studies or alternate dosing regimens may be required to determine if there is any role for the use of IVIG as a treatment for dnDSA.

Outcomes of kidney transplantation using deceased donors with history of diabetes.

Deceased diabetic kidneys are increasingly utilized in transplantation. The relationship of donor's history of diabetes to clinical and histological outcomes was examined. Forty-nine diabetic deceased donor kidneys (D-DM) were transplanted into 26 normal (R-N/D-DM) and 23 diabetic recipients (R-DM/D-DM) and compared to 211 diabetic recipients of normal kidneys(R-DM/D-N) and 466 normal recipients of normal kidneys (R-N/D-N). Patient survival at 5 years was 89.7% in R-N/D-N, 96.2% in R-N/D-DM, 80.1% in R-DM/D-N, and a 71.6% in R-DM/D-DM (P = .008). Death-censored graft survival at 5 years was 86.3% in R-N/D-N, 87.4% in R-N/D-DM, 93.5% in R-DM/D-N, and 87.5% in R-DM/D-DM (P = .24). Multivariable regression analysis showed that compared to non-diabetic recipients, diabetic recipients had a 2- to 3-fold increased risk of mortality. In this cohort, there was no impact on death-censored graft survival of diabetic donor status. Only 6 of 26 post-perfusion biopsies showed evidence of diabetic nephropathy (

A prospective multicenter observational study of cell-mediated immunity as a predictor for cytomegalovirus infection in kidney transplant recipients.

T cell immunity is essential for the control of cytomegalovirus (CMV) infection after transplantation. We evaluated a CMV-specific peptide-based enzyme-linked immunosorbent spot (ELISPOT) assay to determine whether assay results could predict subsequent CMV events. Adult kidney transplant recipients at 43 centers underwent ELISPOT testing to enumerate interferon gamma (IFN-γ) binding spot-forming units (sfu) after stimulation of cells with an overlapping peptide pool of CMV phosphoprotein 65 (pp65) and immediate early-1 (IE-1) protein at the end of antiviral prophylaxis (EOP) and various time points thereafter. The primary outcome was a CMV event in the first posttransplant year. In 583 kidney transplant recipients (260 seropositive donor [D+]/seronegative recipient [R-] and 277 R+), CMV events occurred in 44 of 368 eligible patients (11.8%) at a median of 227 days (range 92-360) posttransplant. A cutoff value of >40 sfu/2.5 × 105  cells for either IE-1 or pp65 was derived as a threshold for positivity, with a negative predictive value of >97% for CMV events. CMV events were significantly lower in assay positive vs assay negative patients (3.0% vs 19.5%, P < .0001 for pp65). Time to CMV event post-EOP was significantly greater in those with sfu >40 at EOP (P < .0001). In this large, multicenter trial of kidney transplant recipients, we show that an assessment of CMV-specific immunity using a novel ELISPOT assay is able to predict protection from CMV infection.

Hospital readmissions following HLA-incompatible live donor kidney transplantation: A multi-center study.

Thirty percent of kidney transplant recipients are readmitted in the first month posttransplantation. Those with donor-specific antibody requiring desensitization and incompatible live donor kidney transplantation (ILDKT) constitute a unique subpopulation that might be at higher readmission risk. Drawing on a 22-center cohort, 379 ILDKTs with Medicare primary insurance were matched to compatible transplant-matched controls and to waitlist-only matched controls on panel reactive antibody, age, blood group, renal replacement time, prior kidney transplantation, race, gender, diabetes, and transplant date/waitlisting date. Readmission risk was determined using multilevel, mixed-effects Poisson regression. In the first month, ILDKTs had a 1.28-fold higher readmission risk than compatible controls (95% confidence interval [CI] 1.13-1.46; P < .001). Risk peaked at 6-12 months (relative risk [RR] 1.67, 95% CI 1.49-1.87; P < .001), attenuating by 24-36 months (RR 1.24, 95% CI 1.10-1.40; P < .001). ILDKTs had a 5.86-fold higher readmission risk (95% CI 4.96-6.92; P < .001) in the first month compared to waitlist-only controls. At 12-24 (RR 0.85, 95% CI 0.77-0.95; P = .002) and 24-36 months (RR 0.74, 95% CI 0.66-0.84; P < .001), ILDKTs had a lower risk than waitlist-only controls. These findings of ILDKTs having a higher readmission risk than compatible controls, but a lower readmission risk after the first year than waitlist-only controls should be considered in regulatory/payment schemas and planning clinical care.

The Incremental Cost of Incompatible Living Donor Kidney Transplantation: A National Cohort Analysis.

Incompatible living donor kidney transplantation (ILDKT) has been established as an effective option for end-stage renal disease patients with willing but HLA-incompatible living donors, reducing mortality and improving quality of life. Depending on antibody titer, ILDKT can require highly resource-intensive procedures, including intravenous immunoglobulin, plasma exchange, and/or cell-depleting antibody treatment, as well as protocol biopsies and donor-specific antibody testing. This study sought to compare the cost and Medicare reimbursement, exclusive of organ acquisition payment, for ILDKT (n = 926) with varying antibody titers to matched compatible transplants (n = 2762) performed between 2002 and 2011. Data were assembled from a national cohort study of ILDKT and a unique data set linking hospital cost accounting data and Medicare claims. ILDKT was more expensive than matched compatible transplantation, ranging from 20% higher adjusted costs for positive on Luminex assay but negative flow cytometric crossmatch, 26% higher for positive flow cytometric crossmatch but negative cytotoxic crossmatch, and 39% higher for positive cytotoxic crossmatch (p < 0.0001 for all). ILDKT was associated with longer median length of stay (12.9 vs. 7.8 days), higher Medicare payments ($91 330 vs. $63 782 p < 0.0001), and greater outlier payments. In conclusion, ILDKT increases the cost of and payments for kidney transplantation.

Early clearance vs persistence of de novo donor-specific antibodies following lung transplantation.

BACKGROUND: The natural history of de novo donor-specific antibodies (dnDSA) after lung transplantation is not well-described. We sought to determine the incidence and risk factors associated with dnDSA and compare outcomes between recipients with transient (or isolated) vs persistent dnDSA after transplantation. METHODS: A single-center review of all lung transplants from 1/2009-7/2013. DSAs were tested eight times in the first year and every 4 months thereafter. Outcomes examined included acute rejection and graft failure. RESULTS: Median follow-up was 18 months (range: 1-61 months), and 24.6% of 333 first-time lung-only transplant recipients developed a dnDSA. Ethnicity, HLA-DQ mismatches, post-transplantation platelet transfusion and Lung Allocation Score >60 were associated with dnDSA (P<.05). Overall graft survival was worse for dnDSA-positive vs negative recipients (P=.025). Of 323 recipients with 1-year follow-up, 72 (22.2%) developed dnDSA, and in 25 (34.7%), the dnDSA was transient and cleared. Recipients with transient dnDSA were less likely to develop acute rejection than those with persistent dnDSA (P=.007). CONCLUSIONS: Early post-lung transplantation, dnDSA occurred in 1/4 of recipients, was associated with peri-transplant risk factors and resulted in decreased survival. Spontaneous clearance of dnDSA, seen in one-third of recipients, was associated with a lower risk of acute rejection.

A Double-Blind, Double-Dummy, Flexible-Design Randomized Multicenter Trial: Early Safety of Single- Versus Divided-Dose Rabbit Anti-Thymocyte Globulin Induction in Renal Transplantation.

A previous nonblinded, randomized, single-center renal transplantation trial of single-dose rabbit anti-thymocyte globulin induction (SD-rATG) showed improved efficacy compared with conventional divided-dose (DD-rATG) administration. The present multicenter, double-blind/double-dummy STAT trial (Single dose vs. Traditional Administration of Thymoglobulin) evaluated SD-rATG versus DD-rATG induction for noninferiority in early (7-day) safety and tolerability. Ninety-five patients (randomized 1:1) received 6 mg/kg SD-rATG or 1.5 mg/kg/dose DD-rATG, with tacrolimus-mycophenolate maintenance immunosuppression. The primary end point was a composite of fever, hypoxia, hypotension, cardiac complications, and delayed graft function. Secondary end points included 12-month patient survival, graft survival, and rejection. Target enrollment was 165 patients with an interim analysis scheduled after 80 patients. Interim analysis showed primary end point noninferiority of SD-rATG induction (p = 0.6), and a conditional probability of <1.73% of continued enrollment producing a significant difference (futility analysis), leading to early trial termination. Final analysis (95 patients) showed no differences in occurrence of primary end point events (p = 0.58) or patients with no, one, or more than one event (p = 0.81), or rejection, graft, or patient survival (p = 0.78, 0.47, and 0.35, respectively). In this rigorously blinded trial in adult renal transplantation, we have shown SD-rATG induction to be noninferior to DD-rATG induction in early tolerability and equivalent in 12-month safety. (Clinical Trials.gov #NCT00906204.).

The mean dietary protein intake at different stages of chronic kidney disease is higher than current guidelines.

The actual dietary protein intake of adults without and with different stages of chronic kidney disease is not known. To evaluate this we performed cross-sectional analyses of 16,872 adults (20 years of age and older) participating in the National Health and Nutrition Examination Survey 2001-2008 who completed a dietary interview by stage of kidney disease. Dietary protein intake was assessed from 24-h recall systematically collected using the Automated Multiple Pass Method. Complex survey analyses were used to derive population estimates of dietary protein intake at each stage of chronic kidney disease. Using dietary protein intake of adults without chronic kidney disease as the comparator, and after adjusting for age, the mean dietary protein intake was 1.30 g/kg ideal body weight/day (g/kgIBW/d) and was not different from stage 1 or stage 2 (1.28 and 1.25 g/kgIBW/d, respectively), but was significantly different in stage 3 and stage 4 (1.22 and 1.13 g/kgIBW/d, respectively). These mean values appear to be above the Institute of Medicine requirements for healthy adults and the NKF-KDOQI guidelines for stages 3 and 4 chronic kidney disease. Thus, the mean dietary protein intake is higher than current guidelines, even after adjusting for age.

Rabbit antithymocyte induction and dosing in deceased donor renal transplant recipients over 60 yr of age.

BACKGROUND: Antithymocyte globulin (rATG) is a commonly used induction agent in renal transplantation; however, data in older kidney recipients are limited. METHODS: We reviewed charts of 301 deceased donor renal transplants who received a protocol consisting of 3-7 doses of rATG and triple maintenance therapy. Outcomes of patients >60 yr of age (n = 45) were compared to those aged 18-59 yr (n = 256). RESULTS: Older recipients had more diabetics, were more likely to receive expanded criteria donor kidneys (p < 0.01), and over 30% were sensitized. Recipients >60 received less cumulative rATG (4.6 vs. 5.1 mg/kg; p < 0.01). Three-yr acute rejection was lower in the >60 group (2% vs. 16%, p < 0.01) although glomerular filtration rates were similar between groups. Actuarial graft survival was similar; however, patient survival in the >60 group at three yr was lower (80% vs. 95%; p = 0.02). Specifically, patients >60 with delayed graft function and rATG cumulative dosing >6 mg/kg had a survival of <50% by two yr. CONCLUSION: Recipients over 60 yr receiving rATG induction have acceptable renal function and a low risk of rejection; however, reduced survival was noted among those receiving >6 mg/kg. These data suggest that when used, lower cumulative dosages of rATG are preferable in the older recipient.

Cardioprotective medication use after renal transplantation.

Cardiovascular disease is the leading cause of death in renal transplant patients. This study compares the use of cardioprotective medications in adult kidney transplant recipients at a single center with recommendations, which have been validated in the general population. Cardioprotective medication use was retrospectively collected post-renal transplant. Patients were defined as high risk if they had pre-transplant coronary heart disease or equivalent risk. "Optimal" treatment was defined as a patient receiving aspirin, statin, angiotensin-converting enzyme inhibitors/angiotensin receptor blocker, and a beta-blocker according to cardiovascular risk. The percentage of high-risk patients optimally treated at one, three, six, and 12 months was 7.7%, 11.5%, 17.6%, and 18.8%, respectively. Although the use of cardioprotective medications was evident in transplant recipients, opportunities exist to increase the use of optimal cardioprotective regimens after renal transplantation.

Mini-incision living donors nephrectomy using anterior muscle-splitting approach with hybrid technique.

BACKGROUND: Significant morbidity is associated with standard open flank living donor nephrectomy. Laparoscopic donor nephrectomy is criticized for a steep learning curve and a tendency to avoid the right kidney. The anterior muscle-splitting technique uses principles or advantages of an open extraperitoneal approach with minimal morbidity and the advantageous muscle-splitting (instead of cutting) procedure. OBJECTIVE: To compare mini-incision laparoscopic instrument-assisted (MILIA) live donor nephrectomy using a muscle-splitting technique to the standard open-flank donor nephrectomy (ODN) approach for efficacy and safety. METHODS: MILIA living donor nephrectomies were performed in 119 donors and compared to a cohort of open-flank nephrectomy donors (n=38) from the same center. Both donor groups were matched for body mass index as well as other personal characteristics. RESULTS: The mean donor age was 35 (range: 18-60) years. The right kidney was procured in 28% of cases. The majority of donors were female (58%) and Caucasian (60%). No differences were observed between MILIA and ODN donors for the age, gender and ethnicity. However, MILIA donors experienced a longer mean±SD operative time (234±47 vs. 197±33 min, p<0.0001) but a shorter hospital stay (4±1 vs. 6±3 days for the ODN group, p<0.0001) and less intraoperative blood loss (215±180 vs. 331±397 mL, p<0.02). No difference was found in the number of units of blood transfused (0.13±0.6 vs. 0.34±1.0 units, p=0.13). Right-sided kidneys were almost equally harvested in both groups (29% of MILIA donors vs. 26% of ODN donors). Post-operatively, MILIA donors had a significantly lower mean pain scores at one week and one month after surgery (p<0.001). They showed significant better post-operative recovery-earlier stopping of pain medications and restoration of other preoperative activities. Moreover, they were better satisfied with their scar appearance. Scores on the short form-36 quality of life questionnaire were comparable for both groups. CONCLUSION: MILIA is a viable option as an alternative for pure laparoscopic donor nephrectomy. MILIA appears to be as safe as open donor nephrectomy and may provide advantages over ODN, such as smaller incision, shorter hospital stay, and less incisional pain. Patient recovery and satisfaction after MILIA are excellent. This technique avoids the possibility of adhesive intestinal obstruction and also improves handling of major complications (e.g., bleeding) of laparoscopic donor nephrectomy. Utilization of this hybrid technique is particularly feasible on smaller (BMI<24 kg/m(2)) and medium-sized (BMI<28 kg/m(2)) donors. We believe that this technique should be adopted by centers that have limited advanced laparoscopic surgical experience and also it could be used selectively for the right donor nephrectomies, even in centers performing hand assisted donor nephrectomies by including a small patch of inferior vena cava for a better quality of right donor kidney during transplantation.

Five years' experience with thymoglobulin induction in a pediatric renal transplant population.

Antibody induction therapy is used in the majority of pediatric patients undergoing renal transplantation. Our center has previously reported short-term outcomes with TMG as induction therapy. We now present our experience over the last five yr. Patients received TMG intra- and post-operatively at a dose of 1.5 mg/kg/day. The dose was decreased to 0.75 mg/kg/day or held dependent on the patient's WBC and platelet counts. Post-transplant immunosuppression also included corticosteroids, MMF, and either TAC or CSA. Patient and graft survival, number of acute rejection episodes, creatinine clearance, incidence and type of infections, and trough levels of calcineurin inhibitor drugs were monitored during the follow-up period. Thirty-four renal transplants were performed in 33 pediatric patients ranging in age from 1.7 to 17.8 yr. Seventeen rejection episodes occurred during the time of follow-up with three patients having more than one episode, but only three episodes occurred within the first year after transplantation. Three patients had graft loss in the first week after transplantation from primary non-function (1) or technical failure/thrombosis (2). Graft losses occurred in seven additional patients during the time of follow-up with the first loss occurring at 17.7 months. Among patients with functional grafts at one wk after transplant, graft survival at one and three yr was 100% and 73% respectively. There were no patient deaths. There were no cases of post-transplant lymphoproliferative disease or other malignancy. One patient had symptomatic CMV disease. TMG is safe and effective as induction therapy in pediatric renal transplant patients. Late graft loss remains a challenge in the pediatric patient population, particularly in adolescents.

Insulin independence achieved using the transmesenteric approach to the portal vein for islet transplantation.

Clinical human islet transplantation has been performed successfully using a percutaneous transhepatic approach to access the portal vein. The risks from percutaneous delivery of islets, such as bleeding and puncturing neighboring structures, can be avoided by a transmesenteric approach to the portal vein, which we have used to stent completely or near-completely occluded portal veins in both cirrhotic and noncirrhotic patients with minimum morbidity. After minilaparotomy, a second-order tributary branch of the mesenteric vein is cannulated to provide endovascular access to the portal vein. The islet preparation is infused through a catheter directed under fluoroscopy from the mesenteric vein to the portal vein. Pre- and postinfusion portograms are obtained to confirm the absence of any interval changes in portal venous flow. We have performed this procedure successfully in three islet-transplant recipients each receiving two infusions on separate occasions, with some of these procedures performed under local anesthesia without complications. The transmesenteric approach promises to be a safe alternative to percutaneous islet delivery.

Short-term outcomes of Thymoglobulin induction in pediatric renal transplant recipients.

No data are currently available that describe the clinical outcomes associated with Thymoglobulin (rabbit polyclonal anti-thymocyte globulin) induction in pediatric renal transplant recipients. We report the outcomes of 17 pediatric renal transplant recipients (mean age 10.1+/-5.2 years) transplanted between 1 August 1999 and 31 July 2001. Eleven patients (65%) were Caucasian and 6 (35%) were African-American. Eleven (65%) recipients received cadaveric allografts. Two patients (12%) were second allograft recipients. One patient had primary allograft non-function secondary to vascular thrombosis. Two patients (12%) had delayed allograft function. Immunosuppression consisted of Thymoglobulin induction (mean number of doses 6+/-1.7) with tacrolimus (62%) or cyclosporine A (38%), mycophenolate mofetil, and prednisone. One year post transplant, patient and graft survival was 100% and 93%, respectively. No acute rejection episodes occurred during the first 6 months after transplantation in any of the recipients. Additionally, no rejection episode occurred among the 14 patients followed for 1 year after transplant. The incidences of asymptomatic cytomegalovirus (CMV) and Epstein-Barr virus (EBV) seroconversion at 1 year in seronegative recipients with a seropositive donor were 100% of 4 patients and 0% of 4 patients, respectively. No symptomatic CMV or EBV infections and no post-transplant lymphoproliferative disease have occurred in any patient. These short-term data suggest that Thymogobulin induction is safe and effective in combination with triple immunosuppressive therapy for preventing early rejection in pediatric renal transplant recipients.

Choice of surgical technique influences perioperative outcomes in liver transplantation.

OBJECTIVE: To examine how the choice of surgical technique influenced perioperative outcomes in liver transplantation. SUMMARY BACKGROUND DATA: The standard technique of orthotopic liver transplantation with venovenous bypass (VVB) is commonly used to facilitate hemodynamic stability. However, this traditional procedure is associated with unique complications that can be avoided by using the technique of liver resection without caval excision (the piggyback technique). METHODS: A prospective comparison of the two procedures was conducted in 90 patients (34 piggyback and 56 with VVB) during a 2.5-year period. Although both groups had similar donor and recipient demographic characteristics, posttransplant outcomes were significantly better for the patients undergoing the piggyback technique. The effect of surgical technique was examined using a stepwise approach that considered its impact on two levels of perioperative and postoperative events. RESULTS: The analysis of the first level of perioperative events found that the piggyback procedure resulted in a 50% decrease in the duration of the anhepatic phase. The analysis of the second level of perioperative events found a significant relation between the anhepatic phase and the duration of surgery and between the anhepatic phase and the need for blood replacement. The analysis of the first level of postoperative events found that the intensive care unit stay was significantly related to both the duration of surgery and the need for blood replacement. The intensive care unit stay was in turn related to the second level of postoperative events, namely the length of hospital stay. Finally, total charges were directly related to length of hospital stay. The overall 1-year actuarial patient and graft survival rates were 94% in the piggyback and 96% in the VVB groups, respectively. CONCLUSIONS: These data demonstrate that surgical choices in complex procedures such as orthotopic liver transplantation trigger a chain of events that can significantly affect resource utilization. In the current healthcare climate, examination of the sequence of events that follow a specific treatment may provide a more complete framework for choosing between treatment alternatives.