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1.
J Thorac Cardiovasc Surg ; 167(3): 1077-1087.e13, 2024 Mar.
Article in English | MEDLINE | ID: mdl-36990918

ABSTRACT

OBJECTIVE: Assessing heart transplant program quality using short-term survival is insufficient. We define and validate the composite metric textbook outcome and examine its association with overall survival. METHODS: We identified all primary, isolated adult heart transplants in the United Network for Organ Sharing/Organ Procurement and Transplantation Network Standard Transplant Analysis and Research files from May 1, 2005, to December 31, 2017. Textbook outcome was defined as length of stay 30 days or less; ejection fraction greater than 50% during 1-year follow-up; functional status 80% to 100% at 1 year; freedom from acute rejection, dialysis, and stroke during the index hospitalization; and freedom from graft failure, dialysis, rejection, retransplantation, and mortality during the first year post-transplant. Univariate and multivariate analyses were performed. Factors independently associated with textbook outcome were used to create a predictive nomogram. Conditional survival at 1 year was measured. RESULTS: A total of 24,620 patients were identified with 11,169 (45.4%, 95% confidence interval, 44.7-46.0) experiencing textbook outcome. Patients with textbook outcome were more likely free from preoperative mechanical support (odds ratio, 3.504, 95% confidence interval, 2.766 to 4.439, P < .001), free from preoperative dialysis (odds ratio, 2.295, 95% confidence interval, 1.868-2.819, P < .001), to be not hospitalized (odds ratio, 1.264, 95% confidence interval, 1.183-1.349, P < .001), to be nondiabetic (odds ratio, 1.187, 95% confidence interval, 1.113-1.266, P < .001), and to be nonsmokers (odds ratio, 1.160, 95% confidence interval,1.097-1.228, P < .001). Patients with textbook outcome have improved long-term survival relative to patients without textbook outcome who survive at least 1 year (hazard ratio for death, 0.547, 95% confidence interval, 0.504-0.593, P < .001). CONCLUSIONS: Textbook outcome is an alternative means of examining heart transplant outcomes and is associated with long-term survival. The use of textbook outcome as an adjunctive metric provides a holistic view of patient and center outcomes.


Subject(s)
Heart Transplantation , Renal Dialysis , Adult , Humans , Treatment Outcome , Heart Transplantation/adverse effects , Proportional Hazards Models , Multivariate Analysis , Graft Survival , Retrospective Studies
2.
JAMA Surg ; 159(2): 211-218, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38055245

ABSTRACT

Importance: Liver malignancies are an increasing global health concern with a high mortality. We review outcomes following liver transplant for primary and secondary hepatic malignancies. Observations: Transplant may be a suitable treatment option for primary and secondary hepatic malignancies in well-selected patient populations. Conclusions and Relevance: Many patients with primary or secondary liver tumors are not eligible for liver resection because of advanced underlying liver disease or high tumor burden, precluding complete tumor clearance. Although liver transplant has been a long-standing treatment modality for patients with hepatocellular carcinoma, recently transplant has been considered for patients with other malignant diagnoses. In particular, while well-established for hepatocellular carcinoma and select patients with perihilar cholangiocarcinoma, transplant has been increasingly used to treat patients with intrahepatic cholangiocarcinoma, as well as metastatic disease from colorectal liver and neuroendocrine primary tumors. Because of the limited availability of grafts and the number of patients on the waiting list, optimal selection criteria must be further defined. The ethics of organ allocation to individuals who may benefit from prolonged survival after transplant yet have a high incidence of recurrence, as well as the role of living donation, need to be further discerned in the setting of transplant oncology.


Subject(s)
Bile Duct Neoplasms , Carcinoma, Hepatocellular , Cholangiocarcinoma , Liver Neoplasms , Liver Transplantation , Neuroendocrine Tumors , Humans , Carcinoma, Hepatocellular/surgery , Liver Transplantation/adverse effects , Liver Neoplasms/secondary , Cholangiocarcinoma/surgery , Neuroendocrine Tumors/secondary , Bile Ducts, Intrahepatic
3.
Medicina (Kaunas) ; 59(7)2023 Jul 13.
Article in English | MEDLINE | ID: mdl-37512101

ABSTRACT

Transplant oncology is a relatively new field in which transplantation is used to treat patients who would otherwise be unresectable. New anticancer treatment paradigms using tumor and transplant immunology and cancer immunogenomics are emerging. In turn, liver transplantation (LT) has become a potential therapy for certain patients with colorectal cancer (CRC) with liver metastasis, hepatocellular (HCC), cholangiocarcinoma (CCA), and metastatic neuroendocrine tumor (NET) of the liver. Although there are established criteria for LT in HCC, evidence regarding LT as a treatment modality for certain gastrointestinal malignancies is still debated. The aim of this review is to highlight updates in the role of LT for certain malignancies, including HCC, metastatic CRC, hilar CCA, and neuroendocrine tumor (NET), as well as contextualize LT use and discuss controversies in transplant oncology.


Subject(s)
Bile Duct Neoplasms , Carcinoma, Hepatocellular , Gastrointestinal Neoplasms , Liver Neoplasms , Liver Transplantation , Neuroendocrine Tumors , Humans , Liver Neoplasms/surgery , Liver Neoplasms/pathology , Carcinoma, Hepatocellular/pathology , Liver Transplantation/adverse effects , Expert Testimony , Treatment Outcome , Gastrointestinal Neoplasms/surgery , Gastrointestinal Neoplasms/pathology , Bile Ducts, Intrahepatic
4.
Vaccines (Basel) ; 11(7)2023 Jun 22.
Article in English | MEDLINE | ID: mdl-37514950

ABSTRACT

The COVID-19 pandemic poses a significant risk for immunosuppressed groups such as transplant patients. The purpose of this study was to improve our understanding of the impact of the COVID-19 pandemic on kidney transplant recipients, including their views on COVID-19 vaccination. Semi-structured interviews were conducted from December 2021 to August 2022 with 38 kidney transplant recipients who had an appointment with their transplant care team within the previous 6 months. We used qualitative thematic analysis to characterize the perspectives of interviewees. Regardless of COVID-19 vaccination status, most interviewees reported utilizing public health measures such as masking, hand washing, and avoiding crowds to protect themselves against COVID-19. Vaccinated interviewees (n = 31) noted that they chose to receive a COVID-19 vaccine because of their increased risk due to their immunocompromised state. For unvaccinated interviewees (n = 7), reasons for not receiving a COVID-19 vaccine included concerns about the safety and efficacy of the vaccine. Both vaccinated and unvaccinated interviewees expressed concerns about the lack of adequate testing of the vaccine in transplant patients and questioned if the vaccine might have unknown side effects for transplant recipients. Regardless of the vaccination status, most interviewees noted having trust in their healthcare team. Interviewees also described interpersonal tensions that arose during the pandemic, many of which surrounded vaccination and other preventive measures that were important to participants to protect their health. Together, these data demonstrate differing concerns and experiences related to the COVID-19 pandemic for vaccinated and unvaccinated transplant recipients. These findings highlight the unique needs of transplant recipients and reveal opportunities to support this vulnerable patient population in efforts to protect their health as the COVID-19 pandemic evolves.

5.
Am J Transplant ; 23(8): 1227-1240, 2023 08.
Article in English | MEDLINE | ID: mdl-37156300

ABSTRACT

Intracardiac thrombosis and/or pulmonary thromboembolism (ICT/PE) is a rare but devastating complication during liver transplantation. Its pathophysiology remains poorly understood, and successful treatment remains a challenge. This systematic review summarizes the available published clinical data regarding ICT/PE during liver transplantation. Databases were searched for all publications reporting on ICT/PE during liver transplantation. Data collected included its incidence, patient characteristics, the timing of diagnosis, treatment strategies, and patient outcomes. This review included 59 full-text citations. The point prevalence of ICT/PE was 1.42%. Thrombi were most often diagnosed during the neohepatic phase, particularly at allograft reperfusion. Intravenous heparin was effective in preventing early-stage thrombus from progressing further and restoring hemodynamics in 76.32% of patients it was utilized for; however, the addition of tissue plasminogen activator or sole use of tissue plasminogen activator offered diminishing returns. Despite all resuscitation efforts, the in-hospital mortality rate of an intraoperative ICT/PE was 40.42%, with nearly half of these patients dying intraoperatively. The results of our systematic review are an initial step for providing clinicians with data that can help identify higher-risk patients. The clinical implications of our results warrant the development of identification and management strategies for the timely and effective treatment of these tragic occurrences during liver transplantation.


Subject(s)
Heart Diseases , Liver Transplantation , Pulmonary Embolism , Thrombosis , Humans , Tissue Plasminogen Activator , Liver Transplantation/adverse effects , Liver Transplantation/methods , Thrombosis/etiology , Thrombosis/diagnosis , Pulmonary Embolism/diagnosis , Pulmonary Embolism/drug therapy , Pulmonary Embolism/etiology
6.
J Am Coll Surg ; 235(4): 624-642, 2022 10 01.
Article in English | MEDLINE | ID: mdl-36102576

ABSTRACT

BACKGROUND: Quality in kidney transplantation is measured using 1-year patient and graft survival. Because 1-year patient and graft survival exceed 95%, this metric fails to measure a spectrum of quality. Textbook outcomes (TO) are a composite quality metric offering greater depth and resolution. We studied TO after living donor (LD) and deceased donor (DD) kidney transplantation. STUDY DESIGN: United Network for Organ Sharing data for 69,165 transplant recipients between 2013 and 2017 were analyzed. TO was defined as patient and graft survival of 1 year or greater, 1-year glomerular filtration rate of greater than 40 mL/min, absence of delayed graft function, length of stay of 5 days or less, no readmissions during the first 6 months, and no episodes of rejection during the first year after transplantation. Bivariate analysis identified characteristics associated with TO, and covariates were incorporated into multivariable models. Five-year conditional survival was measured, and center TO rates were corrected for case complexity to allow center-level comparisons. RESULTS: The national average TO rates were 54.1% and 31.7% for LD and DD transplant recipients. The hazard ratio for death at 5 years for recipients who did not experience TO was 1.92 (95% CI 1.68 to 2.18, p ≤ 0.0001) for LD transplant recipients and 2.08 (95% CI 1.93 to 2.24, p ≤ 0.0001) for DD transplant recipients. Center-level comparisons identify 18% and 24% of centers under-performing in LD and DD transplantation. High rates of TO do not correlate with transplantation center volume. CONCLUSION: Kidney transplant recipients who experience TO have superior long-term survival. Textbook outcomes add value to the current standards of 1-year patient and graft survival.


Subject(s)
Kidney Transplantation , Graft Survival , Humans , Living Donors , Proportional Hazards Models
7.
Ann Surg ; 276(5): 846-853, 2022 11 01.
Article in English | MEDLINE | ID: mdl-35894433

ABSTRACT

OBJECTIVE: To define benchmark values for liver transplantation (LT) in patients with perihilar cholangiocarcinoma (PHC) enabling unbiased comparisons. BACKGROUND: Transplantation for PHC is used with reluctance in many centers and even contraindicated in several countries. Although benchmark values for LT are available, there is a lack of specific data on LT performed for PHC. METHODS: PHC patients considered for LT after Mayo-like protocol were analyzed in 17 reference centers in 2 continents over the recent 5-year period (2014-2018). The minimum follow-up was 1 year. Benchmark patients were defined as operated at high-volume centers (≥50 overall LT/year) after neoadjuvant chemoradiotherapy, with a tumor diameter <3 cm, negative lymph nodes, and with the absence of relevant comorbidities. Benchmark cutoff values were derived from the 75th to 25th percentiles of the median values of all benchmark centers. RESULTS: One hundred thirty-four consecutive patients underwent LT after completion of the neoadjuvant treatment. Of those, 89.6% qualified as benchmark cases. Benchmark cutoffs were 90-day mortality ≤5.2%; comprehensive complication index at 1 year of ≤33.7; grade ≥3 complication rates ≤66.7%. These values were better than benchmark values for other indications of LT. Five-year disease-free survival was largely superior compared with a matched group of nodal negative patients undergoing curative liver resection (n=106) (62% vs 32%, P <0.001). CONCLUSION: This multicenter benchmark study demonstrates that LT offers excellent outcomes with superior oncological results in early stage PHC patients, even in candidates for surgery. This provocative observation should lead to a change in available therapeutic algorithms for PHC.


Subject(s)
Bile Duct Neoplasms , Cholangiocarcinoma , Klatskin Tumor , Liver Transplantation , Benchmarking , Cholangiocarcinoma/surgery , Humans , Klatskin Tumor/pathology , Klatskin Tumor/surgery , Standard of Care
8.
Case Rep Transplant ; 2022: 2058600, 2022.
Article in English | MEDLINE | ID: mdl-35637902

ABSTRACT

Complications are a part of surgery. Spinal infarctions are a dreaded complication of aortic surgery. We present a patient who developed a spinal infarct after a kidney transplant. We were unable to find a causative factor in our search for etiology. In our review of the literature, we were unable to find a similar report. We present this case report to highlight a rare complication of kidney transplantation and to reinforce that patients requiring kidney transplant are complex patients with multiple comorbidities that can cause a multitude of complications in the periop period.

9.
Transplant Direct ; 8(5): e1322, 2022 May.
Article in English | MEDLINE | ID: mdl-35464875

ABSTRACT

Quality in liver transplantation (LT) is currently measured using 1-y patient and graft survival. Because patient and graft survival rates now exceed 90%, more informative metrics are needed. Textbook outcomes (TOs) describe ideal patient outcomes after surgery. This study critically evaluates TO as a quality metric in LT. Methods: United Network for Organ Sharing data for 25 887 adult LT recipients were used to define TO as patient and graft survival >1 y, length of stay ≤10 d, 0 readmissions within 6 mo, absence of rejection, and bilirubin <3 mg/dL between months 2 and 12 post-LT. Univariate analysis identified donor and recipient characteristics associated with TO. Covariates were analyzed using purposeful selection to construct a multivariable model, and impactful variables were incorporated as linear predictors into a nomogram. Five-year conditional survival was tested, and center TO rates were corrected for case complexity to allow for center-level comparisons. Results: The national average TO rate is 37.4% (95% confidence interval, 36.8%-38.0%). The hazard ratio for death at 5 y for patients who do not experience TO is 1.22 (95% confidence interval, 1.11-1.34; P ≤ 0.0001). Our nomogram predicts TO with a C-statistic of 0.68. Center-level comparisons identify 31% of centers as high performing and 21% of centers as below average. High rates of TO correlate only weakly with center volume. Conclusions: The composite quality metric of TO after LT incorporates holistic outcome measures and is an important measure of quality in addition to 1-y patient and graft survival.

10.
Am J Transplant ; 22(7): 1901-1908, 2022 07.
Article in English | MEDLINE | ID: mdl-35182000

ABSTRACT

Liver allocation policy was changed to reduce variance in median MELD scores at transplant (MMaT) in February 2020. "Acuity circles" replaced local allocation. Understanding the impact of policy change on donor utilization is important. Ideal (I), standard (S), and non-ideal (NI) donors were defined. NI donors include older, higher BMI donors with elevated transaminases or bilirubin, history of hepatitis B or C, and all DCD donors. Utilization of I, S, and NI donors was established before and after allocation change and compared between low MELD (LM) centers (MMaT ≤ 28 before allocation change) and high MELD (HM) centers (MMaT > 28). Following reallocation, transplant volume increased nationally (67 transplants/center/year pre, 74 post, p .0006) and increased for both HM and LM centers. LM centers significantly increased use of NI donors and HM centers significantly increased use of I and S donors. Centers further stratify based on donor utilization phenotype. A subset of centers increased transplant volume despite rising MMaT by broadening organ acceptance criteria, increasing use of all donor types including DCD donors (98% increase), increasing living donation, and transplanting more frequently for alcohol associated liver disease. Variance in donor utilization can undermine intended effects of allocation policy change.


Subject(s)
End Stage Liver Disease , Liver Transplantation , Tissue and Organ Procurement , End Stage Liver Disease/surgery , Humans , Policy , Tissue Donors , Waiting Lists
11.
Transplant Proc ; 53(10): 3022-3029, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34772490

ABSTRACT

BACKGROUND: The aim of this review is to provide consensus on the impact of antihuman leukocyte antigen (anti-HLA) de novo donor-specific antibodies (dnDSA) on pancreatic allograft loss. METHODS: We systematically searched electronic databases through August 2020 using Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology. Articles that provided or allowed estimation of the odds ratio (OR) and 95% confidence interval (CI) for pancreatic allograft loss in patients with and without anti-HLA dnDSA were included. RESULTS: Eight studies with a total of 1434 patients were included. Patients with anti-HLA dnDSA had significantly higher odds of graft failure (OR = 4.42, 95% CI [3.15-6.22], I2 = 38%). Pooled data on graft rejection showed that patients with anti-HLA dnDSA have significantly higher odds of rejection than patients without anti-HLA (OR = 3.35, 95% CI [2.28-4.91], I2 = 38%). CONCLUSION: The results of our meta-analysis show that anti-HLA dnDSA is strongly associated with pancreas graft failure and rejection. Surveillance for anti-HLA dnDSA is an important component of post-transplant immune monitoring.


Subject(s)
Kidney Transplantation , Pancreas Transplantation , Graft Rejection , Graft Survival , HLA Antigens , Humans , Isoantibodies , Retrospective Studies , Tissue Donors
15.
Transplant Direct ; 6(1): e515, 2020 Jan.
Article in English | MEDLINE | ID: mdl-32047843

ABSTRACT

Renal injury almost always accompanies the multisystem organ failure that precedes cardiac transplantation and renal function is further compromised by the nephrotoxicity of calcineurin inhibitors posttransplant. Renal dysfunction in turn causes significant morbidity and mortality. The development of belatacept was motivated by need for an alternative to calcineurin-based immunosuppression, particularly in renal transplantation where the nephrotoxicity of calcineurin inhibitors reduce graft longevity and adverse cardiovascular effects of calcineurin inhibitors increase overall mortality. In 2011, the FDA approved belatacept for use in renal transplantation. Seven-year data from the multicenter randomized phase III BENEFIT trial, which compared belatacept with cyclosporine in renal transplant recipients, show belatacept therapy offers both improved renal function and 43% risk reduction for the combined endpoint of graft loss and death. At present, belatacept use is predominantly confined to renal transplant recipients; however, reports of belatacept use in other transplant settings are emerging. Here, we describe successful long-term use of belatacept in a kidney-after-heart transplant recipient and review use of belatacept in cardiothoracic and other nonrenal transplant settings.

16.
Transplant Direct ; 5(10): e494, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31723589

ABSTRACT

In 2018, 81% of the 36, 529 solid organs transplanted in the United States came from deceased donors. These organs were recovered through widespread use of aeromedical and emergency ground transportation systems. Urgently scheduled travel to remote hospitals at night and in varied weather conditions carries risk for the transplant professionals involved. A landmark survey conducted in 2007 demonstrated that 80% of respondents had experienced a "near-miss" event while on a procurement trip, and 15% had been involved in at least 1 accident. One decade later, we sought to revisit the issue of procurement related travel safety. METHODS: A 32 question survey designed to interrogate travel practice, accident frequency, and perceptions of safety was sent to the American Society of Transplant Surgeons membership. RESULTS: Our survey response rate was 20.6%. At least 1 travel accident with bodily injury was reported by 23% of respondents and yet only 7% of respondents reported feeling "unsafe" or "very unsafe" during procurement travel. Sixteen percent of respondents participated in a procurement at a dedicated organ procurement facility, and only 53% of procurement surgeons completed at least 1 deceased donor procurement at their own hospital facility within the preceding 12 months. CONCLUSIONS: In a field where increasingly aggressive organ utilization is the norm, the efficiency and safety of procurement travel merits ongoing consideration. Addressing these concerns takes on new significance as organ allocation policies change geographic distribution to expand the extent of travel required for surgical teams.

17.
Proc Natl Acad Sci U S A ; 112(21): 6682-7, 2015 May 26.
Article in English | MEDLINE | ID: mdl-25964334

ABSTRACT

V-domain immunoglobulin suppressor of T-cell activation (VISTA) is a negative immune-checkpoint protein that suppresses T-cell responses. To determine whether VISTA synergizes with another immune-checkpoint, programmed death 1 (PD-1), this study characterizes the immune responses in VISTA-deficient, PD-1-deficient (KO) mice and VISTA/PD-1 double KO mice. Chronic inflammation and spontaneous activation of T cells were observed in both single KO mice, demonstrating their nonredundancy. However, the VISTA/PD-1 double KO mice exhibited significantly higher levels of these phenotypes than the single KO mice. When bred onto the 2D2 T-cell receptor transgenic mice, which are predisposed to development of inflammatory autoimmune disease in the CNS, the level of disease penetrance was significantly enhanced in the double KO mice compared with in the single KO mice. Consistently, the magnitude of T-cell response toward foreign antigens was synergistically higher in the VISTA/PD-1 double KO mice. A combinatorial blockade using monoclonal antibodies specific for VISTA and PD-L1 achieved optimal tumor-clearing therapeutic efficacy. In conclusion, our study demonstrates the nonredundant role of VISTA that is distinct from the PD-1/PD-L1 pathway in controlling T-cell activation. These findings provide the rationale to concurrently target VISTA and PD-1 pathways for treating T-cell-regulated diseases such as cancer.


Subject(s)
Membrane Proteins/immunology , Programmed Cell Death 1 Receptor/immunology , T-Lymphocytes/immunology , Animals , Antibodies, Monoclonal/administration & dosage , Antigens/administration & dosage , B7-H1 Antigen/deficiency , B7-H1 Antigen/genetics , B7-H1 Antigen/metabolism , Female , Immune Tolerance , Ligands , Lymphocyte Activation , Male , Membrane Proteins/deficiency , Membrane Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Neoplasms, Experimental/immunology , Programmed Cell Death 1 Receptor/deficiency , Programmed Cell Death 1 Receptor/genetics
18.
Proc Natl Acad Sci U S A ; 111(41): 14846-51, 2014 Oct 14.
Article in English | MEDLINE | ID: mdl-25267631

ABSTRACT

V domain-containing Ig suppressor of T-cell activation (VISTA) is a negative checkpoint regulator that suppresses T cell-mediated immune responses. Previous studies using a VISTA-neutralizing monoclonal antibody show that VISTA blockade enhances T-cell activation. The current study describes a comprehensive characterization of mice in which the gene for VISTA has been deleted. Despite the apparent normal hematopoietic development in young mice, VISTA genetic deficiency leads to a gradual accumulation of spontaneously activated T cells, accompanied by the production of a spectrum of inflammatory cytokines and chemokines. Enhanced T-cell responsiveness was also observed upon immunization with neoantigen. Despite the presence of multiorgan chronic inflammation, aged VISTA-deficient mice did not develop systemic or organ-specific autoimmune disease. Interbreeding of the VISTA-deficient mice with 2D2 T-cell receptor transgenic mice, which are predisposed to the development of experimental autoimmune encephalomyelitis, drastically enhanced disease incidence and intensity. Disease development is correlated with the increase in the activation of encephalitogenic T cells in the periphery and enhanced infiltration into the CNS. Taken together, our data suggest that VISTA is a negative checkpoint regulator whose loss of function lowers the threshold for T-cell activation, allowing for an enhanced proinflammatory phenotype and an increase in the frequency and intensity of autoimmunity under susceptible conditions.


Subject(s)
Autoimmunity/genetics , Autoimmunity/immunology , B7 Antigens/genetics , Genetic Predisposition to Disease , Inflammation/pathology , Aging/pathology , Animals , Autoimmune Diseases/genetics , Autoimmune Diseases/immunology , B7 Antigens/deficiency , B7 Antigens/metabolism , Chemokines/metabolism , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/pathology , Hematopoiesis , Lymphocyte Activation/immunology , Mice, Inbred C57BL , Mice, Knockout , Phenotype , Th1 Cells/immunology , Th17 Cells/immunology
19.
J Immunol ; 193(7): 3816-24, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-25172484

ABSTRACT

Recipient CD4 T regulatory cells inhibit the acute T cell-mediated rejection of renal allografts in wild-type mice. The survival of single class II MHC-disparate H-2(bm12) renal allografts was tested in B6.CCR5(-/-) recipients, which have defects in T regulatory cell activities that constrain alloimmune responses. In contrast to wild-type C57BL/6 recipients, B6.CCR5(-/-) recipients rejected the bm12 renal allografts. However, donor-reactive CD8 T cells rather than CD4 T cells were the primary effector T cells mediating rejection. The CD8 T cells induced to bm12 allografts in CCR5-deficient recipients were reactive to peptides spanning the 3 aa difference in the I-A(bm12) versus I-A(b) ß-chains presented by K(b) and D(b) class I MHC molecules. Allograft-primed CD8 T cells from CCR5-deficient allograft recipients were activated during culture either with proinflammatory cytokine-stimulated wild-type endothelial cells pulsed with the I-A(bm12) peptides or with proinflammatory cytokine-simulated bm12 endothelial cells, indicating their presentation of the I-A(bm12) ß-chain peptide/class I MHC complexes. In addition to induction by bm12 renal allografts, the I-A(bm12) ß-chain-reactive CD8 T cells were induced in CCR5-deficient, but not wild-type C57BL/6, mice by immunization with the peptides. These results reveal novel alloreactive CD8 T cell specificities in CCR5-deficient recipients of single class II MHC renal allografts that mediate rejection of the allografts.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , Graft Rejection/immunology , Histocompatibility Antigens Class II/immunology , Kidney Transplantation , Receptors, CCR5/immunology , Allografts , Animals , CD8-Positive T-Lymphocytes/pathology , Cytokines/genetics , Cytokines/immunology , Graft Rejection/genetics , Graft Rejection/pathology , H-2 Antigens/genetics , H-2 Antigens/immunology , Histocompatibility Antigens Class II/genetics , Mice , Mice, Knockout , Receptors, CCR5/genetics
20.
J Am Chem Soc ; 134(25): 10405-18, 2012 Jun 27.
Article in English | MEDLINE | ID: mdl-22591173

ABSTRACT

The thermodynamics of Zn(2+) binding to three peptides corresponding to naturally occurring Zn-binding sequences in transcription factors have been quantified with isothermal titration calorimetry (ITC). These peptides, the third zinc finger of Sp1 (Sp1-3), the second zinc finger of myelin transcription factor 1 (MyT1-2), and the second Zn-binding sequence of the DNA-binding domain of glucocorticoid receptor (GR-2), bind Zn(2+) with Cys(2)His(2), Cys(2)HisCys, and Cys(4) coordination, respectively. Circular dichroism confirms that Sp1-3 and MyT1-2 have considerable and negligible Zn-stabilized secondary structure, respectively, and indicate only a small amount for GR-2. The pK(a)'s of the Sp1-3 cysteines and histidines were determined by NMR and used to estimate the number of protons displaced by Zn(2+) at pH 7.4. ITC was also used to determine this number, and the two methods agree. Subtraction of buffer contributions to the calorimetric data reveals that all three peptides have a similar affinity for Zn(2+), which has equal enthalpy and entropy components for Sp1-3 but is more enthalpically disfavored and entropically favored with increasing Cys ligands. The resulting enthalpy-entropy compensation originates from the Zn-Cys coordination, as subtraction of the cysteine deprotonation enthalpy results in a similar Zn(2+)-binding enthalpy for all three peptides, and the binding entropy tracks with the number of displaced protons. Metal and protein components of the binding enthalpy and entropy have been estimated. While dominated by Zn(2+) coordination to the cysteines and histidines, other residues in the sequence affect the protein contributions that modulate the stability of these motifs.


Subject(s)
Cysteine/chemistry , Thermodynamics , Zinc Fingers , Zinc/chemistry , Circular Dichroism , Magnetic Resonance Spectroscopy , Models, Molecular , Protein Stability
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