Impact of COVID-19 on liver transplant recipients: A nationwide cohort study evaluating hospitalization, transplant rejection, and inpatient mortality

BACKGROUND The coronavirus disease 2019(COVID-19)pandemic has posed a major public health concern worldwide.Patients with comorbid conditions are at risk of adverse outcomes following COVID-19.Solid organ transplant recipients with concurrent immunosuppression and comorbidities are more susceptible to a severe COVID-19 infection.It could lead to higher rates of inpatient complications and mortality in this patient population.However,studies on COVID-19 outcomes in liver transplant(LT)recipients have yielded inconsistent findings.AIM To evaluate the impact of the COVID-19 pandemic on hospital-related outcomes among LT recipients in the United States.METHODS We conducted a retrospective cohort study using the 2019–2020 National Inpatient Sample database.Patients with primary LT hospitalizations and a secondary COVID-19 diagnosis were identified using the International Classi-fication of Diseases,Tenth Revision coding system.The primary outcomes included trends in LT hospitalizations before and during the COVID-19 pandemic.Secondary outcomes included comparative trends in inpatient mortality and transplant rejection in LT recipients.RESULTS A total of 15720 hospitalized LT recipients were included.Approximately 0.8% of patients had a secondary diagnosis of COVID-19 infection.In both cohorts,the median admission age was 57 years.The linear trends for LT hospitalizations did not differ significantly before and during the pandemic(P=0.84).The frequency of in-hospital mortality for LT recipients increased from 1.7% to 4.4% between January 2019 and December 2020.Compared to the pre-pandemic period,a higher association was noted between LT recipients and in-hospital mortality during the pandemic,with an odds ratio(OR)of 1.69[95% confidence interval(CI):1.55-1.84),P<0.001].The frequency of transplant rejections among hospitalized LT recipients increased from 0.2%to 3.6% between January 2019 and December 2020.LT hospitalizations during the COVID-19 pandemic had a higher association with transplant rejection than before the pandemic[OR:1.53(95%CI:1.26-1.85),P<0.001].CONCLUSION The hospitalization rates for LT recipients were comparable before and during the pandemic.Inpatient mortality and transplant rejection rates for hospitalized LT recipients were increased during the COVID-19 pandemic.

Clinical use of donor-derived cell-free DNA in kidney transplantation

Traditional monitoring of kidney transplant recipients for allograft dysfunction caused by rejection involves serial checks of serum creatinine with biopsy of the renal allograft if dysfunction is suspected.This approach is labor-intensive,invasive and costly.In addition,because this approach relies on a rise in serum creatinine above historical baselines,injury to the allograft can be extensive before this rise occurs.In an effort to address this,donor-derived cell-free DNA(dd-cf DNA)is being used with increasing frequency in the clinical setting as a means of diagnosing a rejection of the renal allograft early in the course.This can poten-tially allow for early intervention to minimize not only injury,but the intensity of antirejection therapy needed and the avoidance of side effects.Here,we will review the available methodology for the determination and quantification of dd-cf DNA,the data supporting its use in clinical practice and the limitations of this technology.

Expression of Cytokines in Acute Heart Transplantation Rejection

The expression and changes of local cytokines network were detected in heart transplantation in rats, so as to determine the role of cytokines in the acute rejection of rats of heart trans- plantation. Allografts were divided into 4 groups （n=12 in each group）： group A （control）, group B （IL-2 monoclonal antibody-treated）, group C （CsA-treated） and group D （IL-2 monoclonal antibody＋CsA-treated）. Hearts from DA rats were transplanted into a cervical location in Wistar recipients. The local expression of IL-1β, IL-2, CD25, IL-4, IL-5, IL-6, IL-10, TNFα and INFy was detected at day 1, 3, 5, 7, 9, 11 and 14 by reverse transcription polymerase chain reaction. The results showed that the survival time of allografts was 8.3±1.7, 29.2±7.1 （P〈0.05）, 26.4±5.7 （P〈0.05） and 55.0±10.6 （P〈0.01） days respectively in groups A, B, C and D. The expression of IL-1β, IL-4, IL-10 and IFNy was up-regulated, and that of IL-2, CD25, IL-5, IL-6 and TNFα was significantly inhibited in group A; The expression of IL-1β, IL-5, IL-6, IL-10 and IFNy was up-regulated, and that of IL-2, IL-4 and TNFα was significantly down-regulated in group B; The expression of IL-1β, IL-2, CD25, IL-5, TNFα and IENγ was up-regulated, and that of IL-4, IL-6 and IL-10 was significantly down-regulated in group C; The expression of IL-14, 11-5, IL-6 and 11-10 was up-regulated, and that of IL-1β, IL-2, CD25, TNFα and IFNy was significantly down-regulated in group D. In conclusion, cytokines play an important role in the development of acute transplantation rejection. Different cytokines play different roles in different local environments.

The imbalance of helper T lymphocytes and cytotoxic T lymphocytes in acute renal transplantation rejection

To investigate the imbalance state of helper T lymphocytes （Th） and cytotoxic T lymphocytes （Tc） and the roles of Thl/Th2/Th3 and Tcl/Tc2 cells in renal transplantation rejection, the percentages of these cells in peripheral blood of 24 cases of renal transplantation recipients with acute rejection and the dynamic changes of the CD4/CD8 ratio were determined by flow cytometry analysis, while 30 cases of healthy individuals were set up as controls. In these healthy controls, the percentages of the Thl, Th2 and Th3 cells were （ 10.45 ± 8.15） %, （5.05 ± 4.15） % and （3.90 ± 3.21 ） %, and those of Tcl and %2 cells were （9.83 ± 7.03） % and （4.51 ± 2.17） %, respectively. However, the percentages of Thl and Tcl cells in peripheral blood of the stable recipients after transplantation were （7.29 ± 5.62） % and （7.04 ± 5.15）%, showing definite reduction, while those of Th2, Th3 and Tc2 cells showed significant increase, （ 6.34 ± 5.67） %, （4.94 ± 4.14） % and （ 6.86 ± 4.42） %, respectively. In case of recipients with acute rejection, the percentages of Thl and Tcl cells appeared to be （ 18.55 ± 13.21 ） % and （ 15.84 ± 11.72） %, also showing significant increase, but those of Th2, Th3 and %2 cells appeared to be reduced, （4.19 ± 3.62） %, （3.02 ± 2.83 ） % and （3.88 ± 1.63） %, respectively. Significant differences could be detected among these three groups （ P 〈 0.05）. The CD4/CD8 ratio in cases with acute rejection was higher than those of stable recipients （2.24 ± 0.59 vs 1.95 ± 0.45）, but that of the stable recipients and healthy controls （ 1.98 ± 0.31 ） showed no any significant difference. From the above observation, it is evident that imbalance between Thl, Th2 and Th3 with Tcl and Tc2 cells may exist after renal transplantation and probably, the im- mune imbalance may be induced through the secretion of cytokines INF-γby Thl or Tcl cells , Ⅱ-4 by Th2 and Tc2 cells and TGF-β by Th3.

Efficacy of ursodeoxycholic acid as an adjuvant treatment to prevent acute cellular rejection after liver transplantation: a meta-analysis of randomized controlled trials

BACKGROUND： Acute cellular rejection（ACR） after liver transplantation（LT） is one of the most common problems faced by transplant recipients in spite of advances in immunosuppressive therapy. Recently, clinical trials reported that ursodeoxycholic acid（UDCA） reduced the incidence of ACR significantly.However, others have shown contradictory conclusion. Therefore,we performed a meta-analysis of rigorous randomized controlled trials（RCTs） to determine the efficacy of UDCA in reducing ACR after LT.DATA SOURCES： All RCTs that evaluated efficacy of UDCA as an adjuvant treatment to prevent ACR after LT were searched from PubMed/MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, ScienceDirect databases and Web of Science（from January 1981 to March 2012）. There was no language limitation in these searches. Relevant abstracts of international meetings were also searched. References of each included study were searched manually.RESULTS： A total of 234 patients from four high-quality RCTs（Jadad score 4 to 5） were included in this meta-analysis.Prophylactic use of UDCA did not decrease the incidence of ACR（RR： 0.94, 95% CI： 0.77-1.16, P0.05）, steroid-resistant rejection（RR： 0.77, 95% CI： 0.47-1.27, P0.05） and the number of patients with the multiple episodes of ACR（RR： 0.60, 95% CI：0.28-1.30, P0.05）. Different intervention programs（high-dose vs low-dose UDCA; early vs delayed UDCA treatment） also did not alter the outcomes.CONCLUSIONS： UDCA, as an adjuvant treatment, was not ableto prevent ACR and steroid-resistant rejection after LT. Further trials should be done to determine whether higher dose of UDCA will be beneficial.

Inhibitory effect of cyclosporin A on the immunological rejection of rats with cerebral hemorrhage following transplantation of nerve growth factors transfected glial cells

BACKGROUND： At present, it has been confirmed that immunological rejection exists in the cell transplantation in brain tissue, the effects of immunosuppressant on the immunological rejection and the survival of grafts in brain cell transplantation are worthy being investigated further. OBJECTIVE： To observe the immunological rejection after transgeneic cell transplantation in treating cerebra hemorrhage in rats, and investigate the interventional effect of cyclosprin. DESIGN ： A randomized controlled study SETTINGS： Second Affiliated Hospital of Xuzhou Medical College; First Affiliated Hospital of Nanjing Medica University. MATERIALS： Thirty-five healthy clean-degree SD rats of 6-8 weeks old were used, weighing 200-250 g, either male or female; The FACSort flow cytometer （American BD Company） and NYD-1000 image analytical system were used, The rat-anti-rat CD4 monoclonal antibody, rat-anti-rat CD8 monoclonal antibody, and rat-anti-rat MHC Ⅱ antigen monoclonal antibody were purchased from Santa Cruz Company; SP and DAB kits were purchased from Beijing Zhongshan Bio-engineering Company. XSP-8C2 light microscope was the product of Shanghai Zousun Optical Instrument, Co.,Ltd, and KYKY-3800B electron microscope was the product of China KYKY Technology Development Co.,Ltd. METHODS ： The experiments were carried out in the animal experimental center of Nanjing Medical University from April to July in 2003. ① Model establishment： The rats were anesthetized, and then the coordinates of left internal capsule were identified, and the needle was withdrawn after 120 μL blood was injected into the internal capsule. Adenoviruses were taken as the carriers, after the astrocytes were successfully transfected by nerve growth factor（NGF） gene, 0.2 mL cell suspension was injected into the sites of cerebral hemorrhage. Thirty successfully established rat models were randomly divided into cyclosporin A group （n=18） and control group, the rats were treated with intraperitoneal injection of cyclosporin A （10 mg/kg per day） intraperitoneal injection of saline of the same dosage from the 1^st day after transplantation, once a day for 7 days continuously.② CD4^＋ and CD4^＋ detection： The CD4^＋ and CD4^＋ T lymphocytes in caudal vein were counted with flow cytometer at 15 days after treatment. ③ Morphological observation in the transplanted sites： The rats were killed and then brain tissues were taken out, the transplanted sites and the structure of the normal brain tissue around the transplanted sites were observed with light and electron microscopes. ④Detections of the infiltration of T lymphocyte subsets and expression of major histocompatibility complex （MHC） Ⅱ antigen in the transplanted sites： The image analysis of immunohistochemical sections was performed with the image analytical system, and the integral optical density （IOD） was taken as the statistical value to observe the infiltration of T lymphocyte subsets and expression of MHC Ⅱ antigen in the transplanted sites, and the normal brain tissue around the transplanted sites were taken as controls. MATN OUTCOME MEASURES： ① Countings of CD4^＋ and CD4^＋ in peripheral blood; ②Results of the morphological observation in the transplanted sites; ③ Infiltration of T lymphocyte subsets and expression of MHC Ⅱ antigen in the transplanted sites RESULTS ： Totally 35 rats were used, and 30 were successfully made into models, 5 died during the treatment, the other 25 were involved in the analysis of results. ① Results of CD4^＋ and CD4^＋ T lymphocytes in pedpherel blood： The percentages of CD4^＋ and CD4^＋ T lymphocytes in the cyclosporin A group were （29.20±3.97）% and （20.65±2,02）%, respectively, which were obviously lower than those in the control group [（47,39±3,01）%, （28.30±2.36）%, t=-4.983, 4.012, P 〈 0.05], and the CDC/CD4^＋ ratio was obviously lower than that in the control group （1,41±0.86, 1,64^＋0.69, t=-3. 871, P〈 0.05）.② Morphological results in the transplanted sites： Under optical and electron microscopes, the survival region of the transplant was round, and it had an unobvious migration region with the normal brain tissues, the grafts had normal cellular form. Infiltrations of lymphocytes and monocytes were observed in both groups, and mainly located in the transplanted sites, and the expression of lymphocytes in the cyclosporin A group was markedly lower than that in the control group, and no above-mentioned changes were observed in the normal brain tissue around the transplanted sites. ③ Results of CD. and CD4^＋ T lymphocytes and expression of MHC Ⅱ antigen in the transplanted sites： The CD4^＋ and CD4^＋ T lymphocytes and expression of MHC Ⅱ antigen in the transplanted sites were observed in both groups. The IOD of CD4^＋ and CD4^＋ antigen positive cells in the cyclosporin A group were obviously lower than those in the control group （1.85±0.38, 1.44^＋0.33; 3.33±0.37, 2.648±0.56, /=-4.122, 4.434, P〈 0.05）, and the IOD of MHC Ⅱantigen positive cells was markedly lower than that in the control group （0.76±0.22, 0.94±0.24, t=3.885, P 〈 0.05）. CONCLUSION： There is immunological rejection in brain tissue after the transplantation of NSC transgeneic glial cells. ② The immunosuppressant of cyclosporin A can reduce the immunological rejection after the cell transplantation.

The diagnostic role of heat shock protein 70 in acute rejection after pancreatioduodenal transplantation in rats

Objective To explore the diagnositc role of heat shock protein ( HSP) 70 in acute rejection after pancreatioduodenal transplantation in rats. Methods Groups of Wistar rats underwent total pancreatioduodenal transplantation from allogeneic SD or syngeneic Wistar rats. The grafts were harvested on the posttransplantation day 3,5 and 7 and were used to detect the expression of HSP70 by immunohistochemistry and Western Blotting quantitative methods. The correlation between HSP70 expression and pathological findings was observed. Results The level of HSP70 in the isografts did not change greatly( P 】 0.05); the level of HSP70 in the allografts was increased progressively on the posttransplantation day3, 5 and 7 ( P 【 0.01). There was a significant correlation between HSP70 and pathological score in the allograft group (P 【 0.01, r = 0.934). Conclusion HSP70 involved in pancreas allograft rejection and could be useful for early diagnosis of acute rejection following pancreas transplantation. 8 refs,2 tabs.

Advances in single-cell sequencing:insights from organ transplantation

Single-cell RNA sequencing(scRNA-seq)is a comprehensive technical tool to analyze intracellular and intercellular interaction data by whole transcriptional profile analysis.Here,we describe the application in biomedical research,focusing on the immune system during organ transplantation and rejection.Unlike conventional transcriptome analysis,this method provides a full map of multiple cell populations in one specific tissue and presents a dynamic and transient unbiased method to explore the progression of allograft dysfunction,starting from the stress response to final graft failure.This promising sequencing technology remarkably improves individualized organ rejection treatment by identifying decisive cellular subgroups and cell-specific interactions.

Late complications of pancreas transplant

To summarize the long-term complications after pancreas transplantation that affect graft function,a literature search was carried out on the long-term complications of pancreatic transplantation,namely,complications from postoperative 3rd mo onwards,in terms of loss of graft function,late infection and vascular complications as pseudoaneurysms.The most relevant reviews and studies were selected to obtain the current evidence on these topics.The definition of graft failure varies among different studies,so it is difficult to evaluate,a standardized definition is of utmost importance to know the magnitude of the problem in all worldwide series.Chronic rejection is the main cause of long-term graft failure,occurring in 10%of patients.From the 3rd mo of transplantation onwards,the main risk factor for late infections is immunosuppression,and patients have opportunistic infections like:Cytomegalovirus,hepatitis B and C viruses,Epstein-Barr virus and varicella-zoster virus;opportunistic bacteria,reactivation of latent infections as tuberculosis or fungal infections.Complete preoperative studies and serological tests should be made in all recipients to avoid these infections,adding perioperative prophylactic treatments when indicated.Pseudoaneurysm are uncommon,but one of the main causes of late bleeding,which can be fatal.The treatment should be performed with radiological endovascular approaches or open surgery in case of failure.Despite all therapeutic options for the complications mentioned above,transplantectomy is a necessary option in approximately 50%of relaparotomies,especially in lifethreatening complications.Late complications in pancreatic transplantation threatens long-term graft function.An exhaustive follow-up as well as a correct immunosuppression protocol are necessary for prevention.

Monitoring of Acute Rejection after Orthotopic Heart Tranplantation

Objectives To study the monitoting of rejection after orthotopic heart thansplantation. Methods From 1998 to 2005, 10 othotopic heart thansplans were performed, and acute rejection was monitored by endomyocardial biopsy as well as by clinical features, ECG, ultrasonocardiography and blood serum determination of Tropin Ⅰ, and by the combination of these methods, we analysed the monitoring of acute rejection after the heart transplantation. Results With the combination of clinical features, ECG, ultrasonocardiography and blood serum test, 5 occurences of acute rejection were judged in the postoperative course, which were comfirmed by endomyocardial biopsy to be 2 acute rejections in Ⅰ b degree, 3 acute rejections in Ⅲa degree. Endomyocardial biopsy were routinely performed 21 times postoperatively in which there were 1 acute rejection in Ⅰa degree and 5 acute rejections in Ⅰ b degree. Conclusions Acute rejection is an important factor influencing the postoperative course of heart transplantation, so it is imperative to have an intime, effective and planned monitoring procedure for acute rejection. Endomyocardial biopsy is a sensitive and reliable method in diagnosis of acute rejection, but it is invasive and probable for some complications. The noninvasive method such as clinical features, ECG, ultrasonocardiography and blood serum test can be used as additive means in the diagnosis of acute rejection. Endomyocardial biopsy should be combined with some noninvasive methods in monitoring acute rejection after the heart transplantation.

Mitochondrial transplantation as a promising therapy for mitochondrial diseases

Mitochondrial diseases are a group of inherited or acquired metabolic disorders caused by mitochondrial dysfunction which may affect almost all the organs in the body and present at any age.However,no satisfactory therapeutic strategies have been available for mitochondrial diseases so far.Mitochondrial transplantation is a burgeoning approach for treatment of mitochondrial diseases by recovery of dysfunctional mitochondria in defective cells using isolated functional mitochondria.Many models of mitochondrial transplantation in cells,animals,and patients have proved effective via various routes of mitochondrial delivery.This review presents different techniques used in mitochondrial isolation and delivery,mechanisms of mitochondrial internalization and consequences of mitochondrial transplantation,along with challenges for clinical application.Despite some unknowns and challenges,mitochondrial transplantation would provide an innovative approach for mitochondrial medicine.

A proteomic analysis of allograft rejection in rats after liver transplantation

In order to understand the allograft rejection in orthotopic liver transplantation (OLT), an allograft re- jection rat model was established and studied by proteomic approach. The protein expression profiles of liver tissues were acquired by fluorescence two-dimensional difference gel electrophoresis (2D DIGE) that incorporated a pooled internal standard and reverse fluorescent labeling method. The expression levels of 27 protein spots showed significant changes in acute rejection rats. Among these spots, 19 were identified with peptide mass fingerprinting using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) after tryptic in-gel digestion. The results of the present paper could be helpful for our better understanding of allograft rejection in organ transplantation.

Up-regulated intragraft gene expression, ICAM-1 and IL-2R molecules, and apoptotic epithelial cells during rejection of rat small intestine allografts

Objective To investigate the kinetics and the magnitude of intragraft gene expression of interleukin-2(IL-2), interferon-gamma (IFN-y), perforin and granzyme B, and intragraft expression of interieukin-2receptor (IL-2R) and intercellular adhesion molecule-1 ( ICAM-1 ) during acute rejection episodes, and to analyze the changes in apoptosis in small intestinal allograft rejection.Methods Heterotopic small intestine transplantation was performed with inbred rats F344/N (RT11) and Wistar/A (RT1-Ak, RT1-Ed). All recipients were divided into four groups: group 1 : Wistar, native control;group 2: Wistar→Wistar; group 3: F344→Wistar and group 4: F344→Wistar + cyclosporine A (6 mg·kg-1 ·d-1 I.M. ). The grafts were harvested on postoperative days (PODs) 3, 5 and 7. All samples were examined pathologically. Intragraft mRNA expression of IL-2, IFN-γ, perforin and granzyme B were detected with reverse transcriptase polymerase chain reaction (RT-PCR) and intragraft expression of IL-2R and ICAM-1 were stained using immunohistochemistry. We also analyzed the change in apoptosis rejection with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL).Results Mild acute rejection occurred on POD 3 in the ailograft group, moderate acute rejection on POD 5, and severe acute rejection on POD 7, while none of the isografts had histological evidence of acute rejection. Cyclosporine A could effectively control rejection. Gene expression was virtually negative in the native control. Only on POD 5 was IL-2 mRNA expression of ailografts significantly higher than that of isografts ( P ＜ 0.05). IFN-γ mRNA expression was significantly higher than that of the control groups ( P ＜0.01 ) on PODs 3, 5 and 7, and the level of perforin and granzyme B mRNA expression reached significantly higher levels than in the other two control groups on POD 5 and POD 7. Intragraft IL-2Rexpression of the allograft was significantly higher than that of the other three control groups. Only on POD 3 was intragraft ICAM-1 expression of allografts significantly higher than isografts. The number of apoptotic cells per crypt of allografts was significantly higher than that of the other three control groups on POD 3 and POD 5 ( P ＜ 0.01 ).Conclusion Transcription of IL-2, IFN-γ, perforin and granzyme B, and expression of IL-2R and ICAM-1as well as apoptosis of epithelial cells of the grafts play an important role in small intestine allograft rejection.Intragraft gene expression of IFN-γ and intragraft expression of IL-2R as well as apoptotic epithelial cells may become a specific and sensitive diagnostic method of clinical value. Furthermore, therapeutic strategies to alter these molecules in small intestine transplantation may improve the outcome of current antirejection therapy.

Anti-rejection effect of ethanol extract of Poria cocos wolf in rats after cardiac allograft implantation

Background A living fetus within the maternal uterus provides an example of allogene tolerance in mammals. Poria cocos Wolf is the main component of many Chinese medicinal combination drugs that have therapeutic effects on recurrent spontaneous abortion and that can maintain pregnancy until delivery. It was hypothesized that this herbal medicine can also prolong allograft survival after organ transplantation. Here,in an in vivo study,we report the anti-rejection effect of the ethanol extract of Poria cocos Wolf (EEPCW) in rats after cardiac allograft implantation. Methods Ten normal rats were healthy controls. Eighty rats receiving homologous heart transplants were divided into 4 groups of 20 rats each based on type of treatment: olive oil 8 ml·kg -1 ·d -1 ,EEPCW 25 mg·kg -1 ·d -1 , EEPCW 50 mg·kg -1 ·d -1 or cyclosporin A 5mg·kg -1 ·d -1 . Allograft survival was observed in 10 rats from each group. On the seventh day post transplantation,pathological lesions and percentages of CD_3 +,CD_4 +,and CD_8 + lymphocytes and the CD_4 +/CD_8 + ratio in peripheral blood were assessed in another 10 rats from each group and in 10 normal rats. Results The survival time of donor hearts in the two EEPCW groups was significantly prolonged,to (15.9±2.4) days and (30.0±0.0) days,respectively,compared with (6.7±0.8) days in the control group. Pathological lesions in the two EEPCW groups were also less severe,and the percentages of CD_3 +,CD_4 +,and CD_8 + lymphocytes and CD_4 +/CD_8 + ratio were significantly lower in the EEPCW groups. Conclusions Acute rejection of heart transplants and cellular immune reaction can be effectively suppressed using the EEPCW. Taking advantage of novel immunosuppressants derived from Chinese medicinal herbs used to treat abnormal pregnancy provides a hopeful road for future research and treatment in organ transplantation.

Quantitative chimerism kinetics in relapsed leukemia patients after allogeneic hematopoietic stem cell transplantation

Background Chimerism analysis is an important tool for the surveillance of post-transplant engraftment. It offers the possibility of identifying impending graft rejection and recurrence of underlying malignant or non-malignant disease. Here we investigated the quantitative chimerism kinetics of 21 relapsed leukemia patients after allogeneic hematopoietic stem cell transplantation （HSCT）. Methods A panel of 29 selected sequence polymorphism （SP） markers was screened by real-time polymerase chain reaction （RT-PCR） to obtain the informative marker for every leukemia patient. Quantitative chimerism analysis of bone marrow （BM） samples of 21 relapsed patients and 20 patients in stable remission was performed longitudinally. The chimerisms of BM and peripheral blood （PB） samples of 14 patients at relapse were compared. Results Twenty-one patients experienced leukemia relapse at a median of 135 days （range, 30-720 days） after transplantation. High recipient chimerism in BM was found in all patients at relapse, and increased recipient chimerism in BM samples was observed in 90% （19/21） of patients before relapse. With 0.5% recipient DNA as the cut-off, median time between the detection of increased recipient chimerism and relapse was 45 days （range, 0-120 days）, with 76% of patients showing increased recipient chimerism at least 1 month prior to relapse. Median percentage of recipient DNA in 20 stable remission patients was 0.28%, 0.04%, 0.05%, 0.05%, 0.08%, and 0.05% at 1, 2, 3, 6, 9, and 12 months, respectively, after transplantation. This was concordant with other specific fusion transcripts and fluorescent in situ hybridization examination. The recipient chimerisms in BM were significantly higher than those in PB at relapse （P=-0.001）. Conclusions This SP-based RT-PCR assay is a reliable method for chimerism analysis. Chimerism kinetics in BM can be used as a marker of impending leukemia relapse, especially when no other specific marker is available. Based on our findings, we recommend examining not only PB samples but also BM samples in HSCT patients.

Immature CD4＋ dendritic cells conditioned with donor kidney antigen prolong renal allograft survival in rats

Background AIIogeneic transplant rejection is currently a major problem encountered during organ transplantation. The dendritic cell （DC） is the most effective powerful known professional antigen-presenting cell, and recent studies have found that DCs can also induce immune tolerance, and avoid or reduce the degree of transplant rejection. The aim of this study was to evaluate the effect of transfused immature CD4~ DCs on renal allografts in the rat model. Methods In this study, we induced CD4~ immature DCs from rat bone marrow cells by a cytokine cocktail. The immature CD4~ DCs were identified by morphological analysis and then the suppressive activity of these cells conditioned with donor kidney antigen was evaluated in vitro and in vivo. Results Immature CD4~ DCs conditioned with donor kidney antigen possessed immunosuppressive activity in vitro and they were able to prolong renal transplant survival in an allograft rat model in vivo. Conclusions Our study provides new information on efficacious renal transplantation, which might be useful for understanding the function of immature CD4~ DCs in modulating renal transplant rejection and improving clinical outcome in future studies.

Interleukin-1 receptor antagonist eye drops promoting high-risk corneal allografts survival in rats

Background Immune rejection is the main reason of grafts failure after corneal transplantation. This study was to determine whether interlerkin-1 receptor antagonist (IL-1ra) eye drops could prolong corneal allografts survival in high-risk corneal orthotopic allotransplantation in rat model and to study the effect of IL-1ra on the expression of CD 1-positive cells in the grafts Methods For all experiments, the Sprague-Dawley (SD) rats' corneas were transplanted into Wistar rats' eyes High-risk transplants included those that had been sutured into Wistar recipient beds with corneal neovascularization induced by placement of three interrupted sutures in the host cornea 7 days earlier All the animals were divided, in a masked fashion, into three treatment groups and one control group Each treatment group received IL-1ra eye drops of different concentrations (1 mg/ml, 3 mg/ml, or 5 mg/ml, respectively) four times a day for 30 days The control group received 0 9% normal saline (NS) eye drops in the same way as the treatment groups All allografts were evaluated for signs of rejection from the first day after surgery Ten days later, corneal specimens were processed to examine the expression of CD 1-positive cells and histopathological changes Results The survival time of the transplants was 5 80±0 79, 5 89±1 05, 6 78±0 83, and 9 00±2 36 days respectively in the control or three treatment groups Compared with the control group, 1 mg/ml IL-1ra eye drop did not prolong the survival time of the allografts ( t =0 210, P >0 05) However, 3 mg/ml and 5 mg/ml IL-1ra eye drop did prolong the survival time of the grafts ( t ≥2.627, P <0 05), with the latter showing more obvious effect Immunohistochemical examinations showed a significant decrease in inflammatory cell and CD 1-positive cell infiltration in IL-1ra treated groups compared with the control group Conclusions IL-1ra can promote corneal allograft survival in a dose-dependant manner by reducing the infiltration of CD 1-positive cells in high-risk corneal transplantation