The impact of cytomegalovirus disease and asymptomatic infection on acute renal allograft rejection.

BACKGROUND: Cytomegalovirus (CMV) disease is a risk factor for allograft rejection in renal transplant (RTx) recipients. However, the role of asymptomatic CMV infection remains controversial. OBJECTIVES: To determine the impact of CMV disease and asymptomatic infection on biopsy-proven acute rejection (BPAR) during 12 months post-RTx. STUDY DESIGN: A total of 106 consecutive RTx recipients at risk for CMV (donor and/or recipient CMV seropositive) were followed prospectively for 12 months post-RTx. CMV activity was monitored using nested PCR from whole blood. Three-month prophylaxis with valacyclovir or ganciclovir was given to 94 patients. BPAR episodes were classified according to the Banff 97 criteria. Multivariate Cox proportional hazards model was used to estimate the effect of CMV disease, asymptomatic infection, and other covariates on BPAR. RESULTS: Asymptomatic CMV infection occurred in 23% of the patients and 10% developed CMV disease. The incidence of BPAR was 29%. CMV disease was an independent risk factor for BPAR (HR=3.0, P=0.014), while asymptomatic CMV infection was not (P=0.987). In addition to CMV disease, expanded criteria donor and donor age were independent predictors for BPAR. In univariate analysis, valacyclovir (HR=0.26, P=0.008) decreased the risk of BPAR. A similar trend was observed with ganciclovir (HR=0.42, P=0.058). Only valacyclovir remained significant in multivariate analysis (HR=0.18, P=0.044). CONCLUSIONS: CMV disease, but not asymptomatic infection, is an independent risk factor for BPAR during the first 12 months post-RTx.     

Induction of vascular adhesion protein-1 during liver allograft rejection and concomitant cytomegalovirus infection in rats

Vascular adhesion protein-1 (VAP-1) is an adhesion molecule controlling lymphocyte recirculation through high endothelial venules of the lymph nodes. It has also been shown to be induced and to mediate lymphocyte adhesion at sites of inflammation. We studied the expression of VAP-1 and two other inducible adhesion molecules ICAM-1 and VCAM-1 in our experimental model of rat liver allograft rejection and, in addition, the effect of concomitant rat cytomegalovirus (RCMV) infection on this expression. Expression of VAP-1, ICAM-1, and VCAM-1 was studied in rat liver allografts with or without RCMV infection, isografts, and normal rat liver. Immunoperoxidase technique and monoclonal antibodies including a novel anti-VAP-1 reagent were used. VAP-1 expression was induced by acute rejection in sinusoids, hepatocytes, and also in bile ducts, when compared to the isografts or normal liver, where only blood vessels were consistently positive. Sinusoidal and hepatocyte expression of VAP-1 was prolonged by the presence of RCMV. ICAM-1 and VCAM-1 expression was also induced by acute rejection. However, RCMV increased sinusoidal VCAM-1 expression compared to uninfected grafts. The present experimental study shows that VAP-1 is up-regulated in acute rejection of liver allografts, and that this up-regulation is prolonged by RCMV infection.     

Apoptosis of bile duct epithelial cells in hepatic allograft rejection

Liver biopsy remains the 'gold standard' for monitoring rejection in liver transplant patients. Portal inflammation, bile duct damage and endothelialitis are recognized features of hepatic allograft rejection. The pathogenesis of the bile duct injury during rejection, however, remains unclear. To define the mechanism of bile duct damage, we studied the light- and electronmicroscopic appearance of hepatic tissue from selected patients in whom allograft failure was solely due to rejection. Of the 25 orthotopic liver transplant rejection cases examined, 17 were mild, seven were moderate and one was severe rejection. Light microscopy examination of the damaged bile duct epithelium revealed evidence of apoptosis which was confirmed by electronmicroscopy. Furthermore, there appeared to be a positive correlation between the grade of rejection and the number of apoptotic cells. Also included in the study were 13 cases of chronic active hepatitis and 10 normal livers which showed the least apoptotic cells. We conclude that the identification of apoptotic cells in damaged bile ducts in allograft biopsies might be helpful in the diagnosis of rejection and in assessment of the severity of rejection.     

Apoptosis in the human liver during allograft rejection and end-stage liver disease

The contribution of apoptosis (programmed cell death) to cellular damage in human liver disease is unknown. Using the in situ DNA end labelling method (ISEL), evidence was sought of programmed cell death (PCD) in liver tissue from patients with various liver diseases. In particular, the study aimed to determine whether PCD is involved in either the loss of interlobular bile ducts (vanishing bile duct syndrome—VBDS) or the perivenular hepatocyte drop-out, both of which are characteristic of irreversible graft rejection. Large numbers of apoptotic hepatocytes were found in pervenular areas in tissues taken from patients with chronic graft rejection. Significant hepatocyte apoptosis, was not seen in long-term stable allografts, primary biliary cirrhosis, cholestasis, paracetamol-induced fulminant hepatic failure, or fulminant hepatic failure of indeterminate origin (non-A, non-B, non-C hepatitis). Bile ducts rarely stained positively, but mononuclear cells present in the post-transplant tissues were frequently positive, showing nuclear or cytoplasmic staining. The presence of cytoplasmic staining suggested that some mononuclear cells had ingested apoptotic DNA from other cellular sources. PCD may thus contribute to the perivenular hepatocyte loss in chronic rejection. The absence of ductular epithelial cell staining suggests that PCD is not involved significantly in the bile duct loss of VBDS. Furthermore, apoptosis of monomuclear cells implies that PCD may be involved in regulating the inflammatory cell infiltration of graft rejection.     

T-lymphocyte effects on murine cytomegalovirus pulmonary infection.

Cytomegalovirus (CMV) infections were induced in male BALB/c mice treated with rat monoclonal antibodies (MAb) to deplete selectively CD8 and CD4 cell populations in vivo. The animals were then inoculated intraperitoneally with murine CMV and the infection was monitored virologically and histologically. High concentrations of virus were found in the lungs of mice depleted of CD4 or both CD4 and CD8 cells. These animals developed pulmonary infections that persisted for at least 49 days after inoculation. In contrast, immunologically intact mice and those administered anti-CD8 MAb experienced only a transient infection of the lungs. Focal interstitial infiltrates of mononuclear cells were demonstrated in pulmonary tissues of CD4 MAb-treated animals, but not in normal mice and those receiving the CD8 MAb. Adoptive transfer of CD4 cells to animals (rendered immune-incompetent by thymectomy and irradiation) protected against pulmonary infection and the development of interstitial pneumonia. Mice treated with CD4 MAb failed to produce specific CMV antibody, whereas the depletion of CD8 cells had no effect on antibody elaboration. Administration of anti-CD4 and CD8 MAb did not affect virus replication in the salivary glands, the preferential site for CMV infection in the mouse. Induction of pulmonary infection and interstitial pneumonia by CMV in BALB/c mice is mediated by CD4 T cells.     

Diagnosis of cytomegalovirus infection in cyclosporin-treated renal allograft recipients

The relative merits of antibody response and virus shedding as markers of cytomegalovirus (CMV) infection among cyclosporin-treated renal allograft recipients were analysed. CMV-specific antibody was assayed by IgG-specific radioimmunosorbent test (RIST) and by complement fixation test (CFT). CMV shedding was assayed by virus isolation and by the rapid test immediate early nuclear antigen detection (IENAD). RIST and CFT detected seroconversion in similar numbers of patients, but the former test was the more sensitive when CMV antibody was sought in pretransplant sera to differentiate primary from recurrent infection. IENAD detected or excluded CMV shedding for more urine specimens than virus isolation (462/515 [90%] vs. 366/515 [71%]), but the reverse applied to saliva specimens (33/57 [58%] vs. 54/57 [95%]). The high specificity of IENAD allowed positive results by IENAD to be accepted when virus isolation failed to provide a result. IENAD was, however, less sensitive than virus isolation even when specimens yielding CMV by IENAD, but no result by virus isolation, were included in the analysis (27/44 [61%] vs. 38/44 [86%]). Assays of both antibody response and virus shedding were required to maximise the diagnosis of recurrent CMV infections, but the former assay detected all primary CMV infections. The diagnostic implications of these results are discussed.     

铁离子沉积与心脏移植急性排斥反应相关性研究

目的：探讨铁离子在心脏移植急性排斥反应的作用。 方法： 建立小鼠颈部异位心脏移植模型，实验分为同系移植组（C57BL/6→C57BL/6）和同种异体移植组（BALB/c→C57BL/6），普鲁士蓝染色观察铁离子在心肌组织的沉积情况，免疫组化法观察HO-1在心肌组织的表达。 结果： 铁离子在浸润的巨噬细胞中沉积，HO-1主要在浸润的炎性细胞中表达，两者随急性排斥反应的加重表达上调。 结论： 铁离子沉积与心脏移植急性排斥反应的病理过程相关，且可作为心脏移植急性排斥反应的监测指标。     

Urinary cytodiagnosis of acute renal allograft rejection using the cytocentrifuge.

The clinical diagnosis of acute renal allograft rejection in immunosuppressed recipients can often be predicted or confirmed on the basis of characteristic urinary cytologic findings. Use of cytocentrifugation permits a simple, rapid, reproducible and semiquantitative means of preparing cytologic urinary specimens of diagnostic quality from small quantities of urine. The cytodiagnosis of acute renal rejection was established before or on the same day a clinical diagnosis of rejection was made in the majority of renal transplant cases studied over a 12-month period. Renal tubular cells were found to be the exfoliated cells of greatest value in predicting an acute rejection episode, and their persistence has prognostic importance.     

T suppressor lymphocytes reverse ongoing acute allograft rejection

(LEW X BN)F1 cardiac allografts are rejected within 8 days in untreated LEW recipients. At the critical time point of 5 days after transplantation, the obviously rejecting grafts are enlarged and maximally infiltrated by host cells as shown by 111In-labeled lymphocyte tracer studies. However, when such hearts were retransplanted back to naive (LEW X BN)F1 secondary hosts, they survive indefinitely, showing that even late rejection is reversible in the absence of sustained host immunological drive. Attempts were then made to abrogate this advanced immune responsiveness using Cyclosporine (CsA). CsA therapy (15 mg/kg/day for 7 days) starting from day 5 produced indefinite graft survival, similar as if initiated at the time of operation. Addition of exogenous IL-2, which drives the proliferation of Tc, could not reverse this effect. Serial changes in phenotype of lymphocyte subpopulations infiltrating both acutely rejecting and indefinitely functioning cardiac allografts in unmodified and CsA treated hosts, respectively, were then studied. Ratio of Th:Tc/s cells in acutely rejecting grafts was 1.6 by day 3; it inverted abruptly to 0.7 by day 5-6, suggesting predominance of Tc/s during the later stages of allograft rejection. Similarly, treatment with CsA produced a transient depression of Th, with recovery of original Th:Tc/s ratio during the next 2-3 weeks. Adoptive transfer experiments were then performed to investigate the functional significance of these findings.(ABSTRACT TRUNCATED AT 250 WORDS)     

A quantitative study of the renal corpuscles in acute renal allograft rejection.

A quantitative examination including total and differential counts of nuclei and determination of total glomerular and mesangial areas was carried out in a consecutive series of biopsies from 14 patients with acute renal allograft rejections. The biopsies included in the study were taken within 4--30 days after transplantation because of suspected acute rejection, and histological examination revealed interstitial and vascular signs of rejection without the presence of cortical infarcts. Mesangial area per cent of total area was found to be significantly higher in allografts than in control kidneys, just as a statistically significant increase in the number of mesangial nuclei was demonstrated. Three of the 14 allografts had to be rechanges in these 3 biopsies were more pronounced than those in the remaining biopsies. It is suggested that quantitative glomerular studies might yield data of significance for prediction of the ultimate fate of the graft.     

Differential distribution of tenascin and cellular fibronectins in acute and chronic renal allograft rejection.

BACKGROUND: Acute and chronic renal allograft rejection injuries involve, albeit variably, all compartments of the organ and are associated with significant structural changes. We hoped to gain new insights into these phenomena by determining distribution of certain extracellular matrix proteins known to be involved in architectural remodeling processes. EXPERIMENTAL DESIGN: Frozen tissue samples from biopsies of acute (n = 14) and chronic (n = 12) human renal allograft rejections were studied to compare distribution of tenascin, the extradomains A and B (EDA, EDB), and oncofetal (Onc) isoforms of cellular fibronectin (cFn). Normal kidneys (n = 4) served as controls. Cryosections were immunostained by the avidin-biotin-complex method with monoclonal antibodies specific for those molecules. RESULTS: In acute rejection, reactivity for tenascin and EDA-cFn was increased slightly to moderately in glomerular mesangia and in most vessels while it was intensely and diffusely increased in the interstitium. Rarely were focal EDB-cFn and Onc-cFn reactions seen in lesions deemed to reflect acute injury. In chronic rejection, tenascin and EDA-cFn were strongly increased in most glomerular mesangia and in vascular walls but unevenly in the interstitium. In rare glomerular synechiae and vessels, enhanced staining for tenascin and EDA-cFn as well as EDB-cFn and Onc-cFn was noted while in obsolete glomeruli only EDB-cFn and Onc-cFn were detected. The enhanced distribution of tenascin and EDA-cFn partly reflected that noted during nephrogenesis, whereas staining patterns for EDB-cFn and Onc-cFn differed from their fetal counterparts. CONCLUSIONS: Tenascin and EDA-cFn are strongly and preferentially expressed in the interstitial and vascular compartments of acute and chronic renal rejection injury suggesting that, in these sites, active repair and remodeling occur during both phases of the rejection process irrespective of the changes seen by conventional microscopy. Tenascin, EDA-cFn as well as EDB-cFn and Onc-cFn are all involved, albeit variably, in the glomerular and vascular alterations of chronic rejection. The finding of tenascin and of the three isoforms of cFn in glomerular synechiae with actively proliferating epithelium suggests that certain epithelial cells might partake in the synthesis of these molecules.     

移植物细胞因子表达与小肠移植排斥反应相关性的实验和临床病例研究

目的结合移植物细胞因子表达的实验和临床病例研究，探索早期诊断小肠移植急性排斥反应的细胞因子相关的敏感指标。方法①两例短肠综合症患者接受活体小肠移植术。定期或病情变化时随时行内镜组织学检查并测定受体大鼠移植物sIL-2R、IL-4、IL-6和IFN-γ表达水平。②BN-LEW大鼠部分小肠移植，A组：SBT（n=20）；B组：SBT＋FK506（2．5mg／kg，n=20），术后第1、4、7、14和30天测定受体大鼠移植物sIL-2R、IL-4、IL-6和IFN-γ水平同时取移植肠黏膜行病理组织学检查。结果首例术后67d发生排斥反应，第2例于术后20d和80d分别发生强烈排斥反应。发生排斥反应相应时相均发生IL-2Rα、IFN-γ表达的显著升高，排斥反应控制后IL-2Rα迅速恢复，但IFN-γ仍在较高水平维持较长时间。A组大鼠术后第1天始即显示IL-2Rα、IFN-γ和IL-6表达的显著升高，于术后7d达到最高，移植后14d仍在高水平。B组仅术后第1天出现IL-2Rα、IFN-γ和IL-6表达的迅速升高，第4天已恢复至基本正常。结论移植物IL-2Rα、IFN-γ表达的升高与小肠移植急性排斥反应密切相关，有望成为早期诊断小肠移植急性排斥反应的敏感指标。     

Virological and serological diagnosis of cytomegalovirus infection in bone marrow allograft recipients

To detect cytomegalovirus (CMV) infections, a total of 1,074 cultures of urine, saliva, or blood were collected weekly from 43 consecutive patients undergoing allogeneic bone marrow transplantation. Twenty-three patients were seronegative before transplant and primary infection occurred in 2 (9%). Twenty patients were initially seropositive and recurrent infections occurred in 5 (25%). Three patients in the recurrent group had proven CMV pneumonitis; viraemia was detected in two recipients, while the third had CMV isolated only from bronchial lavage fluid. The serological response of the 43 patients was defined by testing 559 serial sera for specific IgG and IgM antibodies by radioimmunoassay. Passive acquisition of IgG antibodies from blood products was found in 78% of initially seronegative recipients. One patient with primary infection responded in a pattern typical of immunocompetent individuals with long-term production of specific IgG and transient production of specific IgM antibodies. The second patient also had a typical response, but this was delayed until several weeks after the start of virus excretion. In patients with recurrent infections, specific IgM production did not correlate with episodes of virus excretion. Three of five such patients failed to mount a specific IgM response, and these were the only patients in the study to develop CMV pneumonitis. We conclude that CMV infection in bone marrow recipients can only be diagnosed by detection of virus; therefore, the ability of these patients to mount humoral immune responses should not be relied upon for diagnostic purposes.     

细胞凋亡与异体移植

细胞凋亡在器官移植领域越来越受到广泛的重视 ,而且在不同器官的同种异体移植过程中均发现有细胞凋亡发生。本文综述了近年来有关细胞凋亡与移植排斥反应、免疫损伤以及免疫耐受的关系等方面的研究进展     

Complement components in kidney allograft recipients: relationship to cytomegalovirus infection

Serum complement profiles of 19 renal transplant recipients were studied serially before and after renal transplantation to determine if there is any relationship between cytomegalovirus (CMV) infection and alteration in the serum complement (C) levels. Most patients had low serum C3 and C4 levels before transplantation, but afterwards these levels increased in some patients. Clq was elevated before and after transplantation. Factor B was low before transplantation, but after surgery, its level approached normal in patients without cytomegalovirus viremia, whereas in those with viremia, Factor B level became even more depressed. Circulating Factor B fragments were found in the sera of five out of seven patients with active cytomegalovirus infection, which suggests activation of the alternative pathway possibly related to active CMV infection.     

Cellular mechanisms of allograft rejection.

It is generally agreed that a multiplicity of mechanisms are involved in the rejection of various grafts across different histocompatibility barriers. Recent publications have concentrated less on the characterization of the cells involved in the rejection process and more on their initial activation and their infiltration into the graft.     

Neutrophil response and function during acute cytomegalovirus infection in guinea pigs.

The mobilization and functional characteristics of polymorphonuclear leukocytes (PMNs) at the site of an inflammatory stimulus were studied during acute cytomegalovirus infection in guinea pigs. Weanling Hartley strain guinea pigs were inoculated subcutaneously with approximately 10(6) 50% tissue culture infective doses of virulent salivary gland-passaged guinea pig cytomegalovirus. The virus was uniformly present in bone marrow, buffy coat, and casein-elicited peritoneal exudate cells 5 to 7 days after the inoculation. The mean numbers of circulating PMNs in the animals were 2,862/microliters in uninfected controls and 880/microliters in infected animals. The total peritoneal PMNs recovered 14 h after casein injection were 491 X 10(6) and 237 X 10(6) in control and infected animals, respectively. The number of 50% tissue culture infective doses of guinea pig cytomegalovirus per 10(6) purified peritoneal PMNs was 10(2.17). Neutrophil O2 consumption was similar in infected and control animals in response to either stimulation by a neutrophil activator, phorbol myristate acetate, or phagocytosis of Staphylococcus aureus. However, the maximal rate of H2O2 release and the percent killing of S. aureus by peritoneal exudate cells from infected animals were significantly reduced compared with uninfected controls during acute infection. Granulocytopenia, a decreased mobilization of PMNs to the site of the inflammatory stimulus, a diminished cellular release of H2O2 in response to a bacterial stimulus, and a modest reduction in bacterial killing were demonstrated during experimental acute cytomegalovirus infection. Such reductions in granulocyte number and function at inflammatory sites during this type of infection could alter antimicrobial defenses.