Identification and evolution of nsLTPs in the root nodule nitrogen fixation clade and molecular response of Frankia to AgLTP24

Non-specific lipid transfer proteins (nsLTPs) are antimicrobial peptides, involved in several plant biological processes including root nodule nitrogen fixation (RNF). Nodulating plants belonging to the RNF clade establish symbiosis with the nitrogen-fixing bacteria rhizobia (legumes symbiosis model) and Frankia (actinorhizal symbiosis model) leading to root nodule formation. nsLTPs are involved in processes active in early step of symbiosis and functional nodule in both models. In legumes, nsLTPs have been shown to regulate symbiont entry, promote root cortex infection, membrane biosynthesis, and improve symbiosis efficiency. More recently, a nsLTP, AgLTP24 has been described in the context of actinorhizal symbiosis between Alnus glutinosa and Frankia alni ACN14a. AgLTP24 is secreted at an early step of symbiosis on the deformed root hairs and targets the symbiont in the nitrogen-fixing vesicles in functional nodules. nsLTPs are involved in RNF, but their functions and evolutionary history are still largely unknown. Numerous putative nsLTPs were found up-regulated in functional nodules compared to non-infected roots in different lineages within the RNF clade. Here, results highlight that nodulating plants that are co-evolving with their nitrogen-fixing symbionts appear to have independently specialized nsLTPs for this interaction, suggesting a possible convergence of function, which opens perspectives to investigate nsLTPs functions in RNF.

Assessing the conversion of electronic medical record data into antibiotic stewardship indicators

BACKGROUND

Measuring the appropriateness of antibiotic use is crucial for antibiotic stewardship (ABS) programmes to identify targets for interventions.

OBJECTIVES

To assess the technical feasibility of converting electronic medical record (EMR) data into ABS indicators.

METHODS

In this observational feasibility study covering a period of 2 years, the EMRs of patients hospitalized at a large non-university hospital network and receiving at least one dose of a systemic antibiotic were included. ABS indicators measuring steps in the process of antibiotic prescription proposed by the literature were collected and rephrased or defined more specifically to be calculable if needed. Algorithms were programmed in R to convert EMR data into ABS indicators. The indicators were visualized in an interactive dashboard and the plausibility of each output value was assessed.

RESULTS

In total, data from 25 337 hospitalizations from 20 723 individual patients were analysed and visualized in an interactive dashboard. Algorithms could be programmed to compute 89% (25/28) of all pre-selected indicators assessing treatment decisions automatically out of EMR data, with good data quality for 46% (13/28) of these indicators. According to the data quality observed, the most important issues were (i) missing or meaningless information on indication (e.g. 'mild infection') and (ii) data processing issues such as insufficiently categorized metadata.

CONCLUSIONS

The calculation of indicators assessing treatment decisions from EMRs was feasible. However, better data structure and processing within EMR systems are crucial for improving the validity of the results.

A Nonspecific Lipid Transfer Protein with Potential Functions in Infection and Nodulation

The response of Alnus glutinosa to Frankia alni ACN14a is driven by several sequential physiological events from calcium spiking and root-hair deformation to the development of the nodule. Early stages of actinorhizal symbiosis were monitored at the transcriptional level to observe plant host responses to Frankia alni. Forty-two genes were significantly upregulated in inoculated compared with noninoculated roots. Most of these genes encode proteins involved in biological processes induced during microbial infection, such as oxidative stress or response to stimuli, but a large number of them are not differentially modulated or downregulated later in the process of nodulation. In contrast, several of them remained upregulated in mature nodules, and this included the gene most upregulated, which encodes a nonspecific lipid transfer protein (nsLTP). Classified as an antimicrobial peptide, this nsLTP was immunolocalized on the deformed root-hair surfaces that are points of contact for Frankia spp. during infection. Later in nodules, it binds to the surface of F. alni ACN14a vesicles, which are the specialized cells for nitrogen fixation. This nsLTP, named AgLTP24, was biologically produced in a heterologous host and purified for assay on F. alni ACN14a to identify physiological effects. Thus, the activation of the plant immunity response occurs upon first contact, while the recognition of F. alni ACN14a genes switches off part of the defense system during nodulation. AgLTP24 constitutes a part of the defense system that is maintained all along the symbiosis, with potential functions such as the formation of infection threads or nodule primordia to the control of F. alni proliferation. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Temporal and structural patterns of extended-spectrum cephalosporin-resistant Klebsiella pneumoniae incidence in Swiss hospitals

BACKGROUND

Routine surveillance data revealed increasing rates of invasive extended-spectrum cephalosporin-resistant Klebsiella pneumoniae (ESCR-KP) in Switzerland, from 1.3% in 2004 to 8.5% in 2019.

AIM

The main aim of this study was to understand the causes of this recent trend, specifically to identify predictors affecting the incidence of invasive ESCR-KP infections in Switzerland.

METHODS

A retrospective observational multi-centre study was conducted in 21 Swiss hospitals over a period of 11 years (2009-2019). Potential predictor variables for the incidence of invasive ESCR-KP infections were studied with a multiple linear regression model. In an additional analysis, the overall ESCR-KP incidence (all sample sites) was investigated.

FINDINGS

An increasing incidence of invasive ESCR-KP infections from 0.01 to 0.04 patients per 1000 bed-days was observed between 2009 and 2019 and confirmed by multiple linear regression analysis (P < 0.01). ESCR-KP incidence was higher in university hospitals (P < 0.01) and in the French-speaking region than in the German-speaking region (P < 0.01). There was no association with antibiotic consumption. Analysing the overall ESCR-KP incidence (all sample sites) revealed high variability between university hospitals, mainly due to a high proportion of patients with screening isolates at Geneva University Hospital (50% of patients with ESCR-KP).

CONCLUSION

The incidence of invasive ESCR-KP infections increased in Switzerland between 2009 and 2019 and was not associated with antibiotic consumption. Our findings indicate that, in this low-incidence setting, structural factors such as the hospital type and the linguistic region play a more important role in relation to ESCR-KP incidence than the hospital's antibiotic consumption.

[Stem cell-based strategies in vascular surgery]

Critical chronic ischemia in patients with underlying arterial occlusive disease requires vascular reconstructive surgery. The limited supply of suitable small-diameter autologous vascular grafts in many patients and obvious disadvantages of synthetic bypass material demand the development of clinically usable tissue-engineered blood vessel substitutes. Despite substantial progress in the field over the last two decades, their implementation into the clinical routine has been challenging. The limited replicative life span of human adult vascular cells and their slow rate of collagenous matrix production in vitro have posed important problems in the development of mechanically robust and biologically functional engineered grafts. With recent advances in stem cell research, new cell sources for vascular tissue engineering have become available. In particular, the discovery of human induced pluripotent stem (iPS) cells derived from adult differentiated cells, as well as of human multipotent adult mesenchymal stem cells without gene modification requirements and related safety concerns, may advance the development of novel autologous cell-based tissue engineering approaches. Here we discuss recent developments in the field of vascular progenitor cells and opportunities and challenges for the clinical translation of stem cell-engineered vascular tissue substitutes.

Impact of peritoneal carcinomatosis in the disease history of colorectal cancer management: a longitudinal experience of 2406 patients over two decades

Background:

Recent therapeutic developments demand for an update of information on natural history, risk factors and prognosis of peritoneal carcinomatosis (PC) of colorectal origin. Therefore, prospective registry data should provide information about incidence, predictors and outcome.

Methods:

From a prospectively expanded single-institutional database with 2406 consecutive patients with colorectal cancer (CRC), clinical, histological and survival data were analysed for independent risk factors and prognosis. Findings were then stratified to the era of treatment without chemotherapy, 5-Fluorouracil-only and contemporary systemic chemotherapy, respectively.

Results:

Overall, 256 (10.6%) patients were diagnosed with PC thereof 141 (5.85%) with metachronous PC. Independent risk factors for the development of metachronous PC were age <62 years, N2-status, T4-status, location of the primary in the left colon or appendix. In the era of contemporary systemic chemotherapy, prognosis for PC improved only not-significantly (median survival of 17.9 months vs 7.03 months, P=0.054).

Conclusion:

Despite improvement in the overall outcome with prolonged median survival for the complete patient cohort with CRC, those patients with PC have not experienced the same benefit. In the era of contemporary systemic chemotherapy, progress in treatment resulted in only limited survival benefit. Thus, continuous efforts for further therapeutic advancements should be undertaken in these patients diagnosed with PC.

Tumor necrosis factor-α is associated with positive lymph node status in patients with recurrence of colorectal cancer--indications for anti-TNF-α agents in cancer treatment

INTRODUCTION

The progressive growth of malignancies is accompanied by a decline in the immune response through mechanisms which are poorly understood. Apoptosis and induction of inflammation by tumor released cytokines as tumor escape mechanisms have been proposed to play an important role in colorectal carcinogenesis.

METHODS

Expression of Tumor necrosis factor-alpha (TNF-α) was analyzed in colorectal cancer specimen and the cancer cell line HT-29 by immunohistochemistry and RT-PCR. TNF-α expression on protein and mRNA level were correlated with clinical characteristics and impact on survival. TNFR-1 was co-labelled with TNF-α and CD8+ cytotoxic T cells in immunofluorescence double staining experiments.

RESULTS

94% (n=98/104) of the patients with CRC expressed TNF-α. High TNF-α expression was significantly associated with positive lymph node stage and recurrence of the tumor. Multivariate analysis revealed high TNF-α expression as an independent prognostic factor. Immunohistochemistry was correlated with RT-PCR results (τ=0.794). Immunofluorescence double staining experiments revealed increased TNFR-1 expression by CD8+ cells.

CONCLUSIONS

TNF-α expression by tumor cells may be an efficient immunological escape mechanism by inflammation-enhanced metastases and probably by induction of apoptosis in tumor-infiltrating CD8+ immune cells resulting in a down regulation of the tumoral immune response. Our data support the role of tumor-derived TNF-α expression as an important promoter of tumoral immune escape mechanisms and malignant progression, and suggest that analysis on either protein (immunohistochemistry) or RNA level (RT-PCR) can be used effectively in this respect. Targeting TNF-α may be a promising option, especially in cases with high TNF-α expression and positive lymph node metastases.

Effects of three amendments on extractability and fractionation of Pb, Cu, Ni and Sb in two shooting range soils

Contamination of shooting range soils with toxic trace elements, in particular Pb and Sb, is of increasing environmental concern worldwide. We studied the extractability of Sb, and other metals in two shooting range soils: a calcareous soil (pH 8) with low organic carbon (0.5%) and a non-calcareous soil (pH 6.3) with elevated organic carbon content (5%). Both soils contained total concentrations of around 500 mg kg(-1) Pb, 65 mg kg(-1) Cu, 100 mg kg(-1) Zn and 20 mg kg(-1) Sb. We tested the effects of Ca(OH)(2), phosphate and sodium humate amendments on metals and Sb extractability. Extracts with H(2)O and NaNO(3) contained 0.02-0.05% of the total Zn and Pb; 0.1-0.5% of total Ni and Cu and approximately 1% of total Sb. Sequential extraction procedure of Zeien and Brümmer resulted in similar percentages for the sum of the two most labile fractions (F1+F2) in two soils: 10% Pb, and 15-20% Sb. Water and NaNO(3)-extractable Sb concentrations increased after phosphate addition, but were not affected by the addition of sodium humate. The results show that leaching of Sb from shooting ranges into ground and surface waters may generate a serious environmental risk under widely different soils conditions.

Fractionation of persistent organic pollutants in fish oil by high-performance liquid chromatography on a 2-(1-pyrenyl)ethyl silica column

The analysis of persistent organic pollutants in foodstuffs has become necessary for control of their levels in products for human and animal consumption. These analytical procedures usually require a fractionation step in order to separate the different families of pollutants to avoid interferences during the instrumental determination. In this study the separation was carried out on a 2-(1-pyrenyl)ethyl silica column, where analyte fractionation was based on differences in planarity and aromaticity. The fractionation of several types of persistent organic pollutants found in fish oil samples was studied; the pollutants included polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers, and some organochlorine pesticides. Fractions were analyzed by high-resolution gas chromatography with electron-capture detection and high-resolution gas chromatography-high resolution mass spectroscopy. Finally, the whole method (including the purification, fractionation, and instrumental determination steps) was validated and successfully applied to the analysis of several samples of fish oil.

Persistent organic pollutants (PCDD/Fs, dioxin-like PCBs, marker PCBs, and PBDEs) in health supplements on the Spanish market

During the last years, consumption of health supplements has increased in our society. They are recommended as an additional source of minerals, vitamins, omega-3 and omega-6 fatty acids, in the diet. A lot of these supplements contain oils among their components (fish oils or vegetable oils), especially those recommended for their omega-3 content. Due to their persistence and lipophilic characteristics, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), marker PCBs, and polybrominated diphenyl ethers (PBDEs) bioaccumulate in fat tissues, especially in those animals, as fish, which show low metabolic capability. Therefore, the consumption of nutritional supplements with oil components can increase the intake of persistent organic pollutants (POPs) through the diet. The aim of this study was to analyse 15 of these supplements commercialized in Spain to determinate their POPs concentrations and their intake for their consumers. Concentrations of POPs in the dietary supplements studied (PCDD/Fs: 0.04-2.4 pg TEQ g(-1); dl-PCBs: 0.01-12.1 pg TEQ g(-1); marker PCBs: 0.17-116 ng g(-1); and PBDEs: 0.07-18.2 ng g(-1)) were in the low-medium range of those reported in literature for other countries. Vegetable oil and mineral-based supplements showed concentrations of POPs clearly lower than those based on fish oil. Among these, those based on cod liver oil presented the highest concentrations detected in the study, exceeding the maximum levels established in European regulations for marine oils for human consumption. In general, the intake of POPs via the consumption of these supplements would be lower than the intake derived from fish consumption.

Tumor cell dissemination in a human colon cancer animal model: orthotopic implantation or intraportal injection?

BACKGROUND

The development of therapeutic strategies for treatment of metastasized colorectal carcinoma requires biologically relevant and adequate animal models generating both metastases and the dissemination of tumor cells.

METHODS

To prove the efficiency of orthotopic implantation concerning induction of minimal residual disease (MRD) colorectal cancer tissue from 10 patients was transplanted orthotopically into nude mice. In the intraportal injection model 1 x 10(6) HT-29 human colon cancer cells were injected. We investigated by histological studies and CK-20 RT-PCR the occurrence of hematogenous metastases and the dissemination of human colon cancer cells in bone marrow.

RESULTS

Following orthotopic implantation of human colon cancer tissue the lymph node and hepatic metastasis rates were low. MRD as reflected by CK-20 positivity of the bone marrow was present in 22.2%. The intraportal injection of 1 x 10(6) HT-29 human colon cancer cells produced hepatic metastases in up to 89% of all animals. The intraportal injection of 1 x 10(6) cells also generated MRD in the bone marrow in 63% of animals.

CONCLUSIONS

The intraportal injection model represents a biologically relevant and adequate animal model for the induction of both reproducible hepatic metastasis and MRD in the bone marrow. In this regard it seems to be superior to the orthotopic implantation model.

[Antibody treatment in colorectal cancer--what the surgeon needs to know]

Advances in the medical treatment of colorectal cancer patients have resulted in considerable improvements through the introduction of new cytotoxic drugs. The significant progress in molecular and tumour biology has produced a great number of targeted, tumour-specific, monoclonal antibodies that are now in various stages of clinical development. Two of these antibodies, cetuximab (Erbitux) und bevacizumab (Avastin), directed against the epidermal growth factor receptor (EGFR) and the vascular epithelial growth factor (VEGF), respectively, have recently been approved for use in metastatic colorectal cancer. The combination of well-known and newly developed cytotoxic agents with monoclonal antibodies makes the medical treatment of colorectal cancer patients considerably more complex, but also provides additional therapeutic strategies for patients in advanced stages of disease.

Upgrading of wastewater treatment plants for nutrient removal under optimal use of existing structures

Upgrading of wastewater treatment plants under maximum use of existing structures is often an important requirement, but also useful due to a number of aspects. Because of a change in legal effluent requirements, a number of plants in Austria, typically aged 20+ years, were required to be extended. The two stage activated sludge HYBRID-process often provides an interesting design alternative for such plant upgrades, especially in case an anaerobic sludge treatment stage already exists. It provides high nutrient removal capacity at low area demand. The latter is especially important in cases where no or very limited extension area is available making it the key factor to preserve a site for future use. Based on two full stage case studies the adaptation of the plant layout, first operation results and a synthetic cost comparison to a conventional (single stage) plant extension are given.

The ING tumor suppressor genes and their specific role in the pathogenesis of renal cell carcinoma

10045

Background: The inhibitor of growth (ING) family of tumor suppressor genes is involved in cell cycle arrest, regulation of gene transcription as well as DNA repair. p33ING1b plays an important role in the pathogenesis of certain carcinomas by modulation of p53. We analyzed p33ING1b and p29ING4 gene expression together with specific immune responses in patients with renal cell carcinoma (n=50) at different tumor stages. Methods: Peripheral blood lymphocytes (PBMCs) from patients (Robson stage I-IV) were stimulated with pools of synthetic overlapping peptides of the p33ING1b or p29ING4 sequences encompassing the full length sequence of these two genes. PBMCs and tumor specimens were further characterized (ELISPOT, FACS, immunohistology, Real Time PCR). Results: T cells from stage I/II patients expressed higher IL-10 (n=5) than IFN-γ (n=5) levels in response to p29ING4 peptides. However, distinct residues of peptides were found that induced a Th2 type response (IL 10, n=5) in stage III/IV patients. Interestingly, distinct residues induced a Th1 (IFN-γ, n=5) response in the latter patients. Lymphocytes stimulated with p33ING1b peptide pools expressed IFN-γ as well as IL-10, independently from the tumor stage. Remarkably, immunohistochemical staining as well as Real Time PCR analysis of tumor specimens revealed higher numbers of CD4/CD8, CD4/CD25, CD4/Foxp3, CD4/CTLA-4, and NK cells as well as IL-10, IFN-γ, and Annexin V expression at the tumor site of stage I/II patients than later tumor stages. However, stronger staining and gene expression of p33ING1b as well as p29ING4 together with a reduced staining and expression of p53 was observed in stage III/IV patients. A correlation between the stage and the grading of the tumor was not present. Conclusions: In order to exert its function as a growth arrest and apoptosis inducing protein, p53 needs to interact with other tumor suppressor genes like the ING gene family. Subsequently, the loss of ING function may be a potential mechanism for the inactivation of p53 function in renal cell carcinoma. The results of this study may provide the basis for immune therapeutical strategies (induction of apoptosis or of a Th1 response using a vaccination protocol in particular with p29ING4 in the early stage of the disease) in renal cell carcinoma.

No significant financial relationships to disclose.

PD-1/PDL-1 expression in colorectal cancer and its implications for tumor immune evasion

10046

Background: Malignant tumors may evade immunological surveillance by an active downregulation of T cell activation by PD-1 (programmed death 1)/ PDL-1 signaling. This would result in a decreased immune response, thus, promoting tumor growth. Methods: We analyzed the expression of PD-1/PDL-1 genes, cytokines, and T cell subpopulations in tumor tissues of 81 consecutive patients who underwent surgery for primary colorectal cancer according to their UICC stage. Expression of PD-1/PDL-1, T cell subpopulations, and cytokines in tumor tissues were assessed using immunostaining, immunofluorescence, and Real Time PCR. Results: PDL-1 expression on tumor cells was significantly increased, whereas PD-1 expression on tumor cells was decreased at UICC stage III/IV. However, PD-1 expression on infiltrating CD4+ T cells was detectable in patients with advanced tumors whereas PDL-1 expression on CD4+ cells was particularly found at early stages. More regulatory T cells (CD4+CD25+CTLA-4+Foxp3+) were observed in tumors of stage III/IV patients compared to early stages. In addition, a remarkably increased amount of IL-10 was observed in the tumors of UICC III/IV patients. High expression of TGF-ß receptor II in tumors correlated with a progressive course of the disease and tumor relapses, i.e. TGF-ß RII in early tumor stages was indicative for early tumor progress. Conclusions: Our findings indicate that PDL-1 plays a key role during tumor progression and that regulatory T cells are involved in the process of evasion from immune surveillance. The elevated PDL-1 expression on T cells at early tumor stages suggests that PD1/PDL-1 interaction mediates inhibitory signals between T cells enabling the tumor to progress. PDL-1 blockade may prove to be a valuable approach for cancer immunotherapy.

No significant financial relationships to disclose.

Molecular and cellular events associated with ischemia/reperfusion injury

I/R is an important non-specific, antigen independent event, which significantly influences the outcome of transplanted organs. Increasing graft immunogenicity and host alloresponsiveness inflicts additional deleterious effects. Ischemia has also been associated with donor conditions such as brain death and the non-heart-beating donor. As an event surrounding organ procurement, preservation and revascularization occurring early in the transplant process, it initiates a cascade of molecular and cellular events which trigger the release of proinflammatory mediators and attraction of various cell types infiltrating the tissues. This inflammatory event influences both acute functional and structural changes in the organ which contributes to reduced graft survival. Eventually, attenuation of I/R by strategies targeting various mediators and cell populations at different levels of the inflammatory cascade may constitute a means to improve both short and long-term success of solid organ grafts.

The influence of donor brain death on short and long-term outcome of solid organ allografts

Long-term survival rates of solid organ allografts have improved relatively little during the transplant experience despite more effective immunosuppression, better organ preservation techniques and advances in perioperative management. Because grafts of potentially diminished quality are increasingly accepted to reduce the severe shortage of organs, it has become apparent that a variety of donor-associated risk factors may influence adversely their short and long-term outcome. Recent interest has focused particularly on systemic changes occurring after donor brain death (BD). Numbers of experimental and clinical studies have elucidated the complexities of the hemodynamic, metabolic, neurohormonal, and other physiological alterations following this devastating central injury. This article will address the potential derangements in peripheral organs which may influence their behavior after transplantation.

Long-term small bowel allograft function induced by short-term FK 506 application is associated with split tolerance

Functional long-term allograft survival after experimental small bowel transplantation (SBT) is limited by chronic rejection. Initial application of high-dose FK 506 has been shown to induce stable long-term graft function. In order to examine whether this long-term function is associated with donor-specific tolerance, we analyzed the functional status of recipient T cells in vivo and in vitro. One-step orthotopic SBT was performed in the allogeneic Brown Norway (BN)-to-Lewis rat strain combination. FK 506 was given daily at a dose of 2 mg/kg from days 0-5 in the rejection model and from days 0-9 in the long-term functional model. Mean survival time in the rejection model was 98 +/- 2.8 days. Histological examination of these small bowel allografts disclosed signs of chronic rejection. In contrast, all animals of the long-term functional model survived long term (> 250 days) without clinical signs of chronic rejection. The latter model, furthermore, produced evidence of donor-specific tolerance. Whereas heterotopic Dark Agouti (DA) hearts were rejected regularly within 7 days, BN hearts survived indefinitely (> 70 days). In vitro, mixed leukocyte reactivity of CD4+ T cells was similarly strong against donor (BN) antigens as against third-party (DA) antigens. The split tolerance revealed by our in vivo and in vitro results enabled acceptance of both the small bowel allograft without signs of chronic rejection and of donor-specific heart allografts.

Analysis of cellular events in hepatic allografts: donor progenitors induce intragraft chimerism

Long-term graft acceptance and tolerance induction after allogeneic rat liver transplantation are well described. However, the underlying mechanisms remain unclear. In this study we investigated the cellular events within the liver graft during initial immunosuppression and long-term acceptance. Orthotopic liver transplantation was performed in the Dark Agouti (DA)-to-Lewis (LEW) and LEW-to-DA rat strain combination. In order to achieve long-term acceptance, LEW recipients of DA livers were treated with two different short-term therapies. Non-parenchymal cells (NPC) were isolated from liver allografts on days + 10 and + 100 after transplantation and donor-specific leukocytes were immunophenotyped by flow cytometry. Both the monotherapy and triple therapy prolonged graft survival (> 100 days). Liver allografts from LEW donors into DA recipients were spontaneously accepted across a complete MHC mismatch without immunosuppression. Liver allograft rejection was induced by infiltrating alloreactive immunocompetent cells. But the intensities of cell infiltration in the early and late phases after transplantation did not correlate with eventual outcome. Donor-specific NPC decreased to 18-25% on day + 10 in both therapeutic groups, but had rebounded to up to 40% by day + 100. Recurrence of donor-specific cells was caused almost exclusively by rising T cell counts. The persistence of dendritic cells in the late phase after transplantation could be clearly demonstrated. Repopulation by donor-specific T lymphocytes was observed in long-term accepted liver grafts. This recurrence may be based on the differentiation of liver-derived progenitor cells. The persistent coexistence of donor and recipient cells within the liver allograft (intrahepatic chimerism) appears to be characteristic and may be important for long-term acceptance.

Cervical lymphadenitis--a rare case of focal listeriosis

Cervical lymphadenopathy is a condition with a broad differential diagnosis. Malignant tumors, allergic reactions, autoimmune diseases as well as various infectious agents can be the cause. We report the case of a 75-year-old man who had a cervical lymphadenopathy without symptoms of infection. The draining lymph nodes were excised. Histology revealed a granulomatous abscess and culture yielded pure growth of Listeria monocytogenes. Because food is occasionally contaminated with L. monocytogenes, the pathogenesis of this condition may be similar to that of lymph node tuberculosis.

Regulatory functions of self-restricted MHC class II allopeptide-specific Th2 clones in vivo

We studied T-cell clones generated from grafts of rejecting and tolerant animals and investigated the regulatory function of Th2 clones in vitro and in vivo. To prevent allograft rejection, we treated LEW strain recipient rats of WF strain kidney grafts with CTLA4Ig to block CD28-B7 costimulation. We then isolated epitope-specific T-cell clones from the engrafted tissue, using a donor-derived immunodominant class II MHC allopeptide presented by recipient antigen-presenting cells. Acutely rejected tissue from untreated animals yielded self-restricted, allopeptide-specific T-cell clones that produced IFN-gamma, whereas clones from tolerant animals produced IL-4 and IL-10. Adoptive transfer into naive recipients of Th1 clones, but not Th2 clones, induced alloantigen-specific delayed-type hypersensitivity (DTH) responses. In addition, Th2 clones suppressed DTH responses mediated by Th1 clones in vivo and blocked Th1 cell proliferation and IFN-gamma production in vitro. A pilot human study showed that HLA-DR allopeptide-specific T-cell clones generated from patients with chronic rejection secrete Th1 cytokines, whereas those from patients with stable graft function produce Th2 cytokines in response to donor-specific HLA-DR allopeptides. We suggest that self-restricted alloantigen-specific Th2 clones may regulate the alloimmune responses and promote long-term allograft survival and tolerance.