We report on the case of an ABO-incompatible renal re-transplant recipient maintained on an intensified immunosuppressive regimen for recurrent cellular rejection episodes and transplant glomerulopathy who presented with rapidly growing hepatic tumors, radiologically suggestive of hemangiosarcoma. Upon resection and pathological work-up, the lesions revealed alveolar echinococcosis, a rare but potentially life-threatening parasitosis. Usually infection with Echinococcus multilocularis remains asymptomatic for extended periods of time and can go unrecognized for years. In the case presented, we observed an atypically rapid growth pattern of E. multilocularis that might have been due to the extent of the immunosuppressive regimen, which included repetitive anti-CD20 treatments. Retrospectively performed serological studies with enzyme-linked immunosorbent assays known to provide high sensitivity and specificity for the detection of echinococcosis in the general population, yielded ambiguous results in our immunocompromised host, which could be, in part, explained by B-cell depletion and its effects on antibody production and indirect actions on cellular immunity. In conclusion, this is the first report to our knowledge of hepatic alveolar echinococcosis in a renal transplant recipient. This case documents an altered clinical course of the parasitosis and the challenge of serological diagnostic tools under an intensified regimen of immunosuppressive agents, including rituximab.

History and admission findings: A 29-years-old Brazilian woman was admitted to hospital because of progressive dyspnoea, shivering and fever. She reported a noticeable swelling at the right mandible and an ulcerative tumor at the side of the nose.Investigations: Laboratory tests showed normocytic, normochromic anemia with an elevation of the inflammatory parameters. Radiology showed an enlargement of the upper mediastinum. Computed tomography revealed extensive, confluent lymphoma. There were groups of cervical lymph nodes, especially in the area of the right jaw. Bronchoscopy showed extensive space-occupying lesions with severe inflammation of the trachea.Diagnosis: Bronchial biopsy revealed necrotizing, granulomatous inflammation with dense infiltration of lymphatic cells. Small and spheroidal pathogens were seen within giant cells. Grocott-silver stain was positive, indicating histoplasmosis. Histological work-up of the ulcerating tumor at the side of the nose also showed Histoplasma capsulatum.Treatment and course: 8 weeks after starting specific treatment with oral itraconazole the inflammatory parameters had fallen to normal and computed tomography showed regression of the mediastinal bulge.Conclusion: Large mediastinal and cervical lymphatic masses with space-occupying bronchial lesions suggest should, in the dfferential diagnosis, consider not only malignant tumor but also infections. If the patient had been abroad (in this case in Brazil), pathogens like Histoplasma capsulatum, which is not present in Europe, have to be considered. In this immunocompetent patient the severe progression and dissemination of the disease, involving mediastinum, throat and skin, is most unusual.

Background. Optimal treatment of polyomavirus-induced allograft nephropathy (PVAN) with immunosuppressive and antiviral therapy is uncertain at present. Reduced immunosuppression is accompanied by increased risk of rejection, and antiviral agents are nephrotoxic. Leflunomide has immunosuppressive and antiviral properties and may be an alternative treatment agent. We report a two-center experience with use of leflunomide for treatment of PVAN.Patients and Methods. Thirteen renal allograft recipients were diagnosed with biopsy-proven PVAN. Treatment consisted of lowering the calcineurin-inhibitor trough level, discontinuing mycophenolate mofetil therapy, and initiating leflunomide therapy. In 8 of the 13 patients, the serum concentration of the leflunomide active metabolite A771726 was monitored.Results. Exchange of mycophenolate mofetil with leflunomide in patients with PVAN was well tolerated and safe, with no serious adverse effects or episodes of graft rejection. Mean follow-up after transplantation was 717 days, and after initiation of leflunomide therapy was 465 days. With the modified therapy, 12 patients cleared the virus at a mean of 109 days. One graft was lost due to refractory rejection accompanied by a decreasing viral load. In the other 12 patients, graft function stabilized or improved (mean [median] creatinine concentration at diagnosis, 2.39 [2.5] mg/mL, vs 2.27 [2.0] mg/dL at follow-up). Leflunomide concentration did not correlate with treatment efficiency.Conclusions. Treatment of PVAN with leflunomide, a low-dose calcineurin inhibitor, and prednisone seems to reduce viral load and stabilize renal graft function without increasing the risk of rejection. Even low serum concentrations of leflunomide support viral elimination and prevention of graft rejection.

Several protocols have been developed to effectively overcome the blood group barrier in renal transplantation. In the evolution of these protocols, one of the latest steps was the combination of anti-CD20 treatment with antigen-specific immunoadsorptions. Over the last years we have learned that these relatively new protocols carry very promising short-term and intermediate-term results which compare favorably to the outcome of ABO-compatible living donor transplantations. Latest reports suggest that combining immunoadsorptions with rituximab does not result in an increased risk of infectious complications or tumors in the first years after transplantation compared to ABO-compatible living donor transplanta-tions. We recently demonstrated that a majority of patients with isoagglutinin titers >1:128 can be safely transplanted using rituximab and immunoadsorptions without an added risk of early antibody-mediated rejections. We have also shown that a cost saving ‘on-demand strat-egy’ of postoperative immunoadsorptions based on careful titer monitoring can be used as an alternative to preemptively scheduled immunoadsorptions. Although rituximab and antigen-specific immunoadsorptions are significantly less invasive than splenectomy and plasma-pheresis, long-term follow-up of patients treated with a combination of anti-CD20 antibody and antigen-specific immunoadsorption will be needed to benchmark this therapeutic option in relation to more established protocols.

Sesquiterpene lactones are known for their anti-inflammatory activity which has been proven in various assays on DNA, mRNA and protein level. Here we report on the change in the gene expression profile in TNF-alpha stimulated human 293 cells after treatment with parthenolide using a cDNA microarray analysis. Twenty-one of 7028 genes were found to be up- and 18 down-regulated. They encode for chemoattractants, immune system proteins, glycoproteins, metabolism, serine proteinases, and transcription factors. Confirmatory analyses were carried out using quantitative real-time RT-PCR (TaqMan). Additional studies with selected genes revealed the concentration-dependent influence of parthenolide on the expression of these genes.

End stage liver disease caused by chronic infection with the hepatitis C virus (HCV) is a leading indication for liver transplantation, yet outcomes are poor since the liver graft is rapidly re-infected by HCV. Antibodies against the essential HCV receptor CD81 have been shown to inhibit HCV cell entry in vitro and in vivo and may represent an attractive treatment option. However, several CD81 variants exist at low levels in human populations.We aimed to investigate to what extent these variants function as HCV receptors and would be amenable to therapeutic interventions with CD81 antibodies. We used lentiviral expression to introduce wildtype or variant CD81 in the CD81low Lunet N4 cell line. HCV replication cycle steps and neutralization by CD81 antibodies were then investigated using full length HCV reporter viruses (HCVcc) as well as HCV pseudoparticles (HCVpp).We found that all tested CD81 variants support cell entry by HCVpp and HCVcc with an efficiency similar to wildtype CD81. Other replication cycle steps, namely intracellular RNA replication and release of new particles, were also unaffected by the presence of CD81 variants. Importantly, four neutralizing antibodies directed against the CD81 LEL (5A6, JS81, 1D6 and 1.3.3.22) retained their ability to inhibit HCV infection when wildtype CD81 on target cells was replaced with any of the CD81 variants.These data indicate that CD81 variants that exist in the human population are fully functional as HCV receptors and their presence would not diminish the efficacy of therapeutic regimens that include CD81-antibodies.

SummaryThe molecular aetiology of polycythaemia vera (PV) remains unknown and the differential diagnosis between PV and secondary erythrocytosis (SE) can be challenging. Gene expression profiling can identify candidates involved in the pathophysiology of PV and generate a molecular signature to aid in diagnosis. We thus performed cDNA microarray analysis on 40 PV and 12 SE patients. Two independent data sets were obtained: using a two‐step training/validation design, a set of 64 genes (class predictors) was determined, which correctly discriminated PV from SE patients. Separately 253 genes were identified to be upregulated and 391 downregulated more than 1·5‐fold in PV compared with healthy controls (P < 0·01). Of the genes overexpressed in PV, 27 contained Sp1 sites: we therefore propose that altered activity of Sp1‐like transcription factors may contribute to the molecular aetiology of PV. One Sp1 target, the transcription factor NF‐E2 [nuclear factor (erythroid‐derived 2)], is overexpressed 2‐ to 40‐fold in PV patients. In PV bone marrow, NF‐E2 is overexpressed in megakaryocytes, erythroid and granulocytic precursors. It has been shown that overexpression of NF‐E2 leads to the development of erythropoietin‐independent erythroid colonies and that ectopic NF‐E2 expression can reprogram monocytic cells towards erythroid and megakaryocytic differentiation. Transcription factor concentration may thus control lineage commitment. We therefore propose that elevated concentrations of NF‐E2 in PV patients lead to an overproduction of erythroid and, in some patients, megakaryocytic cells/platelets. In this model, the level of NF‐E2 overexpression determines both the severity of erythrocytosis and the concurrent presence or absence of thrombocytosis.

BACKGROUND:For years ABO-incompatible kidney transplantations were preferentially performed in Japanese centers. In order to overcome the increased risk of humoral rejections, patients were treated with multiple sessions of plasmapheresis, intensified immunosuppressive therapy and splenectomy before transplantation. Despite good long-term results regarding patient and organ survival rates, increased morbidity during the early post-transplant period prevented a broad application of this method. Recently, a new protocol including the anti-CD20-antibody (Ab) rituximab and blood group-specific immunoadsorption instead of splenectomy and plasmapheresis was published with excellent short-term results.METHODS:From April 2004 to September 2005, 11 patients were prepared for ABO-incompatible transplantation. All patients received 375 mg/m2 rituximab intravenous 3 to 4 weeks before transplantation. Immunosuppressive therapy consisted of tacrolimus, mycophenolate mofetil and prednisone and was started at least 7 days before transplantation. Intravenous immunoglobulins (0.5 g/kg) were administered the day before transplantation. Immunoglobulin G (IgG)-anti-A or -B Ab titers before starting immunoadsorption treatment ranged between 1 : 4 and 1 : 1024. Immunoadsorption treatment was started in parallel with immunosuppressive medication and was continued until the anti-A or anti -B Ab titers (IgG and IgM) were lowered to the aimed pre-transplant threshold of <1 : 8. During the early postoperative period, additional immunoadsorption treatments were performed, if the titers increased again above 1 : 8 (days 0 to 7) or 1 : 16 (days 8 to 14), respectively.RESULTS:Transplantation could be conducted in eight of 11 patients (two females, six males, mean recipient age 52+/-11 yr). The mean follow-up was 7.0 months (range 4 to 17). The blood group constellation was A1 to 0 in four cases, A2 to 0 in two cases, B to A in one case, and A1 to B in another case, respectively. On average, each patient received seven immunoadsorption treatments. All transplants showed primary function and no humoral rejections occurred. Three of our 11 patients showed rapid increases of isoagglutinin titers after each immunoadsorption treatment and thus could not be transplanted. One patient died 4 months after transplantation with a functioning graft due to sepsis secondary to pseudomembranous enterocolitis. The mean creatinine value of the remaining seven patients now is 1.6 mg/dl.SUMMARY:The use of antigen-specific immunoadsorption and an immunosuppressive regimen consisting of a conventional triple immunosuppressive therapy has shown excellent short-term results. The immunoadsorption treatment using antigen-specific columns is highly effective and even patients with high isoagglutinin titers can be transplanted. This protocol is an option for end-stage renal disease patients who have no blood group-compatible donor.

Introduction: The development and characterization of a genetic model of oral-esophageal squamous cell cancer is important in understanding the underlying molecular mechanisms of squamous carcinogenesis. Cyclin D1 overexpression and p53 mutations are the most common genetic events in human oral/esophageal squamous cell cancer. We established a mouse model in which we demonstrate that tissue specific cyclin D1 overexpression and p53 inactivation cooperate to induce a rapid progression of dysplasia and invasive cancer specific to oral-esophageal epithelium. While abrogation of the pRb and p53 pathways is necessary for the development of oral-esophageal dysplasia and cancer, it is likely that other genetic alterations may be additionally required for the induction and progression of the malignant phenotype. Methods: To distinguish genes present in normal oral and esophageal epithelium from genes specific for oral-esophageal dysplasia, we compared the gene profiles of 6 month old cyclin D1/p53±mice and w/t mice using a NIA (National Institute of Aging) 14k murine cDNA microarray. Cyclin D1/p53±mice developed moderate to severe dysplasia at that time point. After elimination of genes with signals close to background, 5190 genes were available for statistical analysis. Results: Only 83 of the examined genes were significantly regulated in oral esophageal dysplasia when compared with the expression level of normal oral or esophageal tissue (P<0.0003). Hierarchic clustering differentiated dysplastic and normal oral or esophageal epithelium, respectively. Most of the genes identified encoded proteins involved in cellular metabolism, signaling, adhesion, apoptosis and cell cycle. Notably, within this group were p53 interacting genes like PUMA or MDM2, transcription factors like GKLF, genes associated with other GI-cancers like claudin 7 as well as a large group of unknown genes. Conclusions: Expression profiling of dysplastic and normal oral-esophageal epithelium using microarray analysis may help to identify interrelated genes involved in the pathogenesis of oral-esophageal cancer. The analysis of genes expressed in microdissected cancerous lesions compared to normal and dysplastic tissue will further define genes involved in later stages of tumor development.

Background. Hepatitis C virus (HCV) envelope glycoproteins interact with several cell surface proteins including CD81, scavenger receptor B1 and heparan sulfate proteoglycans. The implication of this interaction for target cell function is unknown. Binding of HIV envelope proteins to cell surface receptors has been shown to result in a cascade of signals modulating cellular gene expression favoring viral replication (Cicala et al. 2002; Proc. Natl. Acad. Sci. 99: 9380–9385). In this study we aimed to characterize the cellular response following binding of HCV envelope glycoproteins to target cells. Experimental design. As a ligand for HCV-host cell surface interaction we used noninfectious hepatitis C virus-like particles (HCV-LPs) recently shown to bind and enter human hepatoma target cells (Barth et al. 2003; J. Biol. Chem. in press). Gene expression profiling of HepG2 hepatoma cells following binding of HCV-LP and control preparations was performed using a 7.5k human cDNA microarray. Results. 564 out of 7419 genes were differentially expressed (more than 1.5 fold up- or down-regulated) in hepatoma cells binding virus-like particles compared to control cells. Examination of transcriptional changes revealed a broad and complex transcriptional program induced by HCV-LP binding in target cells. Expression of several genes important for antiviral immune responses and lipid metabolism were significantly modulated by HCV-LP-cell surface interaction. Conclusion. Binding of HCV envelope glycoproteins to target cells results in a cascade of intracellular signals modulating cellular gene expression in the absence of viral replication. These results provide evidence that interaction of the HCV envelope with cell surface molecules alters hepatocyte gene expression and may contribute to functional changes in host cell response observed in vivo. Functional analysis of altered gene expression may give new insights in mechanisms of viral immune escape and persistence.

BACKGROUND:Chronic transplant nephropathy remains a poorly defined inflammatory process that limits the survival rate of most renal transplants. We analyzed the gene profile of chronically rejected kidney transplants to identify candidate genes that characterize chronic transplant nephropathy.METHODS:To distinguish genes present in normal renal tissue or specific for end-stage renal failure, we compared the gene profiles of 13 chronically rejected kidney transplants with 16 normal kidneys and 12 end-stage polycystic kidneys using a 7K human cDNA microarray. After elimination of genes with signals close to background, 2190 genes were available for statistical analysis.RESULTS:More than 20% of the examined genes were significantly regulated when compared with the expression level of normal renal tissue (P<0.0003). Hierarchic clustering based on 571 genes differentiated normal and transplant tissue, and transplant and polycystic kidney tissue. Most of these genes encoded proteins involved in cellular metabolism, transport, signaling, transcriptional activation, adhesion, and the immune response. Notably, comprehensive gene profiling of chronically rejected kidneys revealed two distinct subsets of chronically rejected transplants. Neither clinical data nor histology could explain this genetic heterogeneity.CONCLUSIONS:Microarray analysis of rejected kidneys may help to define different entities of transplant nephropathy, reflecting the multifactorial cause of chronic rejection.