Lymph Node Stromal Cells From Different Draining Areas Distinctly Regulate the Development of Chronic Intestinal Inflammation

The balance between the responsiveness of the intestinal immune system and the gut environment is fundamental for the maintenance of intestinal homeostasis, which is required for an adequate recognition of entering antigens. The disruption of this homeostasis by exaggerated immune response to harmless antigens can lead to the development of intestinal disorders such as inflammatory bowel disease. Stromal cells are sessile non-hematopoietic cells that build the backbone of the lymph node, an important site for the immune response induction, but also contribute to immune response and tolerance induction. However, the knowledge about the role of stromal cells in the regulation of inflammatory responses is still limited. Therefore, in this study we analyzed the influence of stromal cells on the development of chronic intestinal inflammation. Here, we show that intestinal inflammation alters the immune activation of the mesenteric lymph node-derived stromal cells. Podoplanin⁺ and CD21/35⁺ stromal cells showed increased expression of MHC class II molecules, but CD106 expression on CD21/35⁺ cells was reduced. Stromal cells secreted cytokines and chemokines such as CCL7 and CXCL16 influenced the gut-homing phenotype and proliferation of CD4⁺ and CD8⁺ T cells. Furthermore, stromal cells of peripheral lymph nodes transplanted into the mesentery attenuated colitis severity in B6-Il10^-/- mice. The reduced colitis severity in these mice was associated with increased expression of IL4 and distinct activation pattern of stromal cells derived from transplanted peripheral lymph nodes. Altogether, our results demonstrate that lymph node stromal cells impact development of chronic colitis via T cell induction. Moreover, lymph node stromal cells from different draining area due to neonatally imprinted processes distinctly regulate the induction of immune responses.

Nimotuzumab and radiotherapy for treatment of newly diagnosed diffuse intrinsic pontine glioma (DIPG): a phase III clinical study

BACKGROUND

Diffuse intrinsic pontine glioma (DIPG) is a devastating cancer of childhood and adolescence.

METHODS

The study included patients between 3 and 20 years with clinically and radiologically confirmed DIPG. Primary endpoint was 6-month progression-free survival (PFS) following administration of nimotuzumab in combination with external beam radiotherapy (RT). Nimotuzumab was administered intravenously at 150 mg/m² weekly for 12 weeks. Radiotherapy at total dose of 54 Gy was delivered between week 3 and week 9. Response was evaluated based on clinical features and MRI findings according to RECIST criteria at week 12. Thereafter, patients continued to receive nimotuzumab every alternate week until disease progression/unmanageable toxicity. Adverse events (AE) were evaluated according to Common Terminology Criteria for Adverse Events (CTC-AE) Version 3.0 (CTC-AE3).

RESULTS

All 42 patients received at least one dose of nimotuzumab in outpatient settings. Two patients had partial response (4.8%), 27 had stable disease (64.3%), 10 had progressive disease (23.8%) and 3 patients (7.1%) could not be evaluated. The objective response rate (ORR) was 4.8%. Median PFS was 5.8 months and median overall survival (OS) was 9.4 months. Most common drug-related AEs were alopecia (14.3%), vomiting, headache and radiation skin injury (7.1% each). Therapy-related serious adverse events (SAEs) were intra-tumoral bleeding and acute respiratory failure, which were difficult to distinguish from effects of tumor progression.

CONCLUSIONS

Concomitant treatment with RT and nimotuzumab was feasible in an outpatient setting. The PFS and OS were comparable to results achieved with RT and intensive chemotherapy in hospitalized setting.

Participation of the spleen in the IgA immune response in the gut

The role of the spleen in the induction of an immune response to orally administered antigens is still under discussion. Although it is well known that after oral antigen administration specific germinal centres are not only formed in the Peyers patches (PP) and the mesenteric lymph nodes (mLN) but also in the spleen, there is still a lack of functional data showing a direct involvement of splenic B cells in an IgA immune response in the gut. In addition, after removal of mLN a high level of IgA+ B cells was observed in the gut. Therefore, in this study we analysed the role of the spleen in the induction of IgA+ B cells in the gut after mice were orally challenged with antigens. Here we have shown that antigen specific splenic IgM+ B cells after in vitro antigen stimulation as well as oral immunisation of donor mice were able to migrate into the gut of recipient mice, where they predominantly switch to IgA+ plasma cells. Furthermore, stimulation of recipient mice by orally administered antigens enhanced the migration of the splenic B cells into the gut as well as their switch to IgA+ plasma cells. Removal of the mLN led to a higher activation level of the splenic B cells. Altogether, our results imply that splenic IgM+ B cells migrate in the intestinal lamina propria, where they differentiate into IgA+ plasma cells and subsequently proliferate. In conclusion, we demonstrated that the spleen plays a major role in the gut immune response serving as a reservoir of immune cells that migrate to the site of antigen entrance.

Neonatally imprinted stromal cell subsets induce tolerogenic dendritic cells in mesenteric lymph nodes

Gut-draining mesenteric lymph nodes (mLNs) are important for inducing peripheral tolerance towards food and commensal antigens by providing an optimal microenvironment for de novo generation of Foxp3⁺ regulatory T cells (Tregs). We previously identified microbiota-imprinted mLN stromal cells as a critical component in tolerance induction. Here we show that this imprinting process already takes place in the neonatal phase, and renders the mLN stromal cell compartment resistant to inflammatory perturbations later in life. LN transplantation and single-cell RNA-seq uncover stably imprinted expression signatures in mLN fibroblastic stromal cells. Subsetting common stromal cells across gut-draining mLNs and skin-draining LNs further refine their location-specific immunomodulatory functions, such as subset-specific expression of Aldh1a2/3. Finally, we demonstrate that mLN stromal cells shape resident dendritic cells to attain high Treg-inducing capacity in a Bmp2-dependent manner. Thus, crosstalk between mLN stromal and resident dendritic cells provides a robust regulatory mechanism for the maintenance of intestinal tolerance.

Bloodstream infection in paediatric cancer centres--leukaemia and relapsed malignancies are independent risk factors

In a prospective multicentre study of bloodstream infection (BSI) from November 01, 2007 to July 31, 2010, seven paediatric cancer centres (PCC) from Germany and one from Switzerland included 770 paediatric cancer patients (58% males; median age 8.3 years, interquartile range (IQR) 3.8-14.8 years) comprising 153,193 individual days of surveillance (in- and outpatient days during intensive treatment). Broviac catheters were used in 63% of all patients and Ports in 20%. One hundred forty-two patients (18%; 95% CI 16 to 21%) experienced at least one BSI (179 BSIs in total; bacteraemia 70%, bacterial sepsis 27%, candidaemia 2%). In 57%, the BSI occurred in inpatients, in 79% after conventional chemotherapy. Only 56 % of the patients showed neutropenia at BSI onset. Eventually, patients with acute lymphoblastic leukaemia (ALL) or acute myeloblastic leukaemia (AML), relapsed malignancy and patients with a Broviac faced an increased risk of BSI in the multivariate analysis. Relapsed malignancy (16%) was an independent risk factor for all BSI and for Gram-positive BSI.

CONCLUSION

This study confirms relapsed malignancy as an independent risk factor for BSIs in paediatric cancer patients. On a unit level, data on BSIs in this high-risk population derived from prospective surveillance are not only mandatory to decide on empiric antimicrobial treatment but also beneficial in planning and evaluating preventive bundles.

WHAT IS KNOWN

• Paediatric cancer patients face an increased risk of nosocomial bloodstream infections (BSIs). • In most cases, these BSIs are associated with the use of a long-term central venous catheter (Broviac, Port), severe and prolonged immunosuppression (e.g. neutropenia) and other chemotherapy-induced alterations of host defence mechanisms (e.g. mucositis). What is New: • This study is the first multicentre study confirming relapsed malignancy as an independent risk factor for BSIs in paediatric cancer patients. • It describes the epidemiology of nosocomial BSI in paediatric cancer patients mainly outside the stem cell transplantation setting during conventional intensive therapy and argues for prospective surveillance programmes to target and evaluate preventive bundle interventions.

Treatment of recurrent primitive neuroectodermal tumors (PNET) in children and adolescents with high-dose chemotherapy (HDC) and stem cell support: results of the HITREZ 97 multicentre trial

Early studies with high-dose chemotherapy for treatment of relapsed cerebral PNET had shown modest efficacy but considerable toxicity. The HIT97 national trial tested a nonrandomized but stratified relapse protocol using either intensive chemotherapy, potentially high dose, or oral chemotherapy. 72 patients (59 disseminated) whose primary treatment had been surgery (97 %), radiotherapy (88 %), and/or chemotherapy (95 %) were enrolled in the intensive chemotherapy arm at diagnosis of relapse or resistance. As a window for this study they received two courses of a 96-hour infusion with carboplatin and etoposide. A response (complete or partial remission) was documented by MRI. Responders received two more cycles of this therapy and stem cell collection, before they received HDC (carboplatin, etoposide, thiotepa) and stem cell support. All possibilities of local therapy were to be explored and applied. After two courses of chemotherapy there was a 52 % response rate (41/72 patients). The median PFS and OS for all 72 patients were 11.6 and 21.1 months. Patients with medulloblastoma had a longer PFS and OS (12.6 and 22.6 months) than those with other PNETs (3.1 and 12.3 months). Favourable prognostic features were no new signs of clinical impairment and localised disease at relapse diagnosis. For the 27 patients who received HDC the median PFS and OS were 8.4 and 20.2 months, respectively. HDC did not benefit patients with resistant cerebral PNET and was associated with profound haematological and mucosal toxicity (90-100 % grade III, IV), infections (50 % grade III and IV) and severe ototoxicity (50 % grade III, 12.5 % grade IV). Treatment related mortality was 8 %. There was low long-term survival and only 2/72 patients are in continuous remission. Adding HDC in patients who responded to the initial courses of chemotherapy did not improve survival. Patients with relapsed cerebral PNET who respond to conventional chemotherapy do not profit from further augmentation to HDC.

Activated CD4+ T cells enter the splenic T-cell zone and induce autoantibody-producing germinal centers through bystander activation

CD4(+) T (helper) cells migrate in huge numbers through lymphoid organs. However, little is known about traffic routes and kinetics of CD4(+) T-cell subsets within different organ compartments. Such information is important because there are indications that CD4(+) T cells may influence the function of microenvironments depending on their developmental stage. Therefore, we investigated the migration of resting (naïve), activated, and recently activated (memory) CD4(+) T cells through the different compartments of the spleen. Resting and recently activated CD4(+) T cells were separated from thoracic duct lymph and activated CD4(+) T cells were generated in vitro by cross-linking the T-cell receptor and CD28. The present study shows that all three CD4(+) T-cell subsets selectively accumulate in the T-cell zone of the spleen. However, only activated T cells induce the formation of germinal centers (GCs) and autoantibodies in rats and mice. Our results suggest that in a two-step process they first activate B cells independent of the T-cell receptor repertoire and CD40 ligand (CD154) expression. The activated B cells then form GCs whereby CD154-dependent T-cell help is needed. Thus, activated T cells may contribute to the development of autoimmune diseases by activating autoreactive B cells in an Ag-independent manner.

Skin tolerance is supported by the spleen

The repeated application of antigens results in the induction of tolerance. Lymph nodes are responsible for this reaction by producing suppressor cells. Using an in vivo transplantation model, we showed recently that stromal cells from different lymph nodes induce different cell populations for suppression, which all produce a tolerogenic phenotype. In this study, we were interested in the role of the spleen in these tolerance reactions. Therefore, tolerance was induced via feeding or injecting ovalbumin several times in control and splenectomized mice. The delayed-type hypersensitivity (DTH) was measured as well as the cell subset composition of the spleen. The spleen of peripherally tolerized mice showed higher proliferation activity and a specific antibody production compared with orally tolerized mice, where regulatory T cells were predominantly found. Tolerance induction after removal of the spleen resulted in a reduced DTH response in antigen fed animals, whereas skin tolerance induction failed. In conclusion, the results illustrate that lymph nodes from different areas employ their individual pathways for similar immune reactions, and the spleen is part of this reaction initiated at the peripheral site.

Ribavirin treatment of acute and chronic hepatitis E: a single-centre experience

BACKGROUND

The role of ribavirin for treatment of severe acute or chronic hepatitis E virus (HEV) infection is not well defined.

AIMS

To investigate the applicability and efficacy of ribavirin therapy in acute and chronic HEV infections within a large single-centre cohort.

MATERIALS & METHODS

Clinical courses of forty-four German HEV-infected individuals were analysed.

RESULTS

In a prospective case series, we observed spontaneous recovery from acute symptomatic HEV-infection in 10/11 immunocompetent individuals. Ribavirin therapy was initiated in one patient with severe acute HEV-genotype-1e infection who rapidly improved liver function and cleared HEV. Of 15 organ transplant recipients with prolonged HEV viraemia, reduction in immunosuppression led to HEV-clearance in three patients, while ribavirin therapy was initiated in 11 subjects. A rapid response with undetectable HEV-RNA occurred in nine subjects. One patient died after experiencing a virological breakthrough associated with ribavirin dose reduction because of severe anaemia.

DISCUSSION

Ribavirin is a safe treatment option for HEV infections. However, the optimal dose of ribavirin for the treatment of chronic hepatitis E remains to be determined as treatment failure may occur.

Lymph node dissection--understanding the immunological function of lymph nodes

Lymph nodes (LN) are one of the important sites in the body where immune responses to pathogenic antigens are initiated. This immunological function induced by cells within the LN is an extensive area of research. To clarify the general function of LN, to identify cell populations within the lymphatic system and to describe the regeneration of the lymph vessels, the experimental surgical technique of LN dissection has been established in various animal models. In this review different research areas in which LN dissection is used as an experimental tool will be highlighted. These include regeneration studies, immunological analysis and studies with clinical questions. LN were dissected in order to analyse the different cell subsets of the incoming lymph in detail. Furthermore, LN were identified as the place where the induction of an antigen-specific response occurs and, more significantly, where this immune response is regulated. During bacterial infection LN, as a filter of the lymph system, play a life-saving role. In addition, LN are essential for the induction of tolerance against harmless antigens, because tolerance could not be induced in LN-resected animals. Thus, the technique of LN dissection is an excellent and simple method to identify the important role of LN in immune responses, tolerance and infection.

Bloodstream infections in paediatric cancer patients. Prospective comparative study in 2 university hospitals

BACKGROUND

Preventive approaches (including those related to care of long term central venous catheters, CVADs) and the incidence of bloodstream infections (BSI) in 2 German university affiliated paediatric oncology units.

PATIENTS AND METHODS

Non-interventional prospective observational study using the Oncoped surveillance module. Center A included 85 patients in 31 months and Center B 84 patients in 21 months. The populations did not differ in terms of age, gender, malignancy and disease status (first illness vs. relapse). Center A used ports (46 %) and 2 different Broviac catheters (54 %), in Center B nearly all patients with a CVAD had Broviacs (96 %). 30 BSI (24 patients) were diagnosed in Centre A and 28 BSI (22 patients) in Center B. Patients with relapsed malignancy experienced more BSI (51.4 % vs. 20.9 %; p = 0.001). Incidence rates were significantly lower in Center A (3.47 vs. 7.93 BSI/1000 CVAD days; p = 0.037). Poisson regression analysis revealed a significant lower incidence density (BSI/100 inpatient days) for all BSI in Center A (RR 0.47 CI95 0.27-0.81, p = 0.006). Overall, 52 % of all pathogens detected in blood cultures in Center A were Gram-positive (57 % in Center B) and 48 % Gram-negative (43 in Center B). One ALL patient without a CVAD died due to overwhelming sepsis caused by an ESBL-producing E. cloacae isolate.

CONCLUSION

Paediatric cancer treatment centers differ substantially in regard to management of CVADs and in other preventive strategies. The most important use of local surveillance data is longitudinal internal assessment in close cooperation with microbiology and hospital hygiene experts.

Stromal cells directly mediate the re-establishment of the lymph node compartments after transplantation by CXCR5 or CCL19/21 signalling

Lymph nodes (LN) are highly organized and have characteristic compartments. Destruction of these compartments leads to an inability to fulfil their immunological function. However, it is not yet clearly understood which mechanisms are involved in the development and maintenance of this organization. After transplantation of LN into the mesentery, the LN regenerate to fully functional LN. In this study, the question was addressed, how stromal cells in the B-cell follicles (follicular dendritic cells), which were identified by CD21/CD35, and stromal cells in the T-cell area (gp38+ cells) are involved via chemokine signalling. The gp38+ cells and CD21/CD35+ cells were detected in the transplanted LN (EGFP, plt/plt and CXCR5(-/-) mice) over a period of 8 weeks to analyse their competence to reconstruct the compartmental organization. The presence of gp38+ cells was stable during regeneration and these cells reconstructed the T-cell area within 4 weeks. After transplantation of plt/plt LN CCL19/CCL21 expression was observed leading to partial restoration of the T-cell area. In contrast, there were changes in the presence and morphology of CD21/CD35+ cells within the B-cell area during reconstruction, which was dependent on the presence of B cells and CXCL13/CXCR5 signalling. Hence, CD21/CD35+ cells and gp38+ cells are involved in the establishment of the compartmental organization of lymph nodes but using different ways to recruit lymphocytes via chemokine signalling.

Mesenteric lymph nodes are not required for an intestinal immunoglobulin A response to oral cholera toxin

Stimulation of the adaptive immune system in the gut is thought to be mainly initiated in the Peyer's patches as well as in the mesenteric lymph nodes (mLNs) and results in immunoglobulin A (IgA) secretion by plasma cells in the lamina propria. However, the precise role of the mLNs in the development of IgA immune responses is poorly understood. Thus, cholera toxin (CT) was administered to mLN-resected and mLN-bearing animals and the IgA response to CT in the intestine and serum was examined. Levels of CT-specific IgA antibodies and the numbers of cells producing these antibodies in the intestine were increased in mLN-resected rats. Particularly in the distal parts of the intestine, the jejunum and the ileum, IgA responses to orally administered antigens developed were stronger in the intestine after removal of the mLNs. This strongly indicates that the mLNs play a critical role in modulating the expansion of specific IgA responses. After removal of the mLNs, the lymph from the gut flows directly into the blood. It was investigated whether the spleen is involved in the initiation of an immune response to orally administered CT after removal of the mLNs. In the spleens of mLN-resected animals, proliferation was up-regulated, and germinal centres were formed in the follicles. However, CT-specific IgM(+) cells, but no IgA(+) cells, developed. Additionally, an increase of CT-specific IgM in the serum was found in mLN-resected animals. Thus, the data indicate that the spleen is involved in the immune response to CT after mLN resection.

Procalcitonin-a sensitive inflammation marker of febrile episodes in neutropenic children with cancer

OBJECTIVE

Sensitive parameters of inflammations, are rare or of limited validity in neutropenic patients. Procalcitonin (PCT) proven to be a sensitive inflammatory marker in nonneutropenic patients was evaluated for its diagnostic relevance in febrile episodes of neutropenic patients with cancer

METHODS

Plasma levels of PCT were determined by an immunoluminometric assay in children with febrile neutropenic episodes (n=376) starting at the date of admission until the resolution of fever and were correlated with serum levels of the C-reactive protein (CrP). Febrile episodes were classified as fever of unknown origin (FUO), microbiologically or clinically documented infections and were also differentiated according to the site of the infection (unknown, bacteremia, respiratory, soft tissue, gastrointestinal and urinary tract infection).

RESULTS

Independently from the aetiology and the site of infection the PCT peak value occurred mostly on the second hospital day and decreased rapidly in cases of successful antibiotic therapy and with the resolution of fever to the normal range (0.1+/-0.5 microg/l). The highest PCT peak levels at the onset of fever and during the febrile course were observed in patients with gramnegative bacteremia (n = 22, median 12.1 microg/l, range 0.4+/-568.2 microg/l). There was a positive correlation between PCT peak levels and CrP peak levels (r = 0.48, p = 0.001) which mostly were observed 24 h later than for PCT.

CONCLUSIONS

PCT is a sensitive and specific parameter in the diagnostic and in the sequential assessment of febrile neutropenic episodes, especially in gramnegative infections. Its diagnostic accuracy in neutropenic patients is clearly higher than that of CrP.

Stromal mesenteric lymph node cells are essential for the generation of gut-homing T cells in vivo

T cells primed in the gut-draining mesenteric lymph nodes (mLN) are imprinted to express alpha4beta7-integrin and chemokine receptor CCR9, thereby enabling lymphocytes to migrate to the small intestine. In vitro activation by intestinal dendritic cells (DC) or addition of retinoic acid (RA) is sufficient to instruct expression of these gut-homing molecules. We report that in vivo stroma cells, but not DC, allow the mLN to induce the generation of gut tropism. Peripheral LN (pLN) transplanted into the gut mesenteries fail to support the generation of gut-homing T cells, even though gut-derived DC enter the transplants and prime T cells. DC that fail to induce alpha4beta7-integrin and CCR9 in vitro readily induce these factors in vivo upon injection into mLN afferent lymphatics. Moreover, uniquely mesenteric but not pLN stroma cells express high levels of RA-producing enzymes and support induction of CCR9 on activated T cells in vitro. These results demonstrate a hitherto unrecognized contribution of stromal cell delivered signals, including RA, on the imprinting of tissue tropism in vivo.

Stromal cells confer lymph node-specific properties by shaping a unique microenvironment influencing local immune responses

Lymph nodes (LN) consist not only of highly motile immune cells coming from the draining area or from the systemic circulation, but also of resident stromal cells building the backbone of the LN. These two cell types form a unique microenvironment which is important for initiating an optimal immune response. The present study asked how the unique microenvironment of the mesenteric lymph node (mLN) is influenced by highly motile cells and/or by the stromal cells. A transplantation model in rats and mice was established. After resecting the mLN, fragments of peripheral lymph node (pLN) or mLN were inserted into the mesentery. The pLN and mLN have LN-specific properties, resulting in differences of, for example, the CD103(+) dendritic cell subset, the adhesion molecule mucosal addressin cell adhesion molecule 1, the chemokine receptor CCR9, the cytokine IL-4, and the enzyme retinal dehydrogenase 2. This new model clearly showed that during regeneration stromal cells survived and immune cells were replaced. Surviving high endothelial venules retained their site-specific expression (mucosal addressin cell adhesion molecule 1). In addition, the low expression of retinal dehydrogenase 2 and CCR9 persisted in the transplanted pLN, suggesting that stromal cells influence the lymph node-specific properties. To examine the functional relevance of this different expression pattern in transplanted animals, an immune response against orally applied cholera toxin was initiated. The data showed that the IgA response against cholera toxin is significantly diminished in animals transplanted with pLN. This model documents that stromal cells of the LN are active players in shaping a unique microenvironment and influencing immune responses in the drained area.

Sexual precocity associated with an abdominal tumor in an African boy

We report a 3 year-old boy in Tanzania with an abdominal mass and isosexual precocity due to an hCG-secreting hepatoblastoma. Due to the limited availability of local diagnostic testing, surgery and chemotherapy were completed before immunohistochemical and endocrine results were available.

Compassionate use of bevacizumab (Avastin) in children and young adults with refractory or recurrent solid tumors

BACKGROUND

The aim of this study was to evaluate feasibility and toxicity of bevacizumab (Avastin), a monoclonal antibody directed against the vascular endothelial growth factor in children and young adults.

PATIENTS AND METHODS

Fifteen patients (male: n = 8; female: n = 7; median age, 14.6 years) received bevacizumab for recurrent or progressive solid tumors (carcinoma: n = 3; neuroblastoma: n = 2; astrocytoma grade III: n = 2; rhabdomyosarcoma: n = 2; nephroblastoma: n = 2; benign vascular tumors: n = 2; synovial sarcoma: n = 1; and malignant hemangiopericytoma: n = 1) on a compassionate basis. Bevacizumab was administered at 5-10 mg/kg body weight intravenously every 2-3 weeks. Most patients received chemotherapy in addition to bevacizumab. Duration of bevacizumab therapy ranged from 1.5 to 23 months.

RESULTS

Bevacizumab-related side-effects were mild and included hypertonia (n = 2), proteinuria/hematuria (n = 2), epistaxis (n = 2), local erythema (n = 1), and defective wound healing and ascites (n = 1). Radiographic objective responses (partial responses) were observed in two patients with astrocytoma grade III and in one patient each with neuroblastoma and pleomorphic rhabdomyosarcoma, respectively.

CONCLUSIONS

Bevacizumab seems to have a good acute safety profile and some antitumor activity in heavily pretreated children and young adults with recurrent solid tumors. Prospective clinical trials are urgently needed to further evaluate the safety and efficacy of bevacizumab in pediatric patients.

Dendritic cell subsets in lymph nodes are characterized by the specific draining area and influence the phenotype and fate of primed T cells

Dendritic cells (DC) are important in differential T-cell priming. Little is known about the local priming by DC in the microenvironment of different lymph nodes and about the fate of the imprinted T cells. Therefore, freshly isolated rat DC from mesenteric lymph nodes (mLN) and axillary lymph nodes (axLN) were phenotyped and cultured with blood T cells in the presence of the superantigen Mycoplasma arthritidis mitogen (MAM). The phenotype, proliferation and apoptosis of the primed T cells were analysed. Our data show that a common DC population exists in both mLN and axLN. In addition, region-specific DC with an organotypical marker expression imprinted by the drained area were found. Coculture of T cells with DC from mLN or axLN resulted in a distinct shift in the CD4 and CD8 expression of T cells and their phenotype. Furthermore, when these differentially primed mLN and axLN T cells were injected into recipients, mLN-primed T cells survived longer in other lymphoid organs. The results show that the region-specific DC have a unique phenotype and an impact on the ratio of CD4 : CD8 T cells during an immune response in vivo.

Piperacillin-tazobactam in pediatric cancer patients younger than 25 months: a retrospective multicenter survey

Piperacillin-Tazobactam (Pip-Taz) is an evidence-based empirical treatment of febrile neutropenia in adolescents and adults. No data are available in pediatric cancer patients <25 months of age. In this retrospective, multicenter data survey, the analysis focuses on safety, tolerance, and efficacy. The daily dose administered was 240 mg/kg given in three equally divided doses. Data on 156 Pip-Taz treatment courses in 69 children <25 months from five pediatric cancer treatment centers (2001-2005) were analyzed. The median duration of treatment with Pip-Taz was 5 days (range, 1-23 days; 1-12 Pip-Taz courses per patient). Pip-Taz was started on the first day of fever in 90% of all courses, in 6% in the first 72 h, and in 4% as second- or third-line agent. Forty-five percent of all patients were neutropenic. In all patients, the outcome was favorable independent whether Pip-Taz was given as monotherapy (42 courses; 27%) or in combination. Overall, Pip-Taz was well tolerated and discontinued due to adverse events in only two patients who experienced non-life-threatening allergic reactions (skin rash and wheezing). The results of this study are preliminary due to the methodological limitations of a retrospective survey. Taking this bias into consideration, Pip-Taz appears to be a safe, and feasible alternative in pediatric cancer patients with febrile neutropenia <25 months of age suggesting that the inclusion of children of all age groups in future prospective controlled studies evaluating Pip-Taz is justified.

Marked elevation in homocysteine and homocysteine sulfinic acid in the cerebrospinal fluid of lymphoma patients receiving intensive treatment with methotrexate

OBJECTIVE

Interference of methotrexate (MTX) with the metabolism of homocysteine may contribute to MTX neurotoxicity. In this pilot study we measured the concentration of homocysteine and related metabolites in the cerebrospinal fluid (CSF) of patients with primary central nervous system lymphoma undergoing intensive treatment with MTX.

MATERIAL AND METHODS

CSF samples from lymphoma patients (n = 4) were drawn at the end of high-dose MTX infusions (3-5 g/m2/24 h, HDMTX) and one day after intraventricular injections of MTX (3 mg, ICVMTX) or cytarabine (30 mg) and analyzed for homocysteine, cysteine, sulfur-containing excitatory amino acids (cysteine sulfinic acid, cysteic acid, homocysteine sulfinic acid and homocysteic acid), S-adenosylmethionine, 5-methyltetrahydrofolate and MTX. The concentration of homocysteine, cysteine and sulfur-containing excitatory amino acids were also measured in the CSF of a reference population not exposed to MTX. The Wilcoxon signed rank-test and the Friedman test were used to compare concentrations of homocysteine and its metabolites at various time-points during chemotherapy. Comparison of patient and control samples were performed using the Mann-Whitney U-test. Allelic variants of homocysteine metabolism previously shown to influence MTX neurotoxicity (MTHFR c.677C>T, MS c.2756A>G and Tc2 c.776C>G) were also analyzed.

RESULTS

After application of HD- and ICVMTX, the CSF homocysteine concentrations in the lymphoma patients were markedly elevated and significantly higher than those in the control group (p < 0.05, Mann-Whitney U-test), whereas 5-methyltetrahydrofolate was depleted. A rapid elevation of homocysteine sulfinic acid, a sulfur-containg amino acid which was not detected in the CSF of the control group, was observed. One patient developed confluent white matter brain changes visible using MRI. This patient had the lowest concentration of S-adenosylmethionine in the CSF and carried two risk alleles for MTX neurotoxicity.

CONCLUSIONS

In this pilot study, MTX administered either intravenously or intraventricularly, induced marked biochemical alterations in the CSF. Whether these changes can be used to predict MTX-induced neurotoxicity at an early stage in treatment needs to be elucidated in larger clinical trials.

Das humane Bocavirus: Erreger von Atemwegsinfektionen?

The human Bocavirus (HBoV), the second member of the parvovirus family, which displays pathogenicity in humans, has been described in 2005 by Allander et al.. It seems to be distributed worldwide and has been isolated mainly in infants and children with respiratory tract infection. This review covers all studies published on HBoV to February 2007 and discusses this emerging viral pathogen from the perspective of inpatient medical treatment centers.

Final report of a phase II trial of nimotuzumab in the treatment of refractory and relapsed high-grade gliomas in children and adolescents

2006

Background: Despite multimodal therapy most children with high grade gliomas (HGG), including glioblastoma multiforme (GM), anaplastic astrocytoma (AA) and intrinsic pontine glioma (PG) have an infaust prognosis if they relapse or are refractory to the primary treatment. Recently novel therapeutic approaches are investigated in order to improve the survival of these patients while preserving a good quality of life. This multicentre phase II trial was designed to explore the feasibility and efficacy of the h-R3 monoclonal anti-EGFR antibody (nimotuzumab) in the treatment of these patients. Patients and Methods: Pediatric patients with GM, AA or PG with radiologically proven progressive disease following primary or relapse treatment and a life expectancy of less than 4 weeks were eligible to the study. The treatment consisted of an induction therapy including a weekly short infusion of 150 mg/m2 nimotuzumab for six weeks, and in case of non-PD a consolidation therapy of 4 infusions in a 3 week interval. The response was documented by MRI in week 8 and 21 and only clinically in rapidly progresssive disease. Results: Between June 2004 and April 2006 47 patients aged 4 to 17 years (median 11 years) were enrolled in this study. 46 patients were evaluable for response. According to RECIST 14 out of 46 patients showed objective responses (PR n=4, SD n=10) in the MRI as the best response with a median change in the largest diameter of the index lesion of -11% (-50% to +16%). The PR/SD were seen in 2/13 patients with GM, 2/11 with AA and 10/22 with PG. Thirteen patients continued with the consolidation therapy and showed 4 PR, 3 SD and 6 PD in week 21. The median overall survival was 4.4 months (0.3–25.4 months) and was significantly better for repsonders (median 10 months) than for nonresponders (median 4.0 months). No severe side effects related to the study medication were observed. Conclusions: These data suggest that the repeated application of nimotuzumab is well tolerated and safe. Nimotuzumab has cytotoxic efficacy in heavily pre- treated relapsed HGG. Based on this data a phase III trial with nimotuzumab in newly diagnosed diffuse intrinsic pontine gliomas concomittent with radiotherapy was introduced in first quarter 2006.

No significant financial relationships to disclose.

The superantigen-induced polarization of T cells in rat peripheral lymph nodes is influenced by genetic polymorphisms in the IL-4 and IL-6 gene clusters

In recent years, it has become clear that the polarization of T cells depends on the genetic background. However, due to the complexity of the genetic background of each animal, a direct comparison of the phenotype is difficult. In this study, a new rat strain LEW.BN-4-10 carrying the chromosomal regions on chromosomes 4 and 10, which harbor IL-6 and IL-4 gene clusters of BN, has been bred on the genetic background of LEW. It was asked whether these two gene clusters influence the polarization of T cell responses. As a model, the Mycoplasma arthritidis mitogen (MAM)-induced inflammation was used focusing on the microenvironment of the draining lymph node (LN). The effect of differences in these regions was tested by comparing LEW.BN-4-10 and LEW rats under steady-state conditions and upon injection of MAM into the forepaw. Under steady-state conditions, the two strains showed differences in the dendritic cell (DC) subset composition. When MAM was injected, the number of T cells in LEW.BN-4-10 rats producing T(h)2 cytokines such as IL-4 and IL-13 was significantly increased compared with LEW. The data suggest that these differences in the microenvironments in LN of LEW and LEW.BN-4-10 rats resulted in different susceptibility to the disease (increase of cells in LN and paw swelling). In addition, deviations in the distribution and function of injected effector T cells were found in the LN of LEW and LEW.BN-4-10 rats after MAM treatment. The data indicate that the IL-6 and IL-4 gene clusters are involved in polarizing T cell responses in vivo.

Influence of Prolonged Use of Intravenous Administration Sets in Paediatric Cancer Patients on CVAD-related Bloodstream Infection Rates and Hospital Resources

BACKGROUND

To assess the effects of extending the routine intravenous administration set (IVAS) change-interval from 72 h (group 1) to 7 days (group 2) on the incidence density for central venous access device (CVAD)-related bloodstream infections (BSIs) and on resource expenditures in a singlecentre pilot study.

PROCEDURE

Prospective pre-/post-intervention comparison of two consecutive 12-month surveillance periods (2001-2003) in a 17-bed paediatric oncology tertiary care unit. IVAS changes and nosocomial infections (NIs) were prospectively analysed using a standardized unit-based surveillance system (Oncopaed NI).

RESULTS

All 175 eligible patients were enrolled, 96 in group 1 and 79 in group 2. Both groups had similar distributions of primary diagnoses and risk factors. The proportion of IVAS changes performed after 3 days increased from 5.6% to 22.5%, but only 8% of IVASs in group 2 were changed after 7 days. Most IVAS changes (64.8% in group 1 and 92.9% in group 2) were done because of therapeutic interventions (blood products, parenteral nutrition [TNP]) before the scheduled endpoint. Overall, the rates and incidence densities of NIs were significantly lower during the second period. The corresponding results for CVAD-related BSIs did not show significant differences. No death attributable to a NI occurred. The '7-day' strategy resulted in cost savings for devices (3,300 dollars/year) and of nursing time (23 working days/year).

CONCLUSIONS

Extending the routine IVAS change-interval from 3 days to 7 days appears to be safe and cost-effective in a paediatric oncology unit with high infection control standards and continuous surveillance for NIs. These results do not prove that 7-day intervals prevent infections, but they do suggest that this policy probably is not harmful and that a prospectively randomized study with sufficient power is needed.

Diagnosis and treatment of catheter-related infections in paediatric oncology: an update

Otherwise unexplained clinical signs of infection in patients with long-term tunnelled or totally implanted central venous access devices (CVADs) are suspected to be CVAD-associated. Diagnostic methods include catheter swabs, blood cultures and cultures of the catheter tip or port reservoir. In the case of a suspected CVAD-related bloodstream infection in paediatric oncology patients, in-situ treatment without prompt removal of the device can be attempted. Removal of the CVAD should be considered if bacteraemia persists or relapses > or = 72 h after the initiation of (in-vitro effective) antibacterial therapy administered through the line. Timely removal of the device is also recommended if the patient suffers from a complicated infection, or if Staphylococcus aureus, Pseudomonas aeruginosa, multiresistant Acinetobacter baumannii or Candida spp. are isolated from blood cultures. Duration of therapy depends on the immunological recovery of the patient, the pathogen isolated and the presence of related complications, such as thrombosis, pneumonia, endocarditis and osteomyelitis. Antibiotic lock techniques in addition to systemic treatment are beneficial for Gram-positive infections. Although prospectively controlled studies are lacking, the concomitant use of urokinase locks and taurolidine secondary prophylaxis seem to favour catheter salvage.

Results of a phase II trial of h-R3 monoclonal antibody (nimotuzumab) in the treatment of resistant or relapsed high-grade gliomas in children and adolescents

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Background: Children and adolescents suffering from high grade gliomas (HGG) have a poor prognosis when they relapse during or after primary treatment. Thus novel therapeutic approaches as the inhibition of growth-signalling pathways are needed. This multicentre phase II trial was designed to explore the feasibility and efficacy of the h-R3 monoclonal anti-EGFR antibody (Nimotuzumab) in the treatment of these patients. Methods: Pediatric patients with glioblastoma multiforme, anaplastic astrocytoma or intrinsic pontine glioma (PG) with radiologically proven progressive disease following primary or relapse treatment were eligible to the study. The treatment consisted of an induction therapy including a weekly short infusion of 150 mg/m2 Nimotuzumab for six weeks, and in case of non-PD a subsequent consolidation therapy of four infusions in a three week interval. The response was documented by MRI in week 8 and 21. Results: Between June 2004 and August 2005 34 patients aged 5.0 to 17.4 years (median 10.9 years) were enrolled in this study. According to RECIST 12 out of 34 patients showed response (PR n=1, SD n=11) in the MRI of week 8 after the induction therapy with a median change in the largest diameter of the index lesion of −5% (−39 to +16%) accompanied by clinical deterioration in four and markedly clinical improvement in two patients. Surprisingly, 9 PR/SD were seen in the 14 patients with PG. Eight patients continued with the consolidation therapy. So far 5 out of 8 Patients are evaluable for response after consolidation therapy and showed three PR, one SD and one PD in week 21. Eight patients with consolidation therapy are free of progression for a median of 7.5 months (1.2–13.2 months). No severe side effects related to the study medication were observed. Conclusions: These data suggest that the repeated application of Nimotuzumab is well tolerated and safe. It has cytotoxic efficacy in heavily pre-treated relapsed HGG, especially in intrinsic pontine glioma. A phase III study for patients with newly diagnosed PG is warranted.

[Table: see text]

Oral tolerance originates in the intestinal immune system and relies on antigen carriage by dendritic cells

Oral tolerance induction is a key feature of intestinal immunity, generating systemic nonresponsiveness to ingested antigens. In this study, we report that orally applied soluble antigens are exclusively recognized in the intestinal immune system, particularly in the mesenteric lymph nodes. Consequently, the initiation of oral tolerance is impeded by mesenteric lymphadenectomy. Small bowel transplantation reveals that mesenteric lymph nodes require afferent lymph to accomplish the recognition of orally applied antigens. Finally, oral tolerance cannot be induced in CCR7-deficient mice that display impaired migration of dendritic cells from the intestine to the mesenteric lymph nodes, suggesting that immunologically relevant antigen is transported in a cell-bound fashion. These results demonstrate that antigen transport via afferent lymphatics into the draining mesenteric lymph nodes is obligatory for oral tolerance induction, inspiring new therapeutic strategies to exploit oral tolerance induction for the prevention and treatment of autoimmune diseases.

[Human Metapneumovirus in hospitalized children - a review]

The human Metapneumovirus (HMPV) has been discovered by von den Hoogen et al. in 2001 and seems to play an important role as etiologic agent in childhood respiratory tract infections in particular involving infants after the 6th month of life and toddlers. Duly considering the hitherto published studies and retrospective analysis of two HMPV seasons (2002-2004) at our institution this review focuses on children, who had to be hospitalized due to HMPV infection. The analysis confirmed, that among those patients there is a high proportion of children with pre-existing risk factors for a complicated clinical course, a high proportion of children with bronchiolitis or pneumonia and a relevant proportion of children with HMPV related apnoeas, most prevalent in the prematurely born. Although the first HMPV infection takes place somewhat later in infancy, the data do not show that HMPV infection is in general milder than RSV infection in hospitalized children. Clinical symptoms and radiological signs do not permit tentative conclusions on the causative agent. This underlines the necessity of specific diagnostic efforts (in case of HMPV with PCR). HMPV may cause lobar or segmental pneumonias difficult to distinguish from bacterial lower respiratory tract infection. Children admitted to the hospital with an acute exacerbation of asthma bronchiale or cystic fibrosis should not only be tested for RSV but also for HMPV. Prospective studies investigating specific therapeutic interventions or describing the impact and prevention of nosocomial HMPV in fection are awaited for. There has been one report of a meningoencephalitis possibly related to HMPV. Thus, liquor samples in such cases should be tested for HMPV too.

Naive, Effector, and Memory T Lymphocytes Efficiently Scan Dendritic Cells In Vivo: Contact Frequency in T Cell Zones of Secondary Lymphoid Organs Does Not Depend on LFA-1 Expression and Facilitates Survival of Effector T Cells

Contact between T cells and dendritic cells (DCs) is required for their subsequent interaction leading to the induction of adaptive immune responses. Quantitative data regarding the contact frequencies of T cell subsets in different lymphoid organs and species are lacking. Therefore, naive, effector, and memory CD4 T cells were injected into rats in absence of the cognate Ag, and 0.5-96 h later, spleen, lymph nodes, and Peyer's patches were removed. Cryosections were analyzed for contact between donor T cells and endogenous DCs in the T cell zone, and donor cell proliferation. More than 60% of injected naive CD4 T cells were in contact with endogenous DCs at all time points and in all organs analyzed. Surprisingly, we were unable to detect any differences between naive, effector, and memory CD4 T cells despite different expression levels of surface molecules. In addition, contact frequency was similar for T cells in lymphoid organs of rats, mice, and humans; it was unaffected by the absence of LFA-1 (CD11a/CD18), and sustained effector T cells in an activated state. Thus, the architecture of the T cell zone rather than expression patterns of surface molecules determines the contact efficiency between T cells and DCs in vivo.

Carboxypeptidase G2 rescue in patients with methotrexate intoxication and renal failure

The methotrexate (MTX) rescue agent carboxypeptidase G2 (CPDG2) rapidly hydrolyses MTX to the inactive metabolite DAMPA (4-[[2,4-diamino-6-(pteridinyl)methyl]-methylamino]-benzoic acid) and glutamate in patients with MTX-induced renal failure and delayed MTX excretion. DAMPA is thought to be an inactive metabolite of MTX because it is not an effective inhibitor of the MTX target enzyme dihydrofolate reductase. DAMPA is eliminated more rapidly than MTX in these patients, which suggests a nonrenal route of elimination. In a phase II study (May 1997-March 2002), CPDG2 was administered intravenously to 82 patients at a median dose of 50 U kg(-1) (range 33-60 U kg(-1)). Eligible patients for this study had serum MTX concentrations of >10 microM at 36 h or >5 microM at 42 h after start of MTX infusion and documented renal failure (serum creatinine > or =1.5 times the upper limit of normal). Immediately before CPDG2 administration, a median MTX serum level of 11.93 microM (range 0.52-901 microM) was documented. Carboxypeptidase G2 was given at a median of 52 h (range 25-178 h) following the start of an MTX infusion of 1-12 g m(-2) 4-36 h(-1) and resulted in a rapid 97% (range 73-99%) reduction of the MTX serum level. Toxicity related to CPDG2 was not observed. Toxicity related to MTX was documented in about half the patients; four patients died despite CPDG2 administration due to severe myelosuppression and septic complications. In conclusion, administration of CPDG2 is a well-tolerated, safe and a very effective way of MTX elimination in delayed excretion due to renal failure.

Oncological management of pediatric cancer patients belonging to Jehovah's Witnesses: a two-institutional experience report

OBJECTIVES

Aim of this study was to analyze the feasibility of oncological treatment in pediatric patients belonging to Jehovah's Witnesses and to describe the changing policy in performing transfusions and supportive care measures at two German pediatric cancer institutions.

PATIENTS AND METHODS

Over a period of 16 years 21 treatments according to the current cooperative protocols were performed in 14 children of Jehovah's Witnesses. Various hematological supportive care measures such as supplementation with iron, human erythropoietin, interleukin 11, granulocyte colony-stimulating factor and autologous or allogeneic stem cell rescue had been applied. For comparison matched pairs treated in our hospitals not belonging to Jehovah's Witnesses and 50 pediatric and adult oncological patients belonging to Jehovah's Witnesses reviewed from the international literature were analyzed with respect to transfusions and outcome.

RESULTS

So far, 9 of 14 children are surviving 16-195 months (median 26 months). During the primary therapy they received markedly less transfusions than the control cohort (-39,1% red blood cell transfusions and -37,5% platelet transfusions). The review of 50 reported cases showed that oncological therapy can also be successfully performed with a restricted transfusion regimen in children and particularly in adults.

CONCLUSION

Pediatric cancer patients belonging to Jehovah's Witnesses can be treated similarly to other patients. A restrictive transfusion policy and the broad application of hematopoietic supportive care measures may reduce transfusions. This treatment policy and a continuous collaboration with the Hospital Liaison Committee for Jehovah's Witnesses appears to create an oncological treatment situation with a high compliance of patients and parents where court orders may not be necessary.

CD4+ effector T cell distributionin vivo: TGF-β1/TGF-β receptor II interaction during activation mediates accumulation in the target tissue by preferential proliferation

CD4(+) effector T cells generated in mesenteric lymph nodes (mLN) leave into the blood. Although they enter many tissues, mLN effector T cells are later found preferentially in the gut,the drainage area of mLN. We show in the rat that this is not an intrinsic property of mLN T cells. Instead, within the mLN milieu T cells are instructed by cytokines such as transforming growth factor beta 1 (TGF-beta 1) to up-regulate TGF-beta receptor II (TGF-beta RII) during activation. This enables effector T cells to continue proliferation upon subsequent contact with TGF-beta 1 in mLN and gut, and to accumulate in the lymph node draining area, the most likely site of pathogen invasion.

Results of the SIOP 93-01/GPOH Trial and Study for the Treatment of Patients with Unilateral Nonmetastatic Wilms Tumor

BACKGROUND

The treatment of Wilms Tumor is integrated into clinical trials since the 1970's. In contrast to the National Wilms Tumor Study Group (NWTSG) the SIOP trials and studies largely focus on the issue of preoperative therapy to facilitate surgery of a shrunken tumor and to treat metastasis as early as possible.

PATIENTS AND METHODS

In the SIOP 93-01/GPOH trial and study 1 020 patients with a newly diagnosed renal tumor were registered. 847 of them had a histological proven Wilms Tumor, of whom 637 were unilateral localized, and 173 tumors had an other histology [40 congenital mesoblastic nephroma (CMN), 51 clear cell sarcoma (CCSK), 24 rhabdoid tumor (RTK) and 58 other tumors]. Preoperative chemotherapy in benign tumors was given to 1.3 % of the patients. The main objective of the trial was the randomized question, if the postoperative two drug chemotherapy for stage I in intermediate risk or anaplasia can be reduced from conventional 3 courses to an experimental 1 course without loss of efficacy.

RESULTS

519 patients with unilateral nonmetastatic Wilms did receive preoperative chemotherapy. The histology in this group of patients was of intermediate risk in 469 (90 %) patients, 14 (3 %) tumors were low risk and 36 (7 %) high risk. The stage distribution of the tumors was stage I in 315 (61 %), stage II N- in 126 (24 %), stage II N+ in 25 (5 %) and stage III in 36 (7 %) patients. In 17 (3 %) patients the tumor stage remained unclear. Tumor volume was measured in 487 patients before and in 402 after preoperative chemotherapy. The median tumor volume did shrink from 353 to 126 ml. The amount of volume reduction depends on the histological subtype. The event free survival (EFS) after 5 years was 91 % for all patients with unilateral Wilms tumor without distant metastasis. Randomisation was done in 43.7 % for stage I patients and there was no difference in EFS for both treatment arms (90 versus 91 %). The EFS is identical for patients with stage I and II N- (0.92), as well as for stage II N+ and III (0.82). The tumor volume after chemotherapy is a prognostic factor for intermediate risk tumors with the exception of epithelial and stromal predominant tumors. These two subtypes often present as large tumors, they do not shrink during preoperative chemotherapy but they still have an excellent prognosis. On the other hand the prognosis of patients with blastemal predominant subtype after preoperative chemotherapy is worse than in any other patient group of intermediate risk tumors. There are less blastemal predominant tumors compared to primary surgery, but they are chemotherapeutic resistant selected by the preoperative chemotherapy.

CONCLUSION

Patients with unilateral Wilms tumor without metastasis have an excellent prognosis. The post-operative chemotherapy in stage I can be reduced to 4 weeks without worsening treatment outcome. The reduction of the tumor volume could be identified as a helpful marker for stratification of post-operative treatment. Post-chemotherapy blastemal predominant subtype of Wilms tumor has to be classified as high risk tumor. Focal anaplasia has a better prognosis than diffuse anaplasia and will be classified as intermediate risk tumor.

[Differentiated treatment protocols for high- and standard-risk hepatoblastoma--an interim report of the German Liver Tumor Study HB99]

BACKGROUND

Tumor-free survival from hepatoblastoma could be improved to 75 % of all patients by combining surgery with chemotherapy. This figure reaches 90 % for potentially resectable (SR, standard risk) tumors. The outcome of high risk (HR) hepatoblastomas with multifocally disseminating growth in the liver, invasion of large vessels, extrahepatic extension and metastases is still poor, especially since these tumors often rapidly develop resistance against cytotoxic drugs. In the Study HB 99 of the German Society for Pediatric Oncology and Hematology, it is attempted to reach an improved regression and thereby a better prognosis with inauguration of high dose (HD) chemotherapy. This first interim analysis shall evaluate the preliminary results of this strategy.

PATIENTS AND METHODS

53 children with a hepatoblastoma have entered the study. 8 patients were excluded from this analysis because of different or not completed therapy. 10 SR-patients with a small tumor underwent a primary complete (stage I, n = 8) or microscopically incomplete (stage II, n = 2) resection. These received two courses of ifosfamide (3 g/m2), cisplatin (100 mg/m2), and doxorubicin (adriamycin, 60 mg/m2) (IPA). 26 patients with an extended, but potentially resectable tumor (stage III SR) were preoperatively treated with three courses of IPA, followed by a tumor resection and a 4th course of IPA. 9 patients with a HR-hepatoblastoma (3 x stage III HR, 6 x stage IV) were treated with two courses of carboplatin (800 mg/m2) and etoposide (400 mg/m2) (CARBO/VP16). In case of tumor response, they received one or two courses of HD-chemotherapy with carboplatin (2000 mg/m2) and etoposide (2000 mg/m2) after sampling of peripheral stem cells, followed by resection of the primary tumor and metastases, whenever possible. IPA therapy was administered in case of inadequate response to these drugs. The preliminary therapy results were analyzed in relation to the post-surgical stages (I-IV) and to the SIOPEL-PRETEXT (Pretreatment extend of disease) -grouping system (groups I-IV, V, P, E, M). Furthermore, the response of HR-hepatoblastoma to CARBO/VP16, the achieved resectability, and the acute toxicity were evaluated.

RESULTS

40 of 45 (89%) of all hepatoblastoma patients are in remission. 34/36 (94%) SR-patients (stage I - III-SR) are tumor-free, two died of therapy complications. 6 HR-patients are tumor-free, one alive with tumor and two died. In relation to the PRETEXT-grouping, a remission was achieved in 4/4 group I, 14/16 group II, 16/16 group III, 5/6 groups I-III, V, P, E, M, and 1/3 group IV tumors. 6/9 HR-hepatoblastomas were good responders to CARBO/VP16, 5 of these are in remission. 3/9 tumors did not respond, only one could be eradicated by a liver transplantation. In 5/9 HR-patients a R0-resection was possible after chemotherapy, in one a R1-resection, one received a liver transplant, and two tumors remained inoperable. In 4/6 cases lung metastases could be completely removed or, in one case, they had vanished in the CT-scan under chemotherapy. These 4 patients remained in remission. The most frequent severe toxicity of CARBO/VP16 concerned leucopenia (23% of courses) and thrombocytopenia (85% of courses). Under HD therapy severe infections (2/7, 28%) and elevation of transaminases occurred. There was no toxic death.

CONCLUSIONS

A cure rate of over 90% can be reached by conventional cisplatin and doxorubicin containing chemotherapy and radical surgery in SR-hepatoblastoma. 50-60% of all hepatoblastomas respond to CARBO/VP16. In these cases HD-therapy with these drugs is highly efficient and enables a remission in the majority of advanced and metastasised HR-hepatoblastoma. A larger number of patients and longer follow-up have to confirm these results. Therefore, the study will be continued.

The fate of effector T cells in vivo is determined during activation and differs for CD4+ and CD8+ cells

Effector T cells generated in the mesenteric lymph nodes (mLN) are known to accumulate in mLN and the tissue drained by them after circulating in the blood. Their accumulation is due less to preferential entry into mLN but more to preferential proliferation within mLN. The factors regulating the proliferation of effector T cells in vivo are unclear, and it is unknown whether they are different for CD4(+) and CD8(+) effector T cells. Rat T cells from mLN or peripheral lymph nodes (pLN) were stimulated polyclonally via the TCR and CD28 and injected i.v. into congenic recipients. Using three-color flow cytometry and immunohistochemistry, they were identified in mLN, pLN, and blood over time, and proliferation was determined by measuring bromodeoxyuridine incorporation. Only effector mLN T cells showed a significantly increased proliferation rate after entry into mLN compared with that in pLN (2.4 +/- 1.8% vs 0.8 +/- 0.4%). Proliferation among the injected cells was higher when they had contact with dendritic cells within mLN (9.0 +/- 4.3%) than when they did not (4.1 +/- 2.1%). Furthermore, effector mLN T cells which were observed 56 days after injection maintained the capacity for preferential proliferation within mLN. Interestingly, CD4(+) effector mLN T cells proliferated at a higher rate (4.8 +/- 0.7%), remaining in mLN, whereas CD8(+) effector mLN T cells proliferated at a lower rate (3.3 +/- 1.0%) and were able to leave the mLN into the blood. Elucidating the factors regulating the proliferation of effector T cells in vivo will help to modify their distribution for therapeutic purposes.