A pleiotropy scan to discover new susceptibility loci for pancreatic ductal adenocarcinoma

Pleiotropic variants (i.e., genetic polymorphisms influencing more than one phenotype) are often associated with cancer risk. A scan of pleiotropic variants was successfully conducted ten years ago in relation to pancreatic ductal adenocarcinoma susceptibility. However, in the last decade, genetic association studies performed on several human traits have greatly increased the number of known pleiotropic variants. Based on the hypothesis that variants already associated with a least one trait have a higher probability of association with other traits, 61,052 variants reported to be associated by at least one genome wide association study (GWAS) with at least one human trait were tested in the present study consisting of two phases (discovery and validation), comprising a total of 16,055 pancreatic ductal adenocarcinoma (PDAC) cases and 212,149 controls. The meta-analysis of the two phases showed two loci (10q21.1-rs4948550 (P=6.52×10-5) and 7q36.3-rs288762 (P=3.03×10-5) potentially associated with PDAC risk. 10q21.1-rs4948550 shows a high degree of pleiotropy and it is also associated with colorectal cancer risk while 7q36.3-rs288762 is situated 28,558 base pairs upstream of the Sonic Hedgehog (SHH) gene, which is involved in the cell differentiation process and PDAC etiopathogenesis. In conclusion, none of the single nucleotide polymorphisms (SNPs) showed a formally statistically significant association after correction for multiple testing. However, given their pleiotropic nature and association with various human traits including colorectal cancer, the two SNPs showing the best associations with PDAC risk merit further investigation through fine mapping and ad hoc functional studies.

Post-operative C-reactive protein as a strong independent predictor of long-term colorectal cancer outcomes: consistent findings from two large patient cohorts

BACKGROUND

Post-surgery blood-based biomarkers may be useful for guiding treatment and surveillance decisions among colorectal cancer (CRC) patients. However, most candidate biomarkers provide little if any predictive value beyond stage at diagnosis. We aimed to investigate the independent prognostic value of post-operative serum C-reactive protein (CRP), a highly sensitive biomarker of inflammation, for long-term CRC outcomes in two large patient cohorts.

MATERIALS AND METHODS

CRP levels were measured from serum samples of CRC patients collected ≥1 month post-surgery in the German DACHS (n = 1416) and the UK Biobank (n = 1149) cohorts. Associations of post-operative CRP with overall survival (OS) and CRC-specific survival (CSS) were assessed using Cox regression and presented as hazard ratios (HRs) with 95% confidence intervals (CIs), adjusted for key sociodemographic and clinical covariates.

RESULTS

In both cohorts, consistent strong dose-response relationships between post-operative CRP and both OS and CSS were observed. Adjusted HRs (95% CI) for CRP >10 versus <3 mg/l were 1.93 (1.58-2.35) and 2.70 (2.03-3.59) in the DACHS cohort, and 2.70 (1.96-3.71) and 2.61 (1.83-3.72) in the UK Biobank cohort, respectively. Associations between post-operative CRP and OS were particularly strong among younger patients (<65 years at diagnosis; P value for interaction by age <0.01).

CONCLUSIONS

Serum CRP determined a month or more after surgery may be useful as a strong independent prognostic biomarker for guiding therapeutic decisions and for surveillance of the course of disease of CRC patients, particularly those <65 years of age at diagnosis.

Life expectancy associated with different ages at diagnosis of type 2 diabetes in high-income countries: 23 million person-years of observation

BACKGROUND

The prevalence of type 2 diabetes is increasing rapidly, particularly among younger age groups. Estimates suggest that people with diabetes die, on average, 6 years earlier than people without diabetes. We aimed to provide reliable estimates of the associations between age at diagnosis of diabetes and all-cause mortality, cause-specific mortality, and reductions in life expectancy.

METHODS

For this observational study, we conducted a combined analysis of individual-participant data from 19 high-income countries using two large-scale data sources: the Emerging Risk Factors Collaboration (96 cohorts, median baseline years 1961-2007, median latest follow-up years 1980-2013) and the UK Biobank (median baseline year 2006, median latest follow-up year 2020). We calculated age-adjusted and sex-adjusted hazard ratios (HRs) for all-cause mortality according to age at diagnosis of diabetes using data from 1 515 718 participants, in whom deaths were recorded during 23·1 million person-years of follow-up. We estimated cumulative survival by applying age-specific HRs to age-specific death rates from 2015 for the USA and the EU.

FINDINGS

For participants with diabetes, we observed a linear dose-response association between earlier age at diagnosis and higher risk of all-cause mortality compared with participants without diabetes. HRs were 2·69 (95% CI 2·43-2·97) when diagnosed at 30-39 years, 2·26 (2·08-2·45) at 40-49 years, 1·84 (1·72-1·97) at 50-59 years, 1·57 (1·47-1·67) at 60-69 years, and 1·39 (1·29-1·51) at 70 years and older. HRs per decade of earlier diagnosis were similar for men and women. Using death rates from the USA, a 50-year-old individual with diabetes died on average 14 years earlier when diagnosed aged 30 years, 10 years earlier when diagnosed aged 40 years, or 6 years earlier when diagnosed aged 50 years than an individual without diabetes. Using EU death rates, the corresponding estimates were 13, 9, or 5 years earlier.

INTERPRETATION

Every decade of earlier diagnosis of diabetes was associated with about 3-4 years of lower life expectancy, highlighting the need to develop and implement interventions that prevent or delay the onset of diabetes and to intensify the treatment of risk factors among young adults diagnosed with diabetes.

FUNDING

British Heart Foundation, Medical Research Council, National Institute for Health and Care Research, and Health Data Research UK.

Prediction of clinical diagnosis of Alzheimer's disease, vascular, mixed, and all-cause dementia by a polygenic risk score and APOE status in a community-based cohort prospectively followed over 17 years

The strongest genetic risk factor for Alzheimer's disease (AD) is the ε4 allele of Apolipoprotein E (APOE) and recent genome-wide association meta-analyses have confirmed additional associated genetic loci with smaller effects. The aim of this study was to investigate the ability of an AD polygenic risk score (PRS) and APOE status to predict clinical diagnosis of AD, vascular (VD), mixed (MD), and all-cause dementia in a community-based cohort prospectively followed over 17 years and secondarily across age, sex, and education strata. A PRS encompassing genetic variants reaching genome-wide significant associations to AD (excluding APOE) from the most recent genome-wide association meta-analysis data was calculated and APOE status was determined in 5203 participants. During follow-up, 103, 111, 58, and 359 participants were diagnosed with AD, VD, MD, and all-cause dementia, respectively. Prediction ability of AD, VD, MD, and all-cause dementia by the PRS and APOE was assessed by multiple logistic regression and receiver operating characteristic curve analyses. The PRS per standard deviation increase in score and APOE4 positivity (≥1 ε4 allele) were significantly associated with greater odds of AD (OR, 95% CI: PRS: 1.70, 1.45-1.99; APOE4: 3.34, 2.24-4.99) and AD prediction accuracy was significantly improved when adding the PRS to a base model of age, sex, and education (ASE) (c-statistics: ASE, 0.772; ASE + PRS, 0.810). The PRS enriched the ability of APOE to discern AD with stronger associations than to VD, MD, or all-cause dementia in a prospective community-based cohort.

Incident depression and mortality among people with different types of dementia: results from a longitudinal cohort study

PURPOSE

The aim of this study was to investigate the independent and combined association of incident depression and dementia with mortality and to explore whether the magnitude of the association varies according to different types of dementia, including Alzheimer's disease and vascular dementia.

METHODS AND DESIGN

The study was based on a population-based longitudinal cohort consisting of 9940 participants at baseline and followed for over 14 years. The sample used for the analyses included 6114 participants with available information on diagnosis of incident dementia and depression. For survival analyses, Cox regression models with incident dementia (n = 293; 5%) and incident depression (n = 746; 12%) as time-dependent variables were used.

RESULTS

Cox models adjusted for relevant confounders indicated that comorbidity of incident vascular dementia and incident depression was associated with a much higher mortality risk (HR 6.99; 95% CI 3.84-12.75) than vascular dementia in the absence of depression (HR 2.80; 95% CI 1.92-4.08). In contrast, estimates for comorbidity of Alzheimer's disease and depression were slightly lower than those for Alzheimer in absence of depression (HR 3.56; 95% CI 1.83-6.92 and HR 4.19; 95% CI 2.97-5.90, respectively). Incident depression in the absence of incident dementia was only weakly associated with mortality.

CONCLUSIONS

These findings indicate that depression and vascular dementia might have synergistic effects on mortality. The results have relevant public health implications for prevention, routine screening for and early treatment of depression among older people, especially those at risk of vascular dementia.

Association of generalized anxiety symptoms and panic with health care costs in older age-Results from the ESTHER cohort study

BACKGROUND

Little is known specifically about the association between generalized anxiety symptoms or panic and health care costs in older age. The aim of this study was to examine the association between generalized anxiety symptoms, panic and health care costs in people aged 65 and over.

METHODS

Cross-sectional data from the 8-year follow-up of a large, prospective cohort study, the ESTHER study, was used. Individuals aged 65 and over, who participated in the study's home assessment, were included in this analysis (n = 2348). Total and sectoral costs were analyzed as a function of either anxiety symptoms, probable panic disorder, or a panic attack, while controlling for selected covariates, using Two Part and Generalized Linear Models. Covariates were chosen based on Andersen's Behavioral Model of Health Care Use.

RESULTS

There was no significant association between either of the anxiety or panic measures and total health care costs. Stratified by health care sectors, only the occurrence of a panic attack was significantly associated with incurring costs for outpatient non-physician services (OR: 1.99; 95% CI: 1.15-3.45) and inpatient services (OR: 2.14; 95% CI: 1.07-4.28). Other illness-related factors, such as comorbidities and depressive symptoms, were associated with health care costs in several models.

LIMITATIONS

This was a cross-sectional study relying on self-reported data.

CONCLUSION

This study points to an association between a panic attack and sector-specific health care costs in people aged 65 and over. Further research, especially using longitudinal data, is needed.

Unterschiede in der Morbidität nach Krankenversichertenstatus im Alter

Ziel der Studie: Es fehlen bislang Studien, die Morbiditätsunterschiede zwischen GKV und PKV in der älteren Bevölkerung untersuchen. Ziel dieser Studie ist es daher, Unterschiede in der Morbidität zwischen den Versicherten der GKV und PKV im Alter aufzudecken.

Methodik: Es wurden Daten von 2 Follow-Up-Wellen mit einem Abstand von 3 Jahren herangezogen. Diese basieren auf einer bevölkerungsbezogenen Kohortenstudie (ESTHER Studie) im Saarland. Die Morbidität wurde durch Hausarztangaben mit einem generischen Instrument (Cumulative Illness Rating Scale for Geriatrics) erfasst. Zur Schätzung wurde der Between-Schätzer herangezogen, der ausschließlich die Variation zwischen den Individuen quantifiziert. Dabei wurde im Basismodell neben dem Versichertenstatus für das Geschlecht und das Alter kontrolliert. In weiteren Modellen wurde sukzessive ebenfalls für Schulbildung, den Familienstand und das Einkommen kontrolliert.

Ergebnisse: Während in den Spezifikationen ohne Berücksichtigung des Einkommens beträchtliche Unterschiede in der Morbidität zwischen PKV- und GKV-Versicherten erkennbar waren, mindert sich dieser Effekt unter Kontrolle des Einkommens stark und war bei Männern nicht mehr signifikant.

Schlussfolgerung: Zu einem bedeutenden Teil können existierende Morbiditätsunterschiede zwischen Versicherten der GKV und PKV durch Einkommensunterschiede zwischen den beiden Gruppen erklärt werden. Dies zeigt die große Bedeutung der Ausgestaltung des Modells bei der Untersuchung von Morbiditätsunterschieden zwischen GKV und PKV auf.

Impact of prediagnostic smoking and smoking cessation on colorectal cancer prognosis: a meta-analysis of individual patient data from cohorts within the CHANCES consortium

Background

Smoking has been associated with colorectal cancer (CRC) incidence and mortality in previous studies and might also be associated with prognosis after CRC diagnosis. However, current evidence on smoking in association with CRC prognosis is limited.

Patients and methods

For this individual patient data meta-analysis, sociodemographic and smoking behavior information of 12 414 incident CRC patients (median age at diagnosis: 64.3 years), recruited within 14 prospective cohort studies among previously cancer-free adults, was collected at baseline and harmonized across studies. Vital status and causes of death were collected for a mean follow-up time of 5.1 years following cancer diagnosis. Associations of smoking behavior with overall and CRC-specific survival were evaluated using Cox regression and standard meta-analysis methodology.

Results

A total of 5229 participants died, 3194 from CRC. Cox regression revealed significant associations between former [hazard ratio (HR) = 1.12; 95 % confidence interval (CI) = 1.04-1.20] and current smoking (HR = 1.29; 95% CI = 1.04-1.60) and poorer overall survival compared with never smoking. Compared with current smoking, smoking cessation was associated with improved overall (HR<10 years = 0.78; 95% CI = 0.69-0.88; HR≥10 years = 0.78; 95% CI = 0.63-0.97) and CRC-specific survival (HR≥10 years = 0.76; 95% CI = 0.67-0.85).

Conclusion

In this large meta-analysis including primary data of incident CRC patients from 14 prospective cohort studies on the association between smoking and CRC prognosis, former and current smoking were associated with poorer CRC prognosis compared with never smoking. Smoking cessation was associated with improved survival when compared with current smokers. Future studies should further quantify the benefits of nonsmoking, both for cancer prevention and for improving survival among CRC patients, in particular also in terms of treatment response.

Excess mortality after hip fracture in elderly persons from Europe and the USA: the CHANCES project

BACKGROUND

Hip fractures are associated with diminished quality of life and survival especially amongst the elderly.

OBJECTIVE

All-cause mortality after hip fracture was investigated to assess its magnitude.

METHODS

A total of 122 808 participants from eight cohorts in Europe and the USA were followed up for a mean of 12.6 years, accumulating 4273 incident hip fractures and 27 999 deaths. Incident hip fractures were assessed through telephone interviews/questionnaires or national inpatient/fracture registries, and causes of death were verified with death certificates. Cox proportional hazards models and the time-dependent variable methodology were used to assess the association between hip fracture and mortality and its magnitude at different time intervals after the injury in each cohort. We obtained the effect estimates through a random-effects meta-analysis.

RESULTS

Hip fracture was positively associated with increased all-cause mortality; the hazard ratio (HR) in the fully adjusted model was 2.12, 95% confidence interval (CI) 1.76-2.57, after adjusting for potential confounders. This association was stronger amongst men [HR: 2.39, 95% CI: 1.72-3.31] than amongst women [HR: 1.92, 95% CI: 1.54-2.39], although this difference was not significant. Mortality was higher during the first year after the hip fracture [HR: 2.78, 95% CI: 2.12-3.64], but it remained elevated without major fluctuations after longer time since hip fracture [HR (95% CI): 1.89 (1.50-2.37) after 1-4 years; 2.15 (1.81-2.55) after 4-8 years; 1.79 (1.57-2.05) after 8 or more years].

CONCLUSION

In this large population-based sample of older persons across eight cohorts, hip fracture was associated with excess short- and long-term all-cause mortality in both sexes.

Education, marital status, and risk of hip fractures in older men and women: the CHANCES project

The role of socioeconomic status in hip fracture incidence is unclear. In a diverse population of elderly, higher education was found to be associated with lower, whereas living alone, compared to being married/cohabiting, with higher hip fracture risk. Educational level and marital status may contribute to hip fracture risk.

INTRODUCTION

The evidence on the association between socioeconomic status and hip fracture incidence is limited and inconsistent. We investigated the potential association of education and marital status with hip fracture incidence in older individuals from Europe and USA.

METHODS

A total of 155,940 participants (79 % women) aged 60 years and older from seven cohorts were followed up accumulating 6456 incident hip fractures. Information on education and marital status was harmonized across cohorts. Hip fractures were ascertained through telephone interviews/questionnaires or through record linkage with registries. Associations were assessed through Cox proportional hazard regression adjusting for several factors. Summary estimates were derived using random effects models.

RESULTS

Individuals with higher education, compared to those with low education, had lower hip fracture risk [hazard ratio (HR) = 0.84, 95 % confidence interval (CI) 0.72-0.95]. Respective HRs were 0.97 (95 % CI 0.82-1.13) for men and 0.75 (95 % CI 0.65-0.85) for women. Overall, individuals living alone, especially those aged 60-69 years, compared to those being married/cohabiting, tended to have a higher hip fracture risk (HR = 1.12, 95 % CI 1.02-1.22). There was no suggestion for heterogeneity across cohorts (P heterogeneity > 0.05).

CONCLUSIONS

The combined data from >150,000 individuals 60 years and older suggest that higher education may contribute to lower hip fracture risk. Furthermore, this risk may be higher among individuals living alone, especially among the age group 60-69 years, when compared to those being married/cohabiting.

Association of pre- and post-natal parental smoking with offspring body mass index: an 8-year follow-up of a birth cohort

BACKGROUND

Although many epidemiological studies have shown an association between maternal smoking during pregnancy and offspring overweight, it is still under debate whether intrauterine tobacco smoke exposure directly affects offspring obesity or if the association is rather due to confounding by lifestyle factors.

OBJECTIVES

The association of parental smoking habits at pre- and post-natal periods with offspring body mass index (BMI) was investigated, whereas maternal smoking during pregnancy was validated by cord serum cotinine measurements.

METHODS

Multivariable linear regression analysis, based on the German Ulm Birth Cohort Study of 1045 children born in 2000 with annual/biennial follow-up until the age of 8 years (n = 609), was conducted.

RESULTS

BMI of offspring from mothers who smoked during pregnancy and non-smoking mothers differed significantly at 8 years. Maternal smoking during pregnancy was associated with an increase in BMI of 0.73 kg m(-2) [95% confidence interval: 0.21-1.25] in 8-year-old children after adjustment for multiple potential confounding variables. Both pre- and post-natal smoking of fathers (0.34 [0.01-0.66]/0.45 [0.08-0.81]) and of both parents (1.03 [0.43-1.63]/0.56 [0.14-0.98]) were likewise significantly associated with offspring BMI.

CONCLUSIONS

The observed patterns suggest that residual confounding by living conditions in smoking families rather than specific intrauterine exposure to tobacco smoke may account for the increased risk of offspring overweight.

Serum 25-hydroxyvitamin D and incidence of fatal and nonfatal cardiovascular events: a prospective study with repeated measurements

CONTEXT

Several studies suggested that low serum concentrations of 25-hydroxyvitamin D (25(OH)D) are associated with an increased risk of cardiovascular disease (CVD). However, the evidence is still inconclusive, mostly based on CVD mortality and studies with single 25(OH)D measurements.

OBJECTIVE

We aimed to assess the association of 25(OH)D with fatal and nonfatal CVD in the same study population, using repeated 25(OH)D measurements and competing risks analysis.

DESIGN

This was a population-based cohort study (ESTHER study, baseline 2000-2002). Follow-up data, including survival status, were collected after 2, 5, and 8 years. The response rate for survival was 99.9%.

SETTING

Participants were recruited during a health screening examination by their general practitioners. 25(OH)D was measured in blood samples collected at baseline and the 5-year follow-up visit.

PATIENTS OR OTHER PARTICIPANTS

A total of 9949 men and women, aged 50 to 74 years at baseline, with sufficient knowledge of the German language and resident in the German state of Saarland were included in the study.

MAIN OUTCOME MEASURES

Outcomes included CVD, coronary heart disease (CHD), and stroke, in total and differentiated into fatal and nonfatal events.

RESULTS

Overall, 854 study participants had a nonfatal and 176 a fatal CVD event during 8 years of follow-up. Comparing subjects with 25(OH)D levels below 30 nmol/L and above 50 nmol/L resulted in a hazard ratio of 1.27 (95% confidence interval = 1.05-1.54) for total CVD and 1.62 (95% confidence interval = 1.07-2.48) for fatal CVD in a model adjusted for important potential confounders. No significant association for nonfatal CVD was observed. In dose-response analysis, we observed an increased cardiovascular risk at 25(OH)D levels below 75 nmol/L. Results for CHD and stroke were comparable to the results obtained for the composite outcome CVD.

CONCLUSIONS

Our results support evidence that low 25(OH)D levels are associated with moderately increased risk of CVD and indicate that the observed association is much stronger for fatal than for nonfatal events.

Prognostic association of HbA1c and fasting plasma glucose with reduced kidney function in subjects with and without diabetes mellitus. Results from a population-based cohort study from Germany

OBJECTIVE

To determine the risk for incident reduced kidney function (RKF) of subjects with pre-diabetes (impaired fasting glucose (IFG, 5.6-6.9 mmol/L)) or HbA1c-defined pre-diabetes (5.7%-6.4%) and to determine dose-response relationships of fasting glucose and HbA1c with RKF in subjects with manifest diabetes mellitus.

METHOD

In a German population-based cohort, recruited 2000-2002 with ages 50-74 years, log-binomial regression was used to estimate relative risks (RR) with 95% confidence intervals (95%CI) and restricted cubic splines to plot dose-response relationships.

RESULTS

During 8 years of follow-up, 678 of 3538 study participants developed primary RKF. Although RKF risk factor prevalences and RKF incidences were higher in subjects with pre-diabetes than in subjects with normal FPG and/or HbA1c levels, an increased risk did not persist after adjusting for established cardiovascular risk factors (RR(IFG): 0.97 (95% CI: 0.75-1.25) and RR(HbA1c-defined pre-diabetes): 1.03 (95% CI: 0.86-1.23)). In subjects with manifest diabetes, RKF risk increased linearly to a more than three-fold risk with increasing fasting glucose and HbA1c levels (at HbA1c>6.4%).

CONCLUSION

This study provides further evidence that pre-diabetes may not directly contribute to the development of kidney disease. Subjects with pre-diabetes might nevertheless profit from preventive efforts reducing their cardiovascular risk profile because cardiovascular and kidney disease share common risk factors.

Fasting plasma glucose and HbA1c in cardiovascular risk prediction: a sex-specific comparison in individuals without diabetes mellitus

AIMS/HYPOTHESIS

This study aimed to assess the cardiovascular risk of individuals with fasting plasma glucose (FPG)- and/or HbA(1c)-defined prediabetes (5.6-6.9 mmol/l and 39-47 mmol/mol [5.7-6.4%], respectively) or manifest diabetes mellitus and to evaluate whether FPG or HbA(1c) can improve risk prediction beyond that estimated by the Systematic Coronary Risk Evaluation (SCORE) chart in individuals without diabetes mellitus.

METHODS

Cox regression was employed to estimate HRs for primary incident cardiovascular events (CVEs) in a cohort of 8,365 individuals aged 50-74 years. Furthermore, HbA(1c) and FPG were added individually to the variables of the SCORE and measures of model discrimination and reclassification were assessed.

RESULTS

During 8 years of follow-up, 702 individuals had a primary CVE. After adjusting for conventional cardiovascular risk factors, HRs were attenuated close to one for the prediabetes groups (especially for women), whereas a 1.7- and a 1.9-fold increased risk persisted for men and women with diabetes, respectively. Extension of the SCORE variables by either FPG or HbA(1c) did not improve its predictive abilities in individuals without diabetes. There was a non-significant net reclassification improvement for men when HbA(1c) was added (2.2%, p = 0.16).

CONCLUSIONS/INTERPRETATION

The increased cardiovascular risk of individuals with FPG- or HbA(1c)-defined prediabetes can mainly be explained by other cardiovascular risk factors. Adding FPG or HbA(1c) did not significantly improve CVE risk prediction by the SCORE variables in individuals without diabetes mellitus.

Acute transient encephalopathy after paclitaxel infusion: report of three cases

Paclitaxel (Taxol) is a diterpene plant product and antineoplastic agent that promotes the assembly of microtubules as well as stabilizing their formation by preventing depolymerization. Myelosuppression was found to be dose-limiting, but peripheral neurotoxicity is also a well known side-effect. Central nervous system toxicity is rare, probably because paclitaxel does not cross the blood-brain barrier. We observed three patients who presented with acute encephalopathy within 6 h after infusion of paclitaxel at normal doses. All patients had received prior whole brain irradiation (WBI) and one patient had prior brain metastasectomy. Computer tomography and magnetic resonance imaging showed no evidence of cerebral metastases. An effect from other organ toxicities was excluded in all patients. All recovered spontaneously within 4-6 h. From this we can conclude that paclitaxel can cause severe acute transient encephalopathy, which may occur more frequently after prior WBI and/or surgery due to alteration of small vessel function.

Low frequency of enteric infections by Salmonella, Shigella, Yersinia and Campylobacter in patients with acute leukemia

BACKGROUND

Several authors found that isolation of Salmonella, Shigella, Yersinia and Campylobacter spp. (SSYC) from stool cultures after the 3rd day of hospitalization is a rare event. The significance of enteric infections caused by these pathogens has not been systematically investigated in severely immunosuppressed patients with acute leukemia.

PATIENTS AND METHODS

We screened all patients treated on the leukemia ward of a university medical center. A total of 1,185 stool cultures from 371 episodes of diarrhea, mostly following myelosuppressive chemotherapy, were examined for the complete range of classic bacterial enteric pathogens (i.e. SSYC).

RESULTS

Only three (0.25%) cultures from one patient were positive for Salmonella enteritidis. This patient suffered from cholangitis. S. enteritidis could also be detected by liver biopsy. Other infections by classic enteric pathogens were not observed.

CONCLUSION

Symptomatic infections by classic bacterial enteric pathogens in hospitalized patients with acute leukemia are very rare. Stool cultures for these pathogens cannot be recommended as a routine test in uncomplicated diarrhea occurring after the 3rd hospital day.

Interactions between dendritic cells and cytokine-induced killer cells lead to an activation of both populations

Dendritic cells (DCs) are major antigen-presenting cells. They are capable of capturing and processing tumor antigens, expressing lymphocyte costimulatory molecules, and secreting cytokines to initiate immune responses. Here, the authors tested the effect of cytokine-induced killer (CIK) cells, a population that includes CD3+CD56+ cells (natural killer T cells), with regard to their capacity to immunomodulate DCs. Cytokine-induced killer cells were cocultured with autologous DCs generated from peripheral blood mononuclear cells. Expression of markers typical for both populations was measured using flow cytometry, and secretion of interleukin (IL)-12 was determined using enzyme-linked immunosorbent assays. Cytotoxicity assays were performed to investigate the role of IL-12 and the importance of cell-cell interactions. Considering this, receptors for IL-12 and CD40 were blocked and cocultures were performed with cell culture inserts. Coculture of CIK cells led to a significant increase of DC-specific, costimulatory, and antigen-presenting molecules in DC cultures. In addition, coculture resulted in a dramatically increase of IL-12 secretion by DCs and to a significant increase in cytotoxic activity of CIK cells toward carcinoma cells. Blockage of IL-12 uptake decreased the cytolytic activity of CIK cells. Cytokine secretion was shown to be important for activation of CIK cells, and also cellular interactions between DCs and effector cells caused a higher cytolytic capacity. Interactions between DCs and CIK cells caused changes in the surface molecule expression of both populations, led to an increase of IL-12 secretion, and rendered an improved cytotoxic activity. The natural killer T cell subpopulation seems to be responsible for this effect. Therefore, coculture of DCs with CIK cells may have a major impact on immunotherapeutic protocols for patients with cancer.

A novel minimal-size vector (MIDGE) improves transgene expression in colon carcinoma cells and avoids transfection of undesired DNA

Viral and plasmid vectors may cause unwanted immunological side effects resulting from the expression of nontherapeutic genes contained in their sequence. Furthermore, replication-defective viral vectors carry the potential risk of recombination with wild-type viruses or activation of oncogenes. A new vector type for minimalistic, immunologically defined gene expression (MIDGE) may overcome these problems. MIDGE is a minimal-size gene transfer unit containing the expression cassette, including promoter, gene, and RNA-stabilizing sequence, flanked by two short hairpin oligonucleotide sequences. The resulting vector is a small, linear, covalently closed, dumbbell-shaped molecule. DNA not encoding the desired gene is reduced to a minimum. Here, we transfected colon carcinoma cell lines using cationic lipid, cationic polymer, and electroporation with several MIDGE vectors and corresponding plasmids containing transgenes encoding enhanced green fluorescent protein (eGFP) and human interleukin-2 (hIL-2). Transfection efficiency as measured qualitatively and quantitatively with eGFP was found to be comparable for both vector types. However, hIL-2 secretion and eGFP expression were approximately two- to fourfold higher in most cells transfected with these transgenes using MIDGE vectors compared to the plasmid control. This report demonstrates the advantages of this new vector type and its prospects for ex vivo gene therapy studies.

Effects of adenoviral wild-type p53 gene transfer in p53-mutated lymphoma cells

The present study assessed the role of adenoviral vector-mediated wild-type p53 gene transfer in B lymphoma cells. Deficiency of p53-mediated cell death is common in human cancer contributing to both tumorigenesis and chemoresistance. Lymphoma cells are being considered as suitable targets for gene therapy protocols. Recently, we reported an adenoviral protocol leading to highly efficient gene transfer to B lymphoma cells. All lymphoma cell lines (n=5) tested here showed mutations in the p53 gene locus. The aim of this work was to transduce lymphoma cells with the wild-type p53 gene. Using this protocol, 88% of Raji, 75% of Daudi, and 45% of OCI-Ly8-LAM53 cells were transfected with the reporter gene green fluorescent protein at a multiplicity of infection of 200. The expression of green fluorescent protein in CA46 and BL41 cells was 27% and 42%, respectively. At this multiplicity of infection, growth characteristics of lymphoma cell lines were not changed significantly. In contrast, cells transduced with wild-type p53 gene showed an inhibition of proliferation as well as an increase in apoptosis. Cell loss by apoptosis after p53 gene transfer was up to 40% as compared to transduction with an irrelevant vector. In addition, we determined the effects of DNA damage produced by the DNA topoisomerase II inhibitor etoposide on wild-type p53 transfected lymphoma cells. In Ad-p53-transfected Raji cells, treatment with the drug resulted in a marked increase of cell loss in comparison to Ad-beta-Gal-transfected cells (45% vs. 77%). Interestingly, performing cytotoxicity studies, we could show an increased sensitivity of Raji and Daudi cells against immunological effector cells. In conclusion, transduction of wild-type p53 into lymphoma cells expressing mutated p53 was efficient and led to inhibition of proliferation and increase in apoptotic rate in some cell lines dependent on p53 mutation. This protocol should have an impact on the use of lymphoma cells in cancer gene therapy protocols.

Increased sensitivity of myeloid leukemia cell lines: potential of lovastatin as bone-marrow-purging agent

Lovastatin reduces the isoprenylation of p21ras via suppression of mevalonic acid generation. Lovastatin has been shown to reduce tumor cell proliferation in a dose-dependent manner. Here, the potential of lovastatin for purging leukemia cells from bone marrow was investigated using the myeloblastic cell lines K562 and KG-1 as a model system, derived from an erythroleukemia and an acute myelogenous leukemia, respectively. Optimal purging conditions were determined using an MTT proliferation and a leukemia colony assay. Elimination of leukemia cells was time- and dose-dependent. Depletion of K562 was 2.5 logs for 100 microM of lovastatin at 72 h of incubation. Compared to another purging agent, 100 microg/ml mafosfamide had an activity comparable to 100 mM lovastatin. Interestingly, KG-1 acute myelogenous leukemia cells were even more sensitive to lovastatin than K562 cells. In clonogenic assays, 100 microM of lovastatin resulted in a 3- to 4-log reduction of K562 colonies. Lovastatin had a progressive effect on normal hematopoietic progenitor cells. At a concentration of 100 microM of lovastatin, CFU-GM colonies were reduced by 1-2 logs. In conclusion, a differential effect on leukemia and normal progenitor cells could be detected in a clonogenic assay. These results suggest that lovastatin deserves further study as an agent for ex vivo marrow purging.

Transfection of dendritic cells (DCs) with the CIITA gene: increase in immunostimulatory activity of DCs

Dendritic cells (DCs) are the major antigen-presenting cells. They are able to present tumor antigens to immunologic effector cells. MHC class II molecules on DC surfaces play an important role in priming effector cells against tumor cells and their antigens. The transactivator CIITA (MHC class II transactivator) is a non-DNA-binding transactivator, which regulates the expression of MHC class II, HLA-DM, and invariant chain and behaves as a master controller of constitutive and inducible MHC class II gene activation. Here, we transfected DCs with the CIITA gene using a novel transfection technique. The vector system consisted of a plasmid bound to an adenovirus via poly-L-lysine, which is covalently bound to a UV-irradiated adenovirus. After transfection, expression of MHC class II on DCs increased from 27% to 75% on day 2 after transfection. Transfected DCs were co-cultured with immunologic effector cells. Cytotoxicity of effector cells against tumor cells increased after co-culture with transfected DCs to 63% compared to 15% with effector cells co-cultured with irrelevantly transfected DCs (P=.037). This effect was dependent on the timing and period of co-culture. In conclusion, transfection of DCs led to an increase in antitumoral immunostimulatory capacity of DCs. We can further conclude that DCs could be efficiently transfected with the CIITA gene. Transfection of DCs led to an increase in antitumoral immunostimulatory capacity of DCs and may have a major impact on immunotherapeutic protocols for patients with cancer.

Resistance of pancreatic carcinoma cells is reversed by coculturing NK-like T cells with dendritic cells pulsed with tumor-derived RNA and CA 19-9

Immunization with defined tumor antigens is limited to the small number of cancers in which specific tumor antigens have been defined but insufficient tumor material is available to produce an antitumor vaccine. In this study, we investigated whether pulsing dendritic cells (DC) using a liposomal transfer technique with a pancreatic tumor cell line-derived RNA can effectively activate NK-like T cells and tumor immunity. Pulsed DC were cocultured with NK-like T cells, i.e., CD3+CD56+ cells, as immunologic effector cells. Target cells resistant to NK-like T-cell-mediated lysis were used. Total tumor-derived RNA transfected into DC was found to completely reverse tumor cell resistance. Total tumor RNA transfection (30 microg) was found to be superior to poly(A)(+) RNA transfection (5 microg) in inducing NK-like T lymphocytes. Interestingly, additional pulsing of DC with the CA 19-9 peptide in a CA 19-9-positive cell line further increased the sensitivity of pancreas carcinoma cells to NK-like T cells. Treatment of tumor RNA with RNase completely blocked the effect of RNA-transfected DC on NK-like T cells, suggesting that intact tumor-derived RNA is needed for reversal of tumor cell resistance. In conclusion, coculture of NK-like T cells with DC transfected with pancreatic tumor cell line-derived RNA reverses pancreatic tumor cell resistance by directly triggering NK-like T lymphocytes.

Increase in the immunostimulatory effect of dendritic cells by pulsing with serum derived from pancreatic and colorectal cancer patients

Both we and others have observed a relative resistance of solid tumor cells to immunological effector cells in vitro, which may be one reason for the clinical phenomenon of resistance of patients with pancreatic carcinoma or other solid tumors to immunological therapeutic approaches. Dendritic cells (DC) are professional antigen-presenting cells which can process and present tumor-associated antigens such as CA 19-9. Here we tested DC pulsed with serum containing CA 19-9 for their capacity to stimulate immunological effector cells against pancreatic carcinoma cells. Coculture of immunological effector cells with DC led to a significant increase in cytotoxic activity as measured by a lactic dehydrogenase release assay. Most interestingly, cytotoxic activity against tumor cells was further increased using DC pulsed with patient-derived CA 19-9 containing serum. Similar results have been obtained using either autologous or allogeneic serum from patients with pancreas carcinoma. The effect of serum on the cytotoxicity of effector cells increased in a dose-dependent manner. Interestingly, heat inactivation led to a significant loss of immunostimulatory capacity of the serum. Cytotoxicity was partially inhibited by using an antibody directed against CA 19-9 on the surface of the target cells. Best results were obtained when adding CA 19-9 protein to CA 19-9 containing serum for pulsing of DC. In conclusion, DC pulsed with CA 19-9 containing serum increased the cytotoxic activity of immunological effector cells against pancreatic cancer cells. DC pulsed with CA 19-9 containing serum with or without additional exogenous CA 19-9 protein may have an impact on immunotherapeutic protocols for patients with CA 19-9 secreting tumors.

Increase of the immunostimulatory effect of dendritic cells by pulsing with CA 19-9 protein

Previously, a relative resistance of solid tumor cells to immunologic effector cells was shown in vitro. This resistance could be one reason for the clinical phenomenon of resistance of patients with colon carcinoma or other solid tumors to immunologic therapeutic approaches. In this study, dendritic cells (DCs) pulsed with CA 19-9 protein were tested for their immunostimulatory capacity of immunologic effector cells against cells derived from colon and pancreatic carcinoma. Dendritic cell cultures coexpressed CMRF-44 and CD1a, markers typical of DCs, in 31.5% +/- 5.3% after 13 days of culture. Coculture of NK-like T lymphocytes with DCs led to a significant increase in cytotoxic activity, as measured using a lactate dehydrogenase release assay. Cytotoxic activity could be further increased using DCs pulsed with CA 19-9 protein. The effect of CA 19-9 on increasing the cytotoxic effect of NK-like T lymphocytes was dose dependent. Similarly, cocultivation of DCs with NK-like T cells derived from patients with metastatic pancreatic cancer and elevated CA 19-9 serum levels led to a significant increase in cytotoxic activity. In conclusion, DCs pulsed with CA 19-9 protein can increase the cytotoxic activity of immunologic effector cells against colon carcinoma and pancreatic cancer cells. Dendritic cells pulsed with CA 19-9 protein may have an important effect on immunotherapeutic protocols for patients with cancer.