Gastroenterology & Hepatology

Comparison of 2 expandable stents for malignant esophageal disease: A randomized controlled trial (Article)

Heel, N.C.M. van — 2012-07-01T00:00:00Z

Background: Self-expanding metal stents (SEMSs) provide effective palliation in patients with malignant dysphagia. However, although life expectancy is generally limited, reintervention rates because of stent dysfunction are significant. New SEMSs are being designed to overcome this drawback. Objectives: To investigate whether the results of SEMS placement could be improved with a new SEMS design. Patients: Consecutive patients with dysphagia or leakage caused by malignant esophageal disease. Methods: In a multicenter randomized clinical trial, consecutive patients with dysphagia or leakage because of malignant esophageal disease were randomized to placement of a conventional stent or the new stent. Patients were followed up by scheduled telephone calls 1 and 3 months after SEMS insertion. Results: A total of 80 patients (73% male; median age, 67 years [range, 40-92 years]) were included. One patient refused follow-up. Technical success was 100% in both groups. The reintervention rate was 15/40 (38%) for the conventional stent and 4/39 (10%) for the new stent (P = .004). Major complications, including aspiration pneumonia and bleeding, occurred more frequently with the conventional stent (10/40, 25%) than with the new stent (3/39, 8%, P = .04). There was no difference in overall survival between the 2 groups. Limitations: Inclusion of patients with a perforation or fistula. Conclusions: The conventional stent and the new stent were equally effective in the relief of malignant dysphagia and sealing fistulae. The conventional stent was associated with more stent dysfunction and a significantly higher rate of major complications. Patients treated with the new stent also needed significantly fewer reinterventions than did those treated with a conventional stent. This sets the preference for the new stent over the conventional stent for patients with malignant esophageal disease. (Clinical Trial registration number: ABR27137.)

Characterization of a three-dimensional mucosal equivalent: Similarities and differences with native oral mucosa (Article)

Tra, W.M.W. — 2012-02-01T00:00:00Z

The aim of this study was to create and characterize a tissue-engineered mucosal equivalent (TEM) that closely resembles native mucosa. TEM consists of human primary keratinocytes and fibroblasts isolated from biopsies taken from healthy donors and seeded onto a de-epidermized dermis and cultured for 14 days at the air/liquid interface. The structure of TEM was examined and compared with native nonkeratinizing oral mucosa (NNOM). The various components of the newly formed epidermal layer, basement membrane and underlying connective tissue were analyzed using immunohistochemistry. The mucosal substitute presented in this study showed a mature stratified squamous epithelium that was similar to that of native oral mucosa, as demonstrated by K19, desmoglein-3 and involucrin staining. In addition, the expression of basement membrane components collagen type IV, laminin-5 and integrin α6 and β4 in TEM proved to be consistent with native oral mucosa. The expression of PAS, Ki67, K10 and K13, however, appeared to be different in TEM compared to NNOM. Nevertheless, the similarities with native oral mucosa makes TEM a promising tool for studying the biology of mucosal pathologies such as oral mucositis or fibrosis as well as the development of new therapies. Copyright

The Rotterdam Study: 2012 objectives and design update (Article)

Hofman, A. — 2011-08-31T00:00:00Z

Abstract The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Peutz-Jeghers syndrome and family planning: the attitude towards prenatal diagnosis and pre-implantation genetic diagnosis (Article)

Lier, M.G.F. van — 2011-08-10T00:00:00Z

Peutz-Jeghers syndrome (PJS) is a hereditary disorder caused by LKB1 gene mutations, and is associated with considerable morbidity and decreased life expectancy. This study was conducted to assess the attitude of PJS patients towards family planning, prenatal diagnosis (PND) and pregnancy termination, and pre-implantation genetic diagnosis (PGD). In a cross-sectional study, 61 adult PJS patients were asked to complete a questionnaire concerning genetic testing, family planning, PND and PGD. The questionnaire was completed by 52 patients (85% response rate, 44% males) with a median age of 44 (range 18-74) years. A total of 37 (71%) respondents had undergone genetic testing. In all, 24 respondents (46%, 75% males) had children. A total of 15 (29%) respondents reported that their diagnosis of PJS had influenced their decisions regarding family planning, including 10 patients (19%, 9/10 females) who did not want to have children because of their disease. Termination of pregnancy after PND in case of a foetus with PJS was considered 'acceptable' for 15% of the respondents, whereas 52% considered PGD acceptable. In conclusion, the diagnosis of PJS influences the decisions regarding family planning in one third of PJS patients, especially in women. Most patients have a negative attitude towards pregnancy termination after PND, while PGD in case of PJS is judged more acceptable. These results emphasise the importance of discussing aspects regarding family planning with PJS patients, including PND and PGD.European Journal of Human Genetics advance online publication, 10 August 2011; doi:10.1038/ejhg.2011.152.

Breaking the barrier: using extractable fully covered metal stents to treat benign biliary hilar strictures (Article)

Poley, J.W. — 2011-08-08T00:00:00Z

Background: Most benign biliary strictures nowadays are managed endoscopically with plastic stents or with a insertion of a fully covered self-expandable metal stent (fcSEMS). The paradigm for the treatment of benign hilar strictures precludes the use of an fcSEMS because it obstructs the intrahepatic bile ducts, in particular, the contralateral hepatic duct. It is unknown whether use of a plastic stent in the opposite hepatic duct after deployment of an fcSEMS across the liver hilum provides an adequate solution for this problem. Objective: To evaluate the use of an fcSEMS in combination with a contralateral plastic stent in the treatment of benign hilar strictures. Design: Case series. Setting: Tertiary referral hospital. Patients: Two consecutive patients with benign hilar strictures. Interventions: Placement of an intrahepatically deployed fcSEMS in conjunction with a contralateral 10F plastic stent for 4 to 5 months followed by stent removal and cholangiogram. Main Outcome Measurements: Clinical and laboratory follow-up of at least 9 months. Results: In both patients, the indwelling period of the stents was uneventful as was stent removal. Both strictures resolved, and there were no clinical or biochemical signs of a recurrent stricture. Limitations: Small number of patients. Conclusions: Treatment of benign hilar strictures with an fcSEMS deployed across the liver hilum in conjunction with a contralateral plastic stent placement is feasible without ensuing cholangitis caused by bile duct occlusion.

Impeded protein folding and function in active inflammatory bowel disease (Article)

Deuring, J.J. — 2011-08-01T00:00:00Z

The intestinal tract is covered by a total of 300 square metres of IECs (intestinal epithelial cells) that covers the entire intestinal mucosa. For protection against luminal xenobiotics, pathogens and commensal microbes, these IECs are equipped with membrane-bound transporters as well as the ability to secrete specific protective proteins. In patients with active IBD (inflammatory bowel disease), the expression of these proteins, e.g. ABC (ATP-binding cassette) transporters such as ABCG2 (ABC transporter G2) and defensins, is decreased, thereby limiting the protection against various luminal threats. Correct ER (endoplasmic reticulum)-dependent protein folding is essential for the localization and function of secreted and membrane-bound proteins. Inflammatory triggers, such as cytokines and nitric oxide, can impede protein folding, which causes the accumulation of unfolded proteins inside the ER. As a result, the unfolded protein response is activated which can lead to a cellular process named ER stress. The protein folding impairment affects the function and localization of several proteins, including those involved in protection against xenobiotics. In the present review, we discuss the possible inflammatory pathways affecting protein folding and eventually leading to IEC malfunction in patients with active IBD. ©The Authors Journal compilation

Serum HBsAg decline during long-term potent nucleos(t)ide analogue therapy for chronic hepatitis B and prediction of HBsAg loss (Article)

Zoutendijk, R. — 2011-08-01T00:00:00Z

Nucleos(t)ide analogues strongly inhibit viral replication in chronic hepatitis B (CHB) infection, but knowledge of their long-term effect on serum hepatitis B surface antigen (HBsAg) levels and HBsAg loss is lacking. Seventy-five CHB patients with virological response (VR) to ETV or TDF were included. HBsAg decline 2 years after VR was most pronounced in HBeAg-positive patients. Age, alanine aminotransferase, and HBeAg loss were associated with HBsAg decline in HBeAg-positive patients. Predicted median time to HBsAg loss was 36 years for HBeAg-positive and 39 years for HBeAg-negative patients. Thus, most patients treated with ETV and TDF will probably need decades of therapy to achieve HBsAg loss.

The minimal incubation period from the onset of Barrett's oesophagus to symptomatic adenocarcinoma (Article)

Hoed, C.M. den — 2011-07-12T00:00:00Z

Background:The interval between the onset of Barrett's oesophagus (BO) and oesophageal adenocarcinoma (OAC) can be termed the incubation period. However, the unrecorded onset of BO precludes its direct observation.Methods:Determining the range of intervals between BO diagnosis and OAC within the longest observational BO follow-up study. Exclusion criteria were presence of high-grade dysplasia (HGD) or OAC at baseline, death within <2 years of BO diagnosis, oesophagectomy without HGD/OAC and loss to follow-up. A total of 133 patients (M/F 73/60) were taken into account.Results:In 1967 person years of follow-up there were 13 cases of HGD/OAC, (0.66% p.a.; 95% CI 0.58-0.74), 96 patients died without HGD/OAC and 24 survived without HGD/OAC. The mean intervals between BO diagnosis and either HGD/OAC, death or end of follow-up were 10.8, 12.6 and 25.5 years, respectively, and the mean ages at endpoint were 72.5, 80.0 and 68.3 years, respectively. The survivors without HGD/OAC had a lower age at BO diagnosis (mean 42.8 vs 61.2 and 67.4 years, P=0.001). Baseline presence of low-grade dysplasia was associated with progression to HGD/OAC (log rank P=0.001).Conclusion:The Rotterdam BO follow-up cohort revealed a long incubation period between onset of BO and development of HGD/OAC, in patients without HGD/OAC at baseline as illustrated by 24 patients diagnosed with BO at a young age and followed for a mean period of 25.5 years. Their tumour-free survival established a minimum incubation period, suggesting a true incubation period of three decades or more.

The response to TLR ligation of human CD16+CD14- monocytes is weakly modulated as a consequence of persistent infection with the hepatitis C virus (Article)

Peng C. — 2011-07-01T00:00:00Z

Little is known about the frequency and function of CD16+CD14-monocytes from chronic HCV patients. We observed that the absolute numbers and ratio of CD16+CD14-to CD14+CD16-monocytes were similar between chronic HCV patients and healthy individuals. Functionally, we found that CD16+CD14-monocytes are more responsive to TLR8-ligation and only weakly responsive to LPS stimulation in producing TNF as compared to CD14+CD16-monocytes. We found no overt impairment of the function of CD16+CD14-monocytes from patients, except for an augmented induction of MIP-1Î²-producing CD16+CD14-monocytes upon TLR4-ligation. However, the increased frequency of MIP-1Î²-producing CD16+CD14-monocytes was not associated with viral load, ALT or fibrosis level. Our findings indicate that, different from other infectious diseases, the frequency and function of CD16+CD14-monocytes are only minimally altered as a consequence of the persistent state of HCV infections, and our findings therefore do not suggest a role for CD16+CD14-monocytes in HCV pathogenesis.

Response to Bolino et al. (Letter To Editor)

Jonge, P.J.F. de — 2011-07-01T00:00:00Z

Practice patterns for achalasia - Room for improvement? (Letter To Editor)

Leeuwenburgh, I. — 2011-07-01T00:00:00Z

Comparison of non-invasive assessment to diagnose liver fibrosis in chronic hepatitis B and C patients (Article)

Stibbe, K.J.M. — 2011-07-01T00:00:00Z

Objective. Chronic viral hepatitis B and C cause liver fibrosis, leading to cirrhosis. Fibrosis assessment is essential to establish prognosis and treatment indication. We compared seven non-invasive tests, separately and in combination, in chronic hepatitis patients to detect early stages of fibrosis according to the Metavir score in liver biopsy. Material and methods. Galactose and methacetin breath tests (GBT and MBT), biomarkers (hyaluronic acid (HA), aspartate aminotransferase platelet ratio index (APRI), FibroTest, and Fib-4) and transient elastography (TE) were evaluated in 89 patients. Additionally, 31 healthy controls were included for evaluation of breath tests and biomarkers. Results. Serum markers (HA, APRI, FibroTest, and Fib-4) and elastography significantly distinguished non-cirrhotic (F0123) from cirrhotic (F4) patients (p < 0.001, p = 0.015, p < 0.001, p = 0.005, p = 0.006, respectively). GBT, HA, APRI, FibroTest, Fib-4, and TE detected F01 from F234 (p = 0.04, p = 0.011, p = 0.009, p < 0.001, p < 0.001, and p < 0.001, respectively). A combination of different tests (TE, HA, and FibroTest) improved the performance statistically, area under the curve (AUC) = 0.87 for F234, 0.92 for F34, and 0.90 for F4. Conclusion. HA, APRI, FibroTest, Fib-4, and TE reliably distinguish non-cirrhotic and cirrhotic patients. Except for MBT, all tests discriminate between mild and moderate fibrosis. As single tests: FibroTest, Fib-4, and TE were the most accurate for detecting early fibrosis; combining different non-invasive tests increased the accuracy for detection of liver fibrosis to such an extent and thus might be acceptable to replace liver biopsy.

Predictors for neoplastic progression in patients with Barrett's esophagus: A prospective cohort study (Article)

Sikkema, M. — 2011-07-01T00:00:00Z

Objectives: Patients with Barrett's esophagus (BE) have an increased risk of developing esophageal adenocarcinoma (EAC). As the absolute risk remains low, there is a need for predictors of neoplastic progression to tailor more individualized surveillance programs. The aim of this study was to identify such predictors of progression to high-grade dysplasia (HGD) and EAC in patients with BE after 4 years of surveillance and to develop a prediction model based on these factors. Methods: We included 713 patients with BE (2 cm) with no dysplasia (ND) or low-grade dysplasia (LGD) in a multicenter, prospective cohort study. Data on age, gender, body mass index (BMI), reflux symptoms, tobacco and alcohol use, medication use, upper gastrointestinal (GI) endoscopy findings, and histology were prospectively collected. As part of this study, patients with ND underwent surveillance every 2 years, whereas those with LGD were followed on a yearly basis. Log linear regression analysis was performed to identify risk factors associated with the development of HGD or EAC during surveillance. Results: After 4 years of follow-up, 26/713 (3.4%) patients developed HGD or EAC, with the remaining 687 patients remaining stable with ND or LGD. Multivariable analysis showed that a known duration of BE of 10 years (risk ratio (RR) 3.2; 95% confidence interval (CI) 1.3-7.8), length of BE (RR 1.11 per cm increase in length; 95% CI 1.01-1.2), esophagitis (RR 3.5; 95% CI 1.3-9.5), and LGD (RR 9.7; 95% CI 4.4-21.5) were significant predictors of progression to HGD or EAC. In a prediction model, we found that the annual risk of developing HGD or EAC in BE varied between 0.3% and up to 40%. Patients with ND and no other risk factors had the lowest risk of developing HGD or EAC (1%), whereas those with LGD and at least one other risk factor had the highest risk of neoplastic progression (18-40%). Conclusions: In patients with BE, the risk of developing HGD or EAC is predominantly determined by the presence of LGD, a known duration of BE of 10 years, longer length of BE, and presence of esophagitis. One or combinations of these risk factors are able to identify patients with a low or high risk of neoplastic progression and could therefore be used to individualize surveillance intervals in BE.

Endoscopic removal of self-expandable metal stents from the esophagus (with video) (Article)

Heel, N.C.M. van — 2011-07-01T00:00:00Z

Background: Self-expandable metals stents (SEMSs) have increasingly been used as a temporary device to bridge chemoradiotherapy in patients with malignant esophageal disease or in patients with benign esophageal defects or stenosis. Objective: To evaluate the outcome of removal of SEMSs in a large cohort of patients with benign and malignant esophageal disease. Design: Observational study with standardized treatment and follow-up. Setting: Single university center. Patients: Between 2001 and 2010, 95 consecutive patients referred for endoscopic SEMS extraction were included. Interventions: Endoscopic stent removal. Main Outcome Measurements: Technical and functional outcome and complications. Results: A total of 124 stent extractions were undertaken in 95 patients; both partially covered (68%) and fully covered (32%) SEMSs were removed. Three patients had 2 overlapping SEMSs in place. Successful primary removal was achieved in 89%; the secondary removal rate was 96%. Uncomplicated primary removal rate was significantly higher for fully covered versus partially covered stents (P = .035) and for single versus overlapping stents (P = .033). Patients with a complicated stent removal had the stent in place significantly longer compared with patients with an uncomplicated primary stent removal (126 days vs 28 days; P = .01). Surgical removal was required in 3 patients (2.4%). Six moderate and severe complications (5%) related to the endoscopic extraction occurred. Limitations: Retrospective, nonrandomized study design. Conclusions: Primary endoscopic removal of an SEMS is feasible in the majority of patients with benign and malignant esophageal disease. A longer time that a stent is in place and the use of partially covered SEMSs both impede removal. Moreover, overlapping SEMSs should be avoided for temporary use because stent disintegration and subsequent complications may occur.

Predictors of survival in patients with malignant gastric outlet obstruction: A patient-oriented decision approach for palliative treatment (Article)

Jeurnink, S.M. — 2011-07-01T00:00:00Z

Background: Gastrojejunostomy and stentplacement are the most commonly used treatments for malignant gastric outlet obstruction (GOO). The preference for either treatment largely depends on the expected survival. Our objective was to investigate predictors of survival in patients with malignant GOO and to develop a model that could aid in the decision for either gastrojejunostomy or stentplacement. Methods: Prognostic factors for survival were collected from a literature search and evaluated in our patient population, which included 95 retrospectively and 56 prospectively followed cases. All 151 patients were treated with gastrojejunostomy or stentplacement. Results: A higher WHO performance score was the only significant prognostic factor for survival in our multivariable analysis (HR 2.2 95%CI 1.7-2.9), whereas treatment for obstructive jaundice, gender, age, metastases, weight loss, level of obstruction and pancreatic cancer were not. A prognostic model that includes the WHO score was able to distinguish patients with a poor survival (WHO score 3-4, median survival: 31 days) from those with a relatively intermediate or good survival (WHO score 2, median survival: 69 and WHO score 0-1, median survival: 139 days, respectively). Conclusions: Only the WHO score is a significant predictor of survival in patients with malignant GOO. A simple prognostic model is able to guide the palliative treatment decision for either gastrojejunostomy (WHO score 0-1) or stentplacement (WHO 3-4) in patients with malignant GOO.

Hepatitis B surface antigen monitoring and management of chronic hepatitis B (Article)

Sonneveld, M.J. — 2011-07-01T00:00:00Z

Serum hepatitis B surface antigen (HBsAg) levels reflect intrahepatic hepatitis B virus (HBV) covalently closed circular DNA and may be a valuable addition to HBV DNA in the management of patients with chronic hepatitis B (CHB). Among HBeAg-negative CHB patients with low HBV DNA levels, HBsAg quantification may help distinguish those with active CHB from true inactive carriers with a very favourable prognosis, thus limiting the need for long-term intensive monitoring of ALT and HBV DNA levels. In patients treated with peginterferon (PEG-IFN), achievement of a decline in HBsAg during therapy appears to be an important marker for treatment outcome, and several groups have proposed stopping rules based on HBsAg thresholds. A recently described stopping rule incorporating a combination of HBsAg and HBV DNA levels can accurately identify HBeAg-negative patients, especially those with HBV genotype D, not responding to PEG-IFN. Current applications of HBsAg levels in the monitoring of patients treated with nucleo(s)tide analogues are still being evaluated. First data from these studies show that HBsAg decline, and thus subsequent clearance, is confined to those with an active immune response to HBV, such as HBeAg-positive patients with elevated ALT, or those who achieve HBeAg clearance.

The role of mycophenolate mofetil in the management of autoimmune hepatitis and overlap syndromes (Article)

Baven-Pronk, A.M.C. — 2011-07-01T00:00:00Z

Background Treatment failure occurs in 20% of autoimmune hepatitis patients on prednisolone and azathioprine (AZA). There is no established second line treatment. Aim To assess the efficacy of mycophenolate mofetil as second line treatment after AZA-intolerance or AZA-nonresponse in autoimmune hepatitis and overlap syndromes. Methods Consecutive patients from the Dutch Autoimmune Hepatitis Group cohort, consisting of 661 patients, with autoimmune hepatitis or overlap syndromes, AZA-intolerance or AZA-nonresponse and past or present use of mycophenolate mofetil were included. Primary endpoint of mycophenolate mofetil treatment was biochemical remission. Secondary endpoints were biochemical response (without remission), treatment failure and prevention of disease progression. Results Forty-five patients treated with mycophenolate mofetil were included. In autoimmune hepatitis remission or response was achieved in 13% and 27% in the AZA-nonresponse group compared to 67% and 0% in the AZA-intolerance group (P = 0.008). In overlap-syndromes remission or response was reached in 57% and 14% in the AZA-nonresponse group and 63% and 25% of the AZA-intolerance group (N.S.); 33% had side effects and 13% discontinued mycophenolate mofetil. Overall 38% had treatment failure; this was 60% in the autoimmune hepatitis AZA-nonresponse group. Decompensated liver cirrhosis, liver transplantations and death were only seen in the autoimmune hepatitis AZA-nonresponse group (P < 0.001). Conclusions Mycophenolate mofetil induced response or remission in a majority of patients with autoimmune hepatitis and azathioprine-intolerance and with overlap syndromes, irrespective of intolerance or nonresponse for azathioprine. In autoimmune hepatitis with azathioprine nonresponse mycophenolate mofetil is less often effective.

NHERF2 is necessary for basal activity, second messenger inhibition, and LPA stimulation of NHE3 in mouse distal ileum (Article)

Murtazina, R. — 2011-07-01T00:00:00Z

To test the hypothesis that Na+/H+exchanger (NHE) regulatory factor 2 (NHERF2) is necessary for multiple aspects of acute regulation of NHE3 in intact mouse small intestine, distal ileal NHE3 activity was determined using two-photon microscopy/SNARF-4F in a NHERF2-null mouse model. The NHERF2-null mouse ileum had shorter villi, deeper crypts, and decreased epithelial cell number. Basal rates of NHE3 activity were reduced in NHERF2-null mice, which was associated with a reduced percentage of NHE3 in the apical domain and an increase in intracellular NHE3 amount but no change in total level of NHE3 protein. cAMP, cGMP, and elevated Ca2+due to apical exposure to UTP all inhibited NHE3 activity in wild-type mouse ileum but not in NHERF2-null mice, while inhibition by hyperosmolarity occurred normally. The cAMP-increased phosphorylation of NHE3 at aa 552; levels of PKAIIα and cGMP-dependent protein kinase II (cGKII); and elevation of Ca2+were similar in wild-type and NHERF2-null mouse ileum. Luminal lysophosphatidic acid (LPA) stimulated NHE3 in wild-type but not in NHERF2-null ileum. In conclusion, 1) there are inftle structural abnormalities in the small intestine of NHERF2-null mouse which include fewer villus epithelial cells; 2) the decreased basal NHE3 activity and reduced brush border NHE3 amount in NHERF2-null mice show that NHERF2 is necessary for normal basal trafficking or retention of NHE3 in the apical domain; 3) hyperosmolar inhibition of NHE3 occurs similarly in wild-type and NHERF2-null ileum, demonstrating that some inhibitory mechanisms of NHE3 are not NHERF2 dependent; 4) cAMP inhibition of NHE3 is NHERF2 dependent at a step downstream of cAMP/PKAII phosphorylation of NHE3 at aa 552; 5) cGMP- and UTP-induced inhibition of NHE3 are NHERF2 dependent at steps beyond cGKII and the UTP-induced increase of intracellular Ca2+; and 6) LPA stimulation of NHE3 is also NHERF2 dependent.

Letter: Pigmented bowen's disease: A report of two cases (Article)

Vries, N.K. de — 2011-07-01T00:00:00Z

Tight control of STAT5 activity determines human CD34-derived interstitial dendritic cell and langerhans cell development (Article)

Laar, L. van de — 2011-06-15T00:00:00Z

Despite the crucial function of dendritic cells (DC) in immunity, the molecular mechanisms regulating human DC development remain poorly defined. STAT5 regulates various hematopoietic lineages and is activated by GM-CSF, a critical cytokine in DC development. In this study, we investigated the role of STAT5 during differentiation of human CD34+hematopoietic progenitors into precursor DC (pre-DC) and their subsequent differentiation toward interstitial DC and Langerhans cells. Inhibiting STAT5 activity by dominant-negative STAT5 promoted Langerhans cell commitment of hematopoietic progenitors but resulted in loss of pre-interstitial DC development, showing subset-specific regulation. Increasing the low endogenous STAT5 activity by ectopic STAT5 activation downregulated expression of the critical DC transcription factor PU.1 and abrogated commitment to either DC lineage. In contrast, high STAT5 activity was beneficial in already committed pre-DC: terminal DC differentiation was associated with increased endogenous STAT5 phosphorylation levels, JAK2-STAT5 inhibition reduced terminal DC differentiation, and conditional STAT5 activation in pre-DC improved development of BDCA-1+, DC-SIGN+, and Langerin+DC with normal maturation and T cell stimulation. These data show that STAT5 critically regulates human DC development, with specific requirements for the level of STAT5 activation at distinct differentiation stages. By regulating STAT5 activity, cytokines present at specific locations and under different pathophysiological conditions can determine the fate of DC precursors. Copyright