Quantification of mucosal EEC in jejunum. A comparative study of IBS patients and healthy controls.

Background: Enteroendocrine cells (EEC) have been suggested to have a role in the pathogenesis of irritable bowel syndrome (IBS). Although many studies have analysed possible numeric changes of EEC in IBS, the results differ between different studies. One reason might be due to difficulties in standardising the morphometric method.Aim: The aim of this study was to compare two different methods for counting EEC in jejunum biopsies from patients with IBS and healthy controls.Method: Fifty-one patients with IBS and 35 healthy controls were included in the study. Jejunum mucosa was procured using a Watson capsule. Slides were immunostained for serotonin and chromogranin A and then scanned digitally. The morphometry was done by counting cells per high power field (hpf) and per mm2 after defining area of the mucosa. The two methods were compared using Bland Altman analysis.Results: There was no difference in the number of EEC in patients with IBS compared to healthy controls. The number of cells detected by per mm2 area of mucosa were higher than number of cells per hpf. Counting EEC per high power field systematically underestimated the number of cells in the mucosal area.Conclusions: Counting cells per mm2 mucosal area gives a better representation of the number of EEC in small bowel mucosa. The finding of no difference in EEC numbers does not imply an equal function and further studies are needed to evaluate the role, if any of EEC, in IBS.

Massive air embolism as a complication of upper gastrointestinal endoscopy: A case report illustrating a stroke mimic, literature review, and suggested management.

Cerebral air embolism should be considered in case of stroke symptoms during any invasive procedure. Transport to a hospital with neurosurgical/hyperbaric oxygen treatment (HBOT) facility could improve the outcome for the patient. Absence of air on computed tomography (CT) scan should not disqualify a patient from HBOT if air embolism is suspected.

Female-Specific Association Between Variants on Chromosome 9 and Self-Reported Diagnosis of Irritable Bowel Syndrome.

BACKGROUND & AIMS: Genetic factors are believed to affect risk for irritable bowel syndrome (IBS), but there have been no sufficiently powered and adequately sized studies. To identify DNA variants associated with IBS risk, we performed a genome-wide association study (GWAS) of the large UK Biobank population-based cohort, which includes genotype and health data from 500,000 participants. METHODS: We studied 7,287,191 high-quality single nucleotide polymorphisms in individuals who self-reported a doctor's diagnosis of IBS (cases; n = 9576) compared to the remainder of the cohort (controls; n = 336,499) (mean age of study subjects, 40-69 years). Genome-wide significant findings were further investigated in 2045 patients with IBS from tertiary centers and 7955 population controls from Europe and the United States, and a small general population sample from Sweden (n = 249). Functional annotation of GWAS results was carried out by integrating data from multiple biorepositories to obtain biological insights from the observed associations. RESULTS: We identified a genome-wide significant association on chromosome 9q31.2 (single nucleotide polymorphism rs10512344; P = 3.57 × 10-8) in a region previously linked to age at menarche, and 13 additional loci of suggestive significance (P < 5.0×10-6). Sex-stratified analyses revealed that the variants at 9q31.2 affect risk of IBS in women only (P = 4.29 × 10-10 in UK Biobank) and also associate with constipation-predominant IBS in women (P = .015 in the tertiary cohort) and harder stools in women (P = .0012 in the population-based sample). Functional annotation of the 9q31.2 locus identified 8 candidate genes, including the elongator complex protein 1 gene (ELP1 or IKBKAP), which is mutated in patients with familial dysautonomia. CONCLUSIONS: In a sufficiently powered GWAS of IBS, we associated variants at the locus 9q31.2 with risk of IBS in women. This observation may provide additional rationale for investigating the role of sex hormones and autonomic dysfunction in IBS.

Increased Prevalence of Rare Sucrase-isomaltase Pathogenic Variants in Irritable Bowel Syndrome Patients.

Patients with irritable bowel syndrome (IBS) often associate their symptoms to certain foods. In congenital sucrase-isomaltase deficiency (CSID), recessive mutations in the SI gene (coding for the disaccharidase digesting sucrose and 60% of dietary starch)1 cause clinical features of IBS through colonic accumulation of undigested carbohydrates, triggering bowel symptoms.2 Hence, in a previous study,3 we hypothesized that CSID variants reducing SI enzymatic activity may contribute to development of IBS symptoms. We detected association with increased risk of IBS for 4 rare loss-of-function variants typically found in (homozygous) CSID patients, because carriers (heterozygous) of these rare variants were more common in patients than in controls.1,4 Through a 2-step computational and experimental strategy, the present study aimed to determine whether other (dys-)functional SI variants are associated with risk of IBS in addition to known CSID mutations. We first aimed to identify all SI rare pathogenic variants (SI-RPVs) on the basis of integrated Mendelian Clinically Applicable Pathogenicity (M-CAP) and Combined Annotation Dependent Depletion (CADD) predictive (clinically relevant) scores; next, we inspected genotype data currently available for 2207 IBS patients from a large ongoing project to compare SI-RPV case frequencies with ethnically matched population frequencies from the Exome Aggregation Consortium (ExAC).

Functional variants in the sucrase-isomaltase gene associate with increased risk of irritable bowel syndrome.

OBJECTIVE: IBS is a common gut disorder of uncertain pathogenesis. Among other factors, genetics and certain foods are proposed to contribute. Congenital sucrase-isomaltase deficiency (CSID) is a rare genetic form of disaccharide malabsorption characterised by diarrhoea, abdominal pain and bloating, which are features common to IBS. We tested sucrase-isomaltase (SI) gene variants for their potential relevance in IBS. DESIGN: We sequenced SI exons in seven familial cases, and screened four CSID mutations (p.Val557Gly, p.Gly1073Asp, p.Arg1124Ter and p.Phe1745Cys) and a common SI coding polymorphism (p.Val15Phe) in a multicentre cohort of 1887 cases and controls. We studied the effect of the 15Val to 15Phe substitution on SI function in vitro. We analysed p.Val15Phe genotype in relation to IBS status, stool frequency and faecal microbiota composition in 250 individuals from the general population. RESULTS: CSID mutations were more common in patients than asymptomatic controls (p=0.074; OR=1.84) and Exome Aggregation Consortium reference sequenced individuals (p=0.020; OR=1.57). 15Phe was detected in 6/7 sequenced familial cases, and increased IBS risk in case-control and population-based cohorts, with best evidence for diarrhoea phenotypes (combined p=0.00012; OR=1.36). In the population-based sample, 15Phe allele dosage correlated with stool frequency (p=0.026) and Parabacteroides faecal microbiota abundance (p=0.0024). The SI protein with 15Phe exhibited 35% reduced enzymatic activity in vitro compared with 15Val (p<0.05). CONCLUSIONS: SI gene variants coding for disaccharidases with defective or reduced enzymatic activity predispose to IBS. This may help the identification of individuals at risk, and contribute to personalising treatment options in a subset of patients.

miR-16 and miR-103 impact 5-HT4 receptor signalling and correlate with symptom profile in irritable bowel syndrome.

Irritable bowel syndrome (IBS) is a gut-brain disorder involving alterations in intestinal sensitivity and motility. Serotonin 5-HT4 receptors are promising candidates in IBS pathophysiology since they regulate gut motor function and stool consistency, and targeted 5-HT4R selective drug intervention has been proven beneficial in subgroups of patients. We identified a single nucleotide polymorphism (SNP) (rs201253747) c.*61 T > C within the 5-HT4 receptor gene HTR4 to be predominantly present in diarrhoea-IBS patients (IBS-D). It affects a binding site for the miR-16 family and miR-103/miR-107 within the isoforms HTR4b/i and putatively impairs HTR4 expression. Subsequent miRNA-profiling revealed downregulation of miR-16 and miR-103 in the jejunum of IBS-D patients correlating with symptoms. In vitro assays confirmed expression regulation via three 3'UTR binding sites. The novel isoform HTR4b_2 lacking two of the three miRNA binding sites escapes miR-16/103/107 regulation in SNP carriers. We provide the first evidence that HTR4 expression is fine-tuned by miRNAs, and that this regulation is impaired either by the SNP c.*61 T > C or by diminished levels of miR-16 and miR-103 suggesting that HTR4 might be involved in the development of IBS-D.

Increased Expression of Toll-Like Receptors 4, 5, and 9 in Small Bowel Mucosa from Patients with Irritable Bowel Syndrome.

The aim of our study was to compare patients with irritable bowel syndrome (IBS) and healthy controls regarding the expression of toll-like receptors 2, 4, 5, and 9 (TLR2, TLR4, TLR5, and TLR9), the primary mucosal receptors of bacterial components, in small and large bowel mucosa. Methods. We analysed biopsies from jejunum and sigmoid colon of 22 patients (17 females) with IBS aged 18-66 (median: 39) years and 14 healthy volunteers (12 females) aged 22-61 (median: 42) years. Eight patients had constipation-predominant IBS (C-IBS), 7 had diarrhoea-predominant IBS (D-IBS), and 7 had IBS without predominance of constipation or diarrhoea. We analysed mRNA levels for TLRs using quantitative PCR and distribution of TLRs in mucosa using immunohistochemistry. Results. We found increased mRNA expression of TLR4 (mean fold change 1.85 ± 0.31 versus 1.0 ± 0.20; p < 0.05), TLR5 (1.96 ± 0.36 versus 1.0 ± 0.20; p < 0.05) and TLR9 (2.00 ± 0.24 versus 1.0 ± 0.25; p < 0.01) but not of TLR2 in the small bowel mucosa from patients with IBS compared to the controls. There was no significant difference in mRNA levels for TLRs in colon mucosa between patients and controls. Conclusion. Upregulation of TLR4, TLR5, and TLR9 suggests the involvement of bacteria or dysregulation of the immune response to commensal flora in small bowel mucosa in IBS patients.

Prevalence of Eosinophilic Esophagitis and Lymphocytic Esophagitis in Adults with Esophageal Food Bolus Impaction.

Background. The relation of esophageal food bolus impaction (FBI) to eosinophilic esophagitis (EoE) and lymphocytic esophagitis (LyE) is unclear. The aim of this study was to determine the prevalence of EoE and LyE among adults with FBI. Methods. In this retrospective study we analyzed data from all patients referred for gastroscopy during the past 5 years, because of a present or recent episode of FBI. Results. We found 238 patients with FBI (median age 51 (17-96), 71% males). Endoscopic therapy was required in 143 patients. Esophageal biopsies were obtained in 185 (78%) patients. All biopsies were assessed for numbers of eosinophils and lymphocytes. EoE was found in 18% of patients who underwent biopsy. We found 41 patients (22%) who fulfilled the criteria for both EoE and LyE (EoE/LyE). LyE was found in the 9% of patients with FBI. EoE together with EoE/LyE was the leading cause of FBI in patients ≤50 years (64%). GERD was the leading cause of FBI among patients older than 50 years (42%). Conclusions. Our study showed that EoE was the leading cause of FBI in particular among young adults. Our study highlights the need for esophageal biopsies in any patient with FBI.

Diagnostic yield of endomicroscopy for dysplasia in primary sclerosing cholangitis associated inflammatory bowel disease: a feasibility study.

BACKGROUND AND STUDY AIMS: Primary sclerosing cholangitis associated inflammatory bowel disease (PSC-IBD) is characterized by a high risk of colorectal dysplasia. Surveillance colonoscopies with random biopsies have doubtful power for dysplasia detection. Our aim was to prospectively investigate the feasibility and efficacy of pCLE in surveillance colonoscopies in patients with PSC-IBD. PATIENTS AND METHODS: Sixty-nine patients with PSC-IBD underwent colonoscopy in 2 steps. On the way from rectum to cecum, the mucosa was inspected with high definition endoscopy (HDE) and random biopsies were taken according to the standard routine. On the way from cecum to rectum, fluorescein-enhanced pCLE and chromoendoscopy were performed. Regions where random biopsies had been taken, as well as visible lesions, were examined with pCLE and targeted biopsies were taken of lesions suspicious for dysplasia. Two investigators, blinded to histology and endoscopy results, analyzed all pCLE videos off-line. RESULTS: Nineteen biopsies obtained in 13 patients (17 targeted biopsies, 2 random biopsies) revealed the presence of low-grade dysplasia. Thirteen lesions with dysplasia were endoscopically visible but by using pCLE-targeted biopsies, additional endoscopically invisible dysplasias in 4 biopsies obtained from 3 patients were detected. The sensitivity, specificity, and accuracy of pCLE in predicting dysplasia were respectively 89 % (95 % CI: 65 - 98), 96 % (95 % CI: 94 - 97), and 96 % (95 % CI: 94 - 97). pCLE showed a good performance for differentiating neoplastic from non-neoplastic mucosa with negative predictive value of 99 %. CONCLUSIONS: pCLE in PSC-IBD surveillance is feasible and may be a good complement to HDE. Future research should aim at elucidating whether real-time pCLE is applicable in PSC-IBD surveillance.

Use of probe-based confocal laser endomicroscopy (pCLE) in gastrointestinal applications. A consensus report based on clinical evidence.

BACKGROUND: Probe-based confocal laser endomicroscopy (pCLE) provides microscopic imaging during an endoscopic procedure. Its introduction as a standard modality in gastroenterology has brought significant progress in management strategies, affecting many aspects of clinical care and requiring standardisation of practice and training. OBJECTIVE: This study aimed to provide guidance on the standardisation of its practice and training in Barrett's oesophagus, biliary strictures, colorectal lesions and inflammatory bowel diseases. METHODS: Initial statements were developed by five group leaders, based on the available clinical evidence. These statements were then voted and edited by the 26 participants, using a modified Delphi approach. After two rounds of votes, statements were validated if the threshold of agreement was higher than 75%. RESULTS: Twenty-six experts participated and, among a total of 77 statements, 61 were adopted (79%) and 16 were rejected (21%). The adoption of each statement was justified by the grade of evidence. CONCLUSION: pCLE should be used to enhance the diagnostic arsenal in the evaluation of these indications, by providing microscopic information which improves the diagnostic performance of the physician. In order actually to implement this technology in the clinical routine, and to ensure good practice, standardised initial and continuing institutional training programmes should be established.

No difference in small bowel microbiota between patients with irritable bowel syndrome and healthy controls.

Several studies have indicated that colonic microbiota may exhibit important differences between patients with irritable bowel syndrome (IBS) and healthy controls. Less is known about the microbiota of the small bowel. We used massive parallel sequencing to explore the composition of small bowel mucosa-associated microbiota in patients with IBS and healthy controls. We analysed capsule biopsies from the jejunum of 35 patients (26 females) with IBS aged 18-(36)-57 years and 16 healthy volunteers (11 females) aged 20-(32)-48 years. Sequences were analysed based on taxonomic classification. The phyla with the highest total abundance across all samples were: Firmicutes (43%), Proteobacteria (23%), Bacteroidetes (15%), Actinobacteria (9.3%) and Fusobacteria (7.0%). The most abundant genera were: Streptococcus (19%), Veillonella (13%), Prevotella (12%), Rothia (6.4%), Haemophilus (5.7%), Actinobacillus (5.5%), Escherichia (4.6%) and Fusobacterium (4.3%). We found no difference among major phyla or genera between patients with IBS and controls. We identified a cluster of samples in the small bowel microbiota dominated by Prevotella, which may represent a common enterotype of the upper small intestine. The remaining samples formed a gradient, dominated by Streptococcus at one end and Escherichia at the other.

Exploring the genetics of irritable bowel syndrome: a GWA study in the general population and replication in multinational case-control cohorts.

OBJECTIVE: IBS shows genetic predisposition, but adequately powered gene-hunting efforts have been scarce so far. We sought to identify true IBS genetic risk factors by means of genome-wide association (GWA) and independent replication studies. DESIGN: We conducted a GWA study (GWAS) of IBS in a general population sample of 11,326 Swedish twins. IBS cases (N=534) and asymptomatic controls (N=4932) were identified based on questionnaire data. Suggestive association signals were followed-up in 3511 individuals from six case-control cohorts. We sought genotype-gene expression correlations through single nucleotide polymorphism (SNP)-expression quantitative trait loci interactions testing, and performed in silico prediction of gene function. We compared candidate gene expression by real-time qPCR in rectal mucosal biopsies of patients with IBS and controls. RESULTS: One locus at 7p22.1, which includes the genes KDELR2 (KDEL endoplasmic reticulum protein retention receptor 2) and GRID2IP (glutamate receptor, ionotropic, delta 2 (Grid2) interacting protein), showed consistent IBS risk effects in the index GWAS and all replication cohorts and reached p=9.31×10(-6) in a meta-analysis of all datasets. Several SNPs in this region are associated with cis effects on KDELR2 expression, and a trend for increased mucosal KDLER2 mRNA expression was observed in IBS cases compared with controls. CONCLUSIONS: Our results demonstrate that general population-based studies combined with analyses of patient cohorts provide good opportunities for gene discovery in IBS. The 7p22.1 and other risk signals detected in this study constitute a good starting platform for hypothesis testing in future functional investigations.

Human enteroendocrine cell responses to infection with Chlamydia trachomatis: a microarray study.

BACKGROUND: Enteroendocrine cells (EEC) are highly specialized cells producing signalling molecules vital to the normal functions of the gut. Recently, we showed altered protein distribution in Chlamydia infected EEC in vitro. The aim of this study was to perform a microarray analysis of the response pattern of EEC from both large and small bowel to infection in vitro, using Chlamydia trachomatis infection as a model. METHODS: TWO HUMAN EEC LINES: LCC-18, derived from a neuroendocrine colonic tumour, and CNDT-2, derived from a small intestinal carcinoid, were infected using cultured C. trachomatis serovar LGV II strain 434 (ATCC VR-902B). Penicillin G was used to induce persistent infection. We used microarray analysis (Affymetrix GeneChip®) for studying changes in gene expression at different stages of infection. RESULTS: Twenty-four hours after active and persistent infection, 66 and 411 genes in LCC-18 and 68 and 170 genes in CNDT-2 cells, respectively showed mean expression ratios >2-fold compared to non-infected cells. These genes encoded factors regulating apoptosis, cell differentiation, transcription regulation, cytokine activity, amine biosynthesis and vesicular transport. We found significant differences in gene transcription levels between persistently infected and non-infected cells in 10 genes coding for different solute carrier transporters (SLC) and in 5 genes related to endocrine function (GABARAPL1, GRIP1, DRD2, SYT5 and SYT7). CONCLUSIONS: Infected EEC cells exhibit cell-type specific patterns related to vesicular transport, secretion and neurotransmitters. EEC play a pivotal role in regulation of gut motility and an impairment of enteroendocrine function can contribute to motility disorders.

Loss-of-function of the voltage-gated sodium channel NaV1.5 (channelopathies) in patients with irritable bowel syndrome.

BACKGROUND & AIMS: SCN5A encodes the α-subunit of the voltage-gated sodium channel NaV1.5. Many patients with cardiac arrhythmias caused by mutations in SCN5A also have symptoms of irritable bowel syndrome (IBS). We investigated whether patients with IBS have SCN5A variants that affect the function of NaV1.5. METHODS: We performed genotype analysis of SCN5A in 584 persons with IBS and 1380 without IBS (controls). Mutant forms of SCN5A were expressed in human embryonic kidney-293 cells, and functions were assessed by voltage clamp analysis. A genome-wide association study was analyzed for an association signal for the SCN5A gene, and replicated in 1745 patients in 4 independent cohorts of IBS patients and controls. RESULTS: Missense mutations were found in SCN5A in 13 of 584 patients (2.2%, probands). Diarrhea-predominant IBS was the most prevalent form of IBS in the overall study population (25%). However, a greater percentage of individuals with SCN5A mutations had constipation-predominant IBS (31%) than diarrhea-predominant IBS (10%; P < .05). Electrophysiologic analysis showed that 10 of 13 detected mutations disrupted NaV1.5 function (9 loss-of-function and 1 gain-of-function function). The p. A997T-NaV1.5 had the greatest effect in reducing NaV1.5 function. Incubation of cells that expressed this variant with mexiletine restored their sodium current and administration of mexiletine to 1 carrier of this mutation (who had constipation-predominant IBS) normalized their bowel habits. In the genome-wide association study and 4 replicated studies, the SCN5A locus was strongly associated with IBS. CONCLUSIONS: About 2% of patients with IBS carry mutations in SCN5A. Most of these are loss-of-function mutations that disrupt NaV1.5 channel function. These findings provide a new pathogenic mechanism for IBS and possible treatment options.

Genetic variants in CDC42 and NXPH1 as susceptibility factors for constipation and diarrhoea predominant irritable bowel syndrome.

OBJECTIVE: The complex genetic aetiology underlying irritable bowel syndrome (IBS) needs to be assessed in large-scale genetic studies. Two independent IBS cohorts were genotyped to assess whether genetic variability in immune, neuronal and barrier integrity genes is associated with IBS. DESIGN: 384 single nucleotide polymorphisms (SNPs) covering 270 genes were genotyped in an exploratory cohort (935 IBS patients, 639 controls). 33 SNPs with Puncorrected<0.05 were validated in an independent set of 497 patients and 887 controls. Genotype distributions of single SNPs were assessed using an additive genetic model in IBS and clinical subtypes, IBS-C and IBS-D, both in individual and combined cohorts. Trait anxiety (N=614 patients, 533 controls), lifetime depression (N=654 patients, 533 controls) and mRNA expression in rectal biopsies (N=22 patients, 29 controls) were correlated with SNP genotypes. RESULTS: Two SNPs associated independently in the exploratory and validation cohort: rs17837965-CDC42 with IBS-C (ORexploratory=1.59 (1.05 to 1.76); ORvalidation=1.76 (1.03 to 3.01)) and rs2349775-NXPH1 with IBS-D (ORexploratory=1.28 (1.06 to 1.56); ORvalidation=1.42 (1.08 to 1.88)). When combining both cohorts, the association of rs2349775 withstood post hoc correction for multiple testing in the IBS-D subgroup. Additionally, three SNPs in immune-related genes (rs1464510-LPP, rs1881457-IL13, rs2104286-IL2RA), one SNP in a neuronal gene (rs2349775-NXPH1) and two SNPs in epithelial genes (rs245051-SLC26A2, rs17837965-CDC42) were weakly associated with total-IBS (Puncorrected<0.05). At the functional level, rs1881457 increased IL13 mRNA levels, whereas anxiety and depression scores did not correlate with rs2349775-NXPH1. CONCLUSIONS: Rs2349775 (NXPH1) and rs17837965 (CDC42) were associated with IBS-D and IBS-C, respectively, in two independent cohorts. Further studies are warranted to validate our findings and to determine the mechanisms underlying IBS pathophysiology.

Beyond white light endoscopy: the role of optical biopsy in inflammatory bowel disease.

In this review, we will discuss the use of two optical biopsy modalities in inflammatory bowel disease (IBD). The two techniques reviewed here are confocal laser endomicroscopy and endocytoscopy. We will describe the technical performance of the procedure, discuss the clinical indications for optical biopsy in IBD, and highlight active research areas with respect to the pathogenesis of IBD. Clinical indications for optical biopsies in IBD include assessment of mucosal inflammation, dysplasia detection and evaluation of cell shedding for disease relapse. Research application in the area of barrier dysfunction will also be discussed.

Association of TNFSF15 polymorphism with irritable bowel syndrome.

BACKGROUND: Irritable bowel syndrome (IBS) is the most common gastrointestinal disorder, affecting more than 10% of the general population worldwide. Although a genetic component is suspected, unambiguous susceptibility genes have so far not been identified. This study tested the hypothesis that genes contributing to epithelial barrier integrity, control of mucosal immune responses and interactions with bacteria in the gut are associated with IBS. METHODS: Single nucleotide polymorphisms (SNPs) corresponding to top signals of association with Crohn's disease at 30 known susceptibility loci were tested for their effect on IBS risk in 1992 individuals from two independent case-control cohorts from Sweden and the USA. Association tests included a conservative Bonferroni correction for multiple comparisons, and were also performed on specific subgroups of patients characterised by constipation (IBS-C), diarrhoea (IBS-D) or alternating constipation and diarrhoea (IBS-A). RESULTS: The Crohn's disease risk allele rs4263839 G in the TNFSF15 gene was significantly associated with an increased risk of both IBS (p=2.2×10(-5); OR 1.37) and more pronouncedly, IBS-C (p=8.7×10(-7); OR 1.79) in the entire sample. Similar associations and risk effects of the same magnitude were observed in the two cohorts analysed separately. A correlation between rs4263839 genotype and TNFSF15 mRNA expression was detected both in peripheral blood and in rectal mucosal biopsies from healthy individuals (combined p=0.0033). CONCLUSIONS: TNFSF15 is a susceptibility gene for IBS and IBS constipation. As TL1A, the protein encoded by TNFSF15, contributes to the modulation of inflammatory responses, the results support a role of immune activation in IBS.

Improved survival after allogeneic hematopoietic stem cell transplantation in recent years. A single-center study.

We analyzed the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) over the past 2 decades. Between 1992 and 2009, 953 patients were treated with HSCT, mainly for a hematologic malignancy. They were divided according to 4 different time periods of treatment: 1992 to 1995, 1996 to 2000, 2001 to 2005, and 2006 to 2009. Over the years, many factors have changed considerably regarding patient age, diagnosis, disease stage, type of donor, stem cell source, genomic HLA typing, cell dose, type of conditioning, treatment of infections, use of granulocyte-colony stimulating factor (G-CSF), use of mesenchymal stem cells, use of cytotoxic T cells, and home care. When we compared the last period (2006-2009) with earlier periods, we found slower neutrophil engraftment, a higher incidence of acute graft-versus-host disease (aGVHD) of grades II-IV, and less chronic GVHD (cGHVD). The incidence of relapse was unchanged over the 4 periods (22%-25%). Overall survival (OS) and transplant-related mortality (TRM) improved significantly in the more recent periods, with the best results during the last period (2006-2009) and a 100-day TRM of 5.5%. This improvement was also apparent in a multivariate analysis. When correcting for differences between the 4 groups, the hazard ratio for mortality in the last period was 0.59 (95% confidence interval [CI]: 0.44-0.79; P < .001) and for TRM it was 0.63 (CI: 0.43-0.92; P = .02). This study shows that the combined efforts to improve outcome after HSCT have been very effective. Even though we now treat older patients with more advanced disease and use more alternative HLA nonidentical donors, OS and TRM have improved. The problem of relapse still has to be remedied. Thus, several different developments together have resulted in significantly lower TRM and improved survival after HSCT over the last few years.