Next-generation sequencing with a myeloid gene panel in core-binding factor AML showed KIT activation loop and TET2 mutations predictive of outcome.

Clinical outcome and mutations of 96 core-binding factor acute myeloid leukemia (AML) patients 18-60 years old were examined. Complete remission (CR) after induction was 94.6%. There was no significant difference in CR, leukemia-free-survival (LFS) and overall survival (OS) between t(8;21) (N=67) and inv(16) patients (N=29). Univariate analysis showed hematopoietic stem cell transplantation at CR1 as the only clinical parameter associated with superior LFS. Next-generation sequencing based on a myeloid gene panel was performed in 72 patients. Mutations in genes involved in cell signaling were associated with inferior LFS and OS, whereas those in genes involved in DNA methylation were associated with inferior LFS. KIT activation loop (AL) mutations occurred in 25 patients, and were associated with inferior LFS (P=0.003) and OS (P=0.001). TET2 mutations occurred in 8 patients, and were associated with significantly shorter LFS (P=0.015) but not OS. Patients negative for KIT-AL and TET2 mutations (N=41) had significantly better LFS (P<0.001) and OS (P=0.012) than those positive for both or either mutation. Multivariate analysis showed that KIT-AL and TET2 mutations were associated with inferior LFS, whereas age ⩾40 years and marrow blast ⩾70% were associated with inferior OS. These observations provide new insights that may guide better treatment for this AML subtype.

Bacterial stimulation of the TLR-MyD88 pathway modulates the homeostatic expression of ileal Paneth cell α-defensins.

Paneth cell α-defensins are antimicrobial peptides involved in the control of the intestinal microbiota and immunological homeostasis. In mice, they are encoded by multiple, highly homologous genes (Defa). The transcriptional activity of ileal Defa genes was studied in response to pharmacological and genetic perturbations of the intestinal environment of C57BL/6 mice. Defa gene transcription was sensitive to oral antibiotic administration suggesting that commensal microbes regulate Defa expression. Ileal microbiota analysis showed that decreased transcription of Defa genes correlated with depletion of Lactobacillus. Defa expression was partially restored in vivo by lactobacillus administration to antibiotic-treated mice. Defa transcripts were less abundant in ex vivo, microbiota-free intestinal explants but recovered after explant exposure to UV-killed bacteria, Toll-like receptor (TLR)-2 or TLR4 agonists. Genetic deficiency of several TLRs or MyD88 led to dramatic drops in Defa transcription in vivo. These results show that Paneth cell Defa genes are regulated by commensal bacteria through TLR-MyD88 signaling and provide a further understanding of the dysregulation of intestinal homeostasis that occurs as a result of imbalances in the populations of commensal bacteria.

Common association of haemolytic uraemic syndrome with invasive Streptococcus pneumoniae infection in five Chinese paediatric patients.

Haemolytic uraemic syndrome is an important cause of acute renal impairment in childhood. We review the incidence, and clinical and laboratory features of haemolytic uraemic syndrome in a Chinese population. Five patients were identified from 2006 to 2008. All patients were young children with associated invasive Streptococcus pneumoniae pulmonary infection. Serotypes 3, 14, and 19A were confirmed in four patients. The classical post-diarrhoeal form associated with Escherichia coli (O157:H7) infection was not seen. One patient died of acute respiratory failure. Streptococcus pneumoniae infection, as an associated condition in haemolytic uraemic syndrome, is important and relatively common in Chinese patients, especially among children. The acute clinical picture is similar to that reported in the western literature, except for an uncommon association with meningitis. The medium-term renal outcome of the Chinese population appears to be more favourable than the Caucasians. Widespread vaccination against Streptococcus pneumoniae may have resulted in changes in bacterial epidemiology and clinicians should be continuously aware of this severe disease. The use of washed blood components for transfusion in the acute stage requires further study.

Detection and characterisation of beta-globin gene cluster deletions in Chinese using multiplex ligation-dependent probe amplification.

BACKGROUND: Deletions in the beta-globin cluster causing thalassaemia and hereditary persistence of fetal haemoglobin (HPFH) are uncommon and difficult to detect. Data in Chinese are very scarce. AIMS: To use a recently available technique to investigate the frequencies and nature of beta-globin cluster deletions in Chinese. METHODS: 106 subjects with phenotypes of thalassaemia or HPFH and suspected to have deletions in the beta-globin cluster were studied. A commercially available kit employing multiplex ligation-dependent probe amplification (MLPA) was used to screen for deletions. Gap PCR and direct nucleotide sequencing were used to characterise deletions detected. RESULTS: 17 deletions in the beta-globin cluster were found in 17 patients: 8 of Chinese ((A)gammadeltabeta)(0) thalassaemia, 7 of Southeast Asian (Vietnamese) deletion and 2 of Thai ((A)gammadeltabeta)(0) thalassaemia. The only type of deletion detected in deltabeta-thalassaemia was Chinese ((A)gammadeltabeta)(0) thalassaemia. The deletional form of HPFH was rarely seen in only 1 case of Thai ((A)gammadeltabeta)(0) thalassaemia. Deletions presenting as beta-thalassaemia trait and raised HbF were all of the Southeast Asian (Vietnamese) deletion type. When these deletions were co-inherited with classical beta-thalassaemia mutations in compound heterozygous states, the phenotypes could be very variable. CONCLUSIONS: In the Chinese population, there are only relatively few types of deletions seen in the beta-globin cluster. MLPA is a fast and effective way of screening for these deletions. Characterisation of these deletions allows the development of simpler and more specific PCR-based tests for routine diagnostic use. Accurate prediction of phenotype is not always feasible. The molecular defects in many cases of HPFH still await discovery.

The HBS1L-MYB intergenic region on chromosome 6q23 is a quantitative trait locus controlling fetal haemoglobin level in carriers of beta-thalassaemia.

BACKGROUND: Fetal haemoglobin (HbF) level modifies the clinical severity of HBB disorders. Intergenic variants of HBS1L-MYB on chromosome 6q23 have recently been shown to be a major quantitative trait locus (QTL) influencing HbF levels in normal Caucasian adults. METHODS: A unique and well-characterised cohort of 238 Chinese subjects with beta-thalassaemia trait was used to conduct a single-nucleotide polymorphism (SNP) association study for HbF level. RESULTS: Within this locus, 29 trait-associated SNPs in a non-coding 56 kb segment were identified. They were divided into five linkage disequilibrium (LD) blocks in the Chinese participants. CONCLUSIONS: The data independently validate for the first time the significance of the HBS1L-MYB intergenic region in regulating HbF expression in a separate ethnic group that has a high prevalence of beta-thalassaemia. Functional studies to unravel the biological significance of this region in regulating HbF production is clearly indicated, which may lead to new strategies to modify the disease course of severe HBB disorders.