Indoleamine 2,3-dioxygenase-expressing leukemic dendritic cells impair a leukemia-specific immune response by inducing potent T regulatory cells

Background

The immunoregulatory enzyme indoleamine 2,3-dioxygenase, which catalyzes the conversion of tryptophan into kynurenine, is expressed in a significant subset of patients with acute myeloid leukemia, resulting in the inhibition of T-cell proliferation and the induction of regulatory T cells. Acute myeloid leukemia cells can be differentiated into dendritic cells, which have increased immunogenicity and have been proposed as vaccines against leukemia.

Design and Methods

Leukemic dendritic cells were generated from acute myeloid leukemia cells and used as stimulators in functional assays, including the induction of regulatory T cells. Indoleamine 2,3-dioxygenase expression in leukemic dendritic cells was evaluated at molecular, protein and enzymatic levels.

Results

We demonstrate that, after differentiation into dendritic cells, both indoleamine 2,3-dioxygenase-negative and indoleamine 2,3-dioxygenase-positive acute myeloid leukemia samples show induction and up-regulation of indoleamine 2,3-dioxygenase gene and protein, respectively. Indoleamine 2,3-dioxygenase-positive acute myeloid leukemia dendritic cells catabolize tryptophan into kynurenine metabolite and inhibit T-cell proliferation through an indoleamine 2,3-dioxygenase-dependent mechanism. Moreover, indoleamine 2,3-dioxygenase-positive leukemic dendritic cells increase the number of allogeneic and autologous CD4⁺CD25⁺ Foxp3⁺ T cells and this effect is completely abrogated by the indoleamine 2,3-dioxygenase-inhibitor, 1-methyl tryptophan. Purified CD4⁺CD25⁺ T cells obtained from co-culture with indoleamine 2,3-dioxygenase-positive leukemic dendritic cells act as regulatory T cells as they inhibit naive T-cell proliferation and impair the complete maturation of normal dendritic cells. Importantly, leukemic dendritic cell-induced regulatory T cells are capable of in vitro suppression of a leukemia-specific T cell-mediated immune response, directed against the leukemia-associated antigen, Wilms’ tumor protein.

Conclusions

These data identify indoleamine 2,3-dioxygenase-mediated catabolism as a tolerogenic mechanism exerted by leukemic dendritic cells and have clinical implications for the use of these cells for active immunotherapy of leukemia.     

The shufflon of Salmonella enterica serovar Typhi regulates type IVB pilus-mediated bacterial self-association

Previously, it was shown that type IVB pili encoded by the Salmonella enterica serovar Typhi pil operon are used to facilitate bacterial entry into human intestinal epithelial cells in vitro and that such entry is inhibited by purified prepilin (pre-PilS) protein (X.-L. Zhang, I. S. M. Tsui, C. M. C. Yip, A. W. Y. Fung, D. K.-H. Wong, X. Dai, Y. Yang, J. Hackett, and C. Morris, Infect. Immun. 68:3067-3073, 2000). The pil operon concludes with a simple shufflon, and a recombinase gene product (Rci) inverts DNA in the C-terminal region of the pilV gene to allow synthesis of two distinct PilV proteins, PilV1 and PilV2, which are presumptive minor pilus proteins. We show here that the type IVB pili mediate bacterial self-association, but only when the PilV1 and PilV2 proteins are not expressed. This may be achieved in wild-type serovar Typhi by rapid DNA inversion activity of the shufflon. We show that the inversion activity inhibits the expression of genes inserted between the 19-bp inverted repeats used for Rci-mediated recombination and that the activity of Rci increases when DNA is supercoiled. The data suggest that serovar Typhi self-associates under conditions (such as low oxygen tension in the gut) that favor DNA supercoiling. These results explain (i) the function of the serovar Typhi shufflon and (ii) why there are only two possible shufflon states, in contrast to the many possible states of other shufflon systems. The data further indicate that a very early step in serovar Typhi pathogenesis may be type IVB pilus-mediated self-association of bacteria in the anaerobic human small intestine prior to invasion of the human gut epithelium. The suggested type IVB pilus-dependent step in typhoid fever pathogenesis may partially explain the enhanced invasiveness of serovar Typhi for humans.     

急性肺栓塞

急性肺栓塞（acute pulmonary embolism,APE）的临床表现范围从休克（shock）或持续性低血压（sustained hypotension）到轻度呼吸困难（dyspnea）。肺栓塞（pulmonary embolism）甚至有可能是无症状的,并且是在基于其他目的而实施的影像学操作中被诊断出来。     

Edmonton symptom assessment scale: Italian validation in two palliative care settings

In the palliative care setting, the Edmonton Symptom Assessment Scale (ESAS) was developed for use in daily symptom assessment of palliative care patients. ESAS considers the presence and severity of nine symptoms common in cancer patients: pain, tiredness, nausea, depression, anxiety, drowsiness, appetite, well-being and shortness of breath plus an optional tenth symptom, which can be added by the patient. The aim of this study was to validate the Italian version of ESAS and to evaluate an easy quality of life monitoring system that uses a patients self-rating symptom assessment in two different palliative care settings: in-patients and home patients. Eighty-three in-patients and 158 home care patients were enrolled. In the latter group, the Italian validated version of the Symptom Distress Scale (SDS) was also administered at the admission of the patients. The two groups of patients have similar median survival, demographic and clinical characteristics, symptom prevalence and overall distress score at baseline. ESAS shows a good concurrent validity with respect to SDS. The correlation between the physical items of ESAS and SDS was shown to be higher than the correlation between the psychological items. The association of ESAS scores and performance status (PS) showed a trend: the higher the symptom score was, the worse was the PS level. Test–retest evaluation, applied in the in-patient group, showed good agreement for depression, well-being and overall distress and a moderate agreement for all the other items. In conclusion, ESAS can be considered a valid, reliable and feasible instrument for physical symptom assessment in routine palliative care clinical practice with a potentially different responsiveness in different situations or care settings.     

Provider-initiated HIV testing for paediatric inpatients and their caretakers is feasible and acceptable

Objectives  Early diagnosis of HIV-infected children remains a major challenge in Africa. Children who are hospitalised represent an opportunity for HIV diagnosis and appropriate treatment. We introduced HIV Counselling and Testing (HCT) for hospitalised children and their caretakers in Mulago teaching hospital in Uganda to assess its feasibility.
Methods  We analysed routine program data for children and caretakers who were tested between February 2005 and February 2008 to assess the proportion of children and caretakers who were HIV-infected. We also assessed the level of immune suppression (CD4 percentage) in a subset of HIV infected children tested between January 2007 and December 2007.
Results  Caretakers agreed to HIV testing for 8990 (92.8%) of the 9687 children who were offered HIV testing. Among the caretakers, 89.8% agreed to be tested. At the time of hospitalization, 41.3% of the caretakers had previously tested for HIV. Although 313 parents (mothers and fathers) reported that they had previously tested HIV positive, only 113 (36.3%) of these had tested their children prior to hospitalization. Overall HIV prevalence among caretakers was 16.7%. HIV prevalence among children was 12.4%, highest on the nutrition ward (30.8%). Of those children who underwent CD4 counts, 56.4% had a CD4 percentage of <20%.
Conclusion  HCT for hospitalized children and their caretakers identified a significant number of HIV infected children and caretakers. More than half of the children had advanced HIV disease. More intensive efforts are needed to ensure earlier diagnosis and linkage to care for HIV infected children.     

Usefulness of 3′-[F-18]Fluoro-3′-deoxythymidine with Positron Emission Tomography in Predicting Breast Cancer Response to Therapy

Objective The usefulness of 2-deoxy-2-[F-18]fluoro-d-glucose (FDG)–positron emission tomography (PET) in monitoring breast cancer response to chemotherapy has previously been reported. Elevated uptake of FDG by treated tumors can persist however, particularly in the early period after treatment is initiated. 3′-[F-18]Fluoro-3′-deoxythymidine (FLT) has been developed as a marker for cellular proliferation and, in principle, could be a more accurate predictor of the long-term effect of chemotherapy on tumor viability. We examined side-by-side FDG and FLT imaging for monitoring and predicting tumor response to chemotherapy. Methods Fourteen patients with newly diagnosed primary or metastatic breast cancer, who were about to commence a new pharmacologic treatment regimen, were prospectively studied. Dynamic 3-D PET imaging of uptake into a field of view centered over tumor began immediately after administration of FDG or FLT (150 MBq). After 45 minutes of dynamic acquisition, a clinically standard whole-body PET scan was acquired. Patients were scanned with both tracers on two separate days within one week of each other (1) before beginning treatment, (2) two weeks following the end of the first cycle of the new regimen, and (3) following the final cycle of that regimen, or one year after the initial PET scans, whichever came first. (Median and mean times of early scans were 5.0 and 6.6 weeks after treatment initiation; median and mean times for late scans were 26.0 and 30.6 weeks after treatment initiation.) Scan data were analyzed on both tumor-by-tumor and patient-by-patient bases, and compared to each patient's clinical course. Results Mean change in FLT uptake in primary and metastatic tumors after the first course of chemotherapy showed a significant correlation with late (av. interval 5.8 months) changes in CA27.29 tumor marker levels (r = 0.79, P = 0.001). When comparing changes in tracer uptake after one chemotherapy course versus late changes in tumor size as measured by CT scans, FLT was again a good predictor of eventual tumor response (r = 0.74, P = 0.01). Tumor uptake of FLT was near-maximal by 10 minutes after injection. The time frame five to 10 minutes postinjection of FLT produced standardized uptake value (SUV) values highly correlated with SUV values obtained after 45-minute uptake (r = 0.83, P < 0.0001), and changes in these early SUVs after the first course of chemotherapy correlated with late changes in CA27.29 (r = 0.93, P = 0.003). Conclusion A 10-minute FLT-PET scan acquired two weeks after the end of the first course of chemotherapy is useful for predicting longer-term efficacy of chemotherapy regimens for women with breast cancer.     

Lack of interchangeability between visual analogue and verbal rating pain scales: a cross sectional description of pain etiology groups

Background:  

Rating scales like the visual analogue scale, VAS, and the verbal rating scale, VRS, are often used for pain assessments both in clinical work and in research, despite the lack of a gold standard. Interchangeability of recorded pain intensity captured in the two scales has been discussed earlier, but not in conjunction with taking the influence of pain etiology into consideration.     

Ex vivo detection and characterization of early dental caries by optical coherence tomography and Raman spectroscopy

Early dental caries detection will facilitate implementation of nonsurgical methods for arresting caries progression and promoting tooth remineralization. We present a method that combines optical coherence tomography (OCT) and Raman spectroscopy to provide morphological information and biochemical specificity for detecting and characterizing incipient carious lesions found in extracted human teeth. OCT imaging of tooth samples demonstrated increased light backscattering intensity at sites of carious lesions as compared to the sound enamel. The observed lesion depth on an OCT image was approximately 290 microm matching those previously documented for incipient caries. Using Raman microspectroscopy and fiber-optic-based Raman spectroscopy to characterize the caries further, spectral changes were observed in PO4 (3-) vibrations arising from hydroxyapatite of mineralized tooth tissue. Examination of various ratios of PO4 (3-) nu2, nu3, nu4 vibrations against the nu1 vibration showed consistent increases in carious lesions compared to sound enamel. The changes were attributed to demineralization-induced alterations of enamel crystallite morphology and/or orientation. OCT imaging is useful for screening carious sites and determining lesion depth, with Raman spectroscopy providing biochemical confirmation of caries. The combination has potential for development into a new fiber-optic diagnostic tool enabling dentists to identify early caries lesions with greater sensitivity and specificity.     

A pharmacokinetic-based test to prevent severe 5-fluorouracil toxicity

BACKGROUND AND OBJECTIVES: Dihydropyrimidine dehydrogenase (DPD) plays a key role in the catabolism of 5-fluorouracil (5-FU) to 5-fluoro-5,6-dihydrouracil (5-FDHU), and as such, an impairment of DPD has been recognized as an important factor for altered 5-FU and 5-FDHU pharmacokinetics, predisposing patients to the development of severe 5-FU-associated toxicity. Our objectives were to avoid severe 5-FU toxicities in patients with greatly impaired 5-FU and 5-FDHU pharmacokinetics after the administration of a reduced test dose of 5-FU and to investigate possible 5-FU or 5-FDHU pharmacokinetic parameters of the test dose related to the most common drug toxicities that affect patients after the first cycle of 5-FU chemotherapy. METHODS: Pharmacokinetics of 5-FU/5-FDHU and DPD activity in peripheral blood mononuclear cells (PBMCs) were examined in 188 gastrointestinal cancer patients given a test dose of 5-FU, 250 mg/m2, 2 weeks before starting the planned 5-FU treatment of 370 mg/m2 plus l-folinic acid, 100 mg/m2, for 5 days every 4 weeks. Drug levels were examined by HPLC, and toxicities were graded according to World Health Organization criteria. RESULTS: The 5-FU test dose was well tolerated in all patients. Of 188 patients, 3 (1.6%) had marked alterations of 5-FU/5-FDHU pharmacokinetics (ie, 5-FU half-life [t(1/2 beta)] >5 hours, 5-FU total body clearance [CL(TB)] <1 L x h(-1) x m(-2), and 5-FDHU time to reach maximum plasma concentration [t max] > or = 45 minutes); they were excluded from 5-FU treatments and treated with irinotecan, which was well tolerated. The plasma disposition of 5-FU in the remaining 185 patients revealed an area under the curve (AUC) of 3.73 +/- 2.18 h x microg/mL (mean +/- SD), maximum plasma concentration (Cmax) of 16.78 +/- 8.61 microg/mL, and t(1/2 beta) of 0.16 +/- 0.15 hour, whereas the CL(TB) was 65.67 +/- 31.86 L x h(-1) x m(-2). The 5-FDHU plasma profile showed a Cmax value of 3.64 +/- 1.94 microg/mL, whereas the t max value was 26.63 +/- 10.06 minutes, with an AUC value of 3.71 +/- 1.90 h x microg/mL. The PBMC DPD activity was 202.15 +/- 141.14 pmol 5-FDHU x min(-1) x mg(-1) protein (95% confidence interval, 165-239.3 pmol 5-FDHU x min(-1) x mg(-1) protein). A significant correlation between 5-FU AUC and 5-FDHU AUC was found (r = 0.5492, P < .0001), whereas a weaker correlation between PBMC DPD activity and both 5-FDHU AUC (r = 0.328, P = .0121) and 5-FDHU Cmax (r = 0.369, P = .0044) was found. Interestingly, no relationships between PBMC DPD activity and common toxicities were found, whereas 5-FDHU t max values greater than 30 minutes were associated with the risk of moderate to severe neutropenia and diarrhea (P = .0323 and P = .0138, respectively; chi-square test). CONCLUSIONS: This study suggests a successful approach for preventing severe or life-threatening toxicities in gastrointestinal cancer patients who are candidates for standard 5-FU treatment by analyzing the 5-FU and 5-FDHU pharmacokinetic parameters after the administration of a reduced 5-FU test dose.