Histological inflammation in ulcerative colitis in deep remission under treatment with infliximab

BACKGROUND AND OBJECTIVE

There are few data on how histological signs of inflammation develop under treatment with infliximab (IFX). We investigated the patterns of histological features of inflammation in patients with UC in sustained clinical and endoscopic remission under IFX.

METHODS

We performed a retrospective study on 47 patients with UC in clinical and endoscopic remission and undergoing surveillance colonoscopy with biopsies while receiving maintenance therapy with IFX. Each colonic segment was evaluated based on the Mayo endoscopic subscore and the Geboes histology score (range 0-5.4).

RESULTS

Globally, 6110 biopsy specimens were collected from 235 colonoscopies. At the beginning of the follow-up, histological features of inflammation were found in 48.9% of patients receiving maintenance IFX therapy; 25.9% of them had at least moderate inflammation based on histology scores. At the end of the follow-up, when patients were still under endoscopic and clinical remission, 40.4% of patients had at least one biopsy specimen with evidence of any histological inflammation during the follow-up, and 19.1% had biopsy specimens that met the Geboes criteria for histological inflammation and architectural alteration. In none of the different disease locations (pancolitis, left-sided colitis, distal colitis) histological inflammation improved significantly during the follow-up.

CONCLUSIONS

Patients in clinical and endoscopic remission from UC under IFX still frequently have histological features of inflammation.

Development and validation of an endoscopic classification of diverticular disease of the colon: the DICA classification

BACKGROUND

A validated endoscopic classification of diverticular disease (DD) of the colon is lacking at present. Our aim was to develop a simple endoscopic score of DD: the Diverticular Inflammation and Complication Assessment (DICA) score.

METHODS

The DICA score for DD resulted in the sum of the scores for the extension of diverticulosis, the number of diverticula per region, the presence and type of inflammation, and the presence and type of complications: DICA 1 (≤ 3), DICA 2 (4-7) and DICA 3 (>7). A comparison with abdominal pain and inflammatory marker expression was also performed. A total of 50 videos of DD patients were reassessed in order to investigate the predictive role of DICA on the outcome of the disease.

RESULTS

Overall agreement in using DICA was 0.847 (95% confidence interval, CI, 0.812-0.893): 0.878 (95% CI 0.832-0.895) for DICA 1, 0.765 (95% CI 0.735-0.786) for DICA 2 and 0.891 (95% CI 0.845-0.7923) for DICA 3. Intra-observer agreement (kappa) was 0.91 (95% CI 0.886-0.947). A significant correlation was found between the DICA score and C-reactive protein values (p = 0.0001), as well as between the median pain score and the DICA score (p = 0.0001). With respect to the 50 patients retrospectively reassessed, occurrence/recurrence of disease complications was recorded in 29 patients (58%): 10 (34.5%) were classified as DICA 1 and 19 (65.5%) as DICA 2 (p = 0.036).

CONCLUSIONS

The DICA score is a simple, reproducible, validated and easy-to-use endoscopic scoring system for DD of the colon.

Managing ambulatory ulcerative colitis patients with infliximab: a long term follow-up study in primary gastroenterology centers

BACKGROUND

Infliximab (IFX) is the key treatment for ulcerative colitis (UC) unresponsive to standard treatments. The aim of the present study was to assess the efficacy and safety of IFX in treating ambulatory UC patients in primary gastroenterology centers.

METHODS

One hundred and eighteen patients (65 M, 63 F, median age 34 years, range 19-71 years), affected by UC, were treated with IFX. Clinical efficacy, safety, mucosal healing (MH), and histological healing (HH) were assessed at a scheduled follow-up of 42 months.

RESULTS

Percentage of patients with clinical remission persistence at 42-month follow-up was 70.4%. Colectomy occurred in only 3 patients (2.7%). At 42-month follow-up percentage of patients with MH was 44.6%, and percentage of patients with HH was 24.3%. HH at 6-month follow-up occurred in 13 out of 34 patients (38.2%) with C-reactive protein (CRP) <3 and in 8 out of 76 patients (10.5%) with CRP ≥ 3 (p=0.002). Side effects were reported in 16 patients (13.6%): infusion reactions occurred in 7 patients, other severe side-effects occurred in 3 patients, and opportunistic infections occurred in 3 patients (2.5%). Finally, 3 cancers (2.5%) occurred during the follow-up period (1 breast, 1 kidney and 1 rectal cancer). Both univariate and multivariate analyses showed Hb <11.5 g/dL and HH at 6-month follow-up to be significantly associated with treatment failure during follow-up.

CONCLUSIONS

IFX seems to be effective and safe in long-term treatment of outpatients affected by UC.

Effectiveness and safety of infliximab and adalimumab for ambulatory Crohn's disease patients in primary gastroenterology centres

BACKGROUND

Infliximab (IFX) and adalimumab (ADA) are the key treatments for Crohn's Disease (CD), unresponsive to standard treatments. Our aim was to compare the efficacy and safety of IFX and ADA in treating CD in clinical practice.

METHODS

One hundred and twenty-six patients (61 M, 65 F, mean age 36.2 years, range 19-67 years), affected by CD, were treated with infliximab (IFX, 59 patients) or adalimumab (ADA, 66 patients). Clinical efficacy, mucosal healing (MH), histological healing (HH), and safety were assessed. MH was defined complicated if healing of ulcers occurred with deformation of bowel profile and/or complete colonoscopy was impossible because of scars.

RESULTS

Patients were followed-up for 36 months. No difference was found between IFX and ADA in maintaining long-term clinical remission, MH and HH. Complicated MH was present in 17 (28.8%) patients in IFX group and in 7 (10.6%) patients in ADA group (p=0.012). In 9 (15.2%) patients in IFX group and 2 (3.0%) patients in ADA group colonoscopy was incomplete without cecal intubation or terminal ileum exploration (p=0.024). Side effects were similar in both groups.

CONCLUSIONS

Both IFX and ADA seem to be effective and safe in long-term outpatient treatment of CD in clinical practice.

factors influencing mucosal healing in Crohn's disease during infliximab treatment

BACKGROUND/AIMS

The effect of infliximab (IFX) on mucosal healing (MH) in clinical setting, as well as what is the effect of scaring of profound ulcers on bowel, is not well known. Aim of our study was to assess how MH occurs in Crohn's disease (CD) in clinical setting during treatment with IFX.

METHODOLOGY

Forty patients with CD were followed-up. MH and endoscopic remission (ER) were assessed. Some factors were investigated in predicting development of "uncomplicated" (ulcer healing without alteration of bowel profile) or "complicated" (ulcer healing with alteration of bowel profile) MH.

RESULTS

IFX was administered for a mean of 36 months. MH ranged from 67.5% of cases after 6 months to 42.5% of cases after 3 year of treatment. ER ranged from 87.5% of cases after 6 months to 52.5% of cases after 3 year of treatment. Mean CDEIS score decreased from 28 to 8 at the end of follow-up. Uncomplicated MH occurs in 70.37% of patients, complicated MH occurred in 29.63% of patients. Complicated MH was recorded more frequently in patients with severe CDAI (>300 vs. <300, p <0.0362) and higher CDEIS (>35 vs. <35, p >0.0342).

CONCLUSIONS

Complicated MH seems to occur frequently in clinical practice when using IFX, especially in patients with higher indexes of activity at entry.

Effectiveness of adalimumab for ambulatory ulcerative colitis patients after failure of infliximab treatment: a first "real-life" experience in primary gastroenterology centers in Italy

BACKGROUND

Adalimumab (ADA) is the key treatment for ulcerative colitis (UC) unresponsive or intolerant to standard treatments. Our aim was to assess the efficacy and safety of ADA in treating ambulatory UC patients in primary gastroenterology centers.

METHODS

Fifteen patients (6 male, median age 29.9 years, range 22.8-39.9 years) were enrolled. All were previously treated with infliximab (IFX). Clinical activity and endoscopic severity were scored according to the Crohn's disease activity index (CDAI) score and Mayo subscore for endoscopy, respectively. Patients were clinically assessed at weeks 4, 8, and thereafter at weeks 16, 24, 32, 40, 48, and 54. Colonoscopy was performed before starting treatment, at weeks 24 and 54. The co-primary endpoints were clinical remission at 24 and 54 weeks. The secondary endpoints included: 1) sustained clinical remission; 2) steroid-sparing effect; 3) mucosal healing; 4) need for colectomy. Induction dose of ADA was 160 mg at week 0, and then 80 mg at week 2, while ADA maintenance treatment was 40 mg every two weeks.

RESULTS

Clinical remission was obtained in 11 (73.3%) and 15 (100%) patients at weeks 24 and 54 respectively. Ten patients (66.7%) were able to discontinue steroids and were under corticosteroid-free remission at week 54. No patients underwent to colectomy. Eight patients (53.33%) at week 24 and 9 patients (60%) at week 54 achieved complete mucosal healing (Mayo endoscopic score 0). Side effects were reported in 2 of 15 patients (13.3%); none of those patients stopped treatment.

CONCLUSION

ADA seems to be effective and safe in UC outpatients affected by UC, and previously treated with IFX.

Effectiveness of different therapeutic strategies in preventing diverticulitis recurrence

BACKGROUND

Colonic diverticulitis shows a high recurrence rate.

AIMS

To assess the efficacy of three different therapeutic strategies in preventing diverticulitis recurrence.

MATERIALS AND METHODS

One hundred thirty patients suffering from Acute Uncomplicated Diverticulitis (AUD) (81 males, 49 females, mean age 64.71 years, range 40-85) were prospectively assessed. After obtaining remission, considered present when both endoscopic and histological damage were absent, the patients were treated with mesalazine 1.6 g/day (59 patients, group A), or rifaximin 800 mg/day for 7 days every month (52 patients, group B). Clinical, endoscopic and histological follow-up was performed after 6, 12 and thereafter every 12 months after diagnosis of AUD.

RESULTS

Seven patients were excluded from final evaluation because they were lost to follow-up. Fifty-five group A patients and 49 group B patients patients were available for the final assessment at the end of a 24-month follow-up. Sustained remission was significantly higher in group A with respect to group B.

CONCLUSIONS

Patients taking mesalazine have lower risk of diverticulitis recurrence than patients taking rifaximin because of the lower prevalence of persisting endoscopic and histological inflammation.

Performance evaluation of paediatric propofol pharmacokinetic models in healthy young children

BACKGROUND

The performance of eight currently available paediatric propofol pharmacokinetic models in target-controlled infusions (TCIs) was assessed, in healthy children from 3 to 26 months of age.

METHODS

Forty-one, ASA I-II children, aged 3-26 months were studied. After the induction of general anaesthesia with sevoflurane and remifentanil, a propofol bolus dose of 2.5 mg kg(-1) followed by an infusion of 8 mg kg(-1) h(-1) was given. Arterial blood samples were collected at 1, 2, 3, 5, 10, 20, 40, and 60 min post-bolus, at the end of surgery, and at 1, 3, 5, 30, 60, and 120 min after stopping the infusion. Model performance was visually inspected with measured/predicted plots. Median performance error (MDPE) and the median absolute performance error (MDAPE) were calculated to measure bias and accuracy of each model.

RESULTS

Performance of the eight models tested differed markedly during the different stages of propofol administration. Most models underestimated propofol concentration 1 min after the bolus dose, suggesting an overestimation of the initial volume of distribution. Six of the eight models tested were within the accepted limits of performance (MDPE<20% and MDAPE<30%). The model derived by Short and colleagues performed best.

CONCLUSIONS

Our results suggest that six of the eight models tested perform well in young children. Since most models overestimate the initial volume of distribution, the use for TCI might result in the administration of larger bolus doses than necessary.

Influence of obesity on propofol pharmacokinetics: derivation of a pharmacokinetic model

BACKGROUND

The objective of this study was to develop a pharmacokinetic (PK) model to characterize the influence of obesity on propofol PK parameters.

METHODS

Nineteen obese ASA II patients undergoing bariatric surgery were studied. Patients received propofol 2 mg kg(-1) bolus dose followed by a 5-20-40-120 min, 10-8-6-5 mg kg(-1) h(-1) infusion. Arterial blood samples were withdrawn at 1, 3, 5 min after induction, every 10-20 min during propofol infusion, and every 10-30 min for 2 h after stopping the propofol infusion. Arterial samples were processed by high-performance liquid chromatography. Time-concentration data profiles from this study were pooled with data from two other propofol PK studies available at http://www.opentci.org. Population PK modelling was performed using non-linear mixed effects model.

RESULTS

The study involved 19 obese adults who contributed 163 observations. The pooled analysis involved 51 patients (weight 93 sd 24 kg, range 44-160 kg; age 46 sd 16 yr, range 25-81 yr; BMI 33 sd 9 kg m(-2), range 16-52 kg m(-2)). A three-compartment model was used to investigate propofol PK. An allometric size model using total body weight (TBW) was superior to all other models investigated (linear TBW, free fat mass, lean body weight, normal fat mass) for all clearance parameters. Variability in V2 and Q2 was reduced by a function showing a decrease in both parameters with age.

CONCLUSIONS

We have derived a population PK model using obese and non-obese data to characterize propofol PK over a wide range of body weights. An allometric model using TBW as the size descriptor of volumes and clearances was superior to other size descriptors to characterize propofol PK in obese patients.

Safety and effectiveness of infliximab for inflammatory bowel diseases in clinical practice

BACKGROUND AND OBJECTIVES

Our aim was to assess the efficacy and safety of infliximab (IFX) in clinical practice in three Primary Care, Hospital Centers.

MATERIAL AND METHODS

From September 2004 to December 2008 62 patients (28 males, 34 females, mean age 30.25 years, range 15-55 years), affected by ulcerative colitis (UC) (23 pts) or by Crohn's disease (CD) (39 patients) were treated. Clinical efficacy, safety, mucosal healing and quality of life were assessed both in UC and CD.

RESULTS

A total of 746 infusions were performed. IFX was administered for a mean of 26 months (range 8-44 months). 33/39 (84.61%) pts with CD were in remission under treatment with IFX for a mean time of 19 months (range 12-44 months). Mean Crohn Disease Activity Index (CDAI) score decreased from 295 (range 258-346) to 136 (range 98-136) (p < 0.005). Inflammatory Bowel Disease Quality of Life (IBDQL) improved from 48 (at entry) to 198 (at the end of the study) (p < 0.005). 20/23 (86.95%) patients with UC were in remission under treatment with IFX for a mean of 18 months (range 8-34 months). Mean Disease Activity Index (DAI) decreased from 11 (range 9-12) to < 3 (range 2-3) (p < 0.05). Mean Mayo Subscore for Endoscopy decreased from 3 to < 1 (range 0-1). IBDQL improved from 56 (at entry) to 194 (at the end of the study) (p < 0.005). Only 5 patients (8.06%) experienced side-effects.

CONCLUSIONS

Long-term outpatients treatment with IFX seems to be safe and effective in managing patients affected by IBD in clinical practice.

New Insights into the Biological and Clinical Significance of Fecal Calprotectin in Inflammatory Bowel Disease

Nowadays, calprotectin, a cytoplasmatic protein, released by activated neutrophilic polymorphonuclear cells (PMN) and/or monocytes-macrophages (MØ), is considered a good indicator of inflammation in several diseases. Accordingly, fecal calprotectin represents a good predictor of clinical relapse in ulcerative colitis (UC) patients, whereas conflicting results have been reported in Crohn's disease (CD) patients. In our study, in 76 IBD patients (29 CD and 47 UC) fecal calprotectin has been evaluated by a commercial ELISA kit. Results demonstrate that levels of this protein in the stool are significantly more elevated in active CD and UC patients than in normal volunteers. In quiescent CD and UC a trend to higher levels of calprotectin than in the normal counterpart is, however, evident. These data suggest that a low-grade inflammation of the intestinal wall is always present in CD and UC patients, which may predict a clinical relapse risk. In the same group of patients calprotectin levels also were analyzed according to sex and age. A trend to higher values of calprotectin was present in male patients with active or quiescent CD than in their female counterparts. Only in UC patients in remission a trend to calprotectin increase was more marked in the male group than in the female counterpart. When CD and UC patients were divided up according to age, calprotectin positivity peaked between 30-39 years in active CD patients, while in quiescent CD maximum positivity was between 40 and 49 years. However, in both active and quiescent UC patients, calprotectin positivity increased with age. The more precocious detectability of fecal calprotectin in CD patients, as a marker of intestinal mucosa inflammation, may be related to the different histopathology of the two diseases (CD versus UC). However, reduced PMN and/or MØ trafficking from peripheral blood to intestinal mucosa with age by effects of chronic treatment should not be ignored in CD patients.

Detection and quantification of Prymnesium parvum (Haptophyceae) by real-time PCR

AIMS

The ichthyotoxic species Prymnesium parvum (Haptophyceae) is difficult to quantify in a microscopy-based monitoring programme, because the cells are very small, fragile and their morphology can be distorted by the use of fixatives. In the attempt to overcome these problems, a real-time PCR-based method for the rapid and sensitive identification and quantification of P. parvum was developed.

METHODS AND RESULTS

A quantitative real-time PCR assay was optimized with primers designed on the internal transcribed spacer 2 rDNA region of P. parvum. This PCR assay was specific, showing no amplification of DNA extracted from closely related species, and sensitive. Moreover, this method was able to detect and reliably quantify P. parvum cells in preserved environmental samples artificially spiked with known amounts of cultured cells.

CONCLUSIONS

Considering the specificity, sensitivity and applicability to preserved environmental samples, this method may be a useful tool for the monitoring of this toxic species.

SIGNIFICANCE AND IMPACT OF THE STUDY

The real-time PCR method described in this study may represent a progress towards the rapid detection and quantification of P. parvum cells in water-monitoring programmes, allowing the early application of strategies to control bloom events, such as the use of clay minerals.

Study on the oligosaccharides composition of the water-soluble fraction of marine mucilage by electrospray tandem mass spectrometry

The massive accumulation of organic matter, which periodically occurs in the northern Adriatic Sea, and in other locations worldwide, is presently thought to be the results of the aggregation of dissolved organic matter (DOM) into particulate organic matter (POM). This phenomenon is the result of human activities and propitious weather conditions. Although many aspects of the phenomenon are well understood, the trigger mechanisms leading to mucilage formation have not been clarified yet, probably as a consequence of inadequate analytical approaches. In this context, the recent advancements in LC-MS interfacing might contribute in clarifying the mechanism of mucilage formation. In the present paper, hydrophilic interaction liquid chromatography coupled with electrospray tandem mass spectrometry (HILC-ESI-MS/MS) is proposed as an innovative method for the investigation of underivatized oligosaccharides in mucilage samples. Recent findings suggest that the significant presence of these compounds in seawater can play an important role in the initial steps of the agglomeration processes forming gelatinous material. Our results reveal the presence of several maltodextrines in the water-soluble fraction of mucilage macroaggregates, collected in various locations of the northern Adriatic Sea. In our knowledge, the proposed method is the first application of LC-MS in the investigation of marine mucilage.

Capture probe conjugated to paramagnetic nanoparticles for purification of Alexandrium species (Dinophyceae) DNA from environmental samples

AIMS

To develop a rapid, cost-effective and selective Alexandrium DNA extraction procedure from environmental samples in order to provide good-quality template for the downstream PCR-based detection assay.

METHODS AND RESULTS

In this study, we tested a DNA extraction method based on silica-coated, superparamagnetic nanoparticles conjugated to a DNA-capture sequence (probe) complementary to a specific region of 5.8S rDNA of the genus Alexandrium. Cultured Alexandrium catenella cells were used as the harmful algal bloom species for the DNA extraction. Then, a PCR assay was performed with primers specific for the genus Alexandrium to assess the specificity and sensitivity of the nucleic acid extraction method. This method was applied to both cultured and field samples, reaching in both cases a detection limit of one A. catenella cell.

CONCLUSIONS

The results suggest that the use of probe-conjugated paramagnetic nanoparticles could be effective for the specific purification of microalgal DNA in cultured or environmental samples, ensuring sensitivity and specificity of the subsequent PCR assays.

SIGNIFICANCE AND IMPACT OF THE STUDY

The DNA extraction method optimized in this study represents a progress towards the rapid and efficient direct detection of Alexandrium cells in seawater monitoring. In fact, this method requires no other equipment than a magnet and a hybridization oven and, in principle, can be adapted to different toxic microalgal species and can be automated, allowing the processing of a high number of samples.

Thymidine phosphorylase profiles in nonmalignant and malignant pancreatic tissue. Potential therapeutic role of capecitabine on tumoral and endothelial cells and tumor-infiltrating macrophages

The drug capecitabine (CAP) is a thymidine Pi-deoxyribosyltransferase (TP) activated oral fluorpyrimidine that generates 5-fluorouracil (5-FU), preferentially, within tumors. Here, in 38 patients with pancreatic cancer we analyzed immunohistochemical TP expression in pancreatic cancer tissue (PCT) and adjacent nonmalignant pancreatic tissue (ANMPT). In addition, a correlation with the main clinical pathological features was made. Furthermore, TP-positive macrophages (MO) isolated from neoplastic tissue were determined. The mean of TP-positive epithelial cells and endothelial cells in terms of microvessel density was significantly higher in PCT than in ANMPT. Because pancreatic cancer is sensitive to 5-FU, TP-activated oral CAP in tumoral and endothelial cells and tumor infiltrating MO could increase the concentration of 5-FU at tumor site, thus resulting in an enhanced antitumor activity.

Small intestinal contrast ultrasonography-based scoring system: a promising approach for the diagnosis and follow-up of celiac disease

BACKGROUND

Small intestinal ultrasonography with anechoic contrast agents (SICUS) has been shown to have a diagnostic accuracy on small bowel morphology similar to X-ray barium follow-through. Although extremely investigated by transabdominal ultrasonography, celiac disease, a common disorder of the small bowel, has been never studied by SICUS.

AIM

To asses SICUS characteristics of celiac disease patients.

PATIENTS AND METHODS

SICUS was performed using PEG 4000 as contrast agent. Twenty-three patients with celiac disease at the first diagnosis were enrolled and 30 healthy volunteers, matched for sex and age, were selected as control group. Celiac disease diagnosis was based on anti-gluten, anti-endomysium, and anti-transglutaminase positivity as well as jejunal histology. The following seven echographic parameters were considered: liquid endoluminal content before contrast, loop diameter, Kerckring's folds, peristaltic waves, ileal jejunalization, mesenteric lymphoadenomegaly, and Doppler resistance index (RI) of mesenteric superior artery. Statistical analysis was performed by Student's t test for unpaired data; one-way analysis of variance was used to correlate echographic and histologic pictures.

RESULTS

Loop diameter, Kerckring's fold number, peristaltic waves, and Doppler RI appeared to be significantly different between celiac disease patients and controls. Additionally, liquid content, ileal jejunalization, and mesenteric lymphoadenomegaly were present only in the celiacs (52.1%, 47.7%, and 95.6%, respectively), but not in controls. Only Doppler RI values significantly correlated with the histologic degree of damage.

CONCLUSIONS

SICUS could be a reliable and noninvasive technique to confirm a diagnosis of celiac disease performed using conventional investigations. The possibility of investigating the whole small bowel and the safety of repeating examinations could be useful in the follow-up of celiac patients.

Identification of immunodominant hepatitis C virus (HCV)-specific cytotoxic T-cell epitopes by stimulation with endogenously synthesized HCV antigens

Hepatitis C virus (HCV)-specific CD8(+) cytotoxic T lymphocytes (CTL) are believed to play an important role in the pathogenesis of liver cell injury and viral clearance in HCV infection. Because HCV does not efficiently infect human cells in vitro and primary infected hepatocytes cannot be used as stimulator/target cells for CTL analysis, development of efficient systems to activate and expand CTL in vitro, reproducing antigen presentation to CTL occurring during natural infection, is mandatory to study CTL activity and to define the hierarchy of immunodominance of CTL epitopes. To achieve this goal, 5 different defective adenoviruses carrying structural and nonstructural HCV genes (core, core-E1-E2, E2, NS3-NS4A, NS3-NS5A) were used to induce the endogenous synthesis of HCV proteins in human adherent mononuclear cells in vitro and to allow their entry into the HLA class I cytosolic pathway of antigen processing. The cytolytic activity of peripheral blood lympho-mononuclear cells (PBMC) from HLA-A2(+) HCV-infected patients stimulated with recombinant adenovirus-infected cells was tested against target cells either pulsed with a panel of synthetic peptides containing the HLA-A2 binding motif or infected with recombinant vaccinia viruses carrying HCV genes. Our study defines a reproducible system to stimulate and expand HCV-specific CTL in vitro that mimics the conditions of antigen encounter in vivo. By this approach, we have identified several HLA-A2-restricted epitopes that should correspond to immunodominant HCV sequences recognized by CTL during natural infection. Therefore, these amino acid sequences represent ideal candidates for the design of therapeutic vaccines for chronic HCV infection.

Lamivudine treatment can overcome cytotoxic T-cell hyporesponsiveness in chronic hepatitis B: new perspectives for immune therapy

The hepatitis B virus (HBV) cytotoxic T lymphocyte (CTL) response in patients with chronic HBV infection is generally weak or totally undetectable. This inability to mount protective CTL responses is believed to be a crucial determinant of viral persistence, and its correction represents an important objective of immune therapies for chronic hepatitis B. However, amplification of CTL responses in vivo may be ineffective if HBV-specific CD8 cells are either absent or nonresponsive to exogenous stimulation. In this study, we asked whether antiviral treatments able to inhibit viral replication and to reduce viral and antigen load can successfully reconstitute CTL responses creating the appropriate conditions for their therapeutic stimulation. For this purpose, the HBV-specific CTL response before and during lamivudine therapy was studied longitudinally in 6 HLA-A2-positive patients with HBeAg+ chronic hepatitis B. Both HBV-specific cytotoxic T cell activity measured by chromium release assay on peptide stimulation in vitro and CD8+ T cell frequency measured ex vivo by HLA-A2/peptide tetramer staining were significantly augmented by lamivudine therapy. This enhancement followed the reconstitution of CD4 reactivity and the decline of viral load induced by therapy. Our study shows that lamivudine treatment in chronic hepatitis B can restore CTL reactivity, making CTL susceptible to exogenous stimulation. This effect may enhance the probability that T cell-based immune therapies delivered after lamivudine treatment can successfully reconstitute a protective CTL response able to cure chronic HBV infection.

Parasitic diatoms inside antarctic sponges

Antarctic sponges may host large populations of planktonic and benthic diatoms. After settling on the sponge, these diatoms enter its body through pinacocytes (1) and form, there, large mono- or pauci-specific assemblages. Yet the total amount of carbohydrates in the invaded sponge tissue is inversely correlated with that of chlorophyll-a. We suggest, therefore, that endobiont diatoms utilize the products of the metabolism of their host as an energy source. This is the first evidence indicating that an endobiotic autotrophic organism may parasitize its animal host. Moreover, this unusual symbiotic behavior could be a successful strategy that allows the diatom to survive in darkness.

Practice guidelines developed by specialty societies: the need for a critical appraisal

BACKGROUND

There is increasing concern about the quality, reliability, and independence of practice guidelines. Because no information is available on the methodological quality of the guidelines developed by specialty societies, we undertook a survey on those published in peer-reviewed journals.

METHODS

Practice guidelines produced by specialty societies and published in English between January, 1988, and July, 1998, where identified through MEDLINE. Their quality was assessed in terms of whether they reported: the type of professionals and stakeholders involved in the development process; the strategy to identify primary evidence; and an explicit grading of recommendations according to the quality of supporting evidence.

FINDINGS

Overall, 431 guidelines were eligible for the study. Most did not meet the criteria: 67% did not report any description of the type of stakeholders, 88% gave no information on searches for published studies, and 82% did not give any explicit grading of the strength of recommendations. There was improvement over time for searches (from 2% to 18%, p<0.001) and explicit grading of evidence (from 6% to 27%, p<0.001). All three criteria for quality were met in only 22 (5%) guidelines.

INTERPRETATION

Despite improvement over time, the quality of practice guidelines developed by specialty societies is unsatisfactory. Explicit methodological criteria for the production of guidelines shared among public agencies, scientific societies, and patients' associations need to be set up. Common standards of reporting, following the same principles that led to the CONSORT statement for randomised clinical trials, should be promoted.