Heparin-binding-hemagglutinin-induced IFN-gamma release as a diagnostic tool for latent tuberculosis.

BACKGROUND: The detection of latent tuberculosis infection (LTBI) is a major component of tuberculosis (TB) control strategies. In addition to the tuberculosis skin test (TST), novel blood tests, based on in vitro release of IFN-gamma in response to Mycobacterium tuberculosis-specific antigens ESAT-6 and CFP-10 (IGRAs), are used for TB diagnosis. However, neither IGRAs nor the TST can separate acute TB from LTBI, and there is concern that responses in IGRAs may decline with time after infection. We have therefore evaluated the potential of the novel antigen heparin-binding hemagglutinin (HBHA) for in vitro detection of LTBI. METHODOLOGY AND PRINCIPAL FINDINGS: HBHA was compared to purified protein derivative (PPD) and ESAT-6 in IGRAs on lymphocytes drawn from 205 individuals living in Belgium, a country with low TB prevalence, where BCG vaccination is not routinely used. Among these subjects, 89 had active TB, 65 had LTBI, based on well-standardized TST reactions and 51 were negative controls. HBHA was significantly more sensitive than ESAT-6 and more specific than PPD for the detection of LTBI. PPD-based tests yielded 90.00% sensitivity and 70.00% specificity for the detection of LTBI, whereas the sensitivity and specificity for the ESAT-6-based tests were 40.74% and 90.91%, and those for the HBHA-based tests were 92.06% and 93.88%, respectively. The QuantiFERON-TB Gold In-Tube (QFT-IT) test applied on 20 LTBI subjects yielded 50% sensitivity. The HBHA IGRA was not influenced by prior BCG vaccination, and, in contrast to the QFT-IT test, remote (>2 years) infections were detected as well as recent (<2 years) infections by the HBHA-specific test. CONCLUSIONS: The use of ESAT-6- and CFP-10-based IGRAs may underestimate the incidence of LTBI, whereas the use of HBHA may combine the operational advantages of IGRAs with high sensitivity and specificity for latent infection.

Regulatory T cells depress immune responses to protective antigens in active tuberculosis.

RATIONALE: Tuberculosis (TB) remains a leading cause of death, and the role of T-cell responses to control Mycobacterium tuberculosis infections is well recognized. Patients with latent TB infection develop strong IFN-gamma responses to the protective antigen heparin-binding hemagglutinin (HBHA), whereas patients with active TB do not. OBJECTIVES: We investigated the mechanism of this difference and evaluated the possible involvement of regulatory T (Treg) cells and/or cytokines in the low HBHA T-cell responses of patients with active TB. METHODS: The impact of anti-transforming growth factor (TGF)-beta and anti-IL-10 antibodies and of Treg cell depletion on the HBHA-induced IFN-gamma secretion was analyzed, and the Treg cell phenotype was characterized by flow cytometry. MEASUREMENTS AND MAIN RESULTS: Although the addition of anti-TGF-beta or anti-IL-10 antibodies had no effect on the HBHA-induced IFN-gamma secretion in patients with active TB, depletion of CD4(+)CD25(high)FOXP3(+) T lymphocytes resulted in the induction by HBHA of IFN-gamma concentrations that reached levels similar to those obtained for latent TB infection. No effect was noted on the early-secreted antigen target-6 or candidin T-cell responses. CONCLUSIONS: Specific CD4(+)CD25(high)FOXP3(+) T cells depress the T-cell-mediated immune responses to the protective mycobacterial antigen HBHA during active TB in humans.

Seroprotection against tetanus in patients attending an emergency department in Belgium and evaluation of a bedside immunotest.

BACKGROUND: In most emergency departments, tetanus prophylaxis currently relies on vaccination history. Bedside evaluation of tetanus immunity may improve this process. OBJECTIVES: (i) To determine the seroprevalence of tetanus immunity; (ii) to evaluate the accuracy of vaccination history in assessing tetanus immunity; (iii) to identify factors predictive of seroprotection and incorrect history. METHOD: In a prospective observational study, tetanus immunity was assessed in 784 adults using Tétanos Quick Stick (TQS). A questionnaire was completed to obtain vaccination and general histories. Immunity assessed by TQS and by vaccination history were compared with anti-tetanus antibody levels measured by the enzyme-linked immunosorbent assay (seroprotection threshold >0.15 IU/ml). RESULTS: Overall, 64.2% of patients were protected according to TQS results. Four independent predictors of seroprotection were identified: young age, birthplace in Belgium, male sex and occupational medicine consultation. TQS performance was good: kappa=0.71, sensitivity 85.3%, specificity 87.2%, positive predictive value 92.1% and negative predictive value 77.2%. Seven hundred and sixty-two participants responded to the vaccination history: 23.4% said they were protected, 22.1% that they were not and 54.5% did not know. History performance was poor: kappa=0.27, sensitivity 60.3%, specificity 73.3%, positive predictive value 81.8% and negative predictive value 45.8%. Compared with history, TQS offered a significantly better sensitivity, negative and positive predictive values, but specificity was similar. No predictor of an incorrect history was identified. CONCLUSION: Lack of protective immunity against tetanus is frequent but poorly evaluated by history taking. Several demographic characteristics are good predictors of seroprotection. TQS could be a valuable tool in selected patients to improve tetanus prophylaxis in the emergency department.

A phase 1-2 clinical trial of gene therapy for recurrent glioblastoma multiforme by tumor transduction with the herpes simplex thymidine kinase gene followed by ganciclovir.

This study has investigated the effects of herpes simplex thymidine kinase gene (HSV-tk) transfer followed by ganciclovir treatment as adjuvant gene therapy to surgical resection in patients with recurrent glioblastoma multiforme (GBM). The study was open and single-arm, and aimed at assessing the feasibility and safety of the technique and indications of antitumor activity. In 48 patients a suspension of retroviral vector-producing cells (VPCs) was administered by intracerebral injection immediately after tumor resection. Intravenous ganciclovir was infused daily 14 to 27 days after surgery. Patients were monitored for adverse events and for life by regular biosafety assaying. Tumor changes were monitored by magnetic resonance imaging (MRI). Reflux during injection was a frequent occurrence but serious adverse events during the treatment period (days 1-27) were few and of a nature not unexpected in this population. One patient experienced transient neurological disorders associated with postganciclovir MRI enhancement. There was no evidence of replication-competent retrovirus in peripheral blood leukocytes or in tissue samples of reresection or autopsy. Vector DNA was shown in the leukocytes of some patients but not in autopsy gonadal samples. The median survival time was 8.6 months, and the 12-month survival rate was 13 of 48 (27%). On MRI studies, tumor recurrence was absent in seven patients for at least 6 months and for at least 12 months in two patients, one of whom remains recurrence free at more than 24 months. Treatment-characteristic images of injection tracks and intracavity hemoglobin were apparent. In conclusion, the gene therapy is feasible and appears to be satisfactorily safe as an adjuvant to the surgical resection of recurrent GBM, but any benefit appears to be marginal. Investigation of the precise effectiveness of this gene therapy requires prospective, controlled studies.

Doxifluridine and leucovorin: an oral treatment combination in advanced colorectal cancer

Purpose: This study was designed to test the activity and feasibility of an all-oral regimen of levo-leucovorin and doxifluridine (dFUR) in the treatment of advanced colorectal cancer and to establish whether the pharmacokinetics of dFUR and fluorouracil (FU) are affected by demographic and/or biologic parameters. Materials and Methods: One hundred eight patients with histologically proven colorectal cancer received orally administered levo-leucovorin 25 mg followed 2 hours later by dFUR 1,200 mg/m2 on days 1 to 5, with the cycle being repeated every 10 days. Results: Among 62 previously untreated patients, two complete responses (CRs) and 18 partial responses (PRs) were observed (overall response rate, 32%; 95% confidence interval, 21% to 45%). The median response duration was 4 months (range, 2 to 13) and the median survival time, 14 months. Among 46 pretreated patients, there were three CRs and three PRs (response rate, 13%; 95% confidence interval, 5% to 26%). In this group of patients, the median response duration was 4 months (range, 1 to 12) and the median survival time, 12 months. No toxic deaths were observed. The only World Health Organization (WHO) grade 3 to 4 side effect was diarrhea (32 patients). Conclusion: This regimen is active in previously untreated colorectal cancer patients and combines good compliance with safety. Limited but definite efficacy was also detected in the patients previously treated with FU, which suggests incomplete cross- resistance between the two drugs. The pharmacokinetic results suggest that the conversion rate of dFUR to FU increases between days 1 and 5, but that FU levels remain low in comparison to those measured after classical FU therapy. Under the experimental conditions used in this study, the interpatient variability of pharmacokinetic parameters remains largely unexplained by the tested variables.

Multicenter randomized trial of dacarbazine alone or in combination with two different doses and schedules of interferon alfa-2a in the treatment of advanced melanoma

Purpose: Some phase II studies have suggested that the combination of interferons (IFNs) with dacarbazine (DTIC) in the treatment of malignant melanoma (MM) increases the antitumor activity of DTIC alone. In an attempt to confirm this hypothesis, a randomized study was performed with the further intent of observing whether low doses of recombinant interferon alfa-2a (rIFNα2a) could be as effective as intermediate doses. Patients and Methods: Two hundred sixty-six patients were randomized onto three different treatment arms: DTIC 800 mg/m 2 intravenously (IV) days 1 and 21; DTIC plus rIFNα2a 9 mIU intramuscularly (IM) daily; and DTIC plus rIFNα2a 3 mIU IM three times per week. Major prognostic factors were well balanced among the three arms. Chemotherapy was administered for a maximum of eight cycles. After 6 months of therapy, rIFNα2a was continued until disease progression at 3 mIU three times per week in responding patients who had received the combined treatment. Results: The percentage of objective responses did not differ among the three groups (20%, 28%, and 23%, respectively), although a significant prolongation of response duration was observed when rIFNα2a was added to DTIC (2.6 v 8.4 v 5.5 months, respectively). However, this improvement in response duration did not translate into an amelioration of overall survival. The addition of rIFNα2a led to the onset of flu-like syndrome, but in no case was it necessary to withdraw the treatment program and no toxic deaths or life-threatening toxicities were reported. Conclusion: In this study, rIFNα2a significantly prolonged response duration, whereas no effects on response rate and survival were observed; rIFNα2a 3 mIU appeared to be equally effective and better tolerated than 9 mIU.

A dose-finding study of lanreotide (a somatostatin analog) in patients with colorectal carcinoma

BACKGROUND. Laboratory data suggest that insulin-like growth factor-1 (IGE-1) may stimulate the growth of different human tumors. At least in acromegalic patients, somatostatin (SMS) analogs, such as lanreotide, suppress the serum levels of growth hormone (GH) and IGE-1. METHODS. To evaluate the tolerability and biologic activity of different doses of lanreotide in patients with advanced colorectal carcinoma, consecutive groups of 3 patients each were subcutaneous treated with lanreotide at doses of 1, 2, 3, 4, 5, or 6 mg three times a day for 2 months. In the event of Grade 3 side effects, 3 additional patients were treated with the same dose before the next dose escalation. Serum samples were obtained on Days 0, 15, 30, and 60 for serum GH, IGF-1, and lanreotide assessment. RESULTS. Twenty-four patients were enrolled and all were evaluable. Except for the 3 and 6 mg doses, for which the observation of a Grade 3 side effect required that an additional three patients be treated, it was sufficient to treat 3 patients at each dose. The overall incidence of side effects was as follows: changes in bowel habits, 83%; abdominal cramps, 79%; diarrhea, 17%; vomiting, 17%; nausea, 21%; steatorrhea, 78%; hyperglycemia, 35%; laboratory hypothyroidism, 39%; gallstones, 13%; and weight loss, 17%. No evidence of an increase in the incidence, intensity, or duration of side effects was observed with dose escalation. Serum IGF-1 levels were as follows: Day 13: 63%, 60%, and 67% of the baseline values for the low (12 mg), intermediate (3-4 mg), and high (5- 6 mg) dose groups, respectively; Day 30: 63%, 59%, and 51%, respectively; and Day 60: 73%, 69%, and 47%, respectively. Serum lanreotide levels declined during treatment in all of the dose groups (90 ng/mL on Day 15, and 35 ng/mL on Day 60 for the 5-6 mg group; 10 ng/mL on Day 15, and 1.5 ng/mL on Day 60 for the 1-2 mg group). No antitumor activity or tumor marker reduction was observed. CONCLUSIONS. No increase in toxicity was observed when subcutaneous lanreotide doses were escalated to 6 mg three times a day for 2 months. The highest doses seemed to maintain reduced serum IGF-1 levels; with the lowest doses, a 'rebound' in serum IGF-1 levels was observed during treatment. Nevertheless, intermittent subcutaneous injections do not ensure constant serum drug concentrations over time.