Campylobacter gastroenteritis and bacteremia in an asplenic patient with a recent history of Yersinia Enterocolitis: Case report and literature review

In this case report, we present a patient with a history of splenectomy and two recent hospital admissions for severe gastroenteritis with sepsis. The first hospital admission was for Yersinia enterocolitica and the second admission was for Campylobacter fetus gastroenteritis with bacteremia. During both admissions, the patient was treated with a prolonged course of antibiotics and later discharged with full recovery. In our review, we address the risk of enterocolitis in splenectomized patients.

Comparison of bivalent and monovalent SARS-CoV-2 variant vaccines: the phase 2 randomized open-label COVAIL trial

Vaccine protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection wanes over time, requiring updated boosters. In a phase 2, open-label, randomized clinical trial with sequentially enrolled stages at 22 US sites, we assessed safety and immunogenicity of a second boost with monovalent or bivalent variant vaccines from mRNA and protein-based platforms targeting wild-type, Beta, Delta and Omicron BA.1 spike antigens. The primary outcome was pseudovirus neutralization titers at 50% inhibitory dilution (ID50 titers) with 95% confidence intervals against different SARS-CoV-2 strains. The secondary outcome assessed safety by solicited local and systemic adverse events (AEs), unsolicited AEs, serious AEs and AEs of special interest. Boosting with prototype/wild-type vaccines produced numerically lower ID50 titers than any variant-containing vaccine against all variants. Conversely, boosting with a variant vaccine excluding prototype was not associated with decreased neutralization against D614G. Omicron BA.1 or Beta monovalent vaccines were nearly equivalent to Omicron BA.1 + prototype or Beta + prototype bivalent vaccines for neutralization of Beta, Omicron BA.1 and Omicron BA.4/5, although they were lower for contemporaneous Omicron subvariants. Safety was similar across arms and stages and comparable to previous reports. Our study shows that updated vaccines targeting Beta or Omicron BA.1 provide broadly crossprotective neutralizing antibody responses against diverse SARS-CoV-2 variants without sacrificing immunity to the ancestral strain. ClinicalTrials.gov registration: NCT05289037 .

A Multicenter, Controlled Human Infection Study of Influenza A(H1N1)pdm09 in Healthy Adults

BACKGROUND

We evaluated the associations between baseline influenza virus-specific hemagglutination inhibition (HAI) and microneutralization (MN) titers and subsequent symptomatic influenza virus infection in a controlled human infection study.

METHODS

We inoculated unvaccinated healthy adults aged 18-49 years with an influenza A/California/04/2009/H1N1pdm-like virus (NCT04044352). We collected serial safety labs, serum for HAI and MN, and nasopharyngeal swabs for reverse-transcription polymerase chain reaction (RT-PCR) testing. Analyses used the putative seroprotective titer of ≥40 for HAI and MN. The primary clinical outcome was mild-to-moderate influenza disease (MMID), defined as ≥1 postchallenge positive qualitative RT-PCR test with a qualifying symptom/clinical finding.

RESULTS

Of 76 participants given influenza virus challenge, 54 (71.1%) experienced MMID. Clinical illness was generally very mild. MMID attack rates among participants with baseline titers ≥40 by HAI and MN were 64.9% and 67.9%, respectively, while MMID attack rates among participants with baseline titers <40 by HAI and MN were 76.9% and 78.3%, respectively. The estimated odds of developing MMID decreased by 19% (odds ratio, 0.81 [95% confidence interval, .62-1.06]; P = .126) for every 2-fold increase in baseline HAI. There were no significant adverse events.

CONCLUSIONS

We achieved a 71.1% attack rate of MMID. High baseline HAI and MN were associated with protection from illness. Clinical Trials Registration. NCT04044352.

Bivalent and Monovalent SARS-CoV-2 Variant Vaccine Boosters Improve coverage of the known Antigenic Landscape: Results of the COVID-19 Variant Immunologic Landscape (COVAIL) Trial

Vaccine protection against COVID-19 wanes over time and has been impacted by the emergence of new variants with increasing escape of neutralization. The COVID-19 Variant Immunologic Landscape (COVAIL) randomized clinical trial (clinicaltrials.gov NCT05289037) compares the breadth, magnitude and durability of antibody responses induced by a second COVID-19 vaccine boost with mRNA (Moderna mRNA-1273 and Pfizer-BioNTech BNT162b2), or adjuvanted recombinant protein (Sanofi CoV2 preS DTM-AS03) monovalent or bivalent vaccine candidates targeting ancestral and variant SARS-CoV-2 spike antigens (Beta, Delta and Omicron BA.1). We found that boosting with a variant strain is not associated with loss in neutralization against the ancestral strain. However, while variant vaccines compared to the prototype/wildtype vaccines demonstrated higher neutralizing activity against Omicron BA.1 and BA.4/5 subvariants for up to 3 months after vaccination, neutralizing activity was lower for more recent Omicron subvariants. Our study, incorporating both antigenic distances and serologic landscapes, can provide a framework for objectively guiding decisions for future vaccine updates.

Diagnosis and Management of Pulmonary NTM with a Focus on Mycobacterium avium Complex and Mycobacterium abscessus: Challenges and Prospects

BACKGROUND

Nontuberculous mycobacteria (NTM) are ubiquitous. NTM can affect different organs and may cause disseminated diseases, but the pulmonary form is the most common form. Pulmonary NTM is commonly seen in patients with underlying diseases. Pulmonary Mycobacterium avium complex (MAC) is the most common NTM disease and M. abscessus (MAB) is the most challenging to treat. This review is prepared with the following objectives: (a) to evaluate new methods available for the diagnosis of pulmonary MAC or MAB, (b) to assess advances in developing new therapeutics and their impact on treatment of pulmonary MAC or MAB, and (c) to evaluate the prospects of preventive strategies including vaccines against pulmonary MAC or MAB.

METHODS

A literature search was conducted using PubMed/MEDLINE and multiple search terms. The search was restricted to the English language and human studies. The database query resulted in a total of 197 publications. After the title and abstract review, 64 articles were included in this analysis.

RESULTS

The guidelines by the American Thoracic Society (ATS), European Respiratory Society (ERS), European Society of Clinical Microbiology and Infectious Diseases (ESCMID), and Infectious Diseases Society of America (IDSA) are widely applicable. The guidelines are based on expert opinion and there may be a need to broaden criteria to include those with underlying lung diseases who may not fulfill some of the criteria as 'probable cases' for better follow up and management. Some cases with only one culture-positive sputum sample or suggestive histology without a positive culture may benefit from new methods of confirming NTM infection. Amikacin liposomal inhalation suspension (ALIS), gallium containing compounds and immunotherapies will have potential in the management of pulmonary MAC and MAB.

CONCLUSIONS

the prevalence of pulmonary NTM is increasing. The efforts to optimize diagnosis and treatment of pulmonary NTM are encouraging. There is still a need to develop new diagnostics and therapeutics.

Ceftaroline: Systematic Review of Clinical Uses and Emerging Drug Resistance

OBJECTIVE

To assess the success rates of off-label uses of ceftaroline for infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and evaluate emerging ceftaroline resistance.

DATA SOURCES

We queried PubMed/MEDLINE, with the search term "Ceftaroline." Articles were restricted to the English language and year of publication (January 1, 2009-January 31, 2022).

STUDY SELECTION AND DATA EXTRACTION

Clinical trials, observational studies, and case reports that reported efficacy, safety, pharmacokinetics, use in MRSA infections other than acute bacterial skin infection and community-acquired pneumonia, and ceftaroline resistance were selected.

DATA SYNTHESIS

The search pooled 103 publications and all abstracts were reviewed. Forty-six articles that reported efficacy, safety, pharmacokinetics, or off-label use in multiple patients and 7 articles on ceftaroline resistance are used in this review. Ceftaroline has been approved for treatment of acute skin/soft tissue infection and community-acquired pneumonia. Ceftaroline's efficacy in off-label infections ranged from 66.7% to 87.3% depending on the types of infection. There were 14 documented cases of ceftaroline resistance associated with PBP2a changes.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Case series and observational studies have documented success with ceftaroline alone or in combination with vancomycin or daptomycin for treatment of MRSA bone and joint, endovascular, diabetic foot infections, and bacteremia from other causes.

CONCLUSION

Despite the lack of randomized controlled trials, ceftaroline is used as salvage therapy for different MRSA infections. The data from case series and observational studies are promising but ceftaroline should be used judiciously as ceftaroline-resistant MRSA begin to emerge.

Cryptococcal chest wall mass and rib osteomyelitis associated with the use of fingolimod: A case report and literature review

Being introduced in 2010, fingolimod was among the first oral therapies for relapsing multiple sclerosis (MS). Since that time, postmarketing surveillance has noted several case reports of various cryptococcal infections associated with fingolimod use. To date, approximately 15 such case reports have been published. We present the first and unique case of cryptococcal chest wall mass and rib osteomyelitis associated with fingolimod use. The patient presented with left-side chest pain and was found to have a lower left chest wall mass. Computerized tomography (CT) showed chest wall mass with the destruction of left 7th rib. Aspirate from the mass grew Cryptococcus neoformans. The isolate was serotype A. Fingolimod was stopped. The patient received liposomal amphotericin B for 2 weeks and started on fluconazole with a plan to continue for 6–12 months. The follow-up CT in 6 weeks showed a marked decrease in the size of the chest wall mass. In conclusion, our case highlights the atypical and aggressive form of cryptococcal infection possibly related to immunosuppression from fingolimod use.

Clinical features and treatment outcomes of pulmonary Mycobacterium avium-intracellulare complex with and without co-infections

Coinfections are more common in patients with cystic fibrosis and bronchiectasis. Infiltrates on imaging studies are seen more commonly in patients with coinfections, but coinfections did not affect treatment outcomes of pulmonary Mycobacterium avium complex.

SARS-CoV-2 Variant Vaccine Boosters Trial: Preliminary Analyses

Background

Protection from SARS-CoV-2 vaccines wanes over time and is compounded by emerging variants including Omicron subvariants. This study evaluated safety and immunogenicity of SARS-CoV-2 variant vaccines.

Methods

This phase 2 open-label, randomized trial enrolled healthy adults previously vaccinated with a SARS-CoV-2 primary series and a single boost. Eligible participants were randomized to one of six Moderna COVID19 mRNA vaccine arms (50µg dose): Prototype (mRNA-1273), Omicron BA.1+Beta (1 or 2 doses), Omicron BA.1+Delta, Omicron BA.1 monovalent, and Omicron BA.1+Prototype. Neutralization antibody titers (ID 50 ) were assessed for D614G, Delta, Beta and Omicron BA.1 variants and Omicron BA.2.12.1 and BA.4/BA.5 subvariants 15 days after vaccination.

Results

From March 30 to May 6, 2022, 597 participants were randomized and vaccinated. Median age was 53 years, and 20% had a prior SARS-CoV-2 infection. All vaccines were safe and well-tolerated. Day 15 geometric mean titers (GMT) against D614G were similar across arms and ages, and higher with prior infection. For uninfected participants, Day 15 Omicron BA.1 GMTs were similar across Omicron-containing vaccine arms (3724-4561) and higher than Prototype (1,997 [95%CI:1,482-2,692]). The Omicron BA.1 monovalent and Omicron BA.1+Prototype vaccines induced a geometric mean ratio (GMR) to Prototype for Omicron BA.1 of 2.03 (97.5%CI:1.37-3.00) and 1.56 (97.5%CI:1.06-2.31), respectively. A subset of samples from uninfected participants in four arms were also tested in a different laboratory at Day 15 for neutralizing antibody titers to D614G and Omicron subvariants BA.1, BA.2.12.2 and BA.4/BA.5. Omicron BA.4/BA.5 GMTs were approximately one third BA.1 GMTs (Prototype 517 [95%CI:324-826] vs. 1503 [95%CI:949-2381]; Omicron BA.1+Beta 628 [95%CI:367-1,074] vs. 2125 [95%CI:1139-3965]; Omicron BA.1+Delta 765 [95%CI:443-1,322] vs. 2242 [95%CI:1218-4128] and Omicron BA.1+Prototype 635 [95%CI:447-903] vs. 1972 [95%CI:1337-2907).

Conclusions

Higher Omicron BA.1 titers were observed with Omicron-containing vaccines compared to Prototype vaccine and titers against Omicron BA.4/BA.5 were lower than against BA.1 for all candidate vaccines.

Clinicaltrialsgov

NCT05289037.

Femoral artery aneurysm with large hematoma from Pasteurella: case report and literature review

Background

Pasteurella multocida is a well-known gram-negative facultative anaerobe well known for its ability to cause soft tissue infections following animal bite or scratch. Here we present a case with mycotic aneurysm of the superficial femoral artery due to P. multocida infection.

Case presentation

A 62 year old male patient presented with worsening right leg pain and swelling. On examination, he was found to have profound swelling and erythema of the right medial thigh and tenderness to palpation. Computerized tomography showed findings suggestive of right femoral pseudoaneurysm with a large right medial thigh hematoma. Blood cultures grew P. multocida. Patient underwent emergent open resection of the mycotic aneurysm and vascular bypass surgery. Intraoperatively, the site was noted to be grossly infected with multiple pockets of pus which were drained and pus cultures grew P. multocida. The diagnosis of P. multocida bacteremia with right femoral mycotic aneurysm and thigh abscess was made. Patient received 6 weeks of intravenous ceftriaxone and recovered.

Conclusion

Our case is the first report on infection of peripheral vessel with Pasteurella and highlights the importance of prompt surgical intervention and effective antibiotic treatment

Effects of race on the outcome of COVID-19 in hospitalized patients

BACKGROUND AND AIMS

Recent reports indicate that African Americans have higher mortality rates from SARS-CoV-2 coronavirus disease 19 (COVID-19) compared to Caucasians, with more marked differences in the Midwest region of the US. This study was performed to study differences in COVID-19 related mortality and hospital length of stay (LOS) between African Americans and Caucasians in Midwest setting, and identify factors associated with mortality and LOS.

METHODS

Data were collected from the electronic health records (EHR) of patients admitted to hospitals in Midwest region of the US. EHR of 471 COVID-19 patients were reviewed.

RESULTS

Approximately 63% were African Americans and 34% Caucasians. One hundred sixteen variables were tested. There was no significant difference in hospital mortality between African Americans and Caucasians (OR 1, 95% CI 0.48-1.94). Older age, Chronic kidney disease, mental status change, mechanical ventilation, vasopressor support, high neutrophil count, elevated AST and ALT, high lung involvement severity score and elevated CRP were associated with mortality in a univariate analysis (P < 0.05). Multivariable modeling indicated that mechanical ventilation was the only factor that predicted mortality (OR 6, 95% CI: 2.94-12.48). The LOS did not differ in African Americans and Caucasians. The use of oxygen via high flow nasal cannula (Survival Estimate 1.6, 95% CI: 1.20-2.26), low estimated glomerular filtration rate (Survival Estimate 1.4, 95% CI: 1.05-1.82) and mechanical ventilation (Survival Estimate 3.5, 95% CI: 2.72-4.37) were predictors of LOS.

CONCLUSION

This study performed in Midwest setting in the US showed that race did not affect in-hospital mortality and LOS. Our analysis demonstrated new predictors of LOS.

Methylglyoxal affects cognitive behaviour and modulates RAGE and Presenilin-1 expression in hippocampus of aged mice

Methylglyoxal (MG), a potent glycotoxin that can be found in the diet, is one of the main precursors of Advanced glycation end products (AGEs). It is well known that modifications in lifestyle such as nutritional interventions can be of great value for preventing brain deterioration. This study aimed to evaluate in vivo how an oral MG treatment, that mimics a high MG dietary intake, could affect brain health. From our results, we demonstrated that MG administration affected working memory, and induced neuroinflammation and oxidative stress by modulating the Receptor for Advanced glycation end products (RAGE). The gene and protein expressions of RAGE were increased in the hippocampus of MG mice, an area where the activity of glyoxalase 1, one of the main enzymes involved in MG detoxification, was found reduced. Furthermore, at hippocampus level, MG mice showed increased expression of proinflammatory cytokines and increased activities of NADPH oxidase and catalase. MG administration also increased the gene and protein expressions of Presenilin-1, a subunit of the gamma-secretase protein complex linked to Alzheimer's disease. These findings suggest that high MG oral intake induces alteration directly in the brain and might establish an environment predisposing to AD-like pathological conditions.

Variability in the Management of Adults With Pulmonary Nontuberculous Mycobacterial Disease

BACKGROUND

The increasing global prevalence of pulmonary nontuberculous mycobacteria (NTM) disease has called attention to challenges in NTM diagnosis and management. This study was conducted to understand management and outcomes of patients with pulmonary NTM disease at diverse centers across the United States.

METHODS

We conducted a 10-year (2005-2015) retrospective study at 7 Vaccine and Treatment Evaluation Units to evaluate pulmonary NTM treatment outcomes in human immunodeficiency virus-negative adults. Demographic and clinical information was abstracted through medical record review. Microbiologic and clinical cure were evaluated using previously defined criteria.

RESULTS

Of 297 patients diagnosed with pulmonary NTM, the most frequent NTM species were Mycobacterium avium-intracellulare complex (83.2%), M. kansasii (7.7%), and M. abscessus (3.4%). Two hundred forty-five (82.5%) patients received treatment, while 45 (15.2%) were followed without treatment. Eighty-six patients had available drug susceptibility results; of these, >40% exhibited resistance to rifampin, ethambutol, or amikacin. Of the 138 patients with adequate outcome data, 78 (56.5%) experienced clinical and/or microbiologic cure. Adherence to the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) treatment guidelines was significantly more common in patients who were cured (odds ratio, 4.5, 95% confidence interval, 2.0-10.4; P < .001). Overall mortality was 15.7%.

CONCLUSIONS

Despite ATS/IDSA Guidelines, management of pulmonary NTM disease was heterogeneous and cure rates were relatively low. Further work is required to understand which patients are suitable for monitoring without treatment and the impact of antimicrobial therapy on pulmonary NTM morbidity and mortality.

Mitochondria and cellular redox state on the route from ageing to Alzheimer's disease

Several theories have been postulated, trying to explain why and how living organisms age. Despite some controversies and still huge open questions, a growing body of evidence suggest alterations of mitochondrial functionality and redox-homeostasis occur during the ageing process. Oxidative damage and mitochondrial dysfunction do not represent the cause of ageing per se but they have to be analyzed within the complexity of those series of processes occurring during lifespan. The establishment of a crosstalk among them is a shared common feature of many chronic age-related diseases, including neurodegenerative disorders, for which ageing is a major risk factor. The challenge is to understand when and how the interplay between these two systems move towards from normal ageing process to a pathological phenotype. Here in this review, we discuss the crosstalk between mitochondria and cytosolic-ROS. Furthermore, through a visual data mining approach, we attempt to describe the dynamic interplay between mitochondria and cellular redox state on the route from ageing to an AD phenotype.

Flagellin adjuvanted F1/V subunit plague vaccine induces T cell and functional antibody responses with unique gene signatures

Yersinia pestis, the cause of plague, could be weaponized. Unfortunately, development of new vaccines is limited by lack of correlates of protection. We used pre- and post-vaccination sera and peripheral blood mononuclear cells from a flagellin adjuvanted F1/V vaccine trial to evaluate for protective markers. Here, we report for the first time in humans that inverse caspase-3 levels, which are measures of protective antibody, significantly increased by 29% and 75% on days 14 and 28 post-second vaccination, respectively. In addition, there were significant increases in T-cell responses on day 28 post-second vaccination. The strongest positive and negative correlations between protective antibody levels and gene expression signatures were identified for IFNG and ENSG00000225107 genes, respectively. Flagellin/F1/V subunit vaccine induced macrophage-protective antibody and significant CD4⁺ T-cell responses. Several genes associated with these responses were identified that could serve as potential correlates of protection.

Percutaneous BCG enhances innate effector antitumor cytotoxicity during treatment of bladder cancer: a translational clinical trial

Background: Intravesical bacillus Calmette-Guérin (BCG) is the gold standard immunologic agent for treating patients with high-grade non-muscle invasive bladder cancer (NMIBC). Nevertheless, relapse rates remain high and BCG unresponsive NMIBC often requires bladder removal. Preclinical data suggest that priming with percutaneous BCG vaccine could improve response to intravesical BCG. Methods: A single-arm trial (NCT02326168) was performed to study the safety, immunogenicity, and preliminary efficacy of priming. Percutaneous BCG was given 21 days prior to intravesical BCG instillation in patients (n = 13) with high-risk NMIBC. Immune responses were monitored and compared to a sequentially enrolled cohort of nine control patients receiving only intravesical BCG. The effect of BCG on natural killer (NK) and γδ T cell in vitro cytotoxicity was tested. γδ T cell subsets were determined by T cell receptor gene expression with NanoString. Results: Priming was well tolerated and caused no grade ≥3 adverse events. The 3-month disease-free rate for prime patients was 85% (target goal ≥ 75%). Priming boosted BCG-specific immunity at 3 months and increased the activation status of in vitro expanded circulating NK and γδ T cells and their cytotoxicity against bladder cancer cells through receptor NKG2D. BCG enhanced the cytotoxicity of NK and γδ T cells against K562, RT4, and UM-UC6 but not against T24, UM-UC-3, or UM-UC-14 cells. Infiltrating γδ T cell subsets identified in the bladder includes γ9δ2 and γ8δ2. Conclusions: BCG priming is safe and tolerable. Poor sensitivity to NK and γδ T cell cytotoxicity by some bladder tumors represents a potential BCG-resistance mechanism.

Monitoring Caco-2 to enterocyte-like cells differentiation by means of electric impedance analysis on printed sensors

BACKGROUND

Colorectal adenocarcinoma cells (Caco-2) are a widely used model of intestinal barrier to study cancer development, toxicological assessments, absorption and metabolism in food science or drug discovery. Caco-2 spontaneously differentiate into a monolayer expressing several specific characteristics, typically showed by mature enterocytes. For in vitro experiments, it is crucial to identify non-invasive and non-destructive techniques able to evaluate the integrity and differentiation of the cells monolayer. Thus, we aimed to assess these properties by analyzing electrical impedance measurements.

METHODS

Caco-2 cells were differentiated for 21 days. The monolayer integrity and differentiation were primarily evaluated by means of morphological, biochemical and molecular data. Impedance measurements in a range of frequencies from 400 Hz to 50 kHz were performed using a dedicated set up, including customized Aerosol Jet Printed carbon-based sensors.

RESULTS

The trends of RI observed at three different frequencies were able to describe cell growth and differentiation. In order to evaluate which frequencies better correlate with cell differentiation, Principal Component Analysis have been employed and the concordance analysis between RI magnitude and morphological, biochemical and molecular data, highlighted 40 kHz as the optimal frequency to assess Caco-2 cells differentiation process.

CONCLUSION

We demonstrated the feasibility and reliability of applying impedance-based measurements not only to provide information about the monolayer status, but also for cell differentiation monitoring.

GENERAL SIGNIFICANCE

This study underlined the possibility to use a dedicated sensor to assess the integrity and differentiation of Caco-2 monolayer, as a reliable non-destructive alternative to conventional approaches.

BCG Vaccination Induces M. avium and M. abscessus Cross-Protective Immunity

Pulmonary non-tuberculous mycobacterial (NTM) infections particularly caused by Mycobacterium avium complex (MAC) and Mycobacterium abscessus (MAB) are becoming major health problems in the U.S. New therapies or vaccines which will help prevent the disease, shorten treatment duration and/or increase treatment success rates are urgently needed. This study was conducted with the objective of testing the hypothesis that Bacillus Calmette Guerin (BCG), a vaccine used for prevention of serious forms of tuberculosis (TB) in children and adolescents in tuberculosis hyperendemic countries, induces cross-protective T cell immunity against Mycobacterium avium (MAV) and MAB. Human TB and NTM cross-protective T cells were quantified using flow cytometric assays. The ability of BCG expanded T cells to inhibit the intracellular growth of MAV and MAB was assessed in co-cultures with infected autologous macrophages. In both BCG-vaccinated and M. tuberculosis (Mtb)-infected mice, NTM cross-reactive immunity was measured using IFN-γ ELISPOT assays. Our results demonstrate the following key findings: (i) peripheral blood mononuclear cells from TB skin test-positive individuals contain MAV and MAB cross-reactive T cells, (ii) both BCG vaccination and Mtb infection of mice induce MAV and MAB cross-reactive splenic cells, (iii) BCG-expanded T cells inhibit intracellular MAV and MAB, (iv) CD4, CD8, and γδ T cells play important roles in inhibition of intracellular MAV and MAB and (v) BCG vaccination of healthy volunteers induces TB and NTM cross-reactive T cells. In conclusion, BCG-vaccination induces NTM cross-reactive immunity, and has the potential for use as a vaccine or immunotherapy to prevent and/or treat pulmonary NTM disease.

Esophageal Mycobacterium avium-intracellulare infection in a bone marrow transplant patient: Case report and literature review

Mycobacterium avium-intracellulare complex (MAC) is the most common cause of nontuberculous mycobacterial (NTM) disease in humans. We report a case of esophageal MAC disease in a patient who had allogeneic bone marrow transplant for acute lymphoblastic leukemia. Although pulmonary MAC in immunocompromised host is not uncommon, there are only a few cases of NTM-associated esophageal mass reported. Our report and literature review highlight the importance of considering MAC in the differential diagnosis of dysphagia or odynophagia.

Priming with percutaneous bacillus Calmette-Guerin (BCG) prior to intravesical BCG treatment safely improves BCG-specific response in patients with bladder cancer

Bacillus Calmette-Guérin (BCG) is the gold standard immunologic agent for patients with high-grade non-muscle invasive bladder cancer (NMIBC). Nevertheless, responses to BCG are heterogeneous and limited options exist when BCG therapy fails. Preclinical data in animal models of bladder cancer (BC) suggests that priming with percutaneous BCG vaccine prior to intravesical BCG instillation can enhance BCG-specific immunity and improve outcome. To study the safety, immunogenicity and preliminary efficacy of this approach, we administered percutaneous BCG 21 days prior to intravesical BCG instillation in “prime patients” with NMIBC (n=13) in a prospective single-arm clinical trial. Immune responses and clinical outcomes were monitored and compared to a contemporaneous cohort of “control patients” (n=9) receiving intravesical BCG without prior percutaneous BCG. Priming was well tolerated and no grade ≥3 adverse events were observed. Compared to control, prime patients had improvement in both local and systemic measures of BCG-specific immunity, scored by increased post-BCG urinary IL-8 and IL-17A and increased circulating CD4, CD8, and γδ T cell proliferation and effector function in response to BCG. Furthermore, ex vivo cytotoxicity of circulating NK and γδ T cells against RT4 BC was significantly increased in prime patient after BCG treatment and was mediated in part by NKG2D, suggesting an important role of innate effector immune mechanisms underlying BCG’s antitumor activity. Remarkably, no prime patients progressed whereas 3 out of 9 control patients progressed to muscle-invasive disease and underwent cystectomy. Thus, BCG priming safely enhances BCG-specific immunity and could improve outcome for patients with NMIBC.

Epirubicin in Combination Chemotherapy in the Treatment of Advanced Stage Non-Hodgkin's Lymphomas

From April 1981 to May 1984, 23 patients with advanced non-Hodgkin's lymphomas were treated with CEOP (cyclophosphamide, epirubicin, vincristine, and prednisone) or OEPP (vincristine, epirubicin, procarbazine, and prednisone) combination chemotherapy. CR was achieved in 58 % and PR in 31 % of the patients, giving an overall response rate of 89 %. Nine of 15 (60 %) previously untreated patients with unfavorable histology obtained a CR and 5 a PR. Median relapse-free survival was 33 months; median overall survival has not yet been reached, and the probability of survival for CRs was 91 % after 54 months of follow-up. Acute toxicity was quite acceptable, and chronic cardiac toxicity was detected in 6 patients only. In conclusion, epirubicin used in combination chemotherapies induced durable remissions and prolonged survivals in advanced non-Hodgkin's lymphomas.

Influence on Response to Therapy and Overall Survival of Mediastinal Involvement by Hodgkin's Disease

To assess the prognostic significance of mediastinal involvement of Hodgkin's disease, 91 patients with stage I to III disease treated at our Institute were reclassified according to size of mediastinal disease and other clinical and therapeutic characteristics. Complete remission (CR) was achieved in 46 of 67 (81%) patients without mediastinal involvement, and in 16 of 17 (94%) patients with small mediastinal masses, but only in 10 of 17 (59%) patients with large masses (P < 0.05). Twenty-seven of 32 (84%) patients treated with irradiation alone and 26 of 28 (93%) patients treated with combined modality therapy reached a CR, whereas such a result was obtained only in 19 of 31 (61%) patients who received MOPP chemotherapy alone (P < 0.01). In particular, none of the patients with large masses had a CR when treated with chemotherapy alone, whereas no differences in response to therapy were found between patients with large vs. small or no masses when irradiation or combined treatments were utilized. Since combined treatment seems to reach a high proportion of CR and to prevent extranodal relapse, further randomized clinical trials are needed to decide its routine utilization in patients with poor prognostic factors such as large mediastinal adenopathies.

Combination Chemotherapy with Cyclophosphamide, Adriamycin, Vincristine and Prednisone (CHOP) for Non-Hodgkin's Lymphomas with Unfavorable Histology: Preliminary Results

From January 1978 to June 1979, 29 selected, previously untreated patients with unfavorable histology of non-Hodgkin's lymphomas (12 DPDL, 7 DM, 9 DH and 1 DU) were submitted to the combination chemotherapy CHOP (cyclophosphamide, 750 mg/m2 i.v. on day 1; adriamycin, 50 mg/m2 i.v. on day 1; vincristine, 1.4 mg/m2 i.v. on day 1, and prednisone, 100 mg p.o. on day 1 through 5) every 21 days. Eighteen patients were in early stage (I or II) and 11 of them were also submitted to involved field radiotherapy (60Co), immediately before (stage I) or during (stage II) the chemotherapy, with a mean dosage of 4,500 rad. The remaining 11 patients were in advanced stage (III or IV) of disease and were treated with chemotherapy alone. We obtained 20 complete remissions (68%), 8 partial remissions (28 %) and 1 no response (4 %) to therapy. Sixteen of 18 patients (89 %) in early stages and 4 of 11 patients (36 %) in advanced stages achieved a complete remission. The bone marrow toxicity of the chemotherapy was moderate. Nausea, vomiting and diarrhea were frequent but well controlled by the support therapy. The actuarial survival rate of patients, after 18 months of follow-up, is 41 % (40 % in complete remission). The patients who achieved a complete remission are all alive and 65 % of them still relapse free. We believe that the combination chemotherapy CHOP improves the complete remission rate as well as the survival of patients with unfavorable histology of non-Hodgkin's lymphomas.

Combination Chemotherapy (CVP or Chop)-Radiotherapy Approach in Early Stage Non-Hodgkin's Lymphomas

From January 1978 to December 1980, 42 patients with early stage non-Hodgkin's lymphoma other than of the gastrointestinal tract were treated with radiotherapy and combination chemotherapy. Eighteen patients in stage I were submitted to locally extended-field radiotherapy up to a mean dose of 48 Gy with a Co60 source and, after a 3-week rest period, to 6 cycles of combination chemotherapy. Twenty-four patients in stage II received 3 cycles of combination chemotherapy before and after irradiation, the same as for stage I. Combination chemotherapy consisted of cyclophosphamide, vincristine and prednisone (CVP) for 15 cases with favorable histology (3 NWDL, 1 NPDI, 11 DWDL), whereas it included cyclophosphamide, adriamycin, vincristine and prednisone (CHOP) for 27 cases with unfavorable histology (20 DPDL, 3 DM, 4 DH). Complete remission (CR) was achieved in 35/42 (83%) patients, with a highly significant difference between stage I (100%) and stage II (71%). After 42 months of follow-up, the probability of survival for all patients was 72%. Survival was better for stage I (88%) than for stage II (68%) and for favorable histology (87%) as compared to unfavorable histology (70%). Furthermore, survival was highly influenced by response to therapy. Indeed, actuarial survival rate for CR was 91% as compared to a median survival time of 10.2 months for the remaining patients. Four patients, all with poor histology, relapsed after 5–24 (mean 11) months of CR. Only one of them had an extension in extranodal sites and eventually died, despite the salvage treatment utilized. In our experience, locally extended-field irradiation combined with chemotherapy gave a high proportion of CR and seemed to prevent relapses, particularly in extranodal sites.

Reversed isoniazids: Design, synthesis and evaluation against Mycobacterium tuberculosis

Novel reversed isoniazid (RINH) agents were synthesized by covalently linking isoniazid with various efflux pump inhibitor (EPI) cores and their structural motifs. These RINH agents were then evaluated for anti-mycobacterial activity against sensitive, isoniazid mono-resistant and MDR clinical isolates of M. tuberculosis and a selected number of compounds were also tested ex vivo for intracellular activity as well as in the ethidium bromide (EB) assay for efflux pump inhibition efficacy. The potency of some compounds against various strains of M. tuberculosis (4a-c, 7 and 8; H37Rv-MIC₉₉ ≤1.25 µM, R5401-MIC₉₉ ≤2.5 µM, X_61-MIC₉₉ ≤5 µM) demonstrated the potential of the reversed anti-TB agent strategy towards the development of novel anti-mycobacterial agents to address the rapidly growing issue of resistance. Further, macrophage activity with >90% inhibition by 1a-c and 3b (MIC₉₀ ≤13.42 µM) and inhibition of EB efflux demonstrated by these compounds are encouraging.

Risk factors and outcomes for multidrug-resistant Gram-negative bacilli bacteremia

Background

The incidence of multidrug-resistant (MDR) organisms is increasing along with mortality. Identifying risk factors for the development of MDR Gram-negative bacilli (GNB) bacteremia could greatly impact patient care and management.

Methods

Data from the electronic health record of patients with GNB over 13-month period were collected at a single university medical center. Baseline demographic data, risk factor, microbiological data, recurrence of bacteremia, and mortality were recorded.

Results

A total of 177 patients were included in the analysis. MDR GNB occurred in 46 patients (26%). The mortality rate in the MDR group was 34.8% compared to 13.7% in non-MDR group (p = 0.002). In multivariate analysis, diabetes mellitus [DM; odds ratio (OR): 2.8, 95% confidence interval (CI): 1-4.88], previous antibiotic use (OR: 2.93, 95% CI: 1.25-6.87), and urinary catheter as a source of infection (OR 5.96, 95% CI: 1.78-19.94) were significant risk factors for the development of MDR GNB. In addition, end-stage liver disease (OR: 3.64, 95% CI: 1.07-12.3), solid organ malignancy (OR: 3.64, 95% CI: 1.25-10.56), intra-abdominal source of infection (OR: 3.66, 95% CI: 1.14-11.73), inappropriate empiric antibiotics (OR 7.59, 95% CI: 1.68-34.34) and urinary catheter as a source of infection (OR 5.68, 95% CI: 1.37-23.5) were significant factors for mortality in patients with MDR GNB.

Conclusion

Our study provides important information about the risk factors for the development of MDR GNB bacteremia and helps prognosticate patient with MDR GNB.

Design, Synthesis, and Evaluation of Novel Hybrid Efflux Pump Inhibitors for Use against Mycobacterium tuberculosis

Efflux pumps are considered a major potential contributor to the development of various forms of resistance in Mycobacterium tuberculosis leading to the emergence of multidrug-resistant tuberculosis (TB). Verapamil (VER) and tricyclic chemosensitizers such as the phenothiazines are known to possess efflux pump inhibition properties and have demonstrated significant efficacy in various TB disease models. Novel hybrid molecules based on fusion of the VER substructure with various tricyclic, as well as nontricyclic, chemosensitizer cores or their structural motifs are described. These hybrid compounds were evaluated in vitro and ex vivo individually for their intrinsic activity and in combination for their potentiating potential with the frontline anti-TB drugs, rifampin and isoniazid. In addition, efflux pump inhibition was assessed in an ethidium bromide assay. This study led to the identification of novel compounds, termed hybrid efflux pump inhibitors, with intrinsic antimycobacterial activities (MIC₉₀ ≤ 3.17 μg/mL) and intracellular activity in macrophages at a low concentration (≤6.25 μg/mL).

Immunotherapy for tuberculosis: future prospects

Tuberculosis (TB) is still a major global health problem. A third of the world’s population is infected with Mycobacterium tuberculosis. Only ~10% of infected individuals develop TB but there are 9 million TB cases with 1.5 million deaths annually. The standard prophylactic treatment regimens for latent TB infection take 3–9 months, and new cases of TB require at least 6 months of treatment with multiple drugs. The management of latent TB infection and TB has become more challenging because of the spread of multidrug-resistant and extremely drug-resistant TB. Intensified efforts to find new TB drugs and immunotherapies are needed. Immunotherapies could modulate the immune system in patients with latent TB infection or active disease, enabling better control of M. tuberculosis replication. This review describes several types of potential immunotherapies with a focus on those which have been tested in humans.

Safety and Immunogenicity of the Recombinant BCG Vaccine AERAS-422 in Healthy BCG-naïve Adults: A Randomized, Active-controlled, First-in-human Phase 1 Trial

BACKGROUND

We report a first-in-human trial evaluating safety and immunogenicity of a recombinant BCG, AERAS-422, over-expressing TB antigens Ag85A, Ag85B, and Rv3407 and expressing mutant perfringolysin.

METHODS

This was a randomized, double-blind, dose-escalation trial in HIV-negative, healthy adult, BCG-naïve volunteers, negative for prior exposure to Mtb, at one US clinical site. Volunteers were randomized 2:1 at each dose level to receive a single intradermal dose of AERAS-422 (>10(5)-<10(6)CFU=low dose, ≥10(6)-<10(7)CFU=high dose) or non-recombinant Tice BCG (1-8×10(5)CFU). Randomization used an independently prepared randomly generated sequence of treatment assignments. The primary and secondary outcomes were safety and immunogenicity, respectively, assessed in all participants through 182days post-vaccination. ClinicalTrials.gov registration number: NCT01340820.

FINDINGS

Between Nov 2010 and Aug 2011, 24 volunteers were enrolled (AERAS-422 high dose, n=8; AERAS-422 low dose, n=8; Tice BCG, n=8); all were included in the safety and immunogenicity analyses. All 24 subjects had at least one adverse event, primarily expected local reactions. High dose AERAS-422 vaccination induced Ag85A- and Ag85B-specific lymphoproliferative responses and marked anti-mycobacterial activity in a whole blood bactericidal activity culture assay (WBA), but was associated with varicella zoster virus (VZV) reactivation in two vaccinees. These volunteers displayed high BCG-specific IFN-γ responses pre- and post-vaccination possibly predisposing them to autocrine/paracrine negative regulation of immune control of latent VZV. A systems biology transcriptomal approach identified positive correlations between post-vaccination T cell expression modules and WBA, and negative correlations between post-vaccination monocyte expression modules and WBA. The expression of one key macrophage marker (F4/80) was constitutively elevated in the two volunteers with zoster.

INTERPRETATION

The unexpected development of VZV in two of eight healthy adult vaccine recipients resulted in discontinuation of AERAS-422 vaccine development. Immunological and transcriptomal data identified correlations with the development of TB immunity and VZV that require further investigation.

FUNDING

Aeras, FDA, Bill and Melinda Gates Foundation.

A subset of protective γ9δ2 T cells is activated by novel mycobacterial antigens (MPF5P.740)

γ9δ2 T cells provide a natural bridge between innate and adaptive immunity and are prominently induced by both tuberculosis (TB) infection and bacillus Calmette Guérin (BCG) vaccination. Mycobacteria-expanded γ9δ2 T cells represent only a subset of the simple phosphoantigen (IPP and HMBPP)-responsive γ9δ2 T cells, this subset expresses a more oligoclonal set of TCR sequences, and only this subset efficiently recognizes and inhibits intracellular BCG/Mtb. We have been searching for new mycobacterial antigens capable of inducing the unique subset of γ9δ2 T cells that can recognize mycobacteria-infected macrophages and mediate protective effects inhibiting intracellular mycobacterial growth. We first ruled out protein, nucleic acid and apolar lipids with basic separations and enzymatic digestions. Acid hydrolysis, which digests complex carbohydrate structures, had the largest effect on eliminating Mtb fraction specific activity. Organic extractions resulted in sub-fractions with &gt;100 fold enriched specific activity. A combination of MS, NMR, TLC indicate that methyl-glucose lipopolysaccharides (mGLP) are predominant components of the most active fractions. We are currently attempting to use synthetic techniques to confirm the specific activity of mGLP for induction of protective γ9δ2 T cells. These results have important implications for the development of new immunotherapeutic approaches for prevention/treatment of TB.

Granzyme A produced by γ(9)δ(2) T cells induces human macrophages to inhibit growth of an intracellular pathogen

Human γ₉δ₂ T cells potently inhibit pathogenic microbes, including intracellular mycobacteria, but the key inhibitory mechanism(s) involved have not been identified. We report a novel mechanism involving the inhibition of intracellular mycobacteria by soluble granzyme A. γ₉δ₂ T cells produced soluble factors that could pass through 0.45 µm membranes and inhibit intracellular mycobacteria in human monocytes cultured below transwell inserts. Neutralization of TNF-α in co-cultures of infected monocytes and γ₉δ₂ T cells prevented inhibition, suggesting that TNF-α was the critical inhibitory factor produced by γ₉δ₂ T cells. However, only siRNA- mediated knockdown of TNF-α in infected monocytes, but not in γ₉δ₂ T cells, prevented mycobacterial growth inhibition. Investigations of other soluble factors produced by γ₉δ₂ T cells identified a highly significant correlation between the levels of granzyme A produced and intracellular mycobacterial growth inhibition. Furthermore, purified granzyme A alone induced inhibition of intracellular mycobacteria, while knockdown of granzyme A in γ₉δ₂ T cell clones blocked their inhibitory effects. The inhibitory mechanism was independent of autophagy, apoptosis, nitric oxide production, type I interferons, Fas/FasL and perforin. These results demonstrate a novel microbial defense mechanism involving granzyme A-mediated triggering of TNF-α production by monocytes leading to intracellular mycobacterial growth suppression. This pathway may provide a protective mechanism relevant for the development of new vaccines and/or immunotherapies for macrophage-resident chronic microbial infections.

A small subset of human T cells express γ₉δ₂ T cell receptors and recognize unique non-peptide phosphoantigens expressed by microbes and damaged cells, such as cancer. These cells are important because: 1) they reside within skin and mucosal surfaces at critical points of initial pathogen invasion, and 2) they are not restricted by polymorphic HLA types and thus can be activated by the same cognate antigens in highly diverse populations. Many important human pathogens such as the causes of AIDS, malaria, tuberculosis and others induce potent responses in γ₉δ₂ T cells that can be protective. However, the key mechanisms involved in γ₉δ₂ T cell-mediated protective immunity are not well defined. We have found that γ₉δ₂ T cells produce soluble granzyme A which correlates with their ability to protect against intracellular mycobacterial growth. We show directly that highly purified granzyme A alone can trigger human monocytes to control intracellular mycobacteria. We further show that the granzyme A-induced mycobacterial inhibition required production of TNF-α by infected monocytes. These studies may have important implications for future vaccine development and novel therapeutic strategies.

Fournier gangrene from a thirty-two-centimeter rectosigmoid foreign body

BACKGROUND

Medical and surgical problems associated with rectal foreign bodies are rare. Although most rectal foreign bodies can be removed without subsequent sequelae, they pose significant risk of infection.

OBJECTIVES

We report a patient with a 32-cm rectosigmoid foreign body and subsequent development of Fournier gangrene despite successful removal of the foreign body.

CASE REPORT

A 63-year-old Caucasian man with past medical history of diabetes mellitus and depression presented with a chief complaint of "something stuck in my intestine." He admitted that he placed a foreign body in the rectum. Abdominal X-ray study and computed tomography of the abdomen/pelvis showed a conical-shaped 32-cm rectosigmoid foreign body. The foreign body was removed manually and follow-up colonoscopy was done. The patient's condition deteriorated in the first 2 days of hospital stay and he was diagnosed with Fournier gangrene. He required multiple surgeries and received broad-spectrum antibiotic coverage for mixed bacterial flora grown from deep tissue.

CONCLUSION

Rectal foreign bodies can cause Fournier gangrene. A close observation and follow-up is important after removal of rectal foreign bodies.

Spectrophotometric determination of acid volatile sulfide in river sediments by sequential injection analysis exploiting the methylene blue reaction

This paper demonstrates the application of sequential injection analysis to perform sulfide determination using the methylene blue chemistry, based on two reagents: 3.63 mmol l(-1)N,N dimethyl-p-phenylene diamine hydrochloride in 1.1 mol l(-1) HCl solution and 19 mmol l(-1) FeCl(3), also in 1.1 mol l(-1) HCl. These solutions are aspirated inside the holding coil of the sequential injection system as two reagent zones sandwiching the sample zone. Under optimized conditions, the detection limit was calculated at 40 mug l(-1) S(2-), with a linear dynamic range from 0.05 to 2 mg l(-1) S(2-). This linear range can be extended up to 32 mg l(-1) using in-line dilution for sulfide concentrations greater than 2 mg l(-1). The robust characteristic of the SI system with syringe pump leads to very stable analytical curves (precision of 4%), minimizing the laborious preparation of sulfide standards. The method was applied in the determination of acid volatile sulfide in river sediments.

Clinical and bacteriological characteristics of Klebsiella pneumoniae causing liver abscess with less frequently observed multi-locus sequences type, ST163, from Singapore and Missouri, US

BACKGROUND

Klebsiella pneumoniae is the major cause of liver abscesses in several Asian countries. Differences in the type of circulating Klebsiella strains and/or the genetic make up of the host seem to be plausible explanations for this.

METHODS

Two recent K. pneumoniae strains isolated from patients with liver abscess, one from Missouri in the US, and a second one from Singapore, were fully characterized by molecular typing, association of virulent genes, neutrophil phagocytosis, susceptibility to serum killing, and lethality in mice.

RESULTS

Both strains had mucoid colony morphology and were similar in multilocus sequence type (ST-163), drug-susceptibility profile, resistance to phagocytosis and susceptibility to serum killing. Although ST-163 is a single nucleotide variant (SNV) to the major ST-23, which is specific to serotype K1 K. pneumoniae that causes liver abscess in Taiwan, these two isolates differ in capsular serotype. One was serotype K1 and the other K29. Since a serotype K35 with ST163 was reported previously to cause peritonitis, serotype K29 with SNV to ST-23 was not impossible. Pulsed field gel electrophoresis by XbaI digestion showed different restriction patterns. The virulence-associated genes rmpA and aerobactin were only present in the serotype K1 isolate from Singapore and not in the serotype K29 isolate from Missouri. The serotype K1 isolate was also more virulent to mice.

CONCLUSION

The reasons underlying the high prevalence of ST-23 or its SNV in K. pueumonaie liver abscesses is worth further investigation.

Live and inactivated influenza vaccines induce similar humoral responses, but only live vaccines induce diverse T-cell responses in young children

BACKGROUND

Two doses of either trivalent live attenuated or inactivated influenza vaccines (LAIV and TIV, respectively) are approved for young children (≥ 24 months old for LAIV and ≥ 6 months old for TIV) and induce protective antibody responses. However, whether combinations of LAIV and TIV are safe and equally immunogenic is unknown. Furthermore, LAIV is more protective than TIV in children for unclear reasons.

METHODS

Children 6-35 months old were administered, 1 month apart, 2 doses of either TIV or LAIV, or combinations of LAIV and TIV in both prime/boost sequences. Influenza-specific antibodies were measured by hemagglutination inhibition (HAI), and T cells were studied in flow cytometric and functional assays. Highly conserved M1, M2, and NP peptides predicted to be presented by common HLA class I and II were used to stimulate interferon-γ enzyme-linked immunospot responses.

RESULTS

All LAIV and/or TIV combinations were well tolerated and induced similar HAI responses. In contrast, only regimens containing LAIV induced influenza-specific CD4(+), CD8(+), and γδ T cells, including T cells specific for highly conserved influenza peptides.

CONCLUSIONS

Prime/boost combinations of LAIV and TIV in young children were safe and induced similar protective antibodies. Only LAIV induced CD4(+), CD8(+), and γδ T cells relevant for broadly protective heterosubtypic immunity.

CLINICAL TRIALS REGISTRATION

NCT00231907.

Cedecea davisae bacteremia in a neutropenic patient with acute myeloid leukemia

Cedecea are the new members of Enterobacteriacea. Because of their inherent resistance to some antibiotics, the clinical response could be unpredictable making management of Cedecea infection in immunocompromised patients challenging. We report a case of acute myeloid leukemia with central line-related Cedecea bacteremia.

CD46-induced regulatory T cells suppress Mycobacterium tuberculosis-specific effector T cell responses (33.5)

Human regulatory T cells can be generated through a number of known pathways in vivo and in vitro. Simultaneous engagement of the TCR and complement regulator CD46 on human CD4+ T cells induces adaptive Treg development. These CD46-induced Treg, also known as 'complement-induced Treg' or 'cTreg,' have been shown to suppress bystander CD4+ T cells activated in vitro with crosslinking antibodies to CD3 and CD28. Here we offer the first description of cTreg suppression of human effector T cells in an APC-dependent system of pathogen infection. We found that soluble molecules secreted by cTreg suppress Mycobacterium tuberculosis-specific CD4+, CD8+, and γδ T cell responses. These immunosuppressive effects were mediated in part by IL-10 and in part by other as yet unidentified soluble factors acting synergistically with IL-10. In addition, our results indicate that different mechanisms may be involved in the suppression of αβ and γδ T cells. We further show that APC functions were not affected by cTreg, indicating direct suppression of pathogen-specific T cells. Modulating the immunosuppressive functions of this Treg subset could lead to improved tuberculosis therapeutics or vaccines.

A new recombinant bacille Calmette-Guérin vaccine safely induces significantly enhanced tuberculosis-specific immunity in human volunteers

BACKGROUND

One strategy for improving anti-tuberculosis (TB) vaccination involves the use of recombinant bacille Calmette-Guérin (rBCG) overexpressing protective TB antigens. rBCG30, which overexpresses the Mycobacterium tuberculosis secreted antigen Ag85b, was the first rBCG shown to induce significantly greater protection against TB in animals than parental BCG.

METHODS

We report here the first double-blind phase 1 trial of rBCG30 in 35 adults randomized to receive either rBCG30 or parental Tice BCG intradermally. Clinical reactogenicity was assessed, and state-of-the-art immunological assays were used to study Ag85b-specific immune responses induced by both vaccines.

RESULTS

Similar clinical reactogenicity occurred with both vaccines. rBCG30 induced significantly increased Ag85b-specific T cell lymphoproliferation, interferon (IFN)-gamma secretion, IFN-gamma enzyme-linked immunospot responses, and direct ex vivo intracellular IFN-gamma responses. Additional flow cytometry studies measuring carboxyfluorescein succinimidyl ester dilution and intracellular cytokine production demonstrated that rBCG30 significantly enhanced the population of Ag85b-specific CD4(+) and CD8(+) T cells capable of concurrent expansion and effector function. More importantly, rBCG30 significantly increased the number of Ag85b-specific T cells capable of inhibiting intracellular mycobacteria.

CONCLUSIONS

These results provide proof of principal that rBCG can safely enhance human TB immunity and support further development of rBCG overexpressing Ag85b for TB vaccination.

Only a subset of phosphoantigen-responsive gamma9delta2 T cells mediate protective tuberculosis immunity

Mycobacterium tuberculosis and Mycobacterium bovis bacillus Calmette-Guérin (BCG) induce potent expansions of human memory Vgamma(9)(+)Vdelta(2)(+) T cells capable of IFN-gamma production, cytolytic activity, and mycobacterial growth inhibition. Certain phosphoantigens expressed by mycobacteria can stimulate gamma(9)delta(2) T cell expansions, suggesting that purified or synthetic forms of these phosphoantigens may be useful alone or as components of new vaccines or immunotherapeutics. However, we show that while mycobacteria-activated gamma(9)delta(2) T cells potently inhibit intracellular mycobacterial growth, phosphoantigen-activated gamma(9)delta(2) T cells fail to inhibit mycobacteria, although both develop similar effector cytokine and cytolytic functional capacities. gamma(9)delta(2) T cells receiving TLR-mediated costimulation during phosphoantigen activation also failed to inhibit mycobacterial growth. We hypothesized that mycobacteria express Ags, other than the previously identified phosphoantigens, that induce protective subsets of gamma(9)delta(2) T cells. Testing this hypothesis, we compared the TCR sequence diversity of gamma(9)delta(2) T cells expanded with BCG-infected vs phosphoantigen-treated dendritic cells. BCG-stimulated gamma(9)delta(2) T cells displayed a more restricted TCR diversity than phosphoantigen-activated gamma(9)delta(2) T cells. In addition, only a subset of phosphoantigen-activated gamma(9)delta(2) T cells functionally responded to mycobacteria-infected dendritic cells. Furthermore, differential inhibitory functions of BCG- and phosphoantigen-activated gamma(9)delta(2) T cells were confirmed at the clonal level and were not due to differences in TCR avidity. Our results demonstrate that BCG infection can activate and expand protective subsets of phosphoantigen-responsive gamma(9)delta(2) T cells, and provide the first indication that gamma(9)delta(2) T cells can develop pathogen specificity similar to alphabeta T cells. Specific targeting of protective gamma(9)delta(2) T cell subsets will be important for future tuberculosis vaccines.

Comparison of the safety and immunogenicity of ACAM1000, ACAM2000 and Dryvax in healthy vaccinia-naive adults

Currently, more than half of the world's population has no immunity against smallpox variola major virus. This phase I double-blind, randomized trial was conducted to compare the safety and immunogenicity of two clonally derived, cell-culture manufactured vaccinia strains, ACAM1000 and ACAM2000, to the parent vaccine, Dryvax. Thirty vaccinia-naïve subjects were enrolled into each of three groups and vaccines were administered percutaneously using a bifurcated needle at a dose of 1.0x10(8)PFU/mL. All subjects had a primary skin reaction indicating a successful vaccination. The adverse events, 4-fold neutralizing antibody rise and T cell immune responses were similar between the groups.

Anti-tuberculosis drug resistance among retreatment patients seen at St Peter Tuberculosis Specialized Hospital

BACKGROUND

Resistance to first line anti-tuberculosis (TB) drugs is an increasing concern. Drug sensitivity of mycobacterial isolates from patients who failed treatment may indicate the potential sources of spread and the emerging patterns of resistance.

OBJECTIVE

To determine the prevalence of resistance to the main anti TB drugs among re-treatment cases who had previously received loose drugs or the 3FDC regimen in the intensive phase.

METHODS

Mycobacteria were isolated on Lowenstein-Jensen media from sputum of smear positive pulmonary TB patients who visited the St Peter's TB Specialized Hospital, a referral TB Hospital in Addis Ababa, for retreatment between December 2001 and October 2002. The susceptibility of isolates to rifampicin, isoniazid ethambutol and streptomycin was tested using the standard modified proportion method

RESULT

Of the 84 Mycobacterium tuberculosis isolates, resistance to at least one drug was observed in 53.6% and 26.2% of the isolates were multi drug resistant (MDR). MDR was more frequent among patients who had previously been treated with the 3FDC regimen than among patients previously treated with loose drugs (p < 0.05). The proportion of strains resistant to rifampicin and ethambutol was significantly higher than in an earlier report from Addis Ababa.

CONCLUSION

MDR is an emerging problem among re-treatment cases of pulmonary TB in Addis Ababa. The problem of drug resistance should be addressed by operational research on drug regimens, effectiveness and delivery.