Diagnóstico imunológico da tuberculose: problemas e estratégias para o sucesso

Correlation of serum Adenosine Deaminase levels with microbiological parameters in Pulmonary Tuberculosis

Accurate diagnosis of pulmonary tuberculosis is largely based on sputum smear microscopy, culture, and GeneXpert MTB/RIF tests; culture being the gold standard. All these diagnostic tests require sputum sample to be positive for Mycobacterium tuberculosis, while many active TB patients often do not present with M. tuberculosis positive sputum. Biochemical markers play an important role in early diagnosis, disease prevention, and drug response in tuberculosis. This study aims to find the association of serum adenosine deaminase (a biomarker) with the various microbiological parameters like sputum smear microscopy, culture and CBNAAT in pulmonary tuberculosis patients. A total of 40 cases were collected from November 2019 to October 2021, and the presumptive cases of pulmonary tuberculosis diagnosed by Ziehl-Neelsen staining for acid fast bacilli and/or CBNAAT were recruited. Serum adenosine deaminase levels were estimated.The following variables were significantly associated (p < 0.05) with serum adenosine deaminase levels: age, sputum smear microscopy findings, time to culture positivity, CBNAAT category and Ct value (Mean).This study does witness few significant correlations between serum adenosine deaminase levels and various microbiological parameters used in diagnosis of TB, which can be further explored and utilised in diagnosis and treatment of pulmonary tuberculosis.

Pediatric Tuberculosis Management: A Global Challenge or Breakthrough?

Managing pediatric tuberculosis (TB) remains a public health problem requiring urgent and long-lasting solutions as TB is one of the top ten causes of ill health and death in children as well as adolescents universally. Minors are particularly susceptible to this severe illness that can be fatal post-infection or even serve as reservoirs for future disease outbreaks. However, pediatric TB is the least prioritized in most health programs and optimal infection/disease control has been quite neglected for this specialized patient category, as most scientific and clinical research efforts focus on developing novel management strategies for adults. Moreover, the ongoing coronavirus pandemic has meaningfully hindered the gains and progress achieved with TB prophylaxis, therapy, diagnosis, and global eradication goals for all affected persons of varying age bands. Thus, the opening of novel research activities and opportunities that can provide more insight and create new knowledge specifically geared towards managing TB disease in this specialized group will significantly improve their well-being and longevity.

Adapting Clofazimine for Treatment of Cutaneous Tuberculosis by Using Self-Double-Emulsifying Drug Delivery Systems

Although chemotherapeutic treatment regimens are currently available, and considerable effort has been lavished on the development of new drugs for the treatment of tuberculosis (TB), the disease remains deeply intractable and widespread. This is due not only to the nature of the life cycle and extraordinarily disseminated habitat of the causative pathogen, principally Mycobacterium tuberculosis (Mtb), in humans and the multi-drug resistance of Mtb to current drugs, but especially also to the difficulty of enabling universal treatment of individuals, immunocompromised or otherwise, in widely differing socio-economic environments. For the purpose of globally eliminating TB by 2035, the World Health Organization (WHO) introduced the "End-TB" initiative by employing interventions focusing on high impact, integrated and patient-centered approaches, such as individualized therapy. However, the extraordinary shortfall in stipulated aims, for example in actual treatment and in TB preventative treatments during the period 2018-2022, latterly and greatly exacerbated by the COVID-19 pandemic, means that even greater pressure is now placed on enhancing our scientific understanding of the disease, repurposing or repositioning old drugs and developing new drugs as well as evolving innovative treatment methods. In the specific context of multidrug resistant Mtb, it is furthermore noted that the incidence of extra-pulmonary TB (EPTB) has significantly increased. This review focusses on the potential of utilizing self-double-emulsifying drug delivery systems (SDEDDSs) as topical drug delivery systems for the dermal route of administration to aid in treatment of cutaneous TB (CTB) and other mycobacterial infections as a prelude to evaluating related systems for more effective treatment of CTB and other mycobacterial infections at large. As a starting point, we consider here the possibility of adapting the highly lipophilic riminophenazine clofazimine, with its potential for treatment of multi-drug resistant TB, for this purpose. Additionally, recently reported synergism achieved by adding clofazimine to first-line TB regimens signifies the need to consider clofazimine. Thus, the biological effects and pharmacology of clofazimine are reviewed. The potential of plant-based oils acting as emulsifiers, skin penetration enhancers as well as these materials behaving as anti-microbial components for transporting the incorporated drug are also discussed.

The Role of QuantiFERON-TB Gold Plus in Mycobacterium Tuberculosis Detection in a Severe HIV Immunocompromised Patient-Case Report

Tuberculosis (TB) is an important opportunistic infection in HIV-positive people. We are reporting a case of a 31-year-old HIV-infected patient who was hospitalized in July 2021 for dyspnea, cough with mucopurulent sputum and asthenia. He was confirmed to have Serratia liquefaciens pneumonia and acute respiratory failure. The evolution was unfavorable despite the antibiotic, pathogenic and symptomatic treatment. Because the patient had severe immunosuppression (CD4 count = 37 cell/mm3), we used QuantiFERON-TB Gold Plus for the detection of the Mycobacterium tuberculosis infection. The antituberculosis therapy was initiated, which resulted in a significant improvement of the general condition and the patient was discharged with the recommendation to continue antiretroviral therapy, antituberculosis treatment and Trimethoprim/Sulfamethoxazole-single tablet daily for the prophylaxis of Pneumocystis pneumonia.

Belatacept Use after Kidney Transplantation and Its Effects on Risk of Infection and COVID-19 Vaccine Response

Introduction: Belatacept is a common immunosuppressive therapy used after kidney transplantation (KT) to avoid calcineurin-inhibitor (CNI) use and its related toxicities. It is unclear whether its use exposes KT recipients (KTx) to a greater risk of infection or a poorer response to vaccines. Areas covered: We reviewed PubMed and the Cochrane database. We then summarized the mechanisms and impacts of belatacept use on the risk of infection, particularly opportunistic, in two settings, i.e., de novo KTx and conversion from CNIs. We also focused on COVID-19 infection risk and response to SARS-CoV-2 vaccination in patients whose maintenance immunosuppression relies on belatacept. Expert opinion: When belatacept is used de novo, or after drug conversion the safety profile regarding the risk of infection remains good. However, there is an increased risk of opportunistic infections, mainly CMV disease and Pneumocystis pneumonia, particularly in those with a low eGFR, in older people, in those receiving steroid-based therapy, or those that have an early conversion from CNI to belatacept (i.e., <six months post-transplantation). Thus, we recommend, if possible, delaying conversion from CNI to belatacept until at least six months post-transplantation. Optimal timing seems to be eight months post-transplantation. In addition, KTx receiving belatacept respond poorly to SARS-CoV-2 vaccination.

Host and Bacterial Iron Homeostasis, an Underexplored Area in Tuberculosis Biomarker Research

Mycobacterium tuberculosis (Mtb) "a human adapted pathogen" has found multiple ways to manipulate the host immune response during infection. The human immune response to Mtb infection is a highly complex cascade of reactions, with macrophages as preferred intracellular location. Interaction with the host through infection gives rise to expression of specific gene products for survival and multiplication within the host. The signals that the pathogens encounter during infection cause them to selectively express genes in response to signals. One strategy to identify Mtb antigens with diagnostic potential is to identify genes that are specifically induced during infection or in specific disease stages. The shortcomings of current immunodiagnostics include the failure to detect progression from latent infection to active tuberculosis disease, and the inability to monitor treatment efficacy. This highlights the need for new tuberculosis biomarkers. These biomarkers should be highly sensitive and specific diagnosing TB infection, specifically distinguishing between latent infection and active disease. The regulation of iron levels by the host plays a crucial role in the susceptibility and outcome of Mtb infection. Of interest are the siderophore biosynthetic genes, encoded by the mbt-1 and mbt-2 loci and the SUF (mobilization of sulphur) operon (sufR-sufB-sufD-sufC-csd-nifU-sufT), which encodes the primary iron-sulphur cluster biogenesis system. These genes are induced during iron limitation and intracellular growth of Mtb, pointing to their importance during infection.

Past and Present Approaches to Diagnosis of Active Pulmonary Tuberculosis

Tuberculosis disease continues to contribute to the mortality burden globally. Due to the several shortcomings of the available diagnostic methods, tuberculosis disease continues to spread. The difficulty to obtain sputum among the very ill patients and the children also affects the quick diagnosis of tuberculosis disease. These challenges warrant investigating different sample types that can provide results in a short time. Highlighted in this review are the approved pulmonary tuberculosis diagnostic methods and ongoing research to improve its diagnosis. We used the PRISMA guidelines for systematic reviews to search for studies that met the selection criteria for this review. In this review we found out that enormous biosignature research is ongoing to identify host biomarkers that can be used as predictors of active PTB disease. On top of this, more research was also being done to improve already existing diagnostic tests. Host markers required more optimization for use in different settings given their varying sensitivity and specificity in PTB endemic and non-endemic settings.

Deep learning assistance for tuberculosis diagnosis with chest radiography in low-resource settings

Tuberculosis (TB) is a major health issue with high mortality rates worldwide. Recently, tremendous researches of artificial intelligence (AI) have been conducted targeting at TB to reduce the diagnostic burden. However, most researches are conducted in the developed urban areas. The feasibility of applying AI in low-resource settings remains unexplored. In this study, we apply an automated detection (AI) system to screen a large population in an underdeveloped area and evaluate feasibility and contribution of applying AI to help local radiologists detect and diagnose TB using chest X-ray (CXR) images. First, we divide image data into one training dataset including 2627 TB-positive cases and 7375 TB-negative cases and one testing dataset containing 276 TB-positive cases and 619 TB-negative cases, respectively. Next, in building AI system, the experiment includes image labeling and preprocessing, model training and testing. A segmentation model named TB-UNet is also built to detect diseased regions, which uses ResNeXt as the encoder of U-Net. We use AI-generated confidence score to predict the likelihood of each testing case being TB-positive. Then, we conduct two experiments to compare results between the AI system and radiologists with and without AI assistance. Study results show that AI system yields TB detection accuracy of 85%, which is much higher than detection accuracy of radiologists (62%) without AI assistance. In addition, with AI assistance, the TB diagnostic sensitivity of local radiologists is improved by 11.8%. Therefore, this study demonstrates that AI has great potential to help detection, prevention, and control of TB in low-resource settings, particularly in areas with more scant doctors and higher rates of the infected population.

Expression of annexin-A1 in blood and tissue leukocytes of leprosy patients

INTRODUCTION

In leprosy, immune system mediators that regulate the infectious process act in a complex manner and can lead to several clinical outcomes. To understand the behavior of these mediators we quantified the expression of annexin-A1 (ANXA1) in the peripheral blood and plasma as well as tissue leukocytes in all clinical forms of leprosy and compared with healthy controls.

METHODS

Seventy healthy controls and 70 patients with leprosy, tuberculoid (TT) (n = 13), borderline tuberculoid (BT) (n = 15), borderline borderline (BB) (n = 13), borderline lepromatous (BL) (n = 15), and lepromatous leprosy (LL) (n = 14), were selected. Phenotyping of the lymphocyte cells and the intracellular expression of ANXA1 in leukocytes was performed by immunofluorescence. Plasma protein levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Histiocytes and CD4⁺ and CD8⁺ T cells in the skin of BL and LL patients had higher ANXA1 expression. ANXA1 expression was also high in circulating polymorphonuclear, monocytes, and CD4⁺ and CD8⁺ T cells in the blood of LL patients compared to those of TT, BT, BB, and BL patients, and these levels were similar to those in healthy controls. Plasma ANXA1 levels indicate an increase in paracrine release in patients with LL.

CONCLUSIONS

The data indicate that ANXA1 expression is enhanced in the leukocytes and plasma of patients with LL, and may contribute to the inhibition of leukocyte action, leading to inadequate functioning of the immune system and thus contributing to the spread of M. leprae infection.

Microparticles in the pathogenesis of TB: Novel perspectives for diagnostic and therapy management of Mycobacterium tuberculosis infection

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis, usually chronic and has a progressive clinical course. Despite the availability of effective chemotherapy, TB is a leading killer of young adults worldwide and the global multi-drug resistant TB is reaching epidemic proportions. Interrupt transmission through early detection and treatment of the patients is a main element of the drug-resistant TB control strategy. However, many drugable targets in pathogens are already inhibited by current antibiotics and there is not a biomarker that indicate normal or pathogenic biological processes, or pharmacological responses to therapeutic intervention. Studies directed at evaluate key elements of host response to infection may identify biomarkers with measurable characteristics that indicate pathogenic biological processes. Cell-derived microparticles (MPs) are membrane-coated vesicles that represent subcellular elements and have been identified increasingly in a broad range of diseases and emerging as potential novel biomarker to pathological processes. In addition, MPs carry contents from their cells of origin as bioactive molecules as cytokines, enzymes, surface receptors, antigens and genetic information and may provide a means of communication between cells. Molecules-loaded MPs may interplay with the immune system and therefore can acts on inflammation, cell activation and migration. Therefore, MPs may be an important factor to immune process during Mtb infection, especially in pulmonary granulomas and influence the outcome of infection. Their characterization may facilitate an appropriate diagnosis, optimize pharmacological strategies and might be further explored as potential targets for future clinical interventions.

A systematic review on the distribution of Mycobacterium bovis infection among wildlife in the Americas

The occurrence of Mycobacterium bovis infection in wildlife places at risk livestock, public health, and ecosystems that house endangered species. However, data on wild species that may act as possible reservoirs in the Americas are scarce. This systematic review analyses the available data on wildlife in the Americas regarding the infection by M. bovis. We searched articles published in indexed journals using the keywords: "Mycobacterium bovis," "wild," and "animals". After applying the keywords using online databases, during March and August of 2018, we found 12 articles which encompassed 15 species of wild animals, of which three consisted of wild ruminants. The evidence showed that M. bovis is present among the wild animals in the Americas. The methodological limitations for diagnosing M. bovis in wild animals are many, demanding the development of new and more precise tools. Furthermore, new researches are needed to elucidate the role of the wild animals in the epidemiology of M. bovis and its possible impact on production animals and public health.

Influence of epidemiology, immunosuppressive regimens, clinical presentation, and treatment on kidney transplant outcomes of patients diagnosed with tuberculosis: A retrospective cohort analysis

Tuberculosis (TB) mortality is high among kidney transplant (KT) recipients. Although local epidemiology is an important factor, diagnostic/therapeutic challenges and immunosuppressive therapy (ISS) may influence outcomes. We analyzed the cumulative incidence (CumI) of TB in KT recipients receiving a variety of ISS with long-term follow-up. Our retrospective single-center cohort study included all KT procedures performed between January 1, 1998, and August 31, 2014, with follow-up until August 31, 2014. Induction therapy was based on perceived immunological risk; maintenance ISS included prednisone and calcineurin inhibitor (CNI) plus azathioprine (AZA), and mycophenolic acid (MPA) or mechanistic target of rapamycin inhibitor (mTORi). Thirty-four patients received belatacept/MPA. KT was performed on 11 453 patients and followed for 1989 (IQR 932 to 3632) days. Among these, 152 patients were diagnosed with TB (CumI 1.32%). Median time from KT to TB was 18.8 (IQR 7.2 to 60) months, with 59% of patients diagnosed after the first year. Unadjusted analysis revealed an increasing confidence interval (CI) of TB (0.94% CNI/AZA vs 1.6% CNI/MPA [HR = 1.62, 95% CI = 1.13 to 2.34, P = .009] vs 2.85% CNI/mTORi [HR = 2.45, 95% CI = 1.49 to 4.32, P < .001] vs 14.7% belatacept/MPA [HR = 13.14, 95% CI = 5.27 to 32.79, P < .001]). Thirty-seven (24%) patients died, and 39 (25.6%) patients experienced graft loss. Cytomegalovirus infection (P = .02) and definitive ISS discontinuation (P < .001) were associated with death. Rejection (P = .018) and ISS discontinuation (P = .005) occurred with graft loss. TB occurred at any time after KT and was influenced by ISS.

Exploration of some new secretory proteins to be employed for companion diagnosis of Mycobacterium tuberculosis

Tuberculosis (TB) is a highly infectious disease and its early and precise diagnosis is essential to reduce morbidity and mortality of patients. Since the routine diagnostic tests (like Monteux, AFB smear microscopy, chest X-Ray) do not give infallible results, additional tests are always recommended. Therefore to address the concerns about non-specificity of the present battery of diagnostic tests, we have attempted to analyze some unique secretory antigens which could be able to identify the stage specific infection of MTB. In this study, we have used recombinant proteins CFP-10, ESAT-6, Ag85 A, Ag85B, Ag85C, PE3, PE4 and Mycp1 to eliminate heterogeneity and cross reactivity in clinical diagnosis. Amplified genes were cloned and over-expressed in Escherichia coli BL21 (DE3). The recombinantly purified proteins were used as antigens against 158 sera samples of TB patients. Secretory proteins showed better response than the PPD control. Among all the used antigens PE3 and PE4 proteins showed better reactivity levels among all the groups of TB patients. The secretions of CFP-10 and ESAT-6 were also higher as compared to other secretory proteins like Ag85 A, Ag85B, Ag85C and MycP1.The clinical use of these newly identified secretory antigens could be of significant value for the confirmatory, rapid, simple and low-cost diagnosis of TB patients.

Cutaneous tuberculosis: A great imitator

Tuberculosis (TB) is still prevalent in many developing countries and can pose a new potential threat to global health due to international migration. As an uncommon form of extrapulmonary TB, cutaneous TB is complicated in its clinical manifestation, pathogenesis, and classification. Cutaneous TB can be divided into two major categories, true cutaneous TB and tuberculid, depending on the source of infection, the route of transmission, the amount of bacteria, and the immune state of the host. Clinical manifestations may include patches and plaques (lupus vulgaris, TB verrucosa cutis), macules and papules (acute miliary TB, papulonecrotid tuberculid, lichen scrofulosorum), nodules, and abscesses (erythema induratum of Bazin, tuberculous gumma), erosions, and ulcers (tuberculous chancre, orificial TB, scrofuloderma), mimicking diverse skin diseases. Uncommon localizations such as external genitalia, unusual presentations such as nodular granulomatous phlebitis, and coexistence with other morbidities such as Behçet disease and acne inversa or hidradenitis suppurativa deserve special attention. Treatment of both true and tuberculid cutaneous TB follows the same drug regimens of the World Health Organization's recommendation for treatment of new cases of pulmonary TB. Erythema induratum of Bazin may need longer treatment duration and adjuvants such as dapsone, potassium iodide, doxycycline, and corticosteroids to tackle inflammation. Misdiagnosis and undertreatment in daily practice are likely, and contemplation of this classic great imitator in dermatology is warranted.

Nutrition Status Among HIV-Positive and HIV-Negative Inpatients with Pulmonary Tuberculosis

BACKGROUND

The association between tuberculosis (TB) and malnutrition is well recognized. Considering the risk of mortality due to malnutrition in patients with TB, it is necessary to conduct a thorough nutrition assessment to identify individuals at nutrition risk. The study objective was to assess the nutrition status of hospitalized patients with TB, co-infected or not by human immunodeficiency virus (HIV).

METHODS

Patients with confirmed diagnosis of TB were included using a cross-sectional design. Nutrition assessment parameters included: body mass index (BMI), triceps skin-fold thickness (TSF), bioelectrical impedance analysis (BIA), mid-upper-arm circumference (MUAC), mid-arm muscle circumference (MAMC), food frequency questionnaire, Malnutrition Screening Tool (MST), Subjective Global Assessment (SGA), and serum levels of hemoglobin.

RESULTS

A total 108 patients completed the study. Forty-four patients (40.7%) were HIV positive. Considering the BMI, 36.1% of the patients met the criteria for nutrition deficiency. Body fat percentage was low in 27.8% of patients. In addition, more than half of the participants met criteria for malnutrition according to MUAC, MAMC, TSF, SGA, or MST. Malnutrition measured by MAMC was more frequent in HIV-positive patients (n=33, 75.0%) than in HIV-negative patients (n=31, 48.4%) (P = 0.010). Regarding the components of diet, selenium and vitamin C intake among HIV-positive patients was significantly lower than in HIV-negative patients.

CONCLUSIONS

We identified a high prevalence of malnutrition in hospitalized patients with pulmonary TB, regardless of the method used to assess nutrition status. In HIV-positive patients, malnutrition measured by MAMC was more frequent than in HIV-negative patients.

M. bovis infection in pigs: Improvement of the γ-IFN assay efficiency in this species using a maintenance medium

The interferon-gamma (IFN-γ) test measures cell mediated immune response (CMI) during the early stages of tuberculosis infection. Although Bovine Tuberculosis (BT) spread in feral pigs is widely documented in literature, the effectiveness of IFN-γ in this species has been only recently reported. One of the major obstacle of this assay is that whole blood samples should be stimulated with purified protein derivative (PPD) cocktail within 8 h from the blood sampling. This study set up a defined broth culture in which lymphocytes, the cell population predominantly responsible for IFN-γ production, are maintained in a steady-state and their vitality is preserved. The IFN-γ production measured from the samples added with the maintenance medium and stored at 4 °C was similar to the enzyme-linked immunosorbent assay (ELISA) optical density values obtained from the same assay performed within 8 h from sampling.

Update on cutaneous tuberculosis

Tuberculosis continues to draw special attention from health care professionals and society in general. Cutaneous tuberculosis is an infection caused by M. tuberculosis complex, M. bovis and bacillus Calmette-Guérin. Depending on individual immunity, environmental factors and the type of inoculum, it may present varied clinical and evolutionary aspects. Patients with HIV and those using immunobiological drugs are more prone to infection, which is a great concern in centers where the disease is considered endemic. This paper aims to review the current situation of cutaneous tuberculosis in light of this new scenario, highlighting the emergence of new and more specific methods of diagnosis, and the molecular and cellular mechanisms that regulate the parasite-host interaction.

Profile and follow-up of patients with tuberculosis in a priority city in Brazil

OBJECTIVE To analyze the cases of tuberculosis and the impact of direct follow-up on the assessment of treatment outcomes. METHODS This open prospective cohort study evaluated 504 cases of tuberculosis reported in the Sistema de Informação de Agravos de Notificação (SINAN - Notifiable Diseases Information System) in Juiz de Fora, MG, Southeastern Brazil, between 2008 and 2009. The incidence of treatment outcomes was compared between a group of patients diagnosed with tuberculosis and directly followed up by monthly consultations during return visits (287) and a patient group for which the information was indirectly collected (217) through the city's surveillance system. The Chi-square test was used to compare the percentages, with a significance level of 0.05. The relative risk (RR) was used to evaluate the differences in the incidence rate of each type of treatment outcome between the two groups. RESULTS Of the outcomes directly and indirectly evaluated, 18.5% and 3.2% corresponded to treatment default and 3.8% and 0.5% corresponded to treatment failure, respectively. The incidence of treatment default and failure was higher in the group with direct follow-up (p < 0.05) (RR = 5.72, 95%CI 2.65;12.34, and RR = 8.31, 95%CI 1.08;63.92, respectively). CONCLUSIONS A higher incidence of treatment default and failure was observed in the directly followed up group, and most of these cases were neglected by the disease reporting system. Therefore, effective measures are needed to improve the control of tuberculosis and data quality.

IgG, IgM and IgA antibodies against the novel polyprotein in active tuberculosis

BACKGROUND

The present study was aimed to evaluate whether IgG, IgM and IgA antibodies levels detected against a novel Mycobacterium tuberculosis polyprotein 38 F-64 F (with 38 F being the abbreviation for 38kD-ESAT6-CFP10 and 64 F for Mtb8.4-MPT64-TB16.3-Mtb8) are suitable for diagnosing active tuberculosis, and for monitoring the efficacy of chemotherapy on TB patients.

METHODS

In this study, a total of 371 active TB patients without treatment were selected and categorized into S+/C+group (n=143), S-/C+group (n=106) or S-/C- group (n=122). A series of serum samples were collected from 82 active TB patients who had undergone anti-TB chemotherapy for 0-6 months at one month interval. Humoral responses (IgG, IgM and IgA) were determined for the novel Mycobacterium tuberculosis polyprotein using indirect ELISA methods in all of serum samples.

RESULTS

For S+/C+, S-/C+and S-/C- active tuberculosis patients before anti-TB chemotherapy, the sensitivities of tests based on IgG were 65.7%, 46.2% and 52.5% respectively; the sensitivities based on IgM were 21.7%, 24.5% and 18.9%; and the sensitivities based on IgA were 25.2%, 17.9% and 23.8%. By combination of three isotypes, for all active tuberculosis patients, the test sensitivity increased to 70.4% with the specificity being 91.5%. After anti-TB chemotherapy, there were no significant differences between groups with different courses of anti-TB chemotherapy.

CONCLUSIONS

The novel Mycobacterium tuberculosis polyprotein 38 F-64 F represents potential antigen suitable for measuring IgG, IgM and IgA antibodies. However, the serodiagnostic test based on the 38 F-64 F polyprotein appears unsuitable for monitoring the efficacy of chemotherapy.

Opportunities for improved serodiagnosis of human tuberculosis, bovine tuberculosis, and paratuberculosis

Mycobacterial infections—tuberculosis (TB), bovine tuberculosis (bTB), and Johne's disease (JD)—are major infectious diseases of both human and animals. Methods presently in use for diagnosis of mycobacterial infections include bacterial culture, nucleic acid amplification, tuberculin skin test, interferon-γ assay, and serology. Serological tests have several advantages over other methods, including short turn-around time, relatively simple procedures, and low cost. However, current serodiagnostic methods for TB, bTB and JD exhibit low sensitivity and/or specificity. Recent studies that have aimed to develop improved serodiagnostic tests have mostly focused on identifying useful species-specific protein antigens. A review of recent attempts to improve diagnostic test performance indicates that the use of multiple antigens can improve the accuracy of serodiagnosis of these mycobacterial diseases. Mycobacteria also produce a variety of species-specific nonprotein molecules; however, only a few such molecules (e.g., cord factor and lipoarabinomannan) have so far been evaluated for their effectiveness as diagnostic antigens. For TB and bTB, there has been recent progress in developing laboratory-free diagnostic methods. New technologies such as microfluidics and “Lab-on-Chip” are examples of promising new technologies that can underpin development of laboratory-free diagnostic devices for these mycobacterial infections.

A case of emphysematous cystitis complicated with miliary tuberculosis

Background:

Emphysematous cystitis occurs mostly in diabetics with poor glycemic control or in immunocompromised patients. In most cases, diabetes mellitus correlates with the occurrence of emphysematous cystitis. The risk of relapse after tuberculosis cure or treatment completion is high among patients with diabetes mellitus.

Case Report:

A 64-year-old diabetic man suffering from high fever and lower abdominal pain was admitted to the emergency ward. Due to the results of radiographic examinations, he was diagnosed with an emphysematous cystitis. Although the emphysematous cystitis improved with urinary drainage and antibiotic therapy, the high fever recurred and respiratory symptoms appeared. This patient was diagnosed with a crisis of the pulmonary tuberculosis. He was started on the antituberculosis therapy, and he recovered.

Conclusions:

This is the first report of a case of emphysematous cystitis that was complicated with pulmonary tuberculosis.

[Tuberculosis in rheumatoid arthritis patients: the difficulty in making the diagnosis of latent infection]

Since the beginning of the use of anti-TNF in the treatment of rheumatoid arthritis and other inflammatory diseases, cases of pulmonary tuberculosis and extrapulmonary tuberculosis have been reported in patients receiving such treatment. In most cases, the disease develops by the time the patient has received the sixth infusion. Every patient should be evaluated for latent tuberculosis infection prior to the use of a TNF inhibitor. However, the diagnosis of latent tuberculosis infection is a challenge. The tuberculin test, which was the only test available to detect latent tuberculosis infection for nearly a century, presents a number of limitations. Tests based on the detection of the in-vitro production of IFN-gamma by mononuclear cells activated by specific antigens appear to be more accurate and have been studied in patients with rheumatoid arthritis.

Interferon gamma, interferon-gamma-induced-protein 10, and tuberculin responses of children at high risk of tuberculosis infection

BACKGROUND

Children in contact with adults with pulmonary tuberculosis (TB) are at risk for infection and disease progression, and chemoprophylaxis may reduce this risk. The identification of infection is based on the tuberculin skin test (TST) and interferon-gamma (INF-gamma) release assays. Other biomarkers such as interferon-gamma-induced-protein 10 (IP-10) may have potential for the diagnosis of latent TB infections.

OBJECTIVES

To describe IP-10 concentrations and their association to TST and INF-gamma responses in children recently exposed to adults with smear-positive TB in Brazil and Nepal.

METHODS

: Two surveys using the same design were undertaken to describe TST, INF-gamma, and IP-10 responses in 146 children in Nepal and 113 children in Brazil.

RESULTS

The concordance of TST and QuantiFERON-TB gold in-tube (QFT-IT) was high (kappa 0.73 in Brazil and 0.80 in Nepal). IP-10 responses were higher in children with both positive TST and positive QFT-IT (medians 1434 pg/mL in Brazil and 1402 pg/mL in Nepal) and lowest in children with both negative TST and negative QFT-IT (medians 206 pg/mL in Brazil and 81 pg/mL in Nepal). Children with negative TST and positive QFT-IT had higher IP-10 concentrations than children with positive TST but negative QFT-IT.

CONCLUSIONS

IP-10 is a potential marker to identify latent TB infections that is expressed in large quantities and with good agreement with QFT-IT. The reasons for the discrepant results observed are discussed.

Assessment of three commercially available serologic assays for detection of antibodies to Mycobacterium tuberculosis and identification of active tuberculosis

Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a major world disease, with approximately 9 million new cases each year. Identification and treatment of active disease are essential for TB control. Serology may offer increased detection of active disease in patients with a positive tuberculin skin test (TST) or QuantiFERON-TB (QFT-G). The InBios Active TbDetect immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), IBL M. tuberculosis IgG ELISA, and Anda Biologics TB ELISAs were evaluated for the ability to detect M. tuberculosis antibodies in patients with active disease. Agreement, sensitivity, and specificity for each ELISA were determined and compared to those for culture or amplified direct detection and M. tuberculosis low-risk control patients. The InBios Active TbDetect ELISA had an agreement of 96.2%, a sensitivity of 83.3%, and a specificity of 98.9%. The IBL M. tuberculosis ELISA had an agreement of 84.0%, a sensitivity of 5.6%, and a specificity of 100.0%. The agreement, sensitivity, and specificity of the Anda Biologics TB ELISA were 74.2%, 83.3%, and 72.0%, respectively. The sensitivity for detecting M. tuberculosis antibodies in human immunodeficiency virus-associated TB was 50% for both the InBios Active TbDetect ELISA and the Anda Biologics TB ELISA and 0% for the IBL M. tuberculosis ELISA. The positivity rates for InBios Active TbDetect ELISA, IBL M. tuberculosis ELISA, and Anda Biologics TB ELISA in latently infected individuals positive by TST and/or QFT-G were 5.1%, 0.0%, and 30.8%, respectively. It can be concluded that the InBios Active TbDetect IgG ELISA is superior to the other ELISAs in accurately detecting active TB.