Diagnosis of tuberculosis infection using interferon-γ-based assays

Interferon-γ-based assays, collectively known as IFN-γ release assays (IGRAs), have emerged as a reliable alternative to the old tuberculin skin test (TST) for the immunodiagnosis of tuberculosis (TB) infection. The 2 commercially available tests, the enzyme-linked immunosorbent assay (ELISA), QuantiFERON-TB Gold Intube (QFT-IT), and the enzyme-linked immunospot assay (ELISPOT), T-SPOT.TB, are more accurate than TST for the diagnosis of TB, since they are highly specific and correlate better with the existence of risk factors for the infection. According to the available data, T-SPOT.TB obtains a higher number of positive results than QFT-IT, while its specificity seems to be lower. Although the sensitivity of the IFN-γ -based assays may be impaired to some extent by cellular immunosuppression and extreme ages of life, they perform better than TST in these situations. Data from longitudinal studies suggest that IFN-γ-based tests are better predictors of subsequent development of active TB than TST; however this prognostic value has not been consistently demonstrated. This review focuses on the clinical use of the IFN-γ -based tests in different risk TB groups, and notes the main limitations and areas for future development.

Iowa Immunization Program Annual Report 2010, March 31, 2011

The Bureau of Immunization is part of the Division of Acute Disease Prevention and Emergency Response (ADPER) at the Iowa Department of Public Health (IDPH). The ADPER division provides support, technical assistance and consultation to local hospitals, public health agencies, community health centers, emergency medical service programs and local health care providers regarding infectious diseases, disease prevention and control, injury prevention and public health and health care emergency preparedness and response. The division encompasses the Center for Acute Disease Epidemiology (CADE), the Bureau of Immunization and Tuberculosis (ITB), the Bureau of Emergency Medical Services (EMS), the Bureau of Communication and Planning (CAP), the Office of Health Information Technology (HIT), and the Center for Disaster Operations and Response (CDOR). The Bureau of Immunization and Tuberculosis includes the Immunization Program, the Tuberculosis Control Program, and the Refugee Health Program. The mission of the Immunization Program is to decrease vaccine‐preventable diseases through education, advocacy and partnership. While there has been major advancement in expanding immunizations to many parts of Iowa’s population, work must continue with public and private health care providers to promote the program’s vision of healthy Iowans living in communities free of vaccine‐preventable diseases. Accomplishing this goal will require achieving and maintaining high vaccination coverage levels, improving vaccination strategies among under‐vaccinated populations, prompt reporting and thorough investigation of suspected disease cases, and rapid institution of control measures. The Immunization Program is comprised of multiple programs that provide immunization services throughout the state: Adolescent Immunization Program, Adult Immunization Program, Immunization Registry Information System (IRIS), Vaccines for Children Program (VFC), Perinatal Hepatitis B Program, and Immunization Assessment Program.

Iowa Immunization Program Annual Report 2011, February 20, 2012

The Bureau of Immunization is part of the Division of Acute Disease Prevention and Emergency Response (ADPER) at the Iowa Department of Public Health (IDPH). The ADPER division provides support, technical assistance and consultation to local hospitals, public health agencies, community health centers, emergency medical service programs and local health care providers regarding infectious diseases, disease prevention and control, injury prevention and public health and health care emergency preparedness and response. The division encompasses the Center for Acute Disease Epidemiology (CADE), the Bureau of Immunization and Tuberculosis (ITB), the Bureau of Emergency Medical Services (EMS), the Bureau of Communication and Planning (CAP), the Office of Health Information Technology (HIT), and the Center for Disaster Operations and Response (CDOR). The Bureau of Immunization and Tuberculosis includes the Immunization Program, the Tuberculosis Control Program, and the Refugee Health Program. The mission of the Immunization Program is to decrease vaccine‐preventable diseases through education, advocacy and partnership. While there has been major advancement in expanding immunizations to many parts of Iowa’s population, work must continue with public and private health care providers to promote the program’s vision of healthy Iowans living in communities free of vaccine‐preventable diseases. Accomplishing this goal will require achieving and maintaining high vaccination coverage levels, improving vaccination strategies among under‐vaccinated populations, prompt reporting and thorough investigation of suspected disease cases, and rapid institution of control measures. The Immunization Program is comprised of multiple programs that provide immunization services throughout the state: Adolescent Immunization Program, Adult Immunization Program, Immunization Registry Information System (IRIS), Vaccines for Children Program (VFC), Perinatal Hepatitis B Program, and Immunization Assessment Program.

Iowa Immunization Program Annual Report 2012, February 20, 2012

The Bureau of Immunization is part of the Division of Acute Disease Prevention and Emergency Response (ADPER) at the Iowa Department of Public Health (IDPH). The ADPER division provides support, technical assistance and consultation to local hospitals, public health agencies, community health centers, emergency medical service programs and local health care providers regarding infectious diseases, disease prevention and control, injury prevention and public health and health care emergency preparedness and response. The division encompasses the Center for Acute Disease Epidemiology (CADE), the Bureau of Immunization and Tuberculosis (ITB), the Bureau of Emergency Medical Services (EMS), the Bureau of Communication and Planning (CAP), the Office of Health Information Technology (HIT), and the Center for Disaster Operations and Response (CDOR). The Bureau of Immunization and Tuberculosis includes the Immunization Program, the Tuberculosis Control Program, and the Refugee Health Program. The mission of the Immunization Program is to decrease vaccine‐preventable diseases through education, advocacy and partnership. While there has been major advancement in expanding immunizations to many parts of Iowa’s population, work must continue with public and private health care providers to promote the program’s vision of healthy Iowans living in communities free of vaccine‐preventable diseases. Accomplishing this goal will require achieving and maintaining high vaccination coverage levels, improving vaccination strategies among under‐vaccinated populations, prompt reporting and thorough investigation of suspected disease cases, and rapid institution of control measures. The Immunization Program is comprised of multiple programs that provide immunization services throughout the state: Adolescent Immunization Program, Adult Immunization Program, Immunization Registry Information System (IRIS), Vaccines for Children Program (VFC), Perinatal Hepatitis B Program, and Immunization Assessment Program.

2014 Immunizations in Iowa, Iowa Immunization Program Annual Report, January 11, 2016

The Bureau of Immunization is part of the Division of Acute Disease Prevention and Emergency Response (ADPER) at the Iowa Department of Public Health (IDPH). The ADPER division provides support, technical assistance and consultation to local hospitals, public health agencies, community health centers, emergency medical service programs and local health care providers regarding infectious diseases, disease prevention and control, injury prevention and public health and health care emergency preparedness and response. The division encompasses the Center for Acute Disease Epidemiology (CADE), the Bureau of Immunization and Tuberculosis (ITB), the Bureau of Emergency Medical Services (EMS), the Bureau of Communication and Planning (CAP), the Office of Health Information Technology (HIT), and the Center for Disaster Operations and Response (CDOR). The Bureau of Immunization and Tuberculosis includes the Immunization Program, the Tuberculosis Control Program, and the Refugee Health Program. The mission of the Immunization Program is to decrease vaccine‐preventable diseases through education, advocacy and partnership. While there has been major advancement in expanding immunizations to many parts of Iowa’s population, work must continue with public and private health care providers to promote the program’s vision of healthy Iowans living in communities free of vaccine‐preventable diseases. Accomplishing this goal will require achieving and maintaining high vaccination coverage levels, improving vaccination strategies among under‐vaccinated populations, prompt reporting and thorough investigation of suspected disease cases, and rapid institution of control measures. The Immunization Program is comprised of multiple programs that provide immunization services throughout the state: Adolescent Immunization Program, Adult Immunization Program, Immunization Registry Information System (IRIS), Vaccines for Children Program (VFC), Perinatal Hepatitis B Program, and Immunization Assessment Program.

Long-term close follow-up of chorioretinal lesions in presumed ocular tuberculosis.

PURPOSE: To evaluate the long-term outcome (up to 7 years) of presumed ocular tuberculosis (TB) when the therapeutic decision was based on WHO guidelines. METHODS: Twelve out of 654 new uveitic patients (1998-2004) presented with choroiditis and positive tuberculosis skin test (TST) (skin lesion diameter >15 mm). Therapy was administered according to WHO recommendations after ophthalmic and systemic investigation. The area size of ocular lesions at presentation and after therapy, measured on fluorescein and indocyanine green angiographies, was considered the primary outcome. Relapse of choroiditis was considered a secondary outcome. The T-SPOT TB test was performed when it became available. RESULTS: Visual acuity significantly improved after therapy (p=0.0357). The mean total surface of fluorescein lesions at entry was 44.8 ± 20.9 (arbitrary units) and decreased to 32.5 ± 16.9 after therapy (p=0.0165). The mean total surface of indocyanine green lesions at entry was 24.5 ± 13.3 and decreased to 10.8 ± 5.4 after therapy (p=0.0631). The T-SPOT TB revealed 2 false TST-positive results. The mean follow-up was 4.5 ± 1.5 years. Two relapses out of 10 confirmed ocular TB was observed after complete lesion healing, 2.5 years and 4.5 years after therapy, respectively. CONCLUSIONS: A decrease of ocular lesion mean size and a mean improvement of VA were observed after antituberculous therapy. Our long-term follow-up of chorioretinal lesions demonstrated relapse of ocular tuberculosis in 10% of patients with confirmed ocular TB, despite complete initial retinal scarring.

Mycobacterium tuberculosis subverts innate immunity to evade specific effectors.

The macrophage is the niche of the intracellular pathogen Mycobacterium tuberculosis. Induction of macrophage apoptosis by CD4(+) or CD8(+) T cells is accompanied by reduced bacterial counts, potentially defining a host defense mechanism. We have already established that M. tuberculosis-infected primary human macrophages have a reduced susceptibility to Fas ligand (FasL)-induced apoptosis. To study the mechanisms by which M. tuberculosis prevents apoptotic signaling, we have generated a cell culture system based on PMA- and IFN-gamma-differentiated THP-1 cells recapitulating the properties of primary macrophages. In these cells, nucleotide-binding oligomerization domain 2 or TLR2 agonists and mycobacterial infection protected macrophages from apoptosis and resulted in NF-kappaB nuclear translocation associated with up-regulation of the antiapoptotic cellular FLIP. Transduction of a receptor-interacting protein-2 dominant-negative construct showed that nucleotide-binding oligomerization domain 2 is not involved in protection in the mycobacterial infection system. In contrast, both a dominant-negative construct of the MyD88 adaptor and an NF-kappaB inhibitor abrogated the protection against FasL-mediated apoptosis, showing the implication of TLR2-mediated activation of NF-kappaB in apoptosis protection in infected macrophages. The apoptosis resistance of infected macrophages might be considered as an immune escape mechanism, whereby M. tuberculosis subverts innate immunity signaling to protect its host cell against FasL(+)-specific cytotoxic lymphocytes.

Fever of unknown origin in a Swiss-born child: don't miss tuberculosis!

Tuberculosis incidence is low in Switzer land. We report here on a Swiss-born toddler. Tuberculosis manifested with a fever of unknown origin, mimicking an inflammatory or autoimmune disorder triggering a high dose of corticosteroid treatment. The disease went unrecognized for several weeks until development of a miliary tuberculosis with advanced central nervous system involvement. This case highlights the difficulties encountered in diagnosing tuberculosis and in identifying the origin of this case. It reminds us that this disease must never be forgotten when facing a child with persistent fever who must be screened for, before starting immunosuppressive therapy.

Tuberculosis diagnostics and biomarkers: needs, challenges, recent advances, and opportunities.

Tuberculosis is unique among the major infectious diseases in that it lacks accurate rapid point-of-care diagnostic tests. Failure to control the spread of tuberculosis is largely due to our inability to detect and treat all infectious cases of pulmonary tuberculosis in a timely fashion, allowing continued Mycobacterium tuberculosis transmission within communities. Currently recommended gold-standard diagnostic tests for tuberculosis are laboratory based, and multiple investigations may be necessary over a period of weeks or months before a diagnosis is made. Several new diagnostic tests have recently become available for detecting active tuberculosis disease, screening for latent M. tuberculosis infection, and identifying drug-resistant strains of M. tuberculosis. However, progress toward a robust point-of-care test has been limited, and novel biomarker discovery remains challenging. In the absence of effective prevention strategies, high rates of early case detection and subsequent cure are required for global tuberculosis control. Early case detection is dependent on test accuracy, accessibility, cost, and complexity, but also depends on the political will and funder investment to deliver optimal, sustainable care to those worst affected by the tuberculosis and human immunodeficiency virus epidemics. This review highlights unanswered questions, challenges, recent advances, unresolved operational and technical issues, needs, and opportunities related to tuberculosis diagnostics.

Screening for latent tuberculosis infection among undocumented immigrants in Swiss healthcare centres; a descriptive exploratory study.

BACKGROUND: Migration is one of the major causes of tuberculosis in developed countries. Undocumented patients are usually not screened at the border and are not covered by a health insurance increasing their risk of developing the disease unnoticed. Urban health centres could help identify this population at risk. The objective of this study is to assess the prevalence of latent tuberculosis infection (LTBI) and adherence to preventive treatment in a population of undocumented immigrant patients. METHODS: All consecutive undocumented patients that visited two urban healthcare centres for vulnerable populations in Lausanne, Switzerland for the first time were offered tuberculosis screening with an interferon-gamma assay. Preventive treatment was offered if indicated. Adherence to treatment was evaluated monthly over a nine month period. RESULTS: Of the 161 participants, 131 (81.4%) agreed to screening and 125 had complete examinations. Twenty-four of the 125 patients (19.2%; CI95% 12.7;27.2) had positive interferon-gamma assay results, two of which had active tuberculosis. Only five patients with LTBI completed full preventive treatments. Five others initiated the treatment but did not follow through. CONCLUSION: Screening for tuberculosis infection in this hard-to-reach population is feasible in dedicated urban clinics, and the prevalence of LTBI is high in this vulnerable population. However, the low adherence to treatment is an important public health concern, and new strategies are needed to address this problem.

Prevalence of Acute Coronary Syndrome in Patients Suspected for Pulmonary Embolism or Acute Aortic Syndrome: Rationale for the Triple Rule-out Concept.

BACKGROUND: The aims of the study were to evaluate the prevalence of acute coronary syndrome (ACS) among patients presenting with atypical chest pain who are evaluated for acute aortic syndrome (AAS) or pulmonary embolism (PE) with computed tomoangiography (CTA) and discuss the rationale for the use of triple rule-out (TRO) protocol for triaging these patients. METHODS: This study is a retrospective analysis of patients presenting with atypical chest pain and evaluated with thoracic (CTA), for suspicion of AAS/PE. Two physicians reviewed patient files for demographic characteristics, initial CT and final clinical diagnosis. Patients were classified according to CTA finding into AAS, PE and other diagnoses and according to final clinical diagnosis into AAS, PE, ACS and other diagnoses. RESULTS: Four hundred and sixty-seven patients were evaluated: 396 (84.8%) patients for clinical suspicion of PE and 71 (15.2%) patients for suspicion of AAS. The prevalence of ACS and AAS was low among the PE patients: 5.5% and 0.5% respectively (P = 0.0001), while the prevalence of ACS and PE was 18.3% and 5.6% among AAS patients (P = 0.14 and P = 0.34 respectively). CONCLUSION: The prevalence of ACS and AAS among patients suspected clinically of having PE is limited while the prevalence of ACS and PE among patients suspected clinically of having AAS is significant. Accordingly patients suspected for PE could be evaluated with dedicated PE CTA while those suspected for AAS should still be triaged using TRO protocol.

Impact of round-the-clock CSF Gram stain on empirical therapy for suspected central nervous system infections.

The impact of round-the-clock cerebrospinal fluid (CSF) Gram stain on overnight empirical therapy for suspected central nervous system (CNS) infections was investigated. All consecutive overnight CSF Gram stains between 2006 and 2011 were included. The impact of a positive or a negative test on empirical therapy was evaluated and compared to other clinical and biological indications based on institutional guidelines. Bacterial CNS infection was documented in 51/241 suspected cases. Overnight CSF Gram stain was positive in 24/51. Upon validation, there were two false-positive and one false-negative results. The sensitivity and specificity were 41 and 99 %, respectively. All patients but one had other indications for empirical therapy than Gram stain alone. Upon obtaining the Gram result, empirical therapy was modified in 7/24, including the addition of an appropriate agent (1), addition of unnecessary agents (3) and simplification of unnecessary combination therapy (3/11). Among 74 cases with a negative CSF Gram stain and without formal indication for empirical therapy, antibiotics were withheld in only 29. Round-the-clock CSF Gram stain had a low impact on overnight empirical therapy for suspected CNS infections and was associated with several misinterpretation errors. Clinicians showed little confidence in CSF direct examination for simplifying or withholding therapy before definite microbiological results.