Multiple Cytokines Are Released When Blood from Patients with Tuberculosis Is Stimulated with Mycobacterium tuberculosis Antigens

Mycobacterium tuberculosis (Mtb) infection may cause overt disease or remain latent. Interferon gamma release assays (IGRAs) detect Mtb infection, both latent infection and infection manifesting as overt disease, by measuring whole-blood interferon gamma (IFN-γ) responses to Mtb antigens such as early secreted antigenic target-6 (ESAT-6), culture filtrate protein 10 (CFP-10), and TB7.7. Due to a lack of adequate diagnostic standards for confirming latent Mtb infection, IGRA sensitivity for detecting Mtb infection has been estimated using patients with culture-confirmed tuberculosis (CCTB) for whom recovery of Mtb confirms the infection. In this study, cytokines in addition to IFN-γ were assessed for potential to provide robust measures of Mtb infection.Cytokine responses to ESAT-6, CFP-10, TB7.7, or combinations of these Mtb antigens, for patients with CCTB were compared with responses for subjects at low risk for Mtb infection (controls). Three different multiplexed immunoassays were used to measure concentrations of 9 to 20 different cytokines. Responses were calculated by subtracting background cytokine concentrations from cytokine concentrations in plasma from blood stimulated with Mtb antigens.Two assays demonstrated that ESAT-6, CFP-10, ESAT-6+CFP-10, and ESAT-6+CFP-10+TB7.7 stimulated the release of significantly greater amounts of IFN-γ, IL-2, IL-8, MCP-1 and MIP-1β for CCTB patients than for controls. Responses to combination antigens were, or tended to be, greater than responses to individual antigens. A third assay, using whole blood stimulation with ESAT-6+CFP-10+TB7.7, revealed significantly greater IFN-γ, IL-2, IL-6, IL-8, IP-10, MCP-1, MIP-1β, and TNF-α responses among patients compared with controls. One CCTB patient with a falsely negative IFN-γ response had elevated responses with other cytokines.Multiple cytokines are released when whole blood from patients with CCTB is stimulated with Mtb antigens. Measurement of multiple cytokine responses may improve diagnostic sensitivity for Mtb infection compared with assessment of IFN-γ alone

Skin-Test Screening and Tuberculosis Transmission among the Homeless1

We describe the implementation of a mandatory tuberculosis (TB) screening program that uses symptom screening and tuberculin skin testing in homeless shelters. We used the results of DNA fingerprinting of Mycobacterium tuberculosis isolates to evaluate the effect of the program on TB incidence and transmission. After the program was implemented, the proportion of cases among homeless persons detected by screening activities increased, and the estimated TB incidence decreased from 510 to 121 cases per 100,000 population per year. Recent transmission, defined by DNA fingerprinting analysis as clustered patterns occurring within 2 years, decreased from 49% to 14% (p=0.03). Our results suggest that the shelter-based screening program decreased the incidence of TB by decreasing its transmission among the homeless

The impact of breastfeeding patterns on regional differences in infant mortality in Germany, 1910

This paper examines the impact of breastfeeding practices on the large regional differences in infant mortality in Germany around 1910. Breastfeeding is strongly negatively associated with infant mortality and remains so after controlling for public health measures and for demographic, economic, and social factors that also affect infant mortality. But it contributes much less to regional differences in infant mortality than do access to medical care, percentage illegitimate and marital fertility. Breastfeeding is less important than these other factors because it affects fewer causes of death and has a smaller impact on cause-specific infant mortality rates. L'auteur étudie l'impact des pratiques d'allaitement sur les grandes différences régionales de mortalité infantile observées en Allemagne aux alentours de 1910. Il existe une association fortement négative entre l'allaitement et la mortalité infantile, même quand on contrôle les facteurs démographiques, économiques, sociaux et de politique sanitaire, qui, eux aussi, affectent la mortalité infantile. Mais les différences régionales de mortalité infantile s'expliquent nettement moins par l'allaitement que par l'accessibilité des soins médicaux, le taux d'illégitimité des naissances et la fécondité légitime. L'allaitement est un facteur de moindre importance que ceux-ci parce qu'il n'a d'impact que sur un petit nombre de causes de décès, et un faible impact sur les taux de mortalité infantile par cause.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42730/1/10680_2005_Article_BF01796777.pd

Tuberculosis screening by tuberculosis skin test or QuantiFERON-TB Gold In-Tube Assay among an immigrant population with a high prevalence of tuberculosis and BCG vaccination.

RationaleEach year 1 million persons acquire permanent U.S. residency visas after tuberculosis (TB) screening. Most applicants undergo a 2-stage screening with tuberculin skin test (TST) followed by CXR only if TST-positive at > 5 mm. Due to cross reaction with bacillus Calmette-Guérin (BCG), TST may yield false positive results in BCG-vaccinated persons. Interferon gamma release assays exclude antigens found in BCG. In Vietnam, like most high TB-prevalence countries, there is universal BCG vaccination at birth.Objectives1. Compare the sensitivity of QuantiFERON-TB Gold In-Tube Assay (QFT) and TST for culture-positive pulmonary TB. 2. Compare the age-specific and overall prevalence of positive TST and QFT among applicants with normal and abnormal CXR.MethodsWe obtained TST and QFT results on 996 applicants with abnormal CXR, of whom 132 had TB, and 479 with normal CXR.ResultsThe sensitivity for tuberculosis was 86.4% for QFT; 89.4%, 81.1%, and 52.3% for TST at 5, 10, and 15 mm. The estimated prevalence of positive results at age 15-19 years was 22% and 42% for QFT and TST at 10 mm, respectively. The prevalence increased thereafter by 0.7% year of age for TST and 2.1% for QFT, the latter being more consistent with the increase in TB among applicants.ConclusionsDuring 2-stage screening, QFT is as sensitive as TST in detecting TB with fewer requiring CXR and being diagnosed with LTBI. These data support the use of QFT over TST in this population

Tuberculosis screening among visa applicants.

<div><p>a) Number of Vietnamese applicants (N=20,100) for U.S. immigration having a chest radiograph not consistent with TB (Normal-CXR, n=17,802), having a chest radiograph consistent with TB, but not culture confirmed (TB-CXR, n=2,087), or having culture-confirmed pulmonary TB (TB, n=211) by 5-year age group. b) The percentage with a chest radiograph consistent with TB. </p> <p>*APC=annual percent change per year of age.</p></div

Mantoux tuberculin skin test (TST) and QFT-TB Gold In-Tube (QFT) response among participants, by tuberculosis group (rows) and three cutpoints for a positive TST (columns) at 5mm, 10mm, and 15mm induration.

<p>The area within a circle corresponds with the number of participants with a positive test; the area of the intersection of circles corresponds with the number of participants positive by both tests. </p

Figure 3

<div><p><b>Proportion positive QFT-TB Gold In-Tube (QFT) and Mantoux tuberculin skin test (TST) with positive at >5 mm induration (TST-5), >10 mm induration (TST-10), and >15 mm induration (TST-15) among four groups:</b> A) participants with chest radiographs not suggestive of TB (N=479); B) participants with chest radiographs suggestive of TB with negative sputum culture for TB (N=864); C) participants with chest radiographs suggestive of TB with positive sputum culture for TB (N=132); D) all U.S.-bound Vietnamese immigrant applicants (estimated).</p><p>*APC=annual percent change per year of age.</p></div