IFN-γ and IgG responses to Mycobacterium tuberculosis latency antigen Rv2626c differentiate remote from recent tuberculosis infection.

Tuberculin skin test (TST) and IFN-γ release assays are currently used to detect Mycobacterium tuberculosis (Mtb) infection but none of them differentiate active from latent infection (LTBI). Since improved tests to diagnose Mtb infection are required, we studied the immune response to Mtb latency antigen Rv2626c in individuals exposed to the bacteria during different periods. Tuberculosis patients (TB), TB close contacts (CC: subjects exposed to Mtb for less than three months) and healthcare workers (HW: individuals exposed to Mtb at least two years) were recruited and QuantiFERON (QFT) assay, TST and IFN-γ secretion to Rv2626c were analyzed. Twenty-two percent of the individuals assessed had discordant results between QFT and TST tests. Furthermore, QFT negative and QFT positive individuals produced differential levels of IFN-γ against Rv2626c, in direct association with their exposure period to Mtb. Actually, 91% of CC QFT negative subjects secreted low levels of IFN-γ to Rv2626c, whereas 43% of HW QFT negative people produced elevated IFN-γ amounts against Rv2626c. Conversely, 69% of CC QFT positive subjects didn´t produce IFN-γ to Rv2626c. Interestingly, a similar pattern of IgG anti-Rv2626c plasma levels was observed. Therefore, determination of IFN-γ and IgG levels against the dormancy antigen Rv2626c allows to identify established LTBI.

Estudio de los costos intangibles y de la participación del componente familiar en el costo social de la tuberculosis / Study of the Intangible Costs and the Impact of the Household Component in the Social Cost of Tuberculosis

La tuberculosis (TBC) es uno de los principales problemas de salud pública a nivel mundial. Argentina tiene una elevada tasa de incidencia de 30 por cada 100.000 habitantes. Hay datos sobre los costos directos de la tuberculosis, pero poco se conoce sobre su costo social. OBJETIVOS: explorar la relación entre percepción de enfermedad y costos intangibles de la TBC y medir el impacto del componente hogareño en el costo social de la TBC en el Área Metropolitana de Buenos Aires. Métodos : estudio descriptivo cualitativo y cuantitativo de la pérdida de calidad de vida y del costo social sobre una muestra de 30 pacientes con diagnóstico reciente de TBC y residentes en el Partido de Quilmes y 30 controles sanos. Las variables medidas fueron: costos intangibles o de pérdida de calidad de vida medidos con la encuesta SF-36, costos indirectos o de oportunidad y costos directos por atención de enfermedad. Resultados : para la pérdida de calidad de vida, tanto en casos como en controles, el puntaje promedio fue de 39 puntos en los tópicos generales de salud física y salud mental (escala 0 a 100). El costo social atribuible a la enfermedad alcanzó una suma de AR$ 597.78 por caso para el año 2007, con una participación de casi el 38% de la unidad doméstica. El costo estimado total país ascendió a AR$ 6.207.396,47. Conclusiones : en Argentina, la TBC está claramente vinculada con la vulnerabilidad socioeconómica. En las familias más pobres, la enfermedad impacta fuertemente en la unidad familiar, deteriorando una economía doméstica de por sí crítica

Tuberculosis (TB) is a major public health problem in the world. Argentina has a high rate of incidence of 30 cases per 100,000 inhabitants. There is information about direct costs of TB but little is known aboutits social costs. Objectives: To explore the relation ship between perception of disease and intangible costs; and to measure the impact of the house hold component on the social cost of the disease in the Metropolitan Area of Buenos Aires. Methods: quali-quantitative, descriptive study of the loss of quality of life and the TB social costs on a sample of 30 cases with TB living in Quilmes Partyand 30 controls. The variables included were intangible costs or loss of quality of life assessed through the SF-36survey, indirect or opportunity costs and direct costs of the disease health care. Results: for the loss of quality oflife, so cases as controls, the average score was 39 point sin the general issues of physics and mental health (scale 0 to 100). The social costs attributable to the disease reached a sum of AR$ 597.78 per case, with almost 38% paid from the house hold component. The estimated total country cost was AR$ 6.207.396.47 per year. Conclusions: In Argentina, TB is clearly associated to social-economy vulnerability. In poorest families, the disease strongly impacts on the family unit, worsening the already critic domestic economy

[Infectiousness and virulence of multidrug-resistant and drug susceptible tuberculosis in adult contacts]. / Infecciosidad y virulencia de la tuberculosis multirresistente o sensible a drogas antituberculosas en contactos adultos.

Patients carrying multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have been considered traditionally as presenting a diminished epidemiological risk according to animal experimentation results. The experience obtained from the MDRTB/AIDS related epidemics showed MDRTB transmission to immunocompetent health care workers and adults close contacts. In this retrospective study, the infectiousness (measured as the frequency of intradermal test with PPD 2TU over 10 mm) and virulence (cases bacteriologically confirmed) among close contacts of patients with MDR and susceptible TB were evaluated. A total of 97 contacts of 37 MDRTB patients vs. 356 contacts of 100 patients with susceptible TB were studied. No statistical differences were found in PPD 2 UT positivity and TB cases between both contact groups, nor in relation to HIV seropositivity of index cases. According to these observations, MDR strains of M. tuberculosis present similar infectiousness and virulence compared with susceptible strains.

Infecciosidad y virulencia de la tuberculosis multirresistente o sensible a drogas antituberculosas en contactos adultos / Infectiousness and virulence of multidrug-resistant and drug susceptible tuberculosis in adult contacts

Patients carrying multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have been considered traditionally as presenting a diminished epidemiological risk according to animal experimentation results. The experience obtained from the MDRTB/AIDS related epidemics showed MDRTB transmission to immunocompetent health care workers and adults close contacts. In this retrospective study, the infectiousness (measured as the frequency of intradermal test with PPD 2TU over 10 mm) and virulence (cases bacteriologically confirmed) among close contacts of patients with MDR and susceptible TB were evaluated. A total of 97 contacts of 37 MDRTB patients vs. 356 contacts of 100 patients with susceptible TB were studied. No statistical differences were found in PPD 2 UT positivity and TB cases between both contact groups, nor in relation to HIV seropositivity of index cases. According to these observations, MDR strains of M. tuberculosis present similar infectiousness and virulence compared with susceptible strains (AU)#S#a

Infecciosidad y virulencia de la tuberculosis multirresistente o sensible a drogas antituberculosas en contactos adultos / Infectiousness and virulence of multidrug-resistant and drug susceptible tuberculosis in adult contacts

Patients carrying multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have been considered traditionally as presenting a diminished epidemiological risk according to animal experimentation results. The experience obtained from the MDRTB/AIDS related epidemics showed MDRTB transmission to immunocompetent health care workers and adults close contacts. In this retrospective study, the infectiousness (measured as the frequency of intradermal test with PPD 2TU over 10 mm) and virulence (cases bacteriologically confirmed) among close contacts of patients with MDR and susceptible TB were evaluated. A total of 97 contacts of 37 MDRTB patients vs. 356 contacts of 100 patients with susceptible TB were studied. No statistical differences were found in PPD 2 UT positivity and TB cases between both contact groups, nor in relation to HIV seropositivity of index cases. According to these observations, MDR strains of M. tuberculosis present similar infectiousness and virulence compared with susceptible strains (AU)#S#a

Infecciosidad y virulencia de la tuberculosis multirresistente o sensible a drogas antituberculosas en contactos adultos. / [Infectiousness and virulence of multidrug-resistant and drug susceptible tuberculosis in adult contacts]

Patients carrying multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have been considered traditionally as presenting a diminished epidemiological risk according to animal experimentation results. The experience obtained from the MDRTB/AIDS related epidemics showed MDRTB transmission to immunocompetent health care workers and adults close contacts. In this retrospective study, the infectiousness (measured as the frequency of intradermal test with PPD 2TU over 10 mm) and virulence (cases bacteriologically confirmed) among close contacts of patients with MDR and susceptible TB were evaluated. A total of 97 contacts of 37 MDRTB patients vs. 356 contacts of 100 patients with susceptible TB were studied. No statistical differences were found in PPD 2 UT positivity and TB cases between both contact groups, nor in relation to HIV seropositivity of index cases. According to these observations, MDR strains of M. tuberculosis present similar infectiousness and virulence compared with susceptible strains.