Nuevas herramientas para la detección de la tuberculosis latente

RESUMEN

La tuberculosis es un problema serio de salud pública en el mundo, especialmente en países en vía de desarrollo, inclusive Colombia. En nuestro país estamos enfocados en el manejo clínico de los pacientes con tuberculosis activa, pero no hay campañas efectivas que identifiquen y provean terapia a los individuos con las formas latentes de la infección y con alto riesgo de progresar hacia la enfermedad. En esta revisión se plantea la importancia de realizar dichas campañas para evitar la diseminación de la infección en la comunidad. Esto incluye la búsqueda activa y el tratamiento profiláctico de los contactos de casos recientes, así como la de individuos con tuberculosis latente con alto riesgo de desarrollar la enfermedad. En ausencia de una prueba de oro para detectar la tuberculosis latente, la prueba cutánea de la tuberculina se ha utilizado por más de 100 años para dicho fin, a pesar de sus limitaciones de sensibilidad y especificidad. En esta revisión se evalúan las ventajas y desventajas de una nueva generación de inmunoensayos que incluye la prueba comercial Quantiferon y el desarrollo experimental del ELISPOT. Ambas se basan en la detección de IFN ©secretado por linfocitos de sangre periférica cuando se incuban con antígenos específicos del bacilo tuberculoso. Finalmente, se plantea la importancia de desarrollar pruebas moleculares enfocadas en detectar el ADN de la micobacteria como posible complemento a los inmunoensayos descritos.

ABSTRACT

New tools for detection of latent tuberculosis Tuberculosis is a serious public health problem worldwide, particularly in developing countries. In Colombia, the focus is on the clinical management of patients with active disease, but not on preventive programs that identify and treat individuals with a latent tuberculosis infection. This review emphasized the importance of preventative programs and their critical role in the curtailment of infection dissemination in the community. An effective program includes chemoprophylactic treatment of household contacts and detection of individuals with latent tuberculosis infection and with high risk of reactivation of disease. The tuberculin skin test has been used effectively for more than 100 years, despite inherent sensitivity and specificity limitations. Herein the advances provided by a new generation of immunoassays are reviewed, includingthe commercially-available Quantiferon and the experimental development of ELISPOT. Both are based on the detection of IFN....secretion by peripheral T cells upon incubation with Mycobacterium tuberculosis antigens. Finally, the importance of molecular techniques aimed at detecting DNA from the mycobacterium is discussed as a possible complement to the described immunoassays. New tools for detection of latent tuberculosis Tuberculosis is a serious public health problem worldwide, particularly in developing countries. In Colombia, the focus is on the clinical management of patients with active disease, but not on preventive programs that identify and treat individuals with a latent tuberculosis infection. This review emphasized the importance of preventative programs and their critical role in the curtailment of infection dissemination in the community. An effective program includes chemoprophylactic treatment of household contacts and detection of individuals with latent tuberculosis infection and with high risk of reactivation of disease. The tuberculin skin test has been used effectively for more than 100 years, despite inherent sensitivity and specificity limitations. Herein the advances provided by a new generation of immunoassays are reviewed, includingthe commercially-available Quantiferon and the experimental development of ELISPOT. Both are based on the detection of IFN....secretion by peripheral T cells upon incubation with Mycobacterium tuberculosis antigens. Finally, the importance of molecular techniques aimed at detecting DNA from the mycobacterium is discussed as a possible complement to the described immunoassays.