Tuberculosis: Better diagnosis in children
Tuberculosis bacteria in the focus of research.
Rapid and reliable diagnosis of paediatric tuberculosis is still an ongoing problem. The most important prerequisite for successful treatment of active tuberculosis is its early diagnosis. A team of researchers has now developed a novel immunodiagnostic blood test, and has shown that it can significantly improve diagnosis in children. The results have been published in the renowned journal The Lancet Infectious Diseases.
Paediatric tuberculosis is a serious public health problem: An estimated one million children per year develop tuberculosis worldwide. Precise figures are difficult to obtain, especially for children, as the disease can present itself in different forms: A large number of infected people initially do not present with symptoms of the disease as their immune systems are able to contain the bacteria—this condition is termed latent tuberculosis. However, about ten percent develop active tuberculosis, which requires treatment as fast as possible. While adults often show specific clinical symptoms, children often present with symptoms similar to those seen in other more common diseases, such as pneumonia.
Christof Geldmacher and an international research team from the German Center for Infection research (DZIF), the Department of Infectious Diseases and Tropical Medicine of the Ludwig-Maximilian-University of Munich (LMU), the Swiss Tropical and Public Health Institute (Swiss TPH), the NIMR-Mbeya Medical Research Centre (MMRC) and Ifakara Health Institute (IHI) in Tanzania now report positive results on a novel immunodiagnostic method for detection of active tuberculosis. “In this study, we have shown that this assay can rapidly identify active infections in children from tuberculosis endemic regions with high sensitivity and specificity,” Geldmacher explains. The assay was developed in collaboration with MMRC and IHI in Tanzania.
The new blood test measures specific immune defence markers in less than 24 hours. In the event of tuberculosis infection, the body responds to the bacteria with so-called CD4 positive T cells. Several research groups have already shown that in active tuberculosis responding CD4 T cells down-regulate the cell surface protein CD27, which allows for a differentiation between latent and active tuberculosis.
For the first time, Christof Geldmacher and Klaus Reither, Swiss TPH, and their research team have shown that this CD27 based assay (TAM-TB-assay) can improve the diagnosis of paediatric tuberculosis in tuberculosis-endemic areas. “We now have to focus on simplifying the TAM-TB assay and develop it further into a widely applicable product,” Geldmacher stresses. In order to do this, the DZIF, the LMU and the Swiss TPH are planning to collaborate in a broad-based partnership with industrial partners. Widespread implementation of this blood test will take the fight against tuberculosis a step forward.
