Loss of Receptor on Tuberculin-Reactive T-Cells Marks Active Pulmonary Tuberculosis

BACKGROUND: Tuberculin-specific T-cell responses have low diagnostic specificity in BCG vaccinated populations. While subunit-antigen (e.g. ESAT-6, CFP-10) based tests are useful for diagnosing latent tuberculosis infection, there is no reliable immunological test for active pulmonary tuberculosis. Notably, all existing immunological tuberculosis-tests are based on T-cell response size, whereas the diagnostic potential of T-cell response quality has never been explored. This includes surface marker expression and functionality of mycobacterial antigen specific T-cells. METHODOLOGY/PRINCIPAL FINDINGS: Flow-cytometry was used to examine over-night antigen-stimulated T-cells from tuberculosis patients and controls. Tuberculin and/or the relatively M. tuberculosis specific ESAT-6 protein were used as stimulants. A set of classic surface markers of T-cell naive/memory differentiation was selected and IFN-gamma production was used to identify T-cells recognizing these antigens. The percentage of tuberculin-specific T-helper-cells lacking the surface receptor CD27, a state associated with advanced differentiation, varied considerably between individuals (from less than 5% to more than 95%). Healthy BCG vaccinated individuals had significantly fewer CD27-negative tuberculin-reactive CD4 T-cells than patients with smear and/or culture positive pulmonary tuberculosis, discriminating these groups with high sensitivity and specificity, whereas individuals with latent tuberculosis infection exhibited levels in between. CONCLUSIONS/SIGNIFICANCE: Smear and/or culture positive pulmonary tuberculosis can be diagnosed by a rapid and reliable immunological test based on the distribution of CD27 expression on peripheral blood tuberculin specific T-cells. This test works very well even in a BCG vaccinated population. It is simple and will be of great utility in situations where sputum specimens are difficult to obtain or sputum-smear is negative. It will also help avoid unnecessary hospitalization and patient isolation

Parallelization Strategies to Speed-Up Computations for Terrain Analysis on Multi-Core Processors

Efficient computation of regional land-surface parameters for large-scale digital elevation models becomes more and more important, in particular for webbased applications. This paper studies the possibilities of decreasing computing time for such tasks by parallel processing using multi-threads on multi-core processors. As an example of calculations of regional land-surface parameters we investigate the computation of flow directions and propose a modified D8 algorithm using an extended neighborhood. In this paper, we discuss two parallelization strategies, one based on a spatial decomposition, the other based on a two-phase approach. Three datasets of high resolution digital elevation models with different geomorphological types of landscapes are used in our evaluation. While local surface parameters allow for an almost ideal speed-up, the situation is different for the calculation of non-local parameters due to data dependencies. Nevertheless, still a significant decrease of computation time has been achieved. A task pool-based strategy turns out to be more efficient for calculations on datasets with many data dependencies

Improving basin scale shallow landslide modelling using reliable soil thickness maps

Soil thickness is a well-known factor controlling shallow landsliding. Notwithstanding, its spatial organisation over large areas is poorly understood, and in basin scale slope analyses it is often established using simple methods. In this paper, we apply five different soil thickness models in two test sites, and we use the obtained soil thickness maps to feed a slope stability model. Validation quantifies how errors in soil thickness influence the resulting factor of safety and points out which method grants the best results. In particular, in our cases, slope-derived soil thickness patterns produced the worst slope stability assessment, while the use of reliable soil thickness maps obtained by means of a more complex geomorphologically indexed model improved shallow landslides modelling. © 2011 The Author(s)