Promising diagnostic test for sleeping sickness

Around half a million people a year in sub-Saharan Africa are affected by sleeping sickness (human African trypanosomiasis). The disease is fatal in humans if not treated with chemotherapy; however, adverse effects of drug treatment and an increase in drug resistance underline the importance of establishing an accurate diagnostic test for the disease.

In this week’s issue of THE LANCET, Sanjeev Krishna from St George’s Hospital Medical School, London, UK, and colleagues assessed whether mass spectrometry could identify a characteristic protein marker for individuals known to have sleeping sickness. Blood from 85 such individuals was compared with blood samples from 146 patients who had other parasitic or non-parasitic infections. Half the samples were used to calibrate the diagnostic test; the other half served as the main research sample. Mass spectrometry created distinct blood proteomic signatures characteristic of human African trypanosomiasis. The test was shown to have a sensitivity of 100% and a specificity of 98•6% (ie, importantly, a very low chance of recording ‘false-positive’ results).

Professor Krishna comments: “We report the accurate diagnosis of an infection using proteomic signature analysis. The same approach could, equally, be used to improve the diagnostic accuracy of other infections, such as tuberculosis, which can be difficult to detect using conventional tests”.

In an accompanying Commentary (p 1337), Marinus F W te Pas from Wageningen University, Netherlands, states: “methods driven by high technology often have the disadvantages of being expensive and restricted to highly specialised laboratories, and hence are not applicable in the field. But, as the current study suggests, such diagnostic methods should be a starting point to develop new diagnostic methods for the field”.