Plasma Neuron-Specific Enolase is not a reliable biomarker for staging Trypanosoma brucei rhodesiense sleeping sickness patients.

When median NSE levels were compared between early and late-stage patients, results showed a significant (P < 0.02) upregulation among late-stage patients (599.8 ng/mL). No significant differences (P > 0.9) in NSE levels were observed between early-stage patients (300 ng/mL) and controls (454 ng/mL). We used Receiver Operator Characteristic (ROC) curves to explore the likelihood of using plasma NSE as a potential stage biomarker in discriminating between early and late-stage HAT patients. Our results showed that NSE demonstrated an area under the curve (AUC) of 0.702 (95% CI 0.583-0.830). A high staging accuracy for NSE was obtained by using a cutoff of > 346.5 ng/mL with a sensitivity of 68.6% (95% CI 55-79.7%) and a specificity of 93.3% (95% CI 70.2-99.7%). Although our results demonstrate that plasma NSE is upregulated in T. b. rhodesiense sleeping sickness patients, its value in discriminating between late and early-stage patients is limited. However, future studies could consider improving its specificity by combining it with other identified plasma biomarkers.