Improving diagnostic accuracy in visceral leishmaniasis: Chimeric protein-based approach

Endemic to Brazil, Human Visceral Leishmaniasis (HVL), caused by Leishmania infantum and vectored by sand flies, is characterized by a complex and often overlapping set of symptoms, including prolonged fever, weight loss, organomegaly, anaemia, and bleeding. The diagnostic process for HVL is frequently hindered by the disease's nonspecific clinical presentation and the inherent limitations of existing serological assays, which often exhibit suboptimal sensitivity and specificity, predisposing to diagnostic inaccuracies. Developing of sensitive and specific diagnostic assays is crucial for effective HVL control in Brazil, enabling early disease detection and improving treatment outcomes. To enhance diagnostic capabilities, we evaluated the performance of a chimeric protein designed from B-lymphocyte cell epitopes identified through immunoproteomic analysis in serological tests for detecting L. infantum infection. Under the experimental conditions, the chimeric protein demonstrated the following diagnostic performance: 100 % specificity against control samples, 94.12 % specificity against Chagas disease samples, and 100 % sensitivity for HVL-positive individuals. Receiver Operating Characteristic (ROC) curve analysis demonstrated the following performance metrics: area under the curve (AUC) of 0.9960, 100 % sensitivity, and 97.10 % overall specificity, significantly exceeding the performance of the L. infantum soluble antigen (SLiA) ELISA. These findings suggest that the chimeric protein represents a promising antigen for developing of improved HVL diagnostic technologies, potentially reducing the disease's public health impact.