Development of IgM-based rapid serological diagnostic system for the early detection of malaria using ATP-binding cassette transporter

The serological markers in predicting recent exposure and highly sensitive portable serological tools can improve the assessment of malaria transmission status in countries aiming to eliminate malaria. This study aimed to improve field surveillance and early diagnostics with novel biomarker and a homemade portable fluorescence reader to detect Plasmodium vivax -specific immunoglobulin M (IgM). A recombinant P. vivax ATP-binding cassette (r Pv ABC) transporter was predicted for B cell epitopes and assessed P. vivax -specific IgM levels using a newly developed prototype, namely portable on-site diagnostic solution (PODS). The assay was validated using patient sera from South Korea and Thailand by receiver operating characteristic (ROC) curves. PODS showed more than 20% increased sensitivity and specificity than enzyme-linked immunosorbent assay (ELISA): 80.77% sensitivity and 100.00% specificity in South Korea and 73.33% and 93.33% in Thailand. The ROC curves showed that PODS exhibited improved performance based on the increased area under the curve (AUC) value compared to ELISA (AUC, 0.8779 for South Korean; 0.9170 for Thailand). PODS positively correlated with parasite density (r = -0.0828) and days of disease onset (r = 0.3659). Moreover, it was moderately correlated with ELISA (ρ = 0.501, P ' 0 . 05) when determining P. vivax -specific IgM level in patients. Our findings highlight that r Pv ABC is a novel biomarker and that the newly developed PODS can potentially improve malaria early diagnostics by measuring P. vivax -specific IgM.