Detection of circulatory E. granulosus-derived cell-free DNA in the plasma and urine of human cystic echinococcosis using an in-house PCR: a potential promising diagnostic biomarker.

BACKGROUND: The diagnostic tool for identifying cystic echinococcosis (CE) patients at an early stage is currently lacking. However, circulatory cell-free DNA (cfDNA) has shown potential as a biomarker for parasitic infections and could be used for diagnosing CE.

RESEARCH DESIGN AND METHODS: The plasma and urine samples were collected from 39 patients with confirmed CE through imaging and histopathological techniques. All plasma samples were tested for anti-echinococcal antibodies using a commercial ELISA test. Total plasma and urine cfDNA were extracted and an in-house PCR assay was developed to detect E. granulosus specific cfDNA in the samples of CE patients.

RESULTS: Out of the 39 patients, 30 tested positive for E. granulosus using serology, with a sensitivity of 76.9%. Moreover, the detection rates for the cfDNA were 79.5% in plasma samples and 58.97% in urine samples using the 80 bp COX1 gene. The plasma-based PCR and serology test showed the highest agreement (Kappa = 0.53).

CONCLUSIONS: Plasma-based PCR has been found to be a reliable diagnostic tool for identifying CE patients at different cyst stages. It offers validity, speed, and sufficient sensitivity, making it an alternative to serology in diagnosing CE in endemic areas.