Serological evaluation of the schistosome's secretory enzyme phytochelatin synthase and phosphoglycerate mutase for the detection of human Schistosoma japonicum infection.

Secretory enzymes from Schistosoma japonicum are promising candidate antigens in the diagnosis of schistosomiasis. Our previous studies have proven that thioredoxin peroxidase-1 (SjTPx-1) is useful for the detection of this parasitic disease in humans, water buffaloes, and dogs. In this study, we evaluated two more secretory enzymes namely phosphoglycerate mutase (SjPGM) and phytochelatin synthase (SjPCS) with SjTPx-1 as the reference antigen. SjPGM was shown to have good diagnostic potentials in animal samples in previous studies, whereas SjPCS was chosen because of its absence in the mammalian hosts. Serum samples including 96 endemic negative controls, 107 schistosomiasis japonica positive samples, and 31 samples positive for other parasitic trematode infections (Clonorchis sinensis, Opisthorchis viverrini, Paragonimus westermani) were tested with the antigens using enzyme-linked immunosorbent assay. Results showed that SjPCS detected more positive samples and had fewer cross-reactions than SjPGM. With 85.05% sensitivity and 93.55% specificity, SjPCS can therefore be used in the detection of human schistosomiasis.