Immuno-PCR for detection of antigen to Angiostrongylus cantonensis circulating fifth-stage worms.
BACKGROUND
Definitive diagnosis of infestation with Angiostrongylus cantonensis is difficult because the parasitic nematode is undetectable in the cerebrospinal fluid (CSF) of one-half of afflicted patients and the diagnostic sensitivity of ELISA for circulating worm antigens in patient sera is low. We studied immuno-PCR as a diagnostic tool.


METHODS
We studied 30 controls and 60 afflicted patients (30 confirmed by parasitologic analysis of CSF). We used a monoclonal antibody to capture circulating A. cantonensis antigens in serum samples. A DNA label generated by PCR amplification with biotinylated primer was bound by use of streptavidin to a biotinylated third antibody. Circulating antigens sandwiched by monoclonal antibody were detected by PCR amplification of the DNA label.


RESULTS
The detection limit of the ELISA was 100-1000 times higher than that of the immuno-PCR. The concentrations of circulating antigens in patients were markedly higher than those in controls (Wilcoxon rank-sum test, P <0.001). At a cutoff of 0.1 ng/L, sensitivity and specificity for immunodiagnosis of patients with angiostrongyliasis by immuno-PCR were 98% (95% confidence interval, 91-99%) and 100% (93-100%), respectively. The test was positive in all parasitologically confirmed cases.


CONCLUSIONS
Immuno-PCR is a promising technique for diagnosis of A. cantonensis infestation.
Chye
Soi-Moi
SM
Department of Medical Technology, Fooyin University, 151 Chinhsuen Road, Ta-Liao Hsiang, Kaohsiung, Taiwan, ROC. Chmiye@cc.kmu.edu.tw
Lin
Shiu-Ru
SR
Chen
Ya-Lei
YL
Chung
Lee-Yi
LY
Yen
Chuan-Min
CM
D017185:Angiostrongylus cantonensis / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal; D000947:Antigens, Helminth / Q000097:blood* / Q000134:cerebrospinal fluid; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008581:Meningitis / Q000097:blood / Q000134:cerebrospinal fluid / Q000469:parasitology; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D017206:Strongylida Infections / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis
D000911:Antibodies, Monoclonal; D000947:Antigens, Helminth