Diagnostic values of ELISA-IgG4 as compared to ELISA-IgG and indirect immunofluorescence, for the routine diagnosis of bancroftian filariasis in the South Pacific. Application on capillary blood collected on filter paper.

For the serodiagnosis of lymphatic filariasis, serological assays restricted to the detection of specific IgG4 antibodies enhanced the specificity. In French Polynesia, Wuchereria bancrofti is the sole human filaria and other pathogenic parasites are infrequent. In order to define a simple and cheap serological test, we have compared the diagnostic value of indirect immunofluorescence test (IFI-WBp), ELISA-IgG and ELISA-IgG4 assays. The specificity, sensitivity, R.O.C. curves of each test have been analyzed. No significant difference was found between those 3 tests, except that the reproducibility and the predictive value were lower using IFI-WBp than using the two ELISAs. Significant correlation was found between IgG and IgG4 anti-Brugia malayi antibody titers (r = 0.512, p less than 10(-5)). For large scale seropidemiological studies, ELISA-IgG can be performed with finger prick blood absorbed on filter paper, but not ELISA-IgG4. In conclusion, ELISA-IgG a less expensive and less time consuming method than ELISA-IgG4, can be used for the routine serodiagnosis as well as for seroepidemiological studies on bancroftian filariasis in the South Pacific islands.