[Comparative value of 2 western blot techniques for confirmation of hydatidosis diagnosis]

Serological diagnosis of hydatid disease can be performed using different techniques, including ELISA, indirect immunofluorescence (IFI), in-gel immunodiffusion, electrosyneresis (ES), complement fixation technique, hemagglutination, latex sensibilized agglutination. However, all these techniques can lead to discordant results, according to their sensitivity and specificity rates. There is therefore a need for a confirmation technique, which can be either an immuno-electrophoresis assay, or an immunoblot assay. In this study, we compared two Western-Blot (WB) assays: the QualiCode Hydatid disease kit (Immunetics, Cambridge, MA, USA) and an in-house technique. Eighteen sera were tested: 7 sera from 4 patients with confirmed hydatidosis, 4 patients with discrepant serological results using the usual techniques of our laboratory (IFI and ES), one patient without any parasitic disease, and 6 patients with parasitic diseases other than hydatidosis (one with distomatosis, one with toxocarosis, two with alveolar echinococcosis and two with cysticercosis). All 4 patients with proven hydatidosis had a positive WB assay. The diagnosis of hydatidosis was confirmed in one patient with discordant results (IFI/ES) and eliminated for the 3 remaining patients, in which these data were clinically confirmed later on. The negative patient had a negative WB. Of the 6 patients with other parasitic diseases, one with cysticercosis and one with alveolar echinococcosis had a positive WB pattern. Both western-blot assays produced similar results for all patients, although they did not reveal the same proteins. These data provide evidence that WB is a valuable confirmation technique.