Detection of coproantibodies and faecal immune complexes in human trichinellosis

Trichinella spiralis is the nematode causative agent of trichinellosis, an intestinal and tissular parasitosis. Even though an early diagnosis during the intestinal phase is essential to limit the infection in humans, to date, there are no available tests to achieve this goal. Based on the immune response generated by the host's intestinal mucosa, the aim of this work was to develop ELISAs to assess the presence of coproantigens (CAgs), coproantibodies (CAbs) and faecal immune complexes in stool samples of 18 individuals belonging to different outbreaks that have arisen in Argentina. By the methodologies developed in this work it was found that anti-muscle larva excretory-secretory products (ML-ESP) CAbs were detected in 89% of the samples analysed regardless of the time p.i. Anti-ML-ESP IgA, IgG, IgE and IgM were detected in 56%, 56%, 28% and 22% of the individuals respectively. Those samples negative for anti-ML-ESP total immunoglobulins proved positive for anti-adult worm-ESP CAbs. No CAgs were detected in any of the samples. The results obtained in this work indicate that the intestinal immune response in human trichinellosis is featured by all the isotypes of specific immunoglobulins. Furthermore, the detection of antibodies in stool samples, in either the free or complexed form, could be applied to confirm early human trichinellosis.