Trichinella spiralis infection and transplacental passage in human pregnancy

Abstract

Infection by Trichinella spp. during pregnancy still arises many questions. Worldwide an important number of trichinellosis outbreaks have occurred over time where pregnant women were or might have been involved. Parasitological and immunoserological parameters, clinical background and transplacental passage of Trichinella spiralis of six pregnant women, from different outbreaks, were studied. Serum samples were collected from patients and their children: at pregnancy, at delivery, newborn and/or infant (≥1 year-old). Total immunoglobulins (Igs) and isotypes against excretion-secretion products from muscle larvae (ESP-ML) and newborn larvae (NBL) of T. spiralis were detected by immunoserological techniques. Sera helminthocytotoxic activity against NBL was evaluated by antibodies dependent cell cytotoxicity assay. Patients presented similar clinical symptoms. Mother's sera showed differences in the presence and titres of Igs, IgE, IgG1 and IgG4 against NBL surface. All of them showed helminthocytotoxic activity against NBL, four in progesterone dependent manner and the other two by antibodies. Igs anti ESP-ML were present in mother's sera, with differences in the isotypes detected. Anti-ESP-ML IgE, IgA and/or IgM in newborn sera were observed. Three out of four infants showed specific Igs; one even at 8 years-old. The distinct immune response between mothers at pregnancy evidenced by sera helminthocytotoxic activity and immunoserological parameters may be associated with a different parasite burden exposition. Specific Igs observed in newborns would be a suggestion of transplacental passage of this Igs and/or their production by the fetus. Specific Igs found in infants sera suggests that newborn larvae transplacental passage is possible.

Keywords: Helminthocytotoxicity; Human pregnancy; Immunological parameters; Transplacental passage; Trichinella spiralis.