Class specific antibody responses to newborn larva antigens during Trichinella spiralis human infection

A follow-up study of the class antibody responses to newborn larva (NBL) antigens in individuals involved in an outbreak of human trichinellosis was carried out by ELISA assays. The data showed that similar kinetics of antibody responses of different magnitude developed in trichinellosis patients; it was low by week 3, a peak raised by week 5 and decreased from week 7 up to the end of the study. The IgA-ELISA assay was the most sensitive and specific while the IgM was the least sensitive and specific. IgA antibodies to NBL antigens were detected in 80% of patients while IgE, IgG and IgM responses were observed in 44, 31 and 19% of the patients by week 3, respectively. From weeks 5 to 7, IgA antibodies were found in 89 to 100% of the patients while lower percentages (0-82%) were found for the other isotypes. Reactivity of IgA, IgE, IgG and IgM to NBL antigens decreased from week 37 to 57 after infection (0-38%). These results suggest that detection of IgA antibodies may be useful for early diagnosis and epidemiological studies in human trichinellosis.