The sequential appearance of IgG subclasses and IgE during the course of Trichinella spiralis infection.

Earlier studies have shown that IgG1 and IgG4 are the dominant IgG subclasses in the specific response during a chronic helminthic infection. It has also been suggested that IgG4 production results from chronic or repetitive antigenic stimulation and a correlation between IgG4 and IgE levels exists. An outbreak of Trichinella spiralis infection in Poland provided the opportunity to follow the sequential appearance of the IgG subclass and IgE responses in 15 patients during the early stage of Trichinella infection and to compare these observations in sera obtained one year later from the same patients. The results show that the sequential appearance of the IgG subclasses were IgG1 before IgG3 and IgG3 before IgG4. IgG1 antibodies dominated the immune response in all patients. A statistically significant increase in the number of IgG4 positive sera was observed in patients during the chronic stage compared to the findings during the early stage of infection (13% vs 73%; p less than 0.001), supporting the view that IgG4 results from a chronic antigenic stimulation. A correlation between the appearance of IgG4 and IgE was not found. The highest levels of IgE were seen in the first serum samples obtained, with a decrease during the course of infection.