Effect of chemotherapy and reinfection on IgE-containing and IgG-containing circulating immune complexes, serum IgE and IgE antibodies in patients chronically infected with Schistosoma mansoni and Schistosoma haematobium.

The effect of chemotherapy and reinfection on circulating immune complexes (CIC), serum IgE, and parasite-specific IgE antibodies was studied in patients concomitantly infected with Schistosoma mansoni and Schistosoma haematobium. Before chemotherapy IgE- and IgG-containing CIC were present in high concentrations in all patients and IgE antibodies to S. mansoni and to S. haematobium in almost 80% of the cases. Serum IgE was excessively high (median 4,900 ku/1), but decreased to half of its initial value 2 months after chemotherapy. When reinfection with S. haematobium occurred onwards from month 4, the serum IgE reincreased and reached almost the pretreatment level at month 16. Effective chemotherapy was also followed by a rapid decrease of IgE-containing CIC and a slower, but significant, decrease of IgG-containing CIC. However, in contrast to IgE and IgE antibodies, the reinfection did not lead to a reincrease of CIC. It was interesting to note that the concentration of IgE as well as that of IgE-containing CIC was significantly correlated to the intensity of the infection. These investigations demonstrated that high levels of IgE- and IgG-containing CIC are present in chronic human schistosomiasis, but that the concentrations of CIC fall to normal values, when the parasites are eliminated by chemotherapy.