Immunoglobulin E: raised levels in sera and pleural exudates of patients with paragonimiasis.

Serum IgE concentrations of patients with paragonimiasis were determined by a radioimmunosorbent test. The mean concentration was 3,462.3 IU/ml in a group of 13 cases of paragonimiasis miyazakii in which patients showed clinical symptoms and/or positive immunological diagnostic tests, and 1,026.6 IU/ml in a control group of 13 individuals who had eaten uncooked freshwater crabs, Potamon dehaani, but had been found to be free from the infection. Moreover, the IgE level of the pleural exudates obtained from four patients with paragonimiasis miyazakii on the day of bleeding or within several days after was significantly higher than that of their sera, ranging between 4,200 IU/ml and 10,000 IU/ml. This was true also in a case of paragonimiasis westermani. Sera and pleural exudates of patients with both forms of paragonimiasis were applied to immunosorbent columns of Sepharose 4B beads coupled with saline extracts of Paragonimus miyazakii, P. weetermani, or P. ohirai. IgE eluted from the corresponding column was considered to be specific, being around 5% to 10% of the total IgE.