Alterations of IgE immunoglobulin concentration in the serum after megavoltage radiotherapy with large-field technique in patients with Hodgkin's disease.

In patients with Hodgkin's disease, the serum IgE concentrations were determined with the PRIST radioimmunoassay before commencing and after ending systemic megavoltage radiotherapy. 57 patients showed mainly raised serum IgE concentrations before radiotherapy. After the end of radiotherapy, 44 patients were investigated, and a highly significant fall of the IgE concentration was shown in the serum following the radiotherapy. The decrease of IgE concentration was most pronounced in the patients in whom large areas of irradiation were necessary or who displayed B symptoms. In a proportion of the patients, the IgE concentration in the serum could be measured once more six and twelve months after the end of radiotherapy. Although the IgE concentrations rose again after radiotherapy, the initial values before the beginning of radiotherapy had not yet been reached again even twelve months after treatment in 21 patients investigated. A long-lasting immunosuppressant effect of radiotherapy on the serum IgE concentration could thus be demonstrated which corresponds to the effect on the serum IgM concentration described earlier.