Monitoring of interferon treatment in patients with renal cell carcinoma and bladder carcinoma by oligo-A synthetase assay and determination of immunological parameters.

In order to evaluate whether the 2,5-oligo-A synthetase (OAS) is a reliable marker for monitoring a systemic interferon treatment 7 patients suffering from recurrent superficial carcinoma of the bladder and 4 patients with metastatic renal cell carcinoma were monitored during systemic interferon (IFN) treatment. Throughout the study, human recombinant IFN alfa-2c and IFN gamma was used. The 2,5 oligo-A synthetase levels, the natural killer (NK) cell activity and the antibody dependent cellular cytotoxicity (ADCC) were determined according to a defined time schedule after intramuscular (i.m.) administration of IFN. Compared to pretherapeutic values, the 2,5 oligo-A synthetase level of peripheral blood mononucleocyte cells increased 4-10 fold in 8 out of 10 patients after the first IFN administration. The NK-cell activity and the ADCC were augmented too. This, however, was only a short term effect. Stimulation of cellular resistance occurred with the same time course as the elevation of the OAS levels. It can therefore be concluded that determination of OAS levels during interferon therapy can replace measurement of other parameters with regard to stimulation of cellular cytotoxicity.