IMMUNOLOGICAL ALTERATIONS INDUCED BY ADJUVANT TREATMENT OF POSTOPERATIVE COLON-CARCINOMA DUKES-B OR DUKES-C WITH LEVAMISOLE IN COMBINATION WITH 5-FU

Background: Postoperative 5-FU combined with levamisole increases 5 ye ar survival in colon cancer patients (Duke C) by 30% (1). In order to investigate the potential immunological mechanism, we determined lymph ocyte subtypes and markers of immune activation in 22 patients before and during one year of postoperative adjuvant treatment. Methods: Befo re and regularly during treatment, according to the scheme described b y Moertel (1), major lymphocyte subsets were quantified by flow cytome try. Serum neopterin, soluble IL2-receptors, beta 2-microglobulin, TNF -alpha and interferon-gamma were determined by Elisa. Results. The CD4 /CD8 ratio increased significantly after levamisole was added to the t reatment, as did the levels of soluble IL2-receptors. The percentages of T-cells expressing the interleukin 2 receptor followed a similar tr end The levels of neopterin tended to decrease during the combined tre atment course. This was paralleled by a progressive fall in the propor tion of T-cells expressing HLA-DR. Conclusion: The treatment induced s ignificant and consistent alterations in major immunological mediators and lymphocyte subtypes. It remains to be established whether these c hanges are related to the therapeutic effect.