Background. Nucleotide deficiency in the diet of experimental animals reduces cellular immunity, and conversely it is assumed that an increased intake could improve the immunity also in humans. Methods and Results. The authors administered to 12 women with malignant tumours the dietetic preparation Preventan containing nucleotides, 1x 1 mg/day, and followed up for four weeks some immunological parameters. There was a considerable decline of CRP and conversely an increase in the number of T-lymphocytes (CD 3+ ), T-lymphocyte helpers (CD 4+ ) and suppressor/cytotoxic T-lymphocytes (CD 8+ ), almost to double values. There was also an increase of the cytotoxic activation and activated T-lymphocytes. As to parameters of humoral immunity, except for a small rise of IgG, no major changes were recorded and the number of B-lymphocytes did not change (CD 19 ). Conclusions. Supplementation with a dietetic preparation containing nucleotides increases the number of T-lym- phocytes, their sub-populations and their activation, and thus has a favourable impact on cell-mediated immunity as apparent from the marked decline of CRP.

        Key words: nucleotides, cellular immunity, T-lymphocytes.