Inhibition of platelet aggregation and immunomodulation of NK lymphocytes by administration of ascorbic acid.

Platelets aggregation around migrating tumor cells offers protection against the cytotoxic activity of the natural killers cells (NKC). The ascorbic acid in 3 x 10(-3) M concentration completely inhibited platelet aggregation, decreased thromboxane B2 levels, and inhibited the expression of platelet membranic receptor GpIIb/IIIa in non stimulated platelets, and increased the NKC cytotoxicity in an average rate of 105, 61, and 285% in the NKC/targets cells ratios 12.5:1, 25:1 and 50:1 respectively. The results suggest the role of ascorbic acid in increasing the susceptibility of tumor cells to NKC; the ascorbic acid could be used as part of a multidrug therapy to treat diseases which up to now have been treated only through chemotherapy.