Restoration of functional defects in peripheral blood mononuclear cells isolated from cancer patients by thiol antioxidants alpha-lipoic acid and N-acetyl cysteine.

The ability of Alpha-Lipoic Acid (ALA) and N-Acetyl Cysteine (NAC), two active antioxidant agents, to correct in vitro the most significant functional defects of peripheral blood mononuclear cells (PBMC) isolated from advanced stage cancer patients was studied. The proliferative response of PBMC isolated from cancer patients to anti-CD3 monoclonal antibody (MAb) and the expression of CD25 (IL-2R) and CD95 (Fas) on unstimulated and anti-CD3 MAb-stimulated PBMC were studied, and the serum levels of proinflammatory cytokines IL-1, IL-6, TNFalpha as markers of pro-cachectic activity in cancer patients, and the serum levels of IL-2 and sIL-2R were assessed. Twenty patients (mean age 64.6 years) with cancer of lung, ovary, endometrium, and head and neck, all in advanced (III, IV) stage of disease, were studied. The serum levels of IL-1beta, IL-2, IL-6, TNFalpha, and sIL-2R were significantly higher in cancer patients than in normal subjects. The response of PBMC isolated from cancer patients to anti-CD3 MAb was significantly lower than that of controls. The addition of either ALA 0.001 mM or NAC 0.004 mM in the PBMC cultures stimulated with anti-CD3 MAb significantly increased the response of PBMC isolated from cancer patients and normal subjects. After 24 and 72 hr of culture with anti-CD3 MAb, the expression of CD25 and CD95 on PBMC isolated from cancer patients was significantly lower than that of PBMC isolated from normal subjects. The addition of either ALA or NAC into cultures of PBMC isolated from cancer patients significantly increased the percentage of cells expressing CD25 as well as those expressing CD95. The results of the present study show a favorable effect of antioxidant agents ALA and NAC on several important T-cell functions in vitro in advanced-stage cancer patients.