Immunomodulation exerted by cyclophosphamide is not interfered by N-acetyl cysteine

Metabolism of cyclophosphamide (Cy) by liver enzymes results in cytostatic products and acrolein, which exerts urotoxicity. Experiments were designed to determine which metabolites are responsible for Cy-induced immunomodulation. For this purpose, mice were treated simultaneously with Cy and N-acetyl-cysteine (NAC), a thiol compound which reacts with acrolein, and different immunological functions were assayed. Results show that NAC did not interfere with Cy effects on antibody-dependent cellular cytotoxicity (ADCC), NK activity, delayed-type hypersensitivity (DTH) or antibody production, indicating that modulation of these functions by Cy is mediated by its cytostatic metabolites.