JPP 2007, 59: 409–417 © 2007 The Authors Received February 1, 2006 Accepted October 23, 2006 DOI 10.1211/jpp.59.3.0011 ISSN 0022-3573 409 Measurements of oxidative stress status and antioxidant activity in chronic leukaemia patients Mohammed M. H. Al-Gayyar, Laila A. Eissa, Ahmed M. Rabie and Amal M. El-Gayar Abstract There is an interactive relationship between leukaemia and oxidative stress. Leukaemic cells pro- duce larger amounts of reactive oxygen species (ROS) than non-leukaemic cells as they are under a continual state of oxidative siege. So, this study was performed on 20 patients with chronic leukae- mia from the Oncology Centre, Mansoura University. We measured leucocytic H 2 O 2 concentrations and lipid peroxidation as serum malondialdehyde (MDA) concentration, serum total antioxidant activity, plasma ascorbic acid and dehydroascorbic acid concentrations, blood reduced glutathione concentration, haemolysate G6PD activity, blood catalase activity, serum superoxide dismutase (SOD) activity and serum anti-dsDNA concentration. We found that chronic leukaemia patients showed a significant increase (P < 0.05) in leucocytic H 2 O 2 , serum MDA concentration and total anti- oxidant activity either before or after treatment as compared with control group. Also, there was a significant increase in the other parameters (glutathione, catalase and SOD) either before or after treatment, but we found a significant decrease in ascorbic acid concentration and G6PD activity. There was a significant increase in anti-dsDNA concentration either before or after treatment. It can be concluded that leukaemic patients produce larger amounts of ROS than non-leukaemic patients. Also, the increase in antioxidant activity in leukaemic patients is not high enough to counteract the harmful effects of free radicals. This scenario becomes worse after administration of chemotherapy. Chronic leukaemia progresses slowly and permits the growth of a greater number of more developed cells. In general, these more mature cells can carry out some of their normal functions (Rozman & Montserrat 1995). It is classified into chronic lymphocytic leukaemia (CLL) and chronic myelogenous leukaemia (CML). CLL is characterized by accumulation of non-proliferative mature-appearing lymphocytes in blood, marrow, lymph nodes and spleen (O’Brien et al 1995). CML is a clonal stem-cell disorder characterized by prolifera- tion of myelogenous elements at all stages of differentiation (Bennett 1994). Reactive oxygen species (ROS) can initiate lipid peroxidation and DNA damage, leading to mutagenesis, carcinogenesis and cell death if the antioxidant system is impaired (Cross et al 1998). Carcinogenesis and mutagenesis by ROS could contribute to the initiation of cancer in addition to being important in the promotion and progression phase. There is evid- ence that hydroxyl radicals and singlet oxygens are formed in tumour cells and that they are the most powerful oxidizing radicals known to arise in biological systems (Gutowski et al 1998). Superoxide anions (generated by polymorph nuclear leucocytes) are increased in leukae- mic patients. The production of ROS in tumour cells by the action of superoxide anions may follow two pathways (Abou-Seif et al 2000). Firstly, the superoxide anion can react with Fe 3+ to produce Fe 2+ , which can catalyse a Fenton-type production of hydroxyl radicals from H 2 O 2 . This pathway can lead to vast metabolic consequences due to large changes in oxidation reduction potential of the cell. Reduction of H 2 O 2 with Fe 2+ in the presence of the superoxide anion can produce singlet oxygen. Secondly, increased load of superoxide anion can leak through leukaemic leucocytes and can either diffuse directly into the interior of red blood cells (RBCs) or generate an iron-mediated oxidation reduction flux, which can possibly Introduction Dept. of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt Mohammed M. H. Al-Gayyar, Laila A. Eissa, Ahmed M. Rabie, Amal M. El-Gayar Correspondence: L. A. Eissa, Dept. of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt. E-mail: lailaeissa2002@yahoo.com Acknowledgement: Deep appreciation is for all the staff of the Oncology Centre, Mansoura University, especially Dr Maha Ebrahim Esmael, Lecturer of Medical Oncology.