Chemicals: Most of parameters under study were measured by using kits of high quality.
Ethics approval and consent to participate: Written informed consent was obtained from all participants enrolled in the study. The study protocol was approved by the ethical committee of College of Medicine, King Faisal University, Al-Ahsa in collaboration with the King Fahd Hospital, Saudi Arabia.
The present study included 50 male subjects infected only with cutaneous leishmania selected from Center for the Control of Vector Control Leishmania and Malaria, Al-Ahsa City, Saudi Arabia while their age and gender matched controls (N=30) were randomly selected from those attending other clinics or accompanying patients and exhibiting no cutaneous lesions or prior CL history. The duration of illness for CL subjects 4-6 months. Fasting 10 ml blood in the morning were withdrawn from both groups separately at the leishmanial center, Al-Ahssa, Saudi Arabia and immediately transferred from the center of leishmania to our laboratory at the College of Medicine, King Faisal University in an icebox. Each sample was centrifuged at 4000 rpm and the serum was separated and stored at -20oC until analysis. After withdrawing the blood samples from the untreated patients, they were treated by intramuscular injection of sodium stibogluconate (20 mg/kg/day intramuscularly) for 28 days. After 60 days after stop treatment (i.e. after 28 days treating), 10 ml blood freshly samples were withdrawn from the treated patients. The number of the subjects who followed up after treatment is 41. All subjects did not have any medicine for at least a month before taking the blood sample.
Inclusion Criteria: The study was performed in the steady state, i.e., free of acute clinical illness. Furthermore, the patients included in the present study suffered from only CL, while patients who suffered from other diseases CL were excluded.
I- Assays of immune enzymes
i) Estimation of L-Arginase activity (mU/g protein)
The blood arginase activity (ARG, EC. 188.8.131.52) was determined by the method of Iyamu et al. . The L-ornithine produced from L-arginine by ARG was measured to determine the activity of the ARG. ARG activity was expressed in µmol L-ornithine/ min/ per g protein [U/g].
ii) Estimation of Myeloperoxidase activity
Myeloperoxidase activity was measured spectrophotometrically according to the method described by Krawisz et at., . 0.1 ml of serum was combined with 2.9 ml of 50 mM phosphate buffer, pH 6.0, containing 0.167 mg/ml 0-dianisidine hydrochloride and 0.0005% hydrogen peroxide. The change in absorbance at 460 nm was measured with a Boeco S-20 spectrophotometer (Boeco S-20 Spectrophotometer, Hamburg, Germany). One unit of MPO activity was expressed as U/g protein
iii) Estimation of Adenosine deaminase activity:
Serum ADA activity was measured spectrophotometrically according to the method of Giusti and Galanti , in which NH3 generated via the effect of ADA on Adenosine (its substrate). The blue color formed from the reaction of NH3 with indophenol is measured spectrophotometrically at 628 nm. ADA levels were calculated and expressed in unit per g protein (U/g protein).
II- Assays of Antioxidants/Oxidant products
i) Estimation of Superoxide dismutase (SOD) activity. The method described by Halliwell and Gutteridge , was used to estimate the total SOD activity spectrophotometrically (Boeco S-20 Spectrophotometer, Hamburg, Germany) by using test kit obtained from SpinReact Biodiagnostic, Cairo, Egypt. The activity was expressed as percentage of inhibition of formazan/g protein.
ii) Estimation of Catalase (CAT) activity. CAT activity was measured measured spectrophotometrically (Boeco S-20 Spectrophotometer, Hamburg, Germany) according to the Johansson and Borg , method using a standard CAT assay kit Biodiagnostic, Cairo, Egypt, through following the decomposition rate of H2O2 at 240 nm. The results were expressed as U/g protein.
iii) Estimation of Glutathione peroxidase (GSH-Px) activity. GSH-Px activity was assayed based on the decrease of NADPH absorbance at 340 nm according to the method of Flohé and Günzler , by using a diagnostic kit provided by Biodiagnostic, Cairo, Egypt. The results were expressed as mU/g protein.
iv) Determination the reduced glutathione (GSH) concentration
Reduced glutathione (GSH) concentration was determined using the method described by Beutler et al. employing 5,5′-dithiobis(nitrobezoic) acid forming with glutathione thiol groups colored adduct, with spectrophotometric measurement at 412 nm. The results are expressed as μmol/g protein 18].
v) Determination of malondialdehyde (MDA) level. MDA, an end product of Lipid peroxidation, was measured by the method as outlined by Esterbauer et al.,  in which MDA reacts with thiobarbutiric acid (TBA), forming a colored thiobarbituric acid reactive substance (TBARS) complex which was quantified spectrophotometrically at 535 nm by using a diagnostic kit supplied by Biodiagnostic, Cairo, Egypt. The amount of TBARS was calculated using an extinction coefficient of 1.56 × 10−5/M/cm and expressed in nanomoles of MDA per gram protein.
vi) Determination of NO level: The produced nitric oxide (NO) was determined indirectly by measuring the nitrite levels based on Griess reaction .
vi) Serum Protein Estimation: Serum protein content was determined according to the method of Bradford  using bovine serum albumin as standard.