Background: Nephrotic syndrome (NS) defined by massive continued losses of urinary proteins, resulting in hypoalbuminemia and edema. These are associated with complications such as increased susceptibility to infections, thromboembolism, altered lipid and carbohydrate metabolism and losses in binding proteins in the urine. Aim of the study: To evaluate the cytokines levels in different stages of idiopathic nephrotic syndrome (INS) and to determine the histopathological pattern of INS. Patients and Methods: Fifty two children with INS were divided into; steroid-sensitive group I (SS) (18/52) and steroid-resistant group II (SR)(34/52). Both groups subdivided into SS in relapse IA (8/18), SS in remission IB (10/18), and SR in relapse group IIA (25/34) and in remission group IIB (9/34). Twenty age-matched controls compared with data. The following parameters had assessed; serum levels of IFN-γ, IL-2, IL-4, IL-13 and IL-18 by using quantitative colorimetric ELISA test. Renal biopsy specimens were histopathologicaly studied. Results: Serum IFN-γ levels were significantly lower in the relapse phase of SS compared with the remission phase and controls. On the contrary, serum IL-4 and IL-13 levels were significantly higher in the relapse phase of SS and SR compared with the remission phases and controls. IL-18 levels were significantly higher in the relapse phase of SS and SR subgroups compared with the remission phases and the controls respectively. IL-4 and IL-13 significantly correlated with IL-18. All 34 SR nephrotic patients were submitted to renal biopsies, which showed focal segmental glomerulosclerosis (FSGS)(59%) the most common diagnosed entities of INS. Conclusions: Type-2 cytokines predominate in relapse phase of SS and SR patients and one could predict a good response to steroid therapy. IL-18 expression significantly correlated with this type-2 immune response. The primary glomerular diseases in Saudi children and FSGS are the most common diag-nosed entities.
Key words: Cytokines; Histopathological; Idiopathic; Nephrotic Syndrome; Children.