RESUMO
OBJECTIVE: Nephrotic syndrome (NS) is characterized by marked urinary excretion of albumin and other intermediated-size plasma proteins such as transferrin. The aim of this study was to determine the changes of serum iron and transferrin and the relationship between the serum and urinary transferrin. METHODS: The indexes related to iron metabolism, including serum iron, ferritin, transferrin, total iron-binding capacity, transferrin saturation and hematological parameters (Hb, MCV, MCH), and urinary transferrin were measured in 37 children with NS before treatment and at the remission stage. Thirty-five age-matched healthy children served as controls. RESULTS: Serum iron levels (18.8 +/- 3.8 micromol/L) in NS patients before treatment were significantly lower than in the healthy controls (22.2 +/-3.8 micromol/L) and those measured at the remission stage (21.0 +/- 3.5 micromol/L) (P < 0.01). Serum transferrin levels in NS patients before therapy (1.9 +/- 0.3 g/L) also decreased compared with those in the healthy controls (3.1 +/- 0.5 g/L) and those measured at the remission stage (2.9 +/- 0.6 g/L) (P < 0.01). In contrast, serum total iron-binding capacity and transferrin saturation were noticeably higher in NS patients before treatment than those in the healthy controls (total iron-binding capacity 56.4 +/- 9.2 micromol/L vs 50.7 +/- 6.8 micromol, P < 0.01; transferrin saturation 55.7 +/- 9.2 % vs 46.4 +/- 8.2%, P < 0.01) and were also higher than those measured at the remission stage (51.9 +/-7.7 micromol/L and 47.4 +/- 13.3%) (P < 0.01). Serum transferrin positively correlated to serum albumin (r = 0.609, P < 0.01) and negatively correlated to urinary transferrin (r = -0.550, P < 0.01) in NS patients before treatment. CONCLUSIONS: Serum iron and transferrin levels markedly decreased in NS patients, which may be partially related to the urinary loss of transferrin.