RESUMO
PURPOSE: This study was undertaken to investigate oxidant and antioxidant systems in patients with immune thrombocytopenic purpura (ITP). With this purpose, we measured the levels of serum malondialdehyde (MDA), total antioxidant capacity (TAC), total oxidant status (TOS), and other oxidative stress parameters. PATIENTS AND METHODS: Fifty-two pediatric patients with ITP (25 acute, 27 chronic) and 21 healthy children were included in the study. Patients with acute ITP were studied, before and after, methylprednisolone treatment. RESULTS: Hemoglobin, hematocrit, platelet count, and TAC were statistically significantly lower in patients with acute ITP before treatment than those in the control group (P<0.05). In addition, in this group, MDA, TOS levels, and OSI (oxidative stress index) were found to be higher than those in the control group. In chronic ITP group, although hemoglobin hematocrit, platelet counts, and TAC levels were statistically significantly lower than those in the control groups,the mean platelet volume, MDA, TOS, and OSI were found to be statistically significantly higher (P<0.05). Platelet count and mean platelet volume values were statistically significantly lower in patients with acute ITP before treatment than after treatment (P<0.05). We also found a positive correlation between thrombocyte count and TAC, in patients with acute ITP before treatment (r: 0.601, P<0.001) and acute ITP after treatment (r: 0.601, P<0.001) and chronic ITP (r: 0.601, P<0.001). A negative correlation was found between thrombocyte count and serum MDA levels, in patients with acute ITP before treatment (r: -0.356, P<0.001) and acute ITP after treatment (r: -0.356, P<0.001) and chronic ITP (r: -0.356, P<0.001). We also found a negative correlation between thrombocyte count and serum OSI, in patients with acute ITP before treatment (r: -0.494, P<0.001) and acute ITP after treatment (r: -0.494, P<0.001) and chronic ITP (r: -0.494, P<0.001). A negative correlation was found between thrombocyte count and TOS, in patients with acute ITP before treatment (r: -0.470, P<0.001) and acute ITP after treatment (r: -0.470, P<0.001) and chronic ITP (r: -0.470, P<0.001). In conclusion, increased MDA, TOS and OSI, and decreased TAC levels were found in patients with acute and chronic ITP. CONCLUSIONS: On the basis of these findings, we suggest that free oxygen radicals may have an effect on the structural and functional damage of platelets, and on the mechanism of thrombocytopenia in both, acute and chronic ITP.