Increased nitric oxide production by T- and B-cells in idiopathic nephrotic syndrome.

The pathogenesis of idiopathic nephrotic syndrome (INS) remains unclear. To study the role of nitric oxide (NO) in INS, we measured intracellular NO produced by T- and B-cells using a novel fluorescent indicator. Twelve children with INS (mean age 7.3 years; group A-1: in relapse, group A-2: in remission) were enrolled in the study together with 16 children with other renal diseases (9.5 years; group B) and 42 healthy control children (7.7 years; group C). The amount of NO produced by CD3+ cells (T-cells) and CD19+ cells (B-cells) and of plasma NO(x) was measured by flow cytometry and colorimetry, respectively. The average amount of NO produced by CD3+ and CD19+ cells in group A-1 subjects was significantly higher than that produced by these cells in group A-2 and B patients and the healthy controls (group C), respectively (P < 0.01), and it decreased after the patients achieved remission (P < 0.01). Plasma NO(x) levels in group A-1 patients was also highest among the different groups (P < 0.01). There were no significant differences in intracellular NO and plasma NO(x) among group A-2, B, and C subjects (P > 0.05). A significant correlation between plasma NO(x) and urinary protein excretion was found only in group A patients and not in group B patients. We conclude that an aberrant immune system may exist not only in T-cells but also in B-cells, and NO may play some role in INS.