Abstract: Objective To investigate the regulatory function of interleukin- 7 (IL- 7 ) to CD 14+ monocytes activity in children with idiopathic nephrotic syndrome (INS). Methods Thirty-three INS children and fifteen normal controls (NCs) were enrolled. Peripheral CD 14+ monocytes and CD 4+ T cells were isolated. Serum IL- 7 level was measured by ELISA. Mean fluorescence intensity (MFI) and mRNA relative level of CD 127 in CD 14+ monocytes was assessed by flow cytometry and real-time PCR, respectively. CD14+ monocytes from INS children were stimulated with recombinant human IL- 7 . Cytokine expression in cultured supernatants was measured by ELISA. The indirect and direct contact co-culture system was set up between CD 14+ monocytes and CD 4+ T cells. The percentage of interferon-γ-secreting Th 1 cells and IL- 17 -secerting Th 17 cells was measured by flow cytometry. Student t test or paired t test was used for comparison between the two groups. Results Serum IL- 7 was elevated in INS children compared with NCs (P< 0 . 0001 ). There were no significant differences of either CD 127 MFI or CD127 mRNA relative level in CD 14+ monocytes between NCs and INS children (P> 0 . 05 ). IL- 1 β, IL- 6 , IL- 8 , monocyte chemotactic protein- 1 , and tumor necrosis factor-α expression was elevated in IL- 7 stimulated CD 14+ monocytes from INS children compared with unstimulated cells (P<0 . 05 ). In direct contact co-culture system, CD 14+ monocytes from INS children raised Th1 and Th17 percentages in CD4+ T cells from INS children. Moreover, IL- 7 stimulated CD14+ monocytes induced higher Th1 and Th17 cells in comparison with unstimulated CD14+ monocytes (P<0 . 05 ). In direct contact co-culture system, anti-IL- 6 neutralizing antibody suppressed the elevation of Th1 cells, which induced by IL- 7 stimulated CD14+ monocytes from INS children. Conclusion IL- 7 promoted proinflammatory cytokines production by CD 14+ monocytes from INS children. IL- 7 stimulated CD14+ monocytes also induced CD4+ T cells activation via direct contact and IL- 6 secretion in INS children.

Key words: cytokine; monocytes; idiopathic nephrotic syndrome; immunoregulation