Objective To investigate the significance of interleukin-13 ( IL-13) in pat
ients with active lupus nephritis (LN).
Methods Ten healthy volunteers and 16 patients with active LN were included
in this study. The protein level of IL-13 in plasma was examined by enzyme
linked immunosorbent assay (ELISA), and gene expression of IL-13 in periph
eral blood mononuclear cells ( PBMCs) by reverse transcription polymerase c
hain reaction (RT-PCR). Expression of IL-13 mRNA in renal tissue was studie
d by in situ hybridization (ISH) techniques.
Results The level of IL-13 in plasma and the expression of IL-13 mRNA in PB
MCs were significantly higher in LN patients than those in the controls ( P
< 0.001). Increased expression of IL-13 mRNA was detected in renal tissue
of active LN patients compared to those in the controls ( P < 0.001). Analy
sis of the linear correlation indicated that the level of IL-13 mRNA in the
tubulointerstitial area in patients with active LN correlated with the con
centration of serum creatinine (Scr), the glomerular activity index (GAI),
the activity index of tubulointerstitium, and the level of serum C-3 ( P <
0.05 for each).
Conclusion The elevation of IL-13 may play an important role in the molecul
ar pathogenesis of active LN.