Urinary Transforming Growth Factor-beta Induced Gene-h3 (betaig-h3)as a Marker of Lupus Activity in SLE with Nephritis

Kim, Il; Hong, Cheol Ho; Cho, Hyun Seok; You, Sun Jin; Paik, Chang Hee; Lee, Hye Soon; Uhm, Wan Sik; Kim, Tae Hwan; Jun, Jae Bum; Yoo, Dae Hyun; Kim, Think You; Lee, Chang Hwa; Kang, Chong Myung; Park, Moon Hyang; Kim, In San; Bae, Sang Cheol

Abstract

BACKGROUND: TGF-beta-induced gene-h3 (betaig-h3) is a novel gene induced by active TGF-beta and the association with other renal disease is reported. Lupus nephritis is characterized by excessive extracelluar matrix accumulation and the implication that TGF-beta is increased in lupus nephritis is known. We measured the urinary betaig-h3 in lupus nephritis and sought its association with the activity of lupus nephritis through renal biopsy. The objective of this study was to examine urinary betaig-h3 excretion in lupus nephritis and the association with activity of lupus nephritis.
METHODS
Fifteen patients (median age 32.6 2.9 years, range 18~64) who developed lupus nephritis underwent renal biopsy. At the time of biopsy, they showed significant proteinuria. Total urinary betaig-h3 concentration was assayed by enzyme-linked immunoabsorbent assay and expressed as a ratio to urinary creatinine concentration.
RESULTS
There were correlations between urinary betaig-h3 and the reduction of C3 (r= 0.566, p=0.028<0.05), the magnitude of proteinuria (r=0.531, p=0.042<0.05). The Activity Index, Chronicity Index in the renal biopsy, C4, anti-dsDNA Ab titer were not significantly correlated with urinary betaig-h3 excretion, but the patients with high Activity Index had the increased level of urinary betaig-h3. Five patients who had fibrinoid necrosis in renal biopsy showed higher level of urinary betaig-h3 than the others (107.78 43.02 vs. 50.21 10.12 ng/ ml, p=0.061)
CONCLUSION
In this study, There is some correlation between urinary betaig-h3 and the activity of lupus nephritis. Urinary betaig-h3 may play a role in predicting the active lupus nephritis. A further study is needed in large population and in situ expression of betaig-h3.