Background Syndecan-1 (CD138) a member of the integral membrane heparin sulfate proteoglycan family expressed by plasma cells, that has a relevant role on modulating leukocyte recruitment, matrix remodeling, maintaining vascular homeostasis and participating in the adequate functioning of glomerular filtration barrier. Recently, a possible association between CD138 levels and renal involvement in systemic lupus erythematosus (SLE) has been reported (1). On the other hand, B lymphocyte stimulator (BLyS) levels have been correlated with disease activity. To date, there is a lack of studies evaluating the relationship between CD138 levels with other pro-inflammatory molecules and autoantibodies implied in the involvement to organs in SLE.
Objectives To evaluate the association between serum levels of CD138, BLyS, anti-DNA and anti-nucleosome antibodies and clinical characteristics of organ involvement in SLE.
Methods We included 85 patients with SLE and 55 healthy controls. We assessed disease characteristics, disease activity score (m-SLEDAI), and clinical and laboratory variables related with organ involvement. Serum levels of CD138, BLyS, anti-DNA and anti-nucleosomes antibodies were quantified by ELISA. In the statistical analysis we evaluated the correlation between CD138 levels and BLyS with clinical and serological variables in SLE.
Results Higher levels of CD138 were observed in SLE compared with controls (104.1±71.2 vs. 83.9±50.4 respectively, p=0.040). Fifty-three (57%) patients with SLE had an active disease according to m-SLEDAI, and 29 (35%) had renal involvement. CD138 correlated positively with proteinuria (r=0.40, p<0.001), anti-DNA titers (r=0.42, p=0.001) and titers of anti-nucleosome antibodies (r=0.30, p=0.014), but did not correlate with serum creatinine (r=0.18, p=0.11). Instead, BLyS levels correlated significantly with higher creatinine serum levels (r=0.34, p=0.001), without a correlation with proteinuria (r=0.06, p=0.6). We did not observe a correlation between CD138 levels and BLyS (r=0.87, p=0.365) reflecting an independence between both biomarkers.
Conclusions These results suggest that CD-138 levels can be an independent biomarker from lupus nephropathy, correlating with proteinuria, anti-DNA and anti-nucleosome antibodies. A potential role of the changes of CD-138 levels as predictive factors for the development of relapses requires be evaluated in future longitudinal studies.
This project was financed by a grant of the Fondo de Investigacion en Salud del Instituto Mexicano del Seguro Social: (grant FIS/PROT/G13/1202).
Ki-Jo Kim,et al, Elevated Serum Levels of Syndecan-1 Are Associated with Renal Involvement in Patients with Systemic Lupus Erythematosus. J Rheumatol. 2014 Dec 15. pii: jrheum.140568.
Disclosure of Interest None declared