Evaluation of visfatin in patients with systemic lupus erythematosus: Correlation with disease activity and lupus nephritis

ABSTRACT

Renal involvement affects about 50% of SLE patients accounting for significant morbidity and mortality in these patients. The adipokine "visfatin" acting as a growth factor for B-lymphocyte-precursors, exerts several proinflammatory functions. It was demonstrated as a marker of endothelial dysfunction [ED] in chronic kidney disease [CKD] thus could be a factor linking inflammation in SLE and kidney disease. To assess serum visfatin level in SLE patients and its correlation to disease activity and lupus nephritis [LN] in these patients. Serum level of visfatin using enzyme-linked immunosorbent assay [ELISA], chemical and immunological markers of SLE and LN were measured in 40 SLE patients and 40 age and sex matched healthy controls. Disease activity and renal involvement were assessed using SLE Disease Activity Index [SLEDAI] and Renal SLEDAI respectively further dividing patients into active versus inactive and LN versus non-LN respectively. Renal biopsies were taken from LN subgroup and were classified according to the modified WHO classification. A significantly higher serum visfatin level was found on comparing SLE patients [mean 109 +/- 180 ng/ml, median18] with controls [mean 9.4 +/- 11 ng/ml, median2.5] with statistically highly significant difference [z = 5.2, P < 0.001]. Also there was a statistically significant difference as regards serum visfatin level between active SLE patients [mean 173 +/- 111 ng/ml, median 14] and inactive patients [mean 139 +/- 88 ng/ml, median 5] [z = 2.1, P < 0.05] as well as between patients with LN [mean 226 +/- 180 ng/ml, median18] and patients with no LN [mean 101 +/- 140 ng/ml, median 8[2-229]] [z = 2.1, P < 0.05]. Visfatin had a highly significant positive correlation with disease duration [r = 0.48, P < 0.001], SLEDAI [r = 0.62, P < 0.001] as well as ESR, CRP and, renal score [r = 0.45, 0.35, and 0.65, respectively] while inverse correlation with estimated GFR [r = -0.614] and C3 and C4 titre [r = -0.26, r = -0.35, respectively] was recorded. Visfatin showed high sensitivity in detecting active SLE and LN 83% and 85%, respectively. Serum visfatin is strongly associated with LN in SLE patients and is a promising biomarker for prediction of renal involvement in these patients. It reflects SLE activity specially LN activity namely renal score and GFR decline. Further prospective studies are required to confirm visfatin as a destructive mediator of predictive and prognostic value in active lupus nephritis