Levels And Clinical Significance Of S100A8/A9 In Serum Of Patients With Lupus Nephritis

Objective: Lupus nephritis is one of the most common complications of systemic lupus erythematosus which are often accompanied by multiple-system and multiple-organ damage. Lupus nephritis is the most important cause of disability and death in SLE. Although the pathogenesis of LN is not yet entirely clear, imbalance of the secretion of the cytokine network plays a major role in the lupus nephritis. S100A8 and S100A9 are calcium binding proteins of the S100 family in a calcium-dependent manner. It is an important pro-inflammatory cytokine. In recent years,S100A8/A9 plays an important role in autoimmune diseases such as rheumatoid arthritis, inflammatory bowel disease,sjogren’s syndrome; but its expression and possible mechanisms in lupus nephritis are lack of relevant research. We tested level of S100A8/A9 in serum of patients with lupus nephritis and analyzed the relation between S100A8/A9 and clinical parameters to explore its clinical significance.Methods: Fifty-eight patients with LN were selected in accordance with the inclusion and exclusion criteria. There were 50 female patients and 8 male patients. The mean age was(35.93±14.31) years. Patients with LN(LN group) were divided into LN active group with more than 10 points(n=38)and LN inactive group with less than 10 points( n=20) by systemic lupus erythematosus disease activity index. Thirty healthy controls(control group) were individually matched for sex, age and body mass index. Serum levels of S100A8/A9 of LN group and control group were detected by enzyme-linked immunosorbent assay. We used spass13.0 software to analyze data. Rank test was used for comparisons between LN group and control group; one-way analysis of variance was used for comparisons among LN active group, LN inactive group and control group. Spearman rank correlation test was used for correlation analysis. A P-value of 0.05 was regarded as statistically significant difference.Results: 1.Serum level of S100A8/A9 was significantly higher in LN group than those of control group(p<0.01); 2.Serum level of S100A8/A9 was significantly higher in active LN group than in inactive LN group and healthy group,(p<0.01). Serum level of S100A8/A9 was not significantly higher in inactive LN group than in control group(p>0.05); 3.Serum level of S100A8/A9 was positively correlated with anti-dsDNA, c-reactive protein, serum creatinine, 24-hour urine protein and SLEDAI scores(p<0.01 or p<0.05); serum level of S100A8/A9 was negatively correlated with complement C3, C4 and creatinine clearance(p<0.01 or p<0.05). There was no correlation between serum level of S100A8/A9 and erythrocyte sedimentation rate(p>0.05).Conclusion: S100A8/A9 may be involved in the occurrence and development of lupus nephritis. Dynamic observation of serum S100A8/A9 level contributes to monitor LN activity, evaluate the severity of kidney damage, which have important clinical significances for treatment options, efficacy and prognosis in LN patients.