The clinical significance of soluble Mer receptor tyrosine kinase in serum of systemic lupus erythematosus / 中华风湿病学杂志

ABSTRACT

Objective To investigate the clinical significance of soluble Mer receptor tyrosine kinase (sMerTK) in patients of systemic lupus erythematosus.Methods sMerTK was detected in the serum of 101 SLE patients,96 disease controls and 62 healthy controls (HC) by sandwich enzyme-linked immunosorbent assay (ELISA).The relationships between the serum levels of sMerTK and clinical manifestations,laboratory parameters,disease activity were investigated in SLE patients.Comparisons between groups were tested by t-test and x2 test,Correlation of parameters were analyzed by Spearman method.Results sMerTK levels in SLE patients [(10.6±6.0) ng/ml] was significantly higher than disease controls [(4.4±2.0) ng/ml] (t=9.704,P＜0.01) and healthy controls [(2.8±2.5) ng/ml] (t=11.505,P＜0.01).The concentrations in SLE patients were independent of gender,age and disease duration.The levels of sMerTK were negatively correlated with white blood cell (r=-0.236,P=0.017),hemaglobin(r=-0.354,P＜0.01),platelet values (r=-0.310,P=0.002).Compared with the patients without lupus nephritis (LN)[(9±6) ng/ml],patients with LN had higher concentrations in serum [(11±6) ng/ml],and the difference was statistically significant (t =2.071,P=0.041).In addition,sMerTK levels were also correlated with 24 h-urinary protein level (r=0.293,P=0.013),serum creatinine (r=0.250,P=0.035) and e-GFR (r=-0.201,P=0.045).Furthermore this study indicated that sMerTK was negatively correlated with C3 (r=-0.447,P＜0.01) and C4 (r=-0.357,P＜0.01)level,but positively correlated with anti-dsDNA antibody titers (r=0.360,P＜0.01),anti nucleosome antibody (AnuA) (r=0.264,P=0.016) and SLEDAI (r=0.473,P＜0.01).Conclusion sMerTK level is increased in SLE patients.The concentration may associate with hematology changes and lupus nephritis.It may be an indicator of disease activity.