The Expression Of Serum Ficolin-3 And Its Clinical Significance In Patients With Systemic Lupus Erythematosus

[Objective]To investigate the pathogenetic and diagnostic role of serum Ficolin-3 in systemic lupus erythematosus (SLE) patients.[Methods]The serum samples of 46 SLE patients,18 rheumatoid arthritis(RA) patients and 20 normal controls were collected to detect the level of Ficolin-3 by enzyme-linked immunosorbent assay(ELISA). Other clinical datas of SLE patients were obtained simultaneously, included antinuclear antibodies, anti-extractable nuclear antigen antibodies, anti-dsDNA antibodies, complements, blood routine, erythrocyte sedimentation rate, et al. The activity of SLE was valued by the SLE disease activity index (SLEDAI). The correlation of Ficolin-3 with some clinical symptoms and laboratory examinations in SLE was analyzed.[Results]The level of serum Ficolin-3 was (33.24±6.83)μg/ml in SLE patients, significantly higher than that in RA patients [(27.57±6.85)μg/ml, P= 0.02] and normal controls[(11.60±7.73)μg/ml, P= 0.00]. There was no significant difference of serum Ficolin-3 between the stable group and the active group of SLE [(32.91±6.36)μg/ml vs (33.46±7.23)μg/ml, P= 0.79], but both group had significantly higher serum level of Ficolin-3 than RA patients and normal controls (P<0.05). The level of serum Ficolin-3 in RA patients was also significantly higher than that in normal controls (P= 0.00).The serum level of Ficolin-3 in SLE patients without anti-Smith antibodies was significantly higher than that in SLE patients with anti-Smith antibodies [(34.45±6.86)μg/ml vs (29.82±5.71)μg/ml, P= 0.04]. The serum level of Ficolin-3 in SLE patients without anti-SSA antibodies was significantly higher than that in SLE patients with anti-SSA antibodies.[(35.59±7.02)μg/ml vs (31.09±6.02)μg/ml, P= 0.02]. The serum level of Ficolin-3 in SLE patients with thrombocytopenia was also significantly higher than that in SLE patients without thrombocytopenia.[(39.44±8.57)μg/ml vs (32.32±6.14)μg/ml, P= 0.02]. Furthermore, there was a inverse correlation between the level of serum Ficolin-3 and the platelets count (r=-0.45, P< 0.05. No correlation was found between the level of serum Ficolin-3 and the clinical manifestation,such as rash, photosensitivity, mucosal ulcer, arthralgia, nephropathy, serositis. (P > 0.05). There was no correlation of Ficolin-3 with some laboratory examinations, included antinuclear antibodies, anti-dsDNA antibodies, complements, SLEDAI, et al.If the cutoff value of serum Ficolin-3 was defined as 30μg/ml by the receiver operating characteristic curve (ROC), the sensitivity and specificity of Ficolin-3 for the diagnosis of SLE were 76.1% and 66.7%, the area under curve was 0.75. The positive rates of anti-Smith antibodies and anti-dsDNA antibodies in SLE patients were 26.1%(12/46) and 50%(23/46), respectively.While the positive rates of serum Ficolin-3 (≥30μg/ml) were 82.4%(28/34)and 69.6%(16/23) in patients without anti-Smith antibodies and anti-dsDNA antibodies. The positive rates increased to 87%(40/46) and 84.8%(39/46), respectively, if we combined the detection of Ficolin-3 with anti-Smith antibodies and anti-dsDNA antibodies. The anteroposterior rates had significant difference.[Conclusions]The expression of serum Ficolin-3 in SLE was significantly increased, especially in those patients with thrombocytopenia and negative anti-Smith antibodies and anti-SSA antibodies. This indicated a pathogenetic role of Ficolin-3 in SLE. The serum level of Ficolin-3 could help to diagnose SLE, and the combination of Ficolin-3 with anti-Smith antibodies and anti-dsDNA antibodies may significantly increase the sensitivity for the diagnosis of SLE.