皮肌炎患者外周血BDNF水平及受体TrkB在T淋巴细胞表达的研究

The level of BDNF in peripheral blood and expression of receptor TrkB in T lymphocytes in patients with dermatomyositis

目的检测皮肌炎(DM)患者血清中脑源性神经营养因子(BDNF)水平及T淋巴细胞表达酪氨酸激酶B(TrkB)的情况。方法选取25例DM患者,健康对照28例,采用酶联免疫吸附方法检测DM组及健康对照组血清BDNF水平,流式方法检测两组外周血CD3^+CD4^+和CD3^+C D8^+T淋巴细胞表面TrkB的表达情况。根据肺受累情况将DM组分为合并间质性肺炎与不合并间质性肺炎两组。采用魏氏法收集DM患者血沉,免疫比浊法测定C反应蛋白、D二聚体与免疫球蛋白IgG、IgM、IgA,鞘流电阻抗法测定血淋巴细胞数与血小板数,磁珠凝固法测定纤维蛋白原,分析实验室指标与血清BDNF水平的相关性。结果 DM患者血清BDNF水平明显降低,合并间质性肺炎的DM组血清BDNF水平显著低于无间质性肺炎组。DM患者外周血CD3^+CD4^+和CD3^+C D8^+T淋巴细胞表面TrkB表达比例显著增加,DM患者血清BDNF水平与D-二聚体呈负相关,与淋巴细胞计数和血小板计数均呈正相关。结论血清BDNF水平和T淋巴细胞表面TrkB的表达比例可能成为DM患者疾病活动的血清学标记物,尤其是血清BDNF水平严重下降可能预示肺受累。

Objective To investigate serum brain-derived neurotrophic factor(BDNF) level and tyrosine kinase B(TrkB) expression on peripheral blood T cell surface in patients with dermatomyositis(DM). Methods Samples from twenty-five DM patients and twenty-eight healthy controls were evaluated. Serum BDNF level was measured by enzymelinked immunosorbent assay(ELISA) and the percentages of TrkB expression on the surface of CD3^+ CD4^+ and CD3^+ CD8^+ T lymphocytes were measured by flow cytometry. The DM patients were divided into subgroups according to whether they exhibited lung involvement. The erythrocyte sedimentation rate(ESR) of in patients with dermatomyositis was collected by widmanstatten method, the C-reactive protein, D-dimer and immunoglobulin IgG, IgM, IgA were measured by immunoturbidimetry, the number of blood lymphocytes and platelets were measured by sheath impedance method, the fibrinogen was measured by bead coagulation method, and the correlation between laboratory indexes and BDNF level in serum was analyzed. Results Serum BDNF levels in DM patients were decreased(P<0.001). Compared with the DM patients without lung involvement, the BDNF level was decreased in DM patients with lung involvement(P=0.028). In addition, the percentages of TrkB expression on CD3^+ CD4^+ and CD3^+ CD8^+ T cell surface in SLE were significantly higher(P=0.008, P=0.007, respectively). The BDNF level in serum of DM patients was negatively correlated with D-dimer, positively correlated with lymphocyte count and platelet count. Conclusion BDNF level in serum and TrkB expression on T cell surface is a potential serological biomarker for disease activity of DM, the decreased BDNF level in serum imply lung involvement of DM.