Study On The Mechanism Of Tumor Necrosis Factor - Related Apoptosis - Inducing Ligand In The Pathogenesis Of Polymyositis / Dermatomyositis

Objective:1. To analyze the correlated clinical significance by testing the serum tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) level of patients with polymyositis/dermatomyositis (PM/DM).2. To detect the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its death receptors DR4, DR5 on the surface of CD3+ T lymphocytes in patients with polymyositis/dermatomyositis (PM/DM), and investigate the effects of TRAIL on the apoptosis of CD3+ T lymphocytes.3. To study the effect of CD3+ T lymphocytes apoptosis in PM/DM induced by c-FLIP, caspase-8 through detect the expression of c-FLIP, caspase-8 on CD3+ T lymphocytes。Methods:1. sTRAIL was tested by enzyme-linked immunosorbent assay (ELISA). Blood samples were selected from 40 PM/DM patients and 20 healthy volunteers.2. The flow cytometry was employed to detect the expression of TRAIL and its death receptors DR4, DR5 on CD3+ T lymphocytes in 40 patients with polymyositis/dermatomyositis (PM/DM) and 20 healthy subjects. Simontaniously, the apoptosis rate of CD3+ T lymphocytes was detected by flowcytometry.3. The expression of c-FLIP, caspase-8 on CD3+ T lymphocytes was detected by Western BlottingResults:1. The serum level of sTRAIL in PM/DM patients was 1380.71±126.49 ng/L, which significantly higher than healthy control group’s 493.89±33.32 ng/L (P<0.05). And the serum levels of sTRAIL in PM/DM patients with dysphagia was 1775.76 ± 321.95 ng/L, which was significantly higher than 958.24±155.66 ng/L (P<0.05) from patients without dysphagia. There were no differences between sTRAIL from patients with or without interstitial lung disease (P>0.05). The serum levels of sTRAIL in Jo-1 positive group was 562.36±52.99 ng/L, which was significantly lower than in Jo-1 negative group’s 1334.57±181.21 ng/L (P<0.05). Spearman rank correlation analysis showed that level of sTRAIL was negatively correlated with lactic dehydrogenase (LDH) (r=-4.03, P<0.05)2. The expression rate of mTRAIL,DR4 and DR5 on CD3+ T lymphocytes in PM/DM group were 28.39±9.16,27.09±10.34,29.06±9.54,respectively.While in control group, the expression rate of mTRAIL,DR4 and DR5 were 19.87±8.40,19.72± 8.59,19.22±9.27,respectively (P<0.05). The apoptosis rate(%) of CD3+T cells cultured by different concentration (0,5,10,50,100ng/mL) of TRAIL in PM/DM group were 25.63±8.79,33.04±12.31,42.42±10.72,80.74±14.52,69.9± 16.99,respectively.And in control group, the apoptosis rate(%) were 18.72±12.48, 23.23±17.00,24.69±9.15,26.64±13.28,20.32±11.07,respectively.The apoptosis rate (%) of CD3+T lymphocytes in patient group was higher than in control group.3. According to the western blotting results, the expression of c-FLIP was 1.34±0.05, which was significantly higher than in control group 0.44±0.05 (P<0.01). However, the expression of Caspase-8 was 0.67±0.39,0.95±0.21 in PM/DM, control group respectively. And there was no significant difference (P>0.05)Conclusion:TRAIL plays a important role in pathogenesis of PM/DM and its abnormal expression is closely related to PM/DM patients’clinical features. The expression of TRAIL and its death receptors DR4, DR5 is augmented on the surface of CD3+ T lymphocytes, suggesting that the associated apoptosis may have played a role in the pathogenesis of (PM/DM).