| Objective:To explore the mechanism and provide some guidance for the therapy of psoriasis with Triptolide, studies were performed on the ratio of regulatory T cells to total blood T cells of psoriasis patients and healthy controls , the expression of CD69 on blood T cells and blood T cells cycle in response to PHA or PDB plus Ion with different concentrations of Triptolide or Cyclosporin A (CsA )were also determined in these two groups.Methods:Comparative studies were performed between T cells from peripheral blood of psoriasis patients and healthy controls. The ratio of regulatory T cells to total T cells were detected by three-color immunofluorescence flow cytometry; The whole blood were preincubated with Triptolide or CsA for 30minutes and then were incubated with PDB plus Ion or PHA. The percentage of CD69 on T cells labeled with two-color immunofluorescence were determinated by flow cytometry. After lysing the red blood cells, the T cells stained with anti-CD3-FTTC and propidium iodide(PI) were underwent cell cycle studies in response to in vitro stimulation. All samples were detected and analysised by flow cytometer.Results:The percentage of CD4+CD25+T cells and CD8+CD28 T cells to total blood T cells of the psoriasis patients were 2.30±0.35 and 38.85±1.89, respectively, both significantly lower than those of the healthy controls,which were5.67±0.44 and 53.30±2.01,respectively (P<0.01). After treatment with Triptolide for 72h, the percentage of CD4+CD25+T cells to total blood T cells of the psoriassis patients and healthy controls were 2.18±0.32 and 5.58±0.45, while those of the negative controls were 2.21 ±0.41 and 5.64 ±0.56, respectively (P>0.05). The percentage of CD8+CD28- T cells to blood T cells of psoriasis patients and healthy controls were 37.95 + 1.42 vs 51.75 + 1.08, the percentage of the negative controls were 52.20±1.56 vs 38.34 ± 1.75 (P>0.05) .The percentage of CD69 expression on the psoriatic blood T cells incubated 4h with Triptolide and PDB plus ionomycin were 91.88±2.14, 85.45 ± 2.65, 35.34 ± 1.50 and 9.08 ±0.78, according to the concentration of Tri from 8ng/mL, 40ng/mL, 200ng/mL to 1000ng/mL, respectively; while those of the healthy controls were93.78±1.12, 86.10±2.51,39.10± 1.32 and 10.12±1.45, respectively.The same concentration of Triptolide also showed a inhibitory effect CD69 expression on blood T cells stimulated with PHA for 24h. In the psoriasis patients ,the percentage were 57.59± 1.56, 30.06 ± 1.41, 9.81 ± 1.12 and 6.35 ± 1.04, respectively;while those of the healthy controls were 58.72±1.89, 31.27±1.16, 10.19±0.93 and 6.65± 1.13, respectively .The inhibitory effect of Tri was in a dose-dependent manner.Triptolide could block blood T cells cycle progression from G0/G1 phase to S and G2/M phase without phase specificity. Besides ,vital staining analysis revealed that Triptolide did not have significant cytoxicity on blood T cells.Conclusion:The present study shows that psoriasis patients have abnormal T cells activation in peripheral blood .The percentage of regulatory T cells is lower in psoriasis than that of the healthy controls. Triptolide can significantly inhibit CD69 expression on T cells and blocks the T cells cell cycles progression in response to in vitro mitogen stimulation.These results suggest that Tri exerts immunosuppression effect through inhibiting the activation and proliferation of T cells .These data provide useful information about the mechanism underlying effectiveness of Triptolide on treatment of psoriasis.
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