Objective: To study the efficacy and mechanism of thymosin alpha(1) (Talpha(1)) combined with high dose dexamethasone (HD-Dex) in patients with chronic idiopathic thrombocytopenic purpura.
Methods: (1) Out of sixty-six newly diagnosed patients with chronic idiopathic thrombocytopenic purpura, 27 patients received oral HD-Dex at single daily doses of 40 mg for 4 consecutive days, 39 patients received HD-Dex plus Talpha(1) 1.6 mg subcutaneously thrice weekly for 4 weeks. (2) The plasma levels of Talpha(1), IFNgamma, IL-2, IL-4, IL-10 and TGF-beta(1) of the 66 patients and 20 healthy controls were detected with ELISA.
Results: (1) Twelve patients (44.4%) in HD-Dex treatment group and thirty patients (76.9%) in HD-Dex plus Talpha(1) treatment group achieved complete response respectively (P < 0.05). After a follow-up period of 6 months, HD-Dex plus Talpha(1) treatment group showed a significantly greater rate of sustained response (24/39, 61.5%) and a lower replacing rate (15/39, 38.5%) than HD-Dex treatment group (9/26, 34.6%; 17/26, 65.4%) (P < 0.05). (2) After treatment, a remarkable decrease of Talpha(1) levels was seen HD-Dex plus Talpha(1) treatment group [(2.43 +/- 1.47), (1.83 +/- 1.22)] microg/L (P < 0.05). (3) In HD-Dex plus Talpha(1) treatment group, the plasma levels of both IFNgamma and IL-2 were significantly higher [(22.71 +/- 7.98), (28.42 +/- 11.27)] ng/L than those in controls [(10.23 +/- 3.97), (8.73 +/- 8.22)] ng/L (P < 0.01). The levels of both IL-4 and IL-10 were significantly lower [(5.93 +/- 3.85), (3.24 +/- 1.36)] ng/L after treatment as compared with those in the controls [(14.39 +/- 8.03), (8.67 +/- 3.04)] ng/L (P < 0.01). After treatment, IFNgamma and IL-2 decreased [(11.57 +/- 4.33), (14.56 +/- 10.76)] ng/L (P < 0.01) and IL-4 and IL-10 increased greatly [(9.87 +/- 4.82), (7.90 +/- 2.71)] ng/L (P < 0.05). (4) TGF-beta(1) in HD-Dex plus Talpha(1) treatment group significantly increased from [(1.31 +/- 0.71), (4.19 +/- 1.80)] microg/L after treatment (P < 0.01). (5) There was a significantly positive correlation between Talpha(1) and TGF-beta(1) (r = 0.6028, P < 0.05).
Conclusions: (1) Combination therapy of Talpha(1) and HD-Dex seems to be effective and safe in newly diagnosed patients with ITP. (2) Talpha(1) may balance the Th1/Th2/Th3 subgroups and induce a physiologic immunosuppressive effect of NK cells and autoimmune tolerance.