Glucocorticoids (GC) are used as the first-line treatment of immune thrombocytopenia (ITP), but 10-20% of patients are insensitive to them. Regulatory T cells (Tregs) can maintain immune tolerance in autoimmune diseases. The present research pooled 55 patients with newly diagnosed ITP and 44 healthy volunteers from seven hospitals. All patients received GC treatment and were divided into GC-sensitive and GC-insensitive groups according to the curative effect after 2 weeks of treatment. The levels of lymphocyte subgroups and Tregs were recorded. As the results indicated, the levels of CD8(+)CD25(str+) Tregs in the GC-sensitive group were significantly higher than that of the GC-insensitive group (P = 0 center dot 005). The optimal critical value of CD8(+)CD25(str+) Tregs to distinguish GC sensitivity was 0 center dot 09%. With GC therapy the level of CD45RO(+)/CD8(+)CD25(str+) Tregs (activated type) decreased after treatment (P = 0 center dot 02) and the level of CD45RO(-)/CD8(+)CD25(str+) Tregs (initial type) increased slightly (P = 0 center dot 11). There were no obvious changes in the level of CD4(+) Tregs. These findings support that the level of CD8(+)CD25(str+) Tregs and its subgroups have a predictive value in judging the sensitivity to GC among patients with ITP. Trial registration: ; ChiCTR-OON-17014165.