[Profiles of type 1 and type 2 T cells in chronic idiopathic thrombocytopenic purpura]

Abstract

Objective: To explore the profiles of type 1 and type 2 T cells in chronic idiopathic thrombocytopenic purpura (ITP) patients.

Methods: Samples of peripheral blood were collected from 30 chronic ITP patients, 8 males and 22 females, aged 34, 20 being in the active stage, and 10 in the remission stage, and 20 healthy persons, 7 males and 13 females, aged 31. Peripheral blood mononuclear cells (PBMCs) were isolated, cultured, and activated with PMA/ionomycin. Flow cytometry was used to measure the intracellular cytokines interferon (IFN)-gamma and interleukin (IL)-4 in the PBMCs so as to identify the Th1 cells (IFN-gamma(+) IL-4(+) CD4(+) cells), Th2 cells (IFN-gamma(-) IL-4(+) CD4(+) cells), Tc1 cells (IFN-gamma+ IL-4(-) CD8(+) cells), and Tc2 cells (IFN-gamma(-) IL-4(+) CD8(+) cells). The ratios of Th2/Tc2, Th1/Th2, and Tc1/Tc2 were calculated. Samples of spleen tissue were collected from 8 patients with chronic ITP, 3 males and 5 females, aged 30, and 6 patients with hereditary spherocytosis (HS), 3 males and 3 females, aged 35, who underwent splenectomy. Splenocytes were isolated, cultured, and activated with PMA/ionomycin. Real-time PCR was used to detect the mRNA expression of T-bet and GATA-3 in the PBMCs and splenocytes.

Results: The Th1/Th2 ratio of the patients in active stage was 25.62, significantly higher than those of the patients in remission stage (9.86) and the control (8.29, both P < 0.01), and the Tc1/Tc2 ratio of the patients in active stage was 30.23, significantly higher than those of the patients in remission stage (10.10) and the controls (12.58, both P < 0.01). The Th1/Th2 ratio of the splenocytes of the patients in active stage was 41.46, significantly higher than that of the controls (16.30, P < 0.01), and the Tc1/Tc2 ratio of the splenocytes of the active ITP patients was 35.80, not significantly higher than that of the controls (16.30, P = 0.082). The GATA-3 mRNA expression level of the PBMCs of the active ITP patients was one-fifth of that of the controls (P < 0.05) and the GATA-3 mRNA expression level of the splenocytes of the ITP patients was 0.34 of that of the HS patients (P < 0.05), however, there was no difference in the T-bet expression among the 3 groups. The T-bet/GATA-3 ratio of the PBMCs of the active ITP patients was 5.85 times that of the controls and the T-bet/GATA-3 ratio of the splenocytes of the active ITP patients was 2.68 times that of the controls (both P < 0.01).

Conclusion: ITP is a T1 cells (Th1 and Tc1) predominant disease. The T-bet/GATA-3 ratio may provide a surrogate marker of T1/T2 cytokine balance. Shifting the cytokine patterns from T1 to T2 may be a potential immunotherapy for ITP.