Type 1 and Type 2 T-cell Profiles in Idiopathic Thrombocytopenic Purpura

Background And Objectives: Adult idiopathic thrombocytopenic purpura (ITP) is a chronic acquired organ-specific autoimmune hemorrhagic disease characterized by the production of antibodies against antigens on the membranes of platelet, resulting in enhanced Fc-mediated destruction of the platelets by macrophages in the reticuloendothelial system. Dysfunctional cellular immunity is considered important in the pathophysiology of ITP. The aim of this study was to explore the profile of type1 and type2 T cells in chronic ITP patients.

Design And Methods: The balance of Th1/Th2 and Tc1/Tc2 was studied by simultaneous analysis of intracellular cytokines of peripheral blood mononuclear cells and splenocytes in short-term cultures activated with PMA/ionomycin as well as mRNA expression of T-bet and GATA-3 in peripheral blood mononuclear cells and splenocytes using real-time polymerase chain reaction.

Results: Patients with active disease but not patients in remission had significant higher Th1/Th2 (p<0.01) and Tc1/Tc2 (p<0.01) ratios in peripheral blood (PB) and significant higher Th1/Th2 ratio in splenocytes (p<0.01) than those in the control group. The Tc1/Tc2 ratio in splenocytes in ITP patients was higher than that in control, but did not reach significant difference (p=0.082). GATA-3 mRNA expression in ITP patients was significantly lower both in PB (p<0.01) and in splenocytes (p<0.01) than in corresponding samples from controls while there was no difference in T-bet expression.

Interpretation And Conclusions: Our data indicate that ITP is a T1 cell (Th1 and Tc1) predominant disease although the precise mechanisms await further functional assay. The T-bet/GATA-3 ratio may provide a surrogate marker of T1/T2 cytokine balance. Shifting the cytokine patterns from T1 to T2 might be a potential immunotherapy for ITP.