The polymorphisms of T cell-specific TBX21 gene may contribute to the susceptibility of chronic immune thrombocytopenia in Chinese population.

Chronic primary immune thrombocytopenia (ITP) is an acquired autoimmune hemorrhagic disease characterized by both reduced platelet counts and suppression of megakaryocyte and platelet development. T cell-specific T-box transcription factor gene (TBX21) plays a critical role in the development and maintenance of T helper 1 (Th1) cells. Recently, several studies have confirmed that the T-1554C and T-1993C polymorphisms of this gene can influence its expression level and are associated with autoimmune diseases. Therefore, we speculated that TBX21 polymorphisms might be associated with the susceptibility of chronic ITP in Chinese population. We investigated the distributions of TBX21 (T-1514C and T-1993C) polymorphisms in 275 patients with chronic ITP and 261 healthy controls by polymerase chain reaction–restriction fragment length polymorphism. We observed significant overrepresentation of T allele and T/T genotype at T-1993C (but not T-1514C) in patients compared with controls. Stratified analysis by gender and age of disease onset revealed comparable observations in both female and childhood ITP cohorts. In conclusion, the T-1993C polymorphisms of TBX21 gene may be associated with the susceptibility of chronic primary ITP in Chinese population.