Association of FOXP3 gene polymorphisms with chronic immune thrombocytopenia in a Chinese Han population

Forkhead box P3 (Foxp3) is encoded by the human FOXP3, an X-chromosome gene, and is a transcription factor that regulates regulatory T-cell (Treg) development and function. FOXP3 gene polymorphisms have recently been investigated as candidate risk factors in various autoimmune diseases. This study aimed to investigate the possible influence of FOXP3 gene polymorphisms on genetic predisposition to chronic immune thrombocytopenia (ITP).

The study cohort comprised 329 chronic ITP patients and 279 healthy controls, who were genotyped for three polymorphisms in the promoter region of FOXP3 gene, -6054 del/ATT, -3279 A/C, and -924 A/G.

Of the three polymorphisms identified, the -3279 AA genotype was more frequent in female patients with chronic ITP than in female controls (P = .035, OR 0.434, 95% CI 0.223-0.846), and the -3279 A carrier was shown to be associated with the risk of chronic ITP in female cohort (P = .003, OR 0.610, 95% CI 0.437-0.851). Furthermore, the female patients with chronic ITP had remarkably more frequent haplotype -6054 del/-3279 A/-924 A (P = .027, OR 3.584, 95% CI 1.148-11.186) and less haplotype -6054 del/-3279 C/-924 G (P = .039, OR 0.445, 95% CI 0.204-0.973) in comparison with female healthy controls. Although there were no significant differences in the male cohort, when the combined alleles and haplotypes of the two genders were analyzed, the results obtained were similar to those of females.

According to our data, the -3279 A/C polymorphism of FOXP3 gene may be associated with the susceptibility to chronic ITP in Chinese Han population.