Study of T-cell immunoglobulin- and mucin-domain-containing molecule 3 polymorphisms in Egyptian childhood immune thrombocytopenic purpura

The T-cell immunoglobulin- and mucin-domain-containing molecules (TIMs) influence immune regulation. TIM-3, a transmembrane protein expressed on terminally differentiated Th1 cells, is a central regulator of T-cell responses. Dysfunctional T-lymphocyte immunity plays an important role in the pathophysiology of immune thrombocytopenic purpura (ITP). The study aimed to evaluate the possible contribution of TIM-3 polymorphisms to the pathogenesis of ITP and their relation to age of disease onset, clinical course, and response to therapy. Genotyping of TIM-3 -1516G>T, -574T>G, and 4259G>T was performed in 100 childhood ITP patients and 210 healthy individuals by polymerase chain reaction-restriction fragment length polymorphism. No significant differences existed in genotype and allele distributions between patients and controls in all three sites. There was a statistically significant association between the -574T>G T/T genotype and both a lower platelet count and a younger age of disease onset (p = 0.001). A near significant association was found between the 4259G>T T/T genotype and increased disease severity at diagnosis and also between both -574T>G G/G and 4259G>T T/T and a better quality of response (p = 0.07). The study did not detect a risk association between the TIM-3 single-nucleotide polymorphisms and ITP susceptibility. However, it is associated with an earlier disease onset and severity as indicated by the lower platelet count. © 2013 Springer-Verlag London.