[Role of Toll-like receptor 2 in primary immune thrombocytopenia]

The aim of this study was to explore the role of Toll-like receptor (TLR) 2 in primary immune thrombocytopenia (ITP) by detecting TLR2 expression in the peripheral blood lymphocytes of patients with ITP and evaluating the role of TLR2 activation on inflammatory cytokine secretion. A total of 39 ITP patients and 21 normal controls were enrolled in this study. The expression of TLR2 was detected by real-time PCR and flow cytometry, and the concentration of IL-6 and TNF-α in culture supernatant of PBMNC treated with pam3CSK4 for 48 hours were detected by ELISA. The results showed that the expression of TLR2 mRNA in active ITP patients (3.561 ± 0.741) was significantly higher than that in normal controls (1.750 ± 0.314) (P < 0.05), but there was no statistically significant difference between remission ITP patients (2.333 ± 0.448) and normal controls (P > 0.05) . Flow cytometry analysis found that the TLR2 was not expressed on T and B cells, but expressed on all monocytes both from ITP patients and normal controls. Further activation experiment showed that TLR2 activation in vitro could induce the expression of IL-6 (1644 ± 634.0 vs 4111 ± 525.2 pg/ml) and TNF-α (75.37 ± 22.31 vs 326.0 ± 109.9 pg/ml) in PBMNC from ITP patients (both P < 0.05), but just could promote IL-6 expression in normal controls (2119 ± 636.9 vs 4671 ± 315.9 pg/ml)(P < 0.05). It is concluded that the expression of TLR2 mRNA is up-regulated in PBMNC of ITP patients, and this increased TLR2 maybe participate in ITP through inducing secretion of inflammatory cytokines.