Role Of CXCR3and Its Ligand I-TAC In The Pathogenesis Of Immune Thrombocytopenic Purpura

Objective To investigate the roles and significance of the chemokine receptorCXCR3and its ligand I-TAC in the pathogenesis of immune thrombocytopenicpurpura (ITP) and to make clear their levels after immunosuppresive therapy.Methods A total of48ITP patients were enrolled in this study:30with newlydiagnosed or relapse ITP and18in remission after treatment, as well as24healthyvolunteers as controls. Gamma interferon (IFN-γ) and I-TAC in the plasma weredetected by enzyme-linked immunosorbent assay (ELISA). The mRNA expression ofCXCR3in the peripheral blood mononuclear cell (PBMNC) was determined byquantitative real-time polymerase chain reaction (RT-PCR).Results The IFN-γ level in the plasma of ITP patients before the treatment（71.45±17.62pg/ml） were obviously increased than those in the remission group（36.9±14.9pg/ml）and the normal controls（25.28±12.85pg/ml）(all P<0.05), andthose in remission group was higher than those in the controls (P<0.05). In contrast,the levels of I-TAC, there were no statistic difference among patients before thetreatment of ITP（455.56±144.700pg/ml） and remission group（488.24±164.70pg/ml） and the healthy controls（382.97±167.43pg/ml）(P>0.05). Both ITP patientsbefore the treatment（M6.76）（3.03，37.00）and remission groups（M1.76）（0.45，14.18）expressed more CXCR3mRNA (P<0.05). After effective therapy, CXCR3mRNA expression decreased, while it was still higher than those in the controls（M0.12）（0.04，0.28）(P<0.05).Conclusions Our data demonstrated that Th1cytokine (IFN-γ) dominance wasreflected in ITP. Simultaneously, the CXCR3~+cell may play a role in cell-mediatedimmunity through chemotaxis in ITP. In addition to above, this axis is influenced byimmunosuppresive therapy.