OBJECTIVETo explore the expression and clinical significance of Semaphorin4D (Sema4D) mRNA in peripheral blood lymphocyte, Sema4D on platelet surface, soluble Sema4D (sSema4D) in plasma in patients with cerebral infarction.

METHODSTaking 299 patients with cerebral infarction as the case group while 195 healthy adults as the control group. The mRNA expression of Sema4D was detected by Real-time PCR, and Sema4D expression on platelet by flow cytometry, sSema4D by ELISA. Then, the expression of Sema4D on platelet surface and the concentration of sSema4D in plasma of the 195 selected patients following 2 weeks' treatment were tested.

RESULTSThe expression of Sema4D mRNA significantly increased in the case group \[(2.23, 2.66)×10(4) IU/ml\] than in the control group \[(0.49, 0.53)×10(4)IU/ml\] (P < 0.01). The level of Sema4D on platelet surface in the case group (191.62 ± 46.56) significantly decreased than in the control group (303.33 ± 112.66) (P < 0.01). But the concentration of sSema4D in plasma in the case group \[(1.34 ± 0.56) µg/L\] was obviously higher than in the control group \[(0.61 ± 0.31) µg/L\] (P < 0.01). The expression of Sema4D on platelet was obviously relevant with the concentration of sSema4D in plasma in the case group with the correlation coefficient as 0.328 (P < 0.01). The expression of Sema4D on platelet obviously peaked up following 2 weeks' routine therapy in the case group, which was close to that in the control group. Meanwhile the concentration of sSema4D in plasma was downward corrected to the normal in the case group.

CONCLUSIONThe increased expressions and plasma levels, and reduced expressions on platelet of Sema4D in acute period, which returned to normal 2 weeks after treatment in the case group may be related to the occurrence of acute cerebral infarction, reflecting the development process of cerebral infarction.