Objective ：To analyze the expression level of T helper cells in peripheral blood of children with Mycoplasma pneumonia complicated with extrapulmonary manifestations.

Methods： We detected the peripheral T helper cells(CD3+,CD4+,CD8+,CD4+/ CD8+)in the blood of the 97 selected continuous cases of children with Mycoplasma pneumoniae pneumonia before starting treatment,who received treatment in the Children Hospital of Shenyang from Jan.to Dec.2015,and compared with the results of the normal children on the medical conclusions at the same test in the same period(control group,n=35).

Results：The expression intensity of the peripheral CD3+,CD4+, and ratio of CD4+ /CD8+ of the Mycoplasma pneumoniae pneumonia group were significantly lower than the control group,while that of CD8+ was higher (P<0.05～ 0.01).In the 97 children with Mycoplasma pneumoniae pneumonia,43 cases had extrapulmonary manifestations(44.33%), and the CD3+level,the CD4+ level,CD4+ /CD8+ ration in the group with extrapulmonary manifestations were obviously lower than the group without extrapulmonary manifestations,while the CD8+ level was higher than the latter(P<0.05～0.01).

Conclusion： Peripheral blood helper T cells are abnormally expressed in children with Mycoplasma pneumonia;these abnormalities are more obvious in the patients complicated with extrapulmonary manifestations.