Objective To investigate the levels of myeloperoxidase(MPO),neutrophils (PMN) and monocyte chemoattractant protein-4 (MCP-4) in serum of children with bronchial asthma,and to explore the clinical significance. Method The serum levels of MPO,PMN and MCP-4 in 67 cases of bronchial asthma children (asthma group) and 30 healthy children (control group) were measured and compared by using enzyme-linked immunosorbent assay (ELSA). Results 1) The serum level of MPO [(878.43±18.77) U/L ]in acute exacerbation of bronchial asthma was higher than that in the remission group[ (678.62±33.36) U/L ]and healthy controls [(703.17±18.26) U/L ](P<0.05).2)The serum level of MCP-4 in the acute attack of bronchial asthma children [(117.34±18.77) pg/mL] was higher than that in the remission group (55.67±6.13pg/ml) and healthy control group [(33.74±2.98) pg/mL](P<0.05).3) The absolute value of PMN in acute attack of bronchial asthma [(10.31±1.98)×10⁹/L] was higher than that in the remission group [(4.63±1.51)×10⁹/L] and healthy control group [(4.82±1.51)×10⁹/L] (P<0.05).The elevated levels of MPO,PMN and MCP-4 were related to the severity of the disease,and there was a positive correlation between the two(r=0.976,0.989;all P<0.01). Conclusions MPO,PMN and MCP-4 play an important role in bronchial asthma,and is related to airway inflammation.Serum MPO,PMN and MCP-4 can be used as a biochemical indexes of bronchial asthma.The remission of asthma are chronic inflammatory reaction.