Abstract：OBJECTIVE: To study the value of isotype-specific IgM, IgA, IgG and IgE antibodies against Mycoplasma pneumoniae (MP) in the diagnosis of childhood MP infection and the relationship between MP-IgE and asthma attack. METHODS: Specific MP-IgA, MP-IgE and MP-IgG antibodies were measured by ELISA; and specific MP-IgM, with pellet agglutination assay in children with suspected MP infection. Fifty-seven cases with definitive diagnosis of MP infection were followed up for 2-5.5 months. Thirty healthy age-matched children were used as the controls. RESULTS: Of the 372 patients with suspected MP infection, 184 were MP-IgA positive (49.5%), 241 MP-IgM positive (64.8%) and 140 were both MP-IgA and MP-IgM positive. The Chi-squared test showed a significant coincidence between the positive rates of MP-IgA and MP-IgM. MP-IgG positive was found in 105 patients (70.5%) out of 149 cases tested. In the 30 normal controls, only 2 were MP-IgG positive and none, MP-IgA and IgM positive. It was in the second week of the disease course that the positive rates of MP-IgA, MP-IgM and MP-IgG were the highest in 57 patients with definitive diagnosis of MP infection. Recurrent respiratory infection occurs in 25 out of 57 followed-up MP patients. The positive rate of MP-IgA increased significantly in the 25 cases compared the initial positive rate and the titer of MP-IgM also remained high. In the 32 cases without recurrent respiratory infection, the titer of MP-IgM was significantly reduced and the positive rate of MP-IgA did not show differences compared with the initial findings. The positive rate of MP-IgE in patients with MP infection was significantly higher than that in the normal controls and the asthmatic patients without MP infection, but was the same as the asthmatic patients accompanied by MP infection. CONCLUSIONS: The determination of MP-IgA, IgM, IgG and IgE is of importance in increasing the specificity and sensitivity of the diagnosis of MP infection, and especially in the diagnosis of the repeated MP infection. MP-IgE may be associated with the development of asthma attack.
CAO Lan-Fang,XU Ling-Yun,LU Yan-Ming et al. Determination of four isotype-specific antibodies against Mycoplasma pneumoniae[J]. CJCP, 2005, 7(2): 143-146.
