Changes of serum antibody titers in children with community-acquired Mycoplasma pneumoniae pneumonia

Abstract

Objective To study the variation of serum Mycoplasma pneumoniae (MP) antibody in children with community-acquired Mycoplasma pneumoniae pneumonia(CA-MPP), and to explore its early diagnostic value in MPP. Methods A retrospective analysis of case series was performed in 134 children with CA-MPP.The 134 children were admitted and diagnosed as CA-MPP at Department of Pediatrics, the Affiliated Hospital of Qingdao University between January 2013 and December 2014, among whom 56 cases were male and 78 cases were female(the ratio of boys to girls was 1.00︰1.39). The children aged from 6 months to 14 years old with a course of 8-23 days.Particle agglutination was used to detect serum MP antibody, and the changes in the titers were analyzed during 4-21 days of first onset. Results The positive cases of serum antibody(≥1︰160) during 4-7 days, 8-14 days, 15-21 days of first onset was 33/70 cases, 131/143 cases, 65/65 cases, and the positive rate was 41.7%, 91.6% and 100.0%, respectively.Serum MP antibody titers during 4-21 days of first onset were positively correlated with the duration(r=0.832, P=0.000). Seventy-five(88.24%)patients in 85 CA-MPP children diagnosed by paired serum test(an interval of 2 weeks) had a fourfold or greater increase after the onset of 1 week. Conclusions Serum MP antibody titer is closely related to the duration of children with MP infection after the onset of disease.The result also suggested that retesting the antibody titer interval for 1 week may have more diagnostic value in diagnosing MP infection than after an interval of 2 weeks. Key words: Mycoplasma pneumoniae; Community-acquired Mycoplasma pneumoniae pneumonia; Antibody; Titer