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Detection of specific IgA antibodies in the serum of children with Mycoplasma pneumoniae infection

Abstract number: R2738

Matsas M., Antonaki G., Doudoulakakis A., Kalogergas G., Paraskakis I.

Objectives:M. pneumoniae is a significant cause of community acquired pneumonia and is responsible for about 40% of atypical pneumonias. Serology remains the most useful diagnostic tool, though its interpretation is difficult. In children detection of IgM antibodies in serum with the absence of IgG strongly indicated acute M. pneumoniae infection and the presence of IgM and IgG antibodies simultaneously is associated with past infection. The aim of the present study is to investigate the usefulness of IgA antibodies detection in serum for the diagnosis of acute or past M. pneumoniae infection in children.

Methods: Serum samples from 184 outpatient or hospitalized children (90 boys and 94 girls) aged 1,5–14 years old, suspected for M. pneumoniae infection, from January 2007 to September 2010, were tested for the determination of specific IgM and IgG antibodies to M. pneumoniae using Platelia EIA (Biorad). IgG antibodies were discriminated as non significant, low, moderate and high, according to the absorbance reading. Sera were stored at -70°C before the determination of IgA antibodies using ELISA (Virion/Serion).

Results: IgM antibodies were found in 167 out of 184 serum samples. The detection rate of specific IgA antibodies in the group of IgM positive and no significant IgG titer was 38% (31/81), in the group of IgM positive and low IgG titer was 48% (13/27), in the group of IgM positive and moderate IgG titer was 45% (10/22) and in the group of IgM positive and high IgG titer was 78% (29/37). In the group of children with IgM negative and IgG positive, IgA antibodies were detected in 41% (7/17) of samples, mainly with significant IgG titer (5/7).

Conclusion: In adults, the determination of IgA antibodies is useful for early diagnosis of acute M. pneumoniae infection considering that IgA response is more regular than IgM response in these patients. In contrast our results indicate that IgA specific antibodies determination is incapable of differentiating acute or past M. pneumoniae infection in children.

Session Details

Date: 07/05/2011
Time: 00:00-00:00
Session name: Abstracts of 21st ECCMID / 27th ICC
Subject:
Location: Milan, Italy, 7 - 10 May 2011
Presentation type:
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