Seroprevalence of Mycoplasma pneumoniae Specific IgM and IgG Antibodies in Asymptomatic Preschool Aged Children of Tehran, Iran, 2010

Respiratory tract diseases in children are one of the two leading causes of death worldwide and Mycoplasma pneumonia is the most important etiologic agent of respiratory tract infections.
This study aimed at determining the seroprevalence of Mycoplasma pneumoniae specific IgM and IgG antibodies in asymptomatic 5- to 6-year-old children in Tehran, Iran.
This cross sectional study was conducted during summer season of year 2010 in Tehran, North of Iran. Overall, 291 children were enrolled in the study in a sequential method. Blood samples were obtained from each child and the serum was separated and stored frozen at -70°C for later antibody assay. Detection of IgM and IgG antibodies against M. pneumoniae was performed using commercial qualitative Enzyme Linked Immunosorbent Assay (ELISA) kits.
Of the 291 participants in the present study, 156 (53.6%) were female and 135 (46.4%) were male. Overall, 73 (25.1%) serum samples had positive results for M. pneumoniae specific IgG. The frequency of positivity and mean of titers for M. pneumoniae specific IgG antibody among males and females was 31 (23%), 17.4 ± 5.5 U/mL (95% CI 16.77 - 18.03) (ranged from 12.2 to 33 U/mL), and 42 (26.9%); 17.1 ± 4.4 U/mL (95% CI 16.6 - 17.6) (ranged from 12 to 28 U/mL), respectively. Moreover, all tested serum samples for M. pneumoniae-specific IgM were negative.
In summary, our findings present the frequency of recent and previous exposure to M. pneumoniae infection among asymptomatic children aged from 5 to 6 years old in our region. Moreover, findings of such surveillance studies could provide useful insight to compare our situation with others.