Simkania negevensis and newly diagnosed asthma: a case-control study in 1- to 6-year-old children

BACKGROUND: Simkania negevensis is an intracellular bacterium, sharing many characteristics with Chlamydophila and Chlamydia species. S. negevensis infection has been associated with bronchiolitis in infants and with pneumonia and exacerbations of COPD in adults. OBJECTIVE: The aim of the present study was to evaluate, in a case-control setting, whether S. negevensis serology had any association with the onset of asthma in children. METHODS: S. negevensis-specific IgM, IgA and IgG antibodies were measured by microimmunofluorescence in 104 children below school-age with newly diagnosed asthma, and in 122 control children. RESULTS: S. negevensis-specific IgM was detected in two (2%) cases and in nine (8%) of the controls. IgG was detected in 12 (12%) cases and 12 (10%) of the controls. IgA antibodies were absent in all children. The age distribution of the 35 children with S. negevensis-specific antibodies was even, the positivity rate being 11% in the 12- to 23-month-old group and 20-23% in the children aged between 2 and 5 years. CONCLUSION: Although S. negevensis appears to cause infections in the Finnish preschool-aged population, there was no association with asthma.