Our results show that the plasma MBL concentrations compared to IgE values present a relative diagnostic role for bronchial asthma in pediatric patients, because MBL concentrations have higher relevance in the diagnosis of bronchial asthma in children and higher sensitivity and specificity, given that all asthmatic patients had altered MBL values compared to IgE values, which were modified in a few patients with asthma. This evidence concerns the gene MBL2 and asthma.