However, out of five patients with bronchiectasis MRI score higher than zero, three had low IgM levels and two had pneumonia during follow-up, compared to single patient with low IgM and no cases of pneumonia in patients with bronchiectasis score of zero (Χ2(4) = 9.9, p 0.042, and Χ2(4) = 9.6, p 0.047, for pneumonia and low IgM, respectively; Online Resource 1). This evidence concerns the gene CD40LG and susceptibility to pneumonia measurement.