PTX3 levels have previously been linked to inflammatory diseases;22 so it was not surprising to see a correlation between PTX3 levels and neutrophils in sputum, a pro-inflammatory cell,38 and also a cell involved in PTX3 storage.17 PTX3 has also been implemented in bacterial infection,18–21 and our study supports this as we found a correlation between bacterial load (CFU/mL) in sputum at stable and exacerbation states implying that PTX3 expression in the lungs is driven by bacterial infection. The gene discussed is PTX3; the disease is bacterial infectious disease.