Interestingly, although administration of L. lactis would be a similar setting to typical COPD exacerbation induced by bacterial infection, mice pretreated with HO-1 lactis exhibited suppressed neutrophilic inflammation due to alterations in inflammatory mediators (KC and IL-10) through not only local (lung) but also systemic (serum) upregulation of HO-1 (Figure 5 and Figure 6). This evidence concerns the gene HMOX1 and bacterial infectious disease.