Whereas it has been shown that Lcn2 protects against Klebsiella pneumoniae lung infection in mice (42) and a protective role for Lcn2 in allergic airway disease has been demonstrated (43), other report has presented results showing pulmonary Lcn2 impaired bacterial clearance survival in pneumococcal pneumonia (44). Here, LCN2 is linked to pneumococcal pneumonia.