CALCA and bacterial infectious disease: Previous research has demonstrated that serum PCT levels are elevated following bacterial infection, and PCT has been proven to be a useful marker for early diagnosis of bacterial infection and for measuring infectious severity.11, 12, 13, 14 CRP is an acute-phase protein that becomes elevated during infections such as pneumonia and sepsis, and it is predominantly produced by liver cells.15, 16 However, from the viewpoint of the authors, limited information is available on the significance of PCT and CRP in the diagnosis of infection in GPP patients.