In multivariate analysis showed in Table 4, independent risk factors associated with hemorrhagic pneumonia were neutropenia (OR = 4.988, 95% CI 1.040–23.920; P = 0.045), high levels of PCT (OR = 11.322, 95% CI 1.943–65.956; P = 0.007), prior tigecycline therapy within 1 month (OR = 4.482, 95% CI 1.135–17.702; P = 0.032). The gene discussed is CALCA; the disease is Decreased total neutrophil count.