Univariate analysis shows that long-term bed rest, chronic lung disease, autoimmune disease, peripheral artery disease (PAD), tuberculosis history, dyspnea, blood homocysteine, CD4/CD8 ratio, or SIQIIITIII syndrome were closely correlated with the incidence of PE in the bronchiectasis patients (p < 0.05). The gene discussed is CD4; the disease is bronchiectasis.