Comparison of baseline data showed significant differences between the two groups in terms of age, smoking status, diabetes, dyspnea, fever, solid organ transplantation, hematological disease, heart rate, WBC, NLR, PLR, CRP, LDH, blood urea nitrogen (BUN), pH, PaO2/FiO2 ratio (PFR), CD4+ T cell, adjunctive corticosteroid, TMP-SMX, bacteria, cytomegalovirus (CMV), fungus (P < 0.05), as shown in Table 1. This evidence concerns the gene CD4 and hematologic disorder.