MUC5AC and Pleural effusion: However, there were significant differences in clinical features, including maximum temperature, fever duration, wheezing incidence, and presence of extrapulmonary complications, pleural effusion, and atelectasis, as well as percentage of neutrophils, percentage of lymphocytes, neutrophil-to-lymphocyte ratio (NLR), LDH, CRP, D-dimer, ALT, and IgM in serum, and sputum MUC5AC levels (P < 0.05 for all).