Multivariable analyses indicated PCP (R = -0.4767; p<0.05) and Rv (R = -0.5682; p<0.01) to be independent predictors of PaO2/FiO2 decrease at BD+1hr, and serum concentration of IL-6 to be independent factor (R = 0.6729; p<0.001) for PaO2/FiO2 decrease at BD + 5 hours. Here, IL6 is linked to pneumocystosis.