SFTPA2 alleles (rs1965708-C and rs1059046-A) and haplotypes (1A0) predisposing to increased severity were found to be associated with significantly lower PaO2/FiO2 ratios, independent of age, gender, risk factors, secondary bacterial pneumonia, and bacteremia (Figure 4). This evidence concerns the gene SFTPA2 and bacterial infectious disease with sepsis.