FCGR1A and susceptibility to pneumonia measurement: The expression of HLA-DR on monocytes was significantly lower in the pneumonia group (931.17 ± 671.15 vs 1392.53 ± 764.37, P < 0.001), while the expression of CD64 on neutrophils were much higher in the pneumonia group (589.20 ± 605.44 vs 101.11 ± 54.08, P < 0.001).