Four functional FCGR polymorphisms including FCGR2A 131H/R, FCGR3A 158F/V, FCGR3B NA1/NA2, and FCGR2B 232I/T were selected for genotyping after literature review of previous studies on association between FCGR polymorphisms and infectious diseases [11] [12] [13] [14] [15] [16] [17] .