For example, Zúñiga et al. [50] found four polymorphisms associated with severe pneumonia in Influenza A/H1N1, including SNPs in the Fc fragment of immunoglobulin (Ig) G; low-affinity IIA; receptor (FCGR2A), RPA interacting protein (RPAIN); and complement component 1, q subcomponent binding protein (C1QBP) genes. Here, FCGR2A is linked to pneumonia.