With regard to IgG, in primary HIV infection, IgG3 antibody responses rather than IgG1 responses are linked to nAb activity and a drop in viral load [22,42], with a positive correlation with IgG3 and IgG1 response patterns, over IgG2, IgG4, and IgA [43,44,45]. This evidence concerns the gene IGHG3 and HIV infectious disease.