IgG measurements were determined as median fluorescence
intensities (MFI) on the Luminex FLEXMAP 3D analyzer (Luminex
Corporation, Austin, TX) using the Bio-Plex Manager 5.0 software
(Bio-Rad, Hercules, CA). An antiserum specific for each antigen was
used as reference to convert MFI values of total IgG in RLU/ml
(Relative Luminex Units). The limit of quantification (LOQ) of the
assay was determined for each antigen and was considered as
threshold for positive results.