Size exclusion chromatograms of (A) an IVIG (product E, see Table 1) that had been stored at 4°C for 1 year after reconstitution of the freeze-dried product (IVIG-E aged), and that of IVIG-E that was stored at −80°C immediately after reconstitution (IVIG-E fresh) and (B) IVIG-E aged before (before pH 4) and after incubation for 24 hours at 37°C, pH 4.25 (after pH 4).