Neutralization of different echovirus serotypes by individual lots of intravenous immunoglobulin

Replacement therapy using intravenous immunoglobulin (IVIG) preparations in people with antibody deficiencies is effective in preventing the majority of common bacterial and viral infections, yet echovirus break-through infections have occurred. Currently, only limited information on neutralization capacity variability of individual IVIG lots against the different echovirus serotypes is available. Infectivity assays were established for the most prevalent echovirus serotypes (E 9, E 11, E 13, and E 30) circulating in the United States (US) and the European Union (EU). The echovirus serotype-specific neutralization titers of 41 IVIG lots manufactured from either whole blood (Recovered) or collected by apheresis (Source) and from either the US or EU, were determined. Significantly higher (P < 0.0001) neutralization titers against E 11 and E 30 were found in IVIG lots manufactured from US Source plasma compared to US Recovered plasma. Geographically, IVIG lots made from US plasma contained significantly (P < 0.0001) higher neutralization titers against E 9 and E 11 than lots manufactured from EU plasma, whereas lots made from EU plasma showed significantly higher neutralization of E 30. To conclude, IVIG lots differ in their neutralizing antibody content against different echovirus serotypes, depending on plasma collection practices and geographic origin. Based on these results, an informed choice in selecting IVIG lots with the highest available neutralization titer against the specific echovirus serotype would seem to be beneficial during treatment of break-through infections.