Maria R. Farcet, Austria
Takeda Pathogen SafetyPresenter of 1 Presentation
MEASLES VIRUS NEUTRALIZING ANTIBODIES IN IMMUNOGLOBULIN LOTS PRODUCED FROM PLASMA COLLECTED IN EUROPE OR THE UNITED STATES
Abstract
Background and Aims
Widespread vaccination against the measles virus (MV) has reduced disease incidence and led to a progressive decline of MV antibody (MVAb) levels in human plasma, thereby decreasing MVAb levels in individual lots of immunoglobulin (IG). Although IG lot release from the United States (US) requires a minimum MVAb titer, equivalent information is unavailable for other geographies. This analysis assessed regional differences in MVAb titers in IG preparations prepared from plasma collected from the US and European Union (EU).
Methods
MVAb titers were determined in 1739 IG lots fractionated from US (n=1466) and EU (Austria, Germany, and the Czech Republic; n=273) plasma between 2013-2018. Plasma was collected by plasmapheresis (source plasma) or by whole blood donations (recovered plasma). Titers were determined as the reciprocal dilution resulting in 50% MV neutralization (NT50[1:X]) using a fully validated neutralization assay.
Results
Mean (SEM) neutralizing MVAb titers were significantly higher in IG lots from the EU than from the US (1521 [33] vs 1373 [13]; P<0.0001). MVAb titers for IG fractionated from recovered plasma were significantly higher than titers from source plasma (2000 [29] vs 1245 [10]; P<0.0001); this difference was evident in IG from the US and the EU (Figure).
Conclusions
Neutralizing MVAb titer levels in IG lots from the EU are functionally similar but slightly higher than levels in IG lots from the US, supportive of equivalent protection against MV infection. Thus, dosage in the EU could be aligned with US Food and Drug Administration recommendations for IG use as post-exposure MV prophylaxis.