Strategies for screening blood donors to source convalescent H1N1v plasma for intervention therapy.

BACKGROUND AND OBJECTIVES

During the 1918, pandemic blood components were successfully used to treat severe influenza pneumonia. A Proof of Principle trial investigating the clinical benefit of convalescent plasma was proposed in the 2009 H1N1v epidemic with the aim of screening donors for high titre antibody in order to stockpile plasma packs to be used for treatment for severe pneumonia.

MATERIALS AND METHODS

Serum samples were collected from donors. IgG antibody capture format enzyme-linked immunoassays using recombinant proteins (GACELISAs) were compared with microneutralization (MN) and haemagglutination inhibition (HAI). The influence of age and history of influenza-like illness (ILI) on the detection of high titre antibody was examined.

RESULTS

1598 unselected donor sera collected in October and December 2009 were tested by HAI. The HAI and demographic data defined a possible strategy for selective donor screening. One of the GACELISAs was highly specific for recent infection but showed lower sensitivity than HAI.

CONCLUSIONS

During the 2009 pandemic screening 17- to 30-year-old donors by HAI delivered around 10% with high antibody levels. The ELISA using a short recombinant H1N1v HA detected fewer reactives but was more specific for high titre antibody (≥1:256). Screening strategies are proposed based on using HAI on serum or GACELISA on plasma.