Antibody Affinity Against 2009 A/H1N1 Influenza and Pandemrix Vaccine Nucleoproteins Differs Between Childhood Narcolepsy Patients and Controls

Abstract Increased narcolepsy incidence was observed in Sweden following the 2009 influenza vaccination with Pandemrix®. A substitution of the 2009 nucleoprotein for the 1934 variant has been implicated in narcolepsy development. The aims were to determine (a) antibody levels toward wild-type A/H1N1-2009[A/California/04/2009(H1N1)] (NP-CA2009) and Pandemrix-[A/Puerto Rico/8/1934(H1N1)] (NP-PR1934) nucleoproteins in 43 patients and 64 age-matched controls; (b) antibody affinity in reciprocal competitive assays in 11 childhood narcolepsy patients compared with 21 age-matched controls; and (c) antibody levels toward wild-type A/H1N1-2009[A/California/04/2009(H1N1)] (H1N1 NS1), not a component of the Pandemrix vaccine. In vitro transcribed and translated 35S-methionine-labeled H1N1 influenza A virus proteins were used in radiobinding reciprocal competition assays to estimate antibody levels and affinity (Kd). Childhood patients had higher NP-CA2009 (p = 0.0339) and NP-PR1934 (p = 0.0246) antibody levels compa...