Correction: Absence of anti-hypocretin receptor 2 autoantibodies in post pandemrix narcolepsy cases

Following publication of this [1] article, questions were raised about some of the reported methods and results, and about differences between the findings reported in this article and in a previous article published by another group [2]. The PLOS ONE Editors reviewed this matter, and consider that the research reported in the PLOS ONE article is scientifically valid and meets the journal’s publication criteria, but that some items require clarification and additional controls. The authors address these issues below: “As noted in [1], we were unable to replicate some findings reported by Ahmed et al. in [2]. We would like to provide some clarifications regarding some methodological differences between the two studies. First, a statement in the Discussion was inaccurate in relaying the differences between the results of peptide binding affinity to DQ0602. The statement: ‘The fact that NP 111-121 (YDKEEIRRIWR) (116I was underlined) and HCRTR2 34-45 (YDDEEFLRYLWR) did not appear to bind to DQ0602 (unlike what was reported with the Proimmune 1 array by Ahmed et al. [43]) (Fig 2, S19 Table) suggested this epitope was likely irrelevant to DQ0602-associated narcolepsy or differential vaccine risk’ should instead read: The fact that NP 111-121 (YDKEEIR RIWR) (116I was underlined) and HCRTR2 34-45 (YDDEEFLRYLWR) did not appear to bind to DQ0602 (Competition binding results S23 Table this Correction) (Of note, ‘NP109-113 116I’ of Fig 2 in [1] should be corrected to ‘NP109-123 116I’) suggested this HCRTR2 epitope was likely irrelevant to DQ0602-associated narcolepsy or differential vaccine risk. Indeed, S3 Table of Ahmed and Steinman’s Proimmune REVEAL 1 data [2] showed weak binding for RELILYDKEEIRRIWRQANNG (24.4 and 16.9 of REVEAL 1 score at first measure and post 24h, respectively), little binding for RELILYDKEEMRRIWRQANNG (1.5 and 0.5 of REVEAL 1 score at first measure and post 24h, respectively) and no binding for the HCRTR2 peptide (LNPTDYDDEEFLRYLWREYLH) (0.0 of REVEAL 1 score at both first measure and post 24h). We overlooked these small differences. Our results show little binding for RELI LYDKEEIRRIWRQANNG (92.40±2.33% of Bio-EBV binding), very weak binding for RELI LYDKEEMRRIWRQANNG (77.84±1.10% of Bio-EBV binding) and no binding for the HCRTR2 34-45 peptide (98.12±1.38% or 99.85±2.10% of Bio-EBV binding) (competition binding results S23 Table this Correction). This does not change our interpretation. Second, intrigued by the results reported by Ahmed et al. [2], we also conducted our own peptide binding studies to DQ0602 using the Proimmune REVEAL 1 binding assay (See S1 File of this Correction) and compared these results for 144 peptides with our own competition assay that uses DQ0602 monomers bound to Bio-EBV (more than 1,446 peptides have been tested using this platform). Results are shown in S12 Fig this Correction S23 Table this Correction; underlying data and analyses are provided in S2 File of this Correction. Overall, no significant correlation was found between our competition binding assay using Bio-EBV and Proimmune results (r 2 = 0.00795, p = 0.290 at 0h; r 2 = 0.00026, p = 0.848 at S12 Fig this Correction). Classifying our binders into strong (high displacement, 25% of Bio-EBV binding) or weak binders (partial displacement, 25–50% of Bio-EBV binding) in our competition assay and positive versus negative in the Proimmune assay also did not reveal any correlation using χ 2 (all p values>0.56, S2 File of this Correction). Further illustrating this, the known EBV binding epitope of DQ0602 (EBV 486-500 ) [6–8], which was used in our competition binding assay, and HA 273-287 , a strong binder in our assay (8.10±1.53% of Bio-EBV S23 Table this Correction), were found not to bind to DQ0602 using the Proimmune 1 assay (0.0 of REVEAL 1 score at both 0h and post 24h, S1 File of this Correction). This led us to conclude that the Proimmune DQ0602 binding assay was unreliable. However, as these results were peripheral to the message of our manuscript and lack of replication of the presence of anti-HCRTR2 antibodies, these were not included in our original publication.