PBMC from pediatric Pandemrix-associated NT1 patients (NT1) or pediatric Pandemrix-vaccinated healthy controls (C) were stimulated in culture with single 15-mer peptides from influenza (A/reassortant/NYMC X-179A (California/07/2009 × NYMC X-157)(H1N1)) vaccine virus hemagglutinin (HA), neuraminidase (NA) or nucleoprotein (NP) (discovery cohort). Recombinant neuraminidase (rNA) and nucleoprotein (rNP) were used as positive controls. The secretion of IFN-γ (a, c, e) or IL-2 (b, d, f) was measured by FMIA (protein). Results are expressed as the ratio between cytokine concentrations measured in peptide-stimulated and negative control samples (stimulation index). Statistical comparisons between groups were performed, using Kruskal–Wallis and Dunn’s multiple comparisons tests.