Review Claim by Claim

Concise critique & interpretation

• Design strengths: Large screening cohort (n=881) with uniform early childhood immunization and minimal background measles circulation, objective IgG EIA measurement, and use of PCR-SSP with controls and family confirmation for homozygosity, all reduce misclassification risk Hayney et al., methods and cohort
• Key quantitative findings: DQA1*05 enrichment among nonresponders (33.7% vs 19.5%, P=0.017), DQA1*01 enrichment among hyperresponders (50.0% vs 33.7%, P=0.016), and higher DQA1 homozygosity in nonresponders (23.9% vs 9.4%, P=0.037) (see graphs above) Hayney et al., results
• Statistical & power considerations: The analysis compares small case subsets (46 nonresponders, 64 hyperresponders). Multiple tests across HLA alleles + limited case counts increase false-discovery risk and widen confidence intervals; the authors acknowledge limited power for linkage-disequilibrium adjustment and multigene modeling (logistic regression lost significance for DQA1 after adjusting for DRB1 and TAP2) Hayney et al., LD and regression
• Technical caveats: PCR-SSP low-resolution typing cannot detect all rare/new alleles and can mis-assign apparent homozygosity if an allele is not assayed by the primer panel; the authors used internal amplification controls and parental typing but residual typing blindspots remain possible — this can bias homozygosity estimates upward Hayney et al., typing limitations
• Biological plausibility: DQ alpha chain residues influence peptide-binding and helper T-cell presentation, providing a mechanistic basis for allele-dependent differences in humoral response; however, because of strong HLA LD across class II, independent causality is unresolved in this dataset and requires higher-resolution typing, extended haplotypes, or functional peptide-binding assays Hayney et al., biological plausibility

Blindspots, biases & what would change the conclusion

• Small-case sampling and multiple allele comparisons → possible Type I error; replication in larger, multi-ethnic cohorts with correction for multiple testing would either strengthen or refute findings.
• Higher-resolution HLA typing (allele-level sequence-based typing) and full haplotype phasing would be needed to show independent DQA1 effects vs linked DRB1/TAP2 effects.
• Functional assays (peptide-binding, CD4 T-cell activation, B-cell help assays) showing allele-specific differences in antigen presentation for measles epitopes would materially increase causal confidence.