Associations in the MHC region and conditional logistic regression analysis. Plots of the evidence for association between the HLA and cHL, as covariates, are added to the model in a stepwise manner. (A-D) The horizontal axis indicates the location of each SNP along chromosome 6, and the vertical axis, the −log10P values of each SNP (blue) and HLA allele (red), obtained using logistic regression models with different numbers of covariates. (A) Evidence for association obtained from the 1-parameter logistic regression analysis. (B) The remaining signal when rs6903608 is included as a covariate. (C) The signal when rs2281389 is also included in the model. (D) The remaining signal when DQA1*02:01 is also added as a covariate. Multiple red dots on the same locus indicate the −log10P values for different allelic subtypes at the respective locus. The positions of common HLA loci have been marked with vertical dashed lines and annotated accordingly. Note that some loci (DRA1, DPB1) for which imputation results were not available have also been marked in the figure. For all loci, the vertical lines indicate the mean position of the longest transcript. The yellow horizontal line indicates the commonly used 5 × 10−8 threshold for genome-wide significance.
