Influence of Human Rhinovirus (HRV) infection on loci specific DNA methylation in nasal epithelial cells (NECs). A. Principle components analysis (PCA) of methylation microarray data set (389 probes/sample) revealing a clear separation between infected Healthy and Asthmatic NECs along PC2 and PC4 respectively. B-C. Genomic loci and methylation pattern characterizing the response to infection in Healthy (B) and Asthma (C) NECs. Although the majority of loci were group-specific, a common locus (*) was identified between the Healthy and Asthma groups.