IER3 and viral infectious disease: It is interesting that IER3 (Immediate early response 3), which is known to be induced by growth factors, cytokines, ionizing radiation, or viral infection [49] was observed to have extremely high induction of gene expression in B cells of 3 individual smokers (S3E and S6C Figs) but this did not reflect methylation levels in these individuals or smoking dose, and was not associated with any variable identified on our medical history for these participants.