Methylation & Allergic Reactions

When methylation is impaired it can lead to abnormally high levels of histamine. In addition to the effect of methylation on histamine levels, the effect of methyl groups on the TH1/TH2 balance may be a second mechanism by which decreased methylation may increase allergies. There are two sets of T helper cells in the immune system, TH1 and TH2 cells. While TH1 cells are involved in cell mediated immune responses and toning down or regulating TH2 activity, the TH2 cells have been associated with humoral or B cell mediated responses and allergic responses. TH2 cells trigger the activation and recruitment of IgE antibody producing B cells, mast cells and eosinophils that are involved in allergic inflammation. Studies show that decreased methylation of CpG regions in these genes may influence the balance of TH1 and TH2 cells.