IGHD7-27 and myalgic encephalomeyelitis/chronic fatigue syndrome: In the current study, we report hypomethylation of DMPs of genes known to regulate the adaptive immune response such as immunoglobulins and pseudogenes (for example, IGDCC3, IGHD7-27, IGHJ1, IGHJ3 and other) (S6 and S7 Tables) which is in agreement with the reported improvement of ME/CFS cases following B cell depletion therapy [58, 59].