GPR183 and myalgic encephalomeyelitis/chronic fatigue syndrome: The finding that CFS/ME patients of subtype D with EBI2 mRNA upregulation had lower titers of EBNA IgG than the other subtypes (Figure 2D), supports the idea that subtype D is associated with a higher prevalence of EBV latency, as lytic infection is required to expose this antigen to circulating lymphocytes, a necessary step in developing serum EBNA IgG positivity.