Introduction: Studies to ascertain a possible relationship between herpesviruses and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have relied heavily on classical approaches, specifically, serological examination for antibodies against virus proteins, primarily structural, and/or increases in viral load (1–21). These data have been conflicting due in part to several features: the heterogeneity of the disease, high prevalence of the herpesviruses in the population since they can establish lifelong infections, and differences between laboratories. Two additional problems lead to conflicting data in serological studies: which viral antigens are to be used for detection, and what is the possible relationship, if any, of these viral antigens to ME/CFS? These are important questions that must be addressed for any data to provide meaningful insight into the possible contribution of a virus to the pathophysiology of ME/CFS. Although the experimental techniques used in Blomberg’s serological study were appropriate, the selection of specific herpesviruses and viral antigens studied gives a limited view of the humoral response in ME/CFS.
Discussion: Blomberg et al. (22) used a suspension multiplex immunoassay to detect antibodies against various herpesviruses’ antigens, derived from proteins expressed during latency or late lytic replication (Figure 1), with the goal of determining differences in antibody titers against these antigens between ME/CFS patients and controls. However, no rationale was given as to why these particular antigens were chosen and what association, if any, they may have with ME/CFS. This is important because the antigenic properties of the different virus proteins are not the same. As demonstrated in an eloquent study by Vaider-Shalt et al. (23), over the course of their evolution, herpes simplex virus 1 (HSV-1), Epstein-Barr virus (EBV), human herpesvirus 8 (HHV-8), and human cytomegalovirus have decreased the number of epitopes present in virus proteins in order to help them avoid immune detection. Thus, the ability of a virus protein to generate an antibody response is dependent upon the amount of protein present in the host and its antigenicity. It is also not clear why Blomberg et al. (22) included HSV-1/2, human cytomegalovirus, HHV-7, and varicella zoster virus (VZV) in their study since there are no up-to-date literature reports establishing a serological relationship between these viruses and ME/CFS.
Source: Ariza ME. Commentary: Antibodies to Human Herpesviruses in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. Front Immunol. 2020;11:1400. Published 2020 Jul 23. doi:10.3389/fimmu.2020.01400 https://www.frontiersin.org/articles/10.3389/fimmu.2020.01400/full (Full text)