The presence of common herpesviruses (EBV, HHV-6, and HHV-7) in the thyroid gland – implications for disease development and exacerbation

Description

Background
Several human herpesviruses have long been associated with autoimmunity. Strong evidence has been presented for the association between HHV-6 and autoimmune thyroiditis (AIT). Incidental results have also linked other herpesviruses, such as HHV-7 and EBV. This study aims to investigate the prevalence of common herpesviruses in thyroid tissue samples and to elucidate the potential of their involvement in AIT development either on their own or in concert with one another.
Methods
Post-operative thyroid tissue samples and whole blood from 58 AIT patients were used for nucleic acid isolation and subsequent detection of HHV-6, HHV-7, and EBV and HHV-6 active infection markers by nested PCR. Additionally, HHV-6 load was determined by qPCR with a commercially available kit by Saccace.
Results
All thyroid tissue samples harbored the DNA of at least one of the herpesviruses, and only 1/58 blood sample was herpesvirus DNA negative. HHV-6 was most commonly found in thyroid samples 58/58, followed by EBV 45/58, and HHV-7 - 23/58. HHV-6 was found in only 8/58 blood samples. Conversely, EBV and HHV-7 were commonly found in the blood – 50/58 and 43/58, respectively. Statistical analysis revealed that thyroid tissue samples were more frequently HHV-6+ (p<0.01) as compared to blood samples, which were more likely to be HHV-7+ (p<0.01). Active HHV-6 infection was determined in 34/58 thyroid tissue samples. Those thyroid tissue samples that were not actively infected were more frequently EBV+. Thyroid tissue samples harboring HHV-6 and EBV harbored higher median HHV-6 loads than those harboring only HHV-6.
Conclusions
Although HHV-6 remains the most commonly detected virus in autoimmunity-affected thyroid tissues, our results demonstrate that other commonly autoimmunity-associated herpesviruses, especially EBV, may also be linked with autoimmune thyroiditis. Our preliminary results warrant a deeper look into the potential synergistic role of EBV and HHV-6 in AIT.
Acknowledgments: EU Horizon 2020 project “Reducing networking gaps between RSU and internationally leading counterparts in viral infection-induced autoimmunity research (VirA)” (No. 952376)

Period	16 Feb 2024
Event title	Viruses 2024 - A World of Viruses
Event type	Conference
Location	Barcelona, SpainShow on map
Degree of Recognition	International