ABSTRACT
Subacute thyroiditis (SAT) can be triggered by several viral factors in genetically predisposed individuals. In the case of COVID-19, SAT can be induced by SARS-CoV-2 infection as well as COVID-19 vaccination. The aim of this study was to present two cases of SAT triggered by mRNA-based COVID-19 vaccines, with special attention paid to the possible significance of HLA-related SAT susceptibility. In our patients, a strong similarity of HLA profiles with regard not only to SAT high-risk alleles but also to other SAT-unrelated ones was observed. The rare phenomenon of SAT occurrence after COVID-19 vaccination can be HLA-dependent and related to a co-presence of HLA-B*35:03 and -C*04:01. Taking into account the similarity of HLA profiles in both our patients, the co-presence of other alleles, such as HLA-A*03:01, -DQA1:01, DQB1*05:01 as well as some of HLA-DRB1, can also play a role. This hypothesis is strongly consistent with autoimmune/inflammatory syndrome induced by adjuvants (ASIA) being the postulated mechanism of this post-vaccine reaction, as ASIA-related immune reactions are directly associated with HLA-based genetic susceptibility. Further research is necessary to confirm these findings.
ABSTRACT
In the last two years, we have been struggling with the pandemic of SARS-CoV-2, the virus causing COVID-19. Several cases of subacute thyroiditis (SAT) have already been described as directly related to SARS-CoV-2 infection. The clinical course of SAT induced by SARS-CoV-2 can be entirely different from the classic SAT course, and one of the most important differences is a very rapid SAT onset observed in some patients, especially a phenomenon of the simultaneous presence of both diseases. The aim of this report is to compare HLA profile and clinical course of SAT in four patients, in whom SAT was considered as triggered by COVID-19, with special attention paid to the differences between a patient with rare simultaneous presence of SAT and COVID-19, and patients with longer time lag between the diseases. The unusual phenomenon of simultaneous occurrence of COVID-19 and SAT induced by SARS-CoV-2 infection can be HLA-dependent and related to the presence of homozygosity at HLA-B*35. Additionally, the clinical course of SAT triggered by COVID-19 can be HLA-related in regard to the risk of recurrence, and to a variety of other aspects, including severity of thyrotoxicosis.