While CD4+ TCs in thyroid tissues of HT patients could be classified into Th1, Th2, or Th17 subtypes, as previously reported34, CD4+ TCs did not segregate into distinct clusters in our study, and the expression of TC subset marker genes, such as IFNG and TBX21 for Th1, IL4 and GATA3 for Th2, and IL17RA and RORC for Th17, were low and sporadic (Supplementary Fig. 5C). Here, RORC is linked to hematocrit.