FOXP3 and hematocrit: In the present study, increased mRNA expression of T-bet, a master regulator of the Th1 lineage, was observed in severely affected, hypothyroid patients, both treated and untreated, but not in spontaneously euthyroid HT counterparts; in addition, the prototypical Treg FOXP3 message closely mirrored T-bet expression patterns in both HT stages.