Moreover, Guclu et al. observed that restoration of euthyroidism (by L-T4 therapy) in HT patients with previous hypothyroidism had no significant effect on concentration of IL-4 in serum (1.44 ± 0.63 vs. 1.57 ± 0.89 pg/mL) [46]. This evidence concerns the gene IL4 and hematocrit.