Epitopes, Avidity, and IgG Subclasses of Tyrosine Hydroxylase Autoantibodies in Vitiligo and Alopecia Areata Patients

The study investigated the presence and specificity of tyrosine hydroxylase (TH) autoantibodies in patients with vitiligo and alopecia areata (AA). Researchers identified two major antibody-binding sites on the TH protein, located between amino acids 1-14 and 61-80. Among 18 patients with vitiligo, 94% had antibodies against the first epitope, and 61% against the second. In 6 patients with AA, 83% had antibodies against the first epitope, and 33% against the second. The findings suggested that the humoral immune response to TH in these conditions was heterogeneous, with patients potentially having antibodies to multiple TH epitopes. The study concluded that TH antibodies in vitiligo and AA patients could recognize identical epitopes.