TPO and hypothyroidism: Previously, we observed that Lo-expressor transgenics depleted of CD25 positive cells before immunization with TSHR adenovirus (A-subunit or holoreceptor) developed massive thyroid lymphocytic infiltration and thyroid damage associated with hypothyroidism and autoantibody spreading to the other two major thyroid autoantigens, thyroglobulin (Tg) and thyroid peroxidase (TPO)[2], [4].