TPO and hypothyroidism: Manvi et al. reported a prevalence of hypothyroidism with elevated anti-TPO in 8.6% of their patients, suggestive of autoimmune thyroid function; however, there was no significant difference in the prevalence of thyroid autoimmunity between psoriatic patients and the normal population [23]. In the Rotterdam Study, an association was not found between anti-TPO positivity and thyroid function with prevalent psoriatic disease [24].