CTLA4 and Hashimoto thyroiditis: We therefore investigated the presence of anti-TPO antibodies in patients with hypothyroidism and also analyzed the frequencies of CTLA4 3’ UTR CT60, exon 1 +49 A/G and TG E33 polymorphisms and CTLA4 expression in autoimmune hypothyroidism patients and controls from Gujarat as indicators of thyroid disorder susceptibility.