Two different kinds of TPOabs

[Guest guest]

This article implies that TPOabs (thyroperoxidase antibodies) are not

all the same. These researchers found that some TPOabs do nothing,

while others bind to peroxidase enzyme. This means a person can be

positive for TPOab, but not have any disease activity.

Anti-thyroid peroxidase antibodies in sera from healthy subjects and

from patients with chronic thyroiditis: differences in the ability to

inhibit thyroid peroxidase activities

Y. KOHNO 1 , F. YAMAGUCHI*, K. SAITO 1 , H. NIIMI 1 , T. NISHIKAWA†

T. HOSOYA*

1 Department of Pediatrics, School of Medicine, Japan *Faculty of

Pharmaceutical Sciences. Chiba University, Chiba, Japan †Department

of Second Internal Medicine, School of Medicine, Japan

Correspondence to Dr Yoichi Kohno, Department of Pediatrics, School

of Medicine, Chiba University, 1-8-1 Inohana, Chiba 280, Japan.

Copyright 1991 Blackwell Science Ltd, Oxford

KEYWORDS

autoantibody • thyroid peroxidase • epitopc • autoimmunity • chronic

thyroiditis

ABSTRACT

A significant percentage (6.4%) of healthy subjects was found to

contain anti-thyroid peroxidase (TPO) antibodies in their sera.

However, in contrast with IgG from sera of patients with chronic

thyroiditis, IgG from sera of healthy subjects did not inhibit TPO

activities both in guaiacol and iodide assays. In addition, anti-TPO

antibodies from healthy subjects did not block the inhibition of

enzyme activities by anti-TPO antibodies from patients. These

findings suggest that anti-TPO antibodies from healthy subjects do

not bind to the epitopes relating to substrate-combining sites of

TPO. Thus, the specificities of anti-TPO antibodies in healthy

subjects may differ from those in cases of chronic thyroiditis.