Purified Protein Derivative Reaction and Urinary Immunosuppressive Acidic Protein in Patients With Subacute Thyroiditis

Abstract

Recently we reported1-2 that in acute phase of subacute thyroiditis (SAT) serum immunosuppressive acidic protein (IAP), a type of α1-acid glycoprotein measured by single radial immunodiffusion method is increased, and peripheral K cell activity measured by the modified plaquemethod of Biberfeld et al. was decreased and negatively correlated with serum IAP. Inhibition rate of K cells from a normal subject by sera of patients with SAT in acute phase was higher than that in recovery phase and those of normal control. Purified IAP inhibited K cell activity of normal subject in a dose-dependent manner. Circulating immune-complex measured by modified solid phase Clq-binding assay was almost normal and had no correlation with serum IAP in SAT. Trypsynization of K cells resulted in no change of K cells in both normal subjects and patients with SAT. From these results, it is conceivable that the K cell function is activated to destroy the affected cells probably by virus in the very early phase of SAT and that the K cell activity in SAT might be suppressed by IAP produced from macrophages as defense mechanism against the endless destruction of affected cells by K cells.