Influence of thyroxine on serum soluble interleukin-2 receptor alpha levels in thyroid disorders.
BACKGROUND
Activation of cell-mediated immunity by soluble interleukin-2 receptor alpha (sIL-2Ralpha) release is well documented. The aim of this study was to measure serum concentrations of sIL-2Ralpha in patients with autoimmune and non-autoimmune thyroid disorders in different stages of thyroid function, before and after administration of l-thyroxine (l-T4) and its discontinuation as well as before and during methimazole administration.


METHODS
The study included 80 females: 16 with Graves' disease, 15 with Hashimoto's thyroiditis and subclinical hypothyroidism, 14 with Hashimoto's thyroiditis with fibrosis and clinical hypothyroidism, 20 after subtotal thyroidectomy following nodular non-toxic goitre and 15 healthy controls. Patients were examined at two different time points. Serum concentrations of sIL-2Ralpha were measured with the use of enzyme immunoassay technique.


RESULTS
Souble IL-2Ralpha serum concentration increased in patients with untreated Graves' disease and decreased after methimazole treatment. In Hashimoto's thyroiditis, the sIL-2Ralpha level was within the normal range, in Hashimoto's thyroiditis with clinical hypothyreosis it was low and after l-T4 administration it increased in both patient groups. After thyroidectomy, patients treated with l-T4, had increased levels of sIL-2Ralpha which decreased after discontinuation of therapy. There were a significant positive correlation between sIL-2Ralpha and free thyroxine in patients with (i). Graves' disease both before and after methimazole administration, (ii). Hashimoto's thyroiditis (with subclinical hypothyroidism) both before and after l-T4 therapy, (iii). Hashimoto's thyroiditis with fibrosis and (iv). overt hypothyroidism before l-T4 administration and in individuals during long-term l-T4 treatment (after subtotal thyroidectomy).


CONCLUSIONS
Serum sIL-2Ralpha concentration in autoimmune thyroid diseases depends on thyroid function. In both autoimmune and non-autoimmune thyroid diseases, thyroxine stimulates the release of sIL-2Ralpha.
Zwirska-Korczala
K
K
Department of Physiology, Medical University of Silesia, Zabrze, Poland. kkorcz@slam.katowice.pl
Berdowska
A
A
Jochem
J
J
Sitkiewicz
A
A
Birkner
E
E
Polaniak
R
R
Jedrzejowska-Szypułka
H
H
Korzonek-Szlacheta
I
I
D000328:Adult; D013956:Antithyroid Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D005260:Female; D006111:Graves Disease / Q000097:blood / Q000188:drug therapy / Q000601:surgery; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy / Q000601:surgery; D053645:Interleukin-2 Receptor alpha Subunit; D008297:Male; D008713:Methimazole / Q000627:therapeutic use; D008875:Middle Aged; D018123:Receptors, Interleukin / Q000097:blood / Q000187:drug effects*; D013959:Thyroid Diseases / Q000097:blood* / Q000188:drug therapy / Q000601:surgery; D013965:Thyroidectomy; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000188:drug therapy / Q000601:surgery; D013974:Thyroxine / Q000494:pharmacology*
D013956:Antithyroid Agents; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit; D018123:Receptors, Interleukin; D008713:Methimazole; D013974:Thyroxine