Levels of Soluble Human Leukocyte Antigen Class 1 are Increased in Graves' Disease and Toxic Multinodular Goiter and Correlate with the Levels of Triiodothyronine

Abstract

Soluble human leukocyte antigens class 1 (sHLA-1) are postulated to play a role in immunomodulation. Thyroid hormones and thyroid stimulating hormone influence expression of major histocompatibility complex(MHC) class 1 genes. We hypothesized similar changes in sHLA-1 with changes in the thyroid hormone. We measured serum levels of sHLA-1 in 140 normal controls, 11 patients with toxic multinodular goiter and 26 patients with active Graves' disease. On follow-up 1 year after treatment for Graves' disease, we repeated the measurement of the levels of sHLA-1 in 21 patients. Levels of sHLA-1 were markedly elevated in the group of patients with active Graves' disease compared to the normal controls (p = 0.00016). The levels of sHLA-1 were also elevated significantly in patients with toxic multinodular goiter compared to normal controls (p = 0.034). There is no significant difference between genders and the two races tested among patients with Graves' disease in contrast to controls. Free triiodothyronine(T₃) levels positively correlated with the levels of sHLA-1 (r = 0.61). On follow-up after treatment for Graves' disease, levels of sHLA-1 decreased by 62% with p = 0.0006 (active Graves vs. follow-up). We conclude that there is a definite association between thyroid hormones and sHLA-1 levels.