T-lymphocyte subsets in pregnant women with Graves' disease

T-lymphocyte subpopulations, anti-thyroid microsomal antibody titres, and free triiodothyronine and free thyroxine levels were investigated in 10 patients with Graves' disease before, during and after pregnancy. Twenty pregnant subjects and 100 normal age-matched, non-pregnant female volunteers served as controls. Pregnant patients with Graves' disease showed decrease levels of free triiodothyronine and free thyroxine, and decreased titres of anti-thyroid microsomal antibodies, with clinical remission during the second and third trimesters of pregnancy. Post partum, 9 patients showed clinical relapse, and all showed a return of enhanced levels of free triiodothyronine, free thyroxine and anti-thyroid microsomal antibodies. The percentage and absolute number of total T-lymphocytes (OKT3+) and OKT4+ cells significantly decreased during pregnancy in patients with Graves' disease and in normal women. Post partum, OKT3+ and OKT4+ cells returned to pre-pregnancy levels in both groups. In Graves patients and in controls, the percentage and absolute number of OKT8+ cells during pregnancy and post partum were not significantly different from pre-pregnancy levels. Lastly, the OKT4+/OKT8+ ratio, which decreased in normal subjects at the three sampling times during pregnancy, decreased only in the last two trimesters of pregnancy in patients with Graves' disease.