Suppression of peripheral blood natural killer cell activity by excess thyroid hormone

M. Papic, J. Stein-Streilein, M. Zakarija, J. M. McKenzie, J. Guffee, M. A. Fletcher

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Natural killer (NK) cells were assessed in patients with hyperthyroxinemia due to Graves' disease or treatment with thyroxine (T4). Cytolytic activity was measured with 51Cr-labeled K562 tumor cells and NK enumeration was by flow cytometry using NKH-1 monoclonal antibody to identify the relevant surface marker. Activity was uniformly decreased in association with hyperthyroxinemia, regardless of the underlying pathology; however, there was no reduction in the number of NKH-1+ cells. NK activity was enhanced by addition of interleukin 2 (IL-2) in both control and patients' cells although the value in the latter instance failed to reach the basal control level. Production of IL-2 by lymphocytes from hyperthyroxinemic subjects, in response to phytohemagglutinin, was also reduced. Since NK cells are thought to act as a defense against viral infections and some malignancies and may play a role in autoregulation of the immune system, this effect of T4 may have significant biological implications.

Original languageEnglish
Pages (from-to)404-408
Number of pages5
JournalJournal of Clinical Investigation
Issue number2
StatePublished - Apr 2 1987
Externally publishedYes


ASJC Scopus subject areas

  • Medicine(all)

Cite this

Papic, M., Stein-Streilein, J., Zakarija, M., McKenzie, J. M., Guffee, J., & Fletcher, M. A. (1987). Suppression of peripheral blood natural killer cell activity by excess thyroid hormone. Journal of Clinical Investigation, 79(2), 404-408.