Cytokine production by natural killer lymphocytes in follicular and luteal phase of the ovarian cycle in humans

PROBLEM: The aim of this study was to test the hypothesis that, during luteal phase of the ovarian cycle, as compared with follicular phase, the cytokine productive capacity of peripheral natural killer (NK)-lymphocytes in humans is shifted towards a "Th2-type"-like response. METHOD OF STUDY: Intracellular Th1 and Th2 cytokine production by in vitro activated peripheral NK-lymphocytes in a whole blood preparation of the follicular and the luteal phase of the ovarian cycle was measured by flow cytometry. RESULTS: There was no difference in interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10 cytokine production in activated NK-lymphocytes when comparing luteal phase with follicular phase of the ovarian cycle. However, there was a significant increase in peripheral NK-lymphocyte number in luteal phase compared with follicular phase. CONCLUSION: The cytokine productive capacity of peripheral NK-lymphocytes is not shifted towards a "Th2-type"-like response in the luteal phase as compared with the follicular phase of the ovarian cycle in humans.