The immune response during the luteal phase of the ovarian cycle: a Th2-type response?

Objective: To test the hypothesis that during the luteal phase of the ovarian cycle, as compared with the follicular phase, the peripheral immune response is shifted toward a type-2 response. Design: Prospective study. Setting: Academic research setting. Patient(s): Women with regular menstrual cycles. Intervention(s): Blood samples were collected between days 6 and 9 of the menstrual cycle and 6-9 days after the LH surge. Main Outcome Measure(s): Intracellular cytokine production of interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10 after in vitro stimulation of lymphocytcs as well as total white blood cell (WBC) count, differential WBC count, and plasma 17 beta -E-2 and P concentrations. Result(s): Mean plasma 17 beta -E-2 and P concentrations, WBC count, and mean granulocyte, monocyte, and lymphocyte counts were significantly increased in the luteal phase as compared with the follicular phase of the ovarian cycle. Production of type-1 cytokines (IFN-gamma and IL-2) and production of the type-2 cytokine IL-10 did not vary between the phases of the ovarian cycle. Production of the type-2 cytokine IL-4, however, was significantly increased in the luteal phase as compared with the follicular phase of the ovarian cycle. Conclusion(s): During the luteal phase of the ovarian cycle, the immune response is shifted toward a Th2-type response, as reflected by increased IL-4 production in this phase of the cycle. These results may suggest that increased levels of P and 17 beta -E-2 in the luteal phase of the ovarian cycle play a role in the deviation of the immune response toward a type-2 response. (Fertil Steril(R) 2000;74:1008-13. (C)2000 by American Society for Reproductive Medicine.)