Summary :

Natural killer cells are one of the major components of the innate immune system. The natural killer cells are present in peripheral blood as well as in some target organs like spleen, liver, uterus etc. Uterine natural killer cells secrete many cytokines and growth factors which may play a role in implantation. Alteration in the number of uterine natural killer cells subset has been suggested as a cause for recurrent miscarriage as well as implantation failure. Measurement of uterine natural killer cells is technologically challenging and requires invasive endometrial biopsy.

The purpose of this study was to find out whether there is any correlation between the number peripheral blood NK cells and the number of uterine NK cells, so that the results of measuring the peripheral blood natural killer cells can be extrapolated to the uterine natural killer cells thereby avoiding the invasive testing.

We will be doing a retrospective analysis of the hospital records between May 2017 to October 2017.  Infertile patients between ages 25 to 38years who have undergone measurement of peripheral blood and uterine natural killer cells will be included.  Women with previous history of abortion or recurrent implantation failure will be included in this study. Women with irregular cycles, women with antiphospholipid antibody syndrome and who were on oral contraceptive pills will be excluded. The patients included had undergone both the peripheral blood and uterine (endometrial) sample on the same day in the mid luteal phase of menstrual cycle(Day 22 to Day 26 of menstrual cycle). The percentage of CD 56 bright and CD 16 dim as well as CD 56 dim and CD 16 bright in the samples were analyzed by flow cytometry.

By this study we will know whether there is a correlation between the number of peripheral and uterine NK cells in the secretory phase and if there is a correlation we can avoid the invasive uterine biopsy.