Introduction
Patients frequently undergo an endometrial biopsy (lining of the uterus) when they are being studied for recurrent pregnancy losses, IVF failures and implantation failures. These studies are performed by pathologists using stains that provide them with structural information about the endometrium. Within the endometrium there are immune cells known as lymphocytes. We know that there are many different types. Unfortunately, with conventional techniques the different types of lymphocytes have the same appearance. In our clinic we need to know what types and quantities of lymphocytes are present in order to make a proper diagnosis prior to treatment.

Immune pathology studies can be applied to these biopsy specimens revealing the nature of these lymphocytes. These tests are performed at our laboratory by an immunopathologist, a physician who is both a pathologist and immunologist. These studies are currently directed toward the assessment of two types of such lymphocytes: CD57+ cells and T regulatory cells.

Cells that are positive for the CD57 immune marker normally do not appear in the uterine lining (endometrium). Dr. Winger (our immunopathologist) has written a scientific paper in which he discusses CD57 cells in the uterine lining (Winger EE: CD57+ cells and recurrent spontaneous abortion. Am J Reprod Immunol 2007; 58:311– 314).

CD57 marked cells may also be improperly migrating NK cells from the blood. Whatever their source, we at the Center believe that their presence is undesirable.

These lymphocytes are not normally seen in the uterus of fertile women. To find if a woman has this problem an endometrial biopsy is done by a gynecologist on cycle day 26 or a few days before menstruation.

Experience at our Center has shown that many individuals with infertility have increased numbers of CD 57+ cells in the blood, and increased cytotoxicity (killing power) when tested in the NK assay.