INTRODUCTION: Many widely used international histological textbooks claim that the epithelium of the human uterine tube consists of two, three, and, eventually, four types of cells. Most discrepancies among these textbooks relate to debates regarding the presence or absence of basal cells, whether the peg/intercalary cells and secretory cells are the same or distinct cell populations, and if the epithelium contains a population of immunologically active cells (T- and B-lymphocytes, NK cells, macrophages and dendritic cells) or dispersed endocrine cells. METHODS: Uterine tubes were obtained from 22 women (average age: 46.73 y) undergoing gynecological surgery. The women were in fertile age, mostly in the middle of the menstrual cycle (ovulation phase). Tissue samples were processed for immunohistochemistry using primary antibodies against proliferation markers (Ki67 and PCNA), immune system cells (CD1a, CD3, CD4, CD8, CD20, CD45RO, CD56, CD68, granzyme B and S100) and disperse endocrine cells (chromogranin A and synaptophysin). RESULTS: Most of the mature tubal epithelial cells, ciliated cells, and secretory cells were mitotically active (PCNA+), a population of basal undifferentiated cells was not identified. The dividing cells had a narrow-shaped nucleus (Ki67 positive). These cells were morphologically identical to - by the terminology mentioned - intercalary cells, assuming they represented actually dividing cells (epitheliocytus tubarius mitoticus). The tubal "basal cells" displayed small, hyperchromatic nuclei and very pale cytoplasm (clear cytoplasmic halo). They were located in the epithelium adjacent to the basement membrane, were non-mitotically active and their immunophenotype corresponded to intraepithelial regulatory T-lymphocytes (CD3+, CD8+, CD45RO+, CD4-, CD20-, CD56- and granzyme B-). Intraepithelial B-lymphocytes were only rarely identified. Intraepithelial NK cells, dendritic cells, macrophages and dispersed endocrine cells were not identified. CONCLUSIONS: We recommend replacing the term "epitheliocytus tubarius basalis" in the Terminologia Histologica with the term "lymphocytus T intraepithelialis tubarius", which represents intraepithelial regulatory T-cells (CD8+, CD45RO+) of the uterine tube. Additionally, we propose that intercalary/peg cells are actively dividing cells, instead of effete or degenerating cells. Finally, the histological nomenclature should be corrected in a way that peg/intercalary cells are not considered synonymous terms for secretory cells.

3rd Department of Surgery Faculty of Medicine Comenius University and Hospital of The Brothers of Saint John of God Bratislava Namestie SNP 10 Bratislava 814 65 Slovakia

Department of Anatomy 2nd Faculty of Medicine Charles University U nemocnice 3 Prague 128 00 Czech Republic; Department of Health Care Studies College of Polytechnics Tolstého 16 Jihlava 586 01 Czech Republic

Institute of Histology and Embryology Faculty of Medicine Comenius University in Bratislava Špitálska Street 24 Bratislava 813 72 Slovakia

Institute of Histology and Embryology Faculty of Medicine Comenius University in Bratislava Špitálska Street 24 Bratislava 813 72 Slovakia; Department of Gynecology and Obstetrics AGEL General Hospital Mederčská Street 39 945 75 Komárno Slovakia

Institute of Pathological Anatomy Faculty of Medicine Comenius University in Bratislava Špitálska Street 24 Bratislava 813 72 Slovakia

References provided by Crossref.org

Morphology of the immune cells in the wall of the human uterine tube and their possible impact on reproduction-uterine tube as a possible immune privileged organ

Scanning electron microscopic study of the human uterine tube epithelial lining: surgical biopsy samples and epithelial cell culture

Functional Morphology of the Human Uterine Tubes in the 21st Century: Anatomical Novelties and Their Possible Clinical Applications

Immunohistochemical and Scanning Electron Microscopic Confirmation of the Lymphatic Lacunae in the Uterine Tube Mucosal Folds. What Are the Clinical Implications?

Microbiota of female genital tract - functional overview of microbial flora from vagina to uterine tubes and placenta

From a Passive Conduit to Highly Dynamic Organ. What are the Roles of Uterine Tube Epithelium in Reproduction?