Evaluation of the cervical cytobrush sampling technique for the preparation of CD45+ mononuclear cells from the human...

A cytobrush technique developed to prepare mononuclear cells from the intraepithelial layer of the endocervix has been evaluated. Specimens yielded approximately 4-6x10(6) cells, of which 10-15% were CD45+. Between 10% and 15% of these CD45+ cells were mononuclear leukocytes. The non-leukocyte cell fraction exhibited high levels of autofluorescence and for flow cytometry analysis, it was necessary to exclude these cells by gating. Macrophages constituted approximately 60% and T lymphocytes, 40% of the mononuclear cells in cytobrush samples. The CD4/CD8 T-cell ratio was similar to that observed in blood. In 9 of 13 specimens, B lymphocytes constituted less than 1% of the mononuclear cell fraction suggesting that the mononuclear cells were derived from the intraepithelial compartment rather then the deeper lamina propria. Lack of B lymphocytes also indicates minimal blood contamination in these samples, a conclusion supported by labelling for the red blood cell (RBC) glycoprotein glycophorin A. However, the need to monitor all samples for possible blood contamination was indicated by 4 of 13 samples in which B lymphocytes accounted for 2-8% of the mononuclear cells.