Implications of blood contamination for assessment of local cellular immunity in the endocervix.

Cervical cytobrushes provide a tool to sample endocervical T cells for assessment of local immunity. However, most previous studies in HIV-seropositive women have excluded samples containing blood and hence have analyzed selected populations of patients. As determined by multiple-parameter flow cytometric analysis of T lymphocytes from two sequential cytobrushes and concurrently collected blood samples, this study found a minimal effect of blood contamination on cervical T cell phenotypic parameters in normal women. The consequences of blood in endocervical samples will ultimately depend on the design and objective of each study, but these data suggest studies could be more inclusive and should not automatically discard samples that contain red blood cells.