Abstract
Purpose: :
Uveitis and primary intraocular lymphoma (PIOL) are diseases associated with the invasion of lymphocytes into various regions of the eye, accompanied by the secretion of inflammatory cytokines. Vitreous biopsy remains the mainstay for diagnosis of ocular lymphoma however despite the array of diagnostic tests, the ‘diagnostic yield’ is only approximately 20%. The resulting biopsies are typically large in volume and have a very small numbers of cells, making cellular characterization difficult when using flow cytometry. The first aim of this study was to demonstrate how the adhesion of cells from human vitreous biopsies to a system of antibody-coated microfluidic channels could be used to identify the subpopulations and the receptor expression of lymphocytes and other leukocytes present in vitreous biopsies. The second aim was to map the full cytokine profiles of these vitreous biopsies using an antibody-coated pillar array within a microfluidic device.
Methods: :
A system of antibody-coated microfluidic chips that consisted of geometrical features to enhance receptor-ligand interactions during cell adhesion was used. These chips were used to immunophenotype model vitreous biopsy samples with known numbers (10,000 to 50,000) of cells as well as human vitreous biopsies. The cells in the samples were interrogated for the expression of common T-lymphocyte, B-lymphocyte, monocyte and epithelial markers. The non-cellular component of the vitreous biopsies was then analyzed for the presence of cytokines using a separate device.
Results: :
Cell subpopulations were identified in both the mock and human vitreous biopsies by the cell adhesion system. Captured cells were then stained for other markers to investigate the expression of other receptors. The presence of specific cytokines was also detected with highly sensitive levels of detection. Accurate identification of cell populations and their receptor expression with the detection and quantification of cytokines present may uncover possible correlations between cell type/cytokine presence and disease type.
Conclusions: :
A system of antibody-functionalized microfluidic devices is capable of characterizing the cellular and cytokine content of vitreous and aqueous humor biopsy samples. This system can be used as an alternative to conventional approaches such as cytopathology, ELISA, and flow cytometry in a point-of-care setting.
Keywords: clinical research methodology • detection • cytokines/chemokines