Analysing Tear Protein, Conjunctival Cells, and Imaging Eyes in Patients With Rheumatoid Arthritis and Systemic Lupus Erythematosus

Background and Rationale

Inflammatory autoimmune disease and eye involvement Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE) are chronic systemic autoimmune diseases of unknown etiology [2]. Ocular manifestations may range from conditions which cause distressing symptoms of discomfort, such as dry eye syndrome, to potentially sight-threatening conditions such as retinal vasculitis. The ocular surface is agreed to be the site most commonly affected by systemic autoimmune diseases, manifesting as dry eye syndrome. However, its related complications are poorly addressed [1,2]. The severity of ocular surface inflammation may be related to systemic immunology since systemic treatment will alter the signs of ocular surface disease.

EyePRIMTM (Opia Technologies) Impression Cytology Device Studies have shown that this method of combining flow cytometry with OSIC is useful to phenotype recovered cells from the superficial layers of the ocular surface [3]. There has been recent advances in clinical techniques for obtaining conjunctival cells for reseach studies. An example of an award winning device is the EyePRIMTM (Opia Technologies).

Previous studies have shown that EyePRIMTM is able to obtain sufficient cells for flow cytometry for immune markers [4]. In the study, the ocular surface of three healthy patients were analysed using EyePRIMTM and conventional semi-circular Supor PES filters for flow cytometry. One EyePRIMTM was used to impression the lateral bulbar conjunctiva and a second, the medial bulbar conjunctiva of the same eye. Cells were recovered from both EyePRIMTM using gentle agitation with a pipette tip for one minute, and then stained with antibody markers for leukocytes (CD45), CD16, epCAM, HLA-DR and a dead cell exclusion dye. Results have shown that the mean corrected total cell count collected using EyePRIMTM was greater than conventional methods (475,544 cells vs 335,226 cells). Out of the total cells collected, the mean corrected number of lymphocytes found via staining with CD45 antibody was around 1000.

Advances in clinical phenotyping Dry eye is a common ocular surface disease mediated by inflammation. It is postulated that dry eye in the context of systemic autoimmune diseases is caused by the infiltration of activated T lymphocytes into the bulbar conjunctiva, beginning a vicious cycle of chronic inflammation of the ocular surface [5]. In the dry eye database at SNEC/SERI (unpublished data), we found higher levels of fluorescein corneal staining, indicating presence of punctate epithelial erosions in patients with RA compared to dry eye patients without systemic autoimmune diseases. While we have not personally conducted studies on SLE patients, it is documented in existing literature that significant signs of dry eye have been detected in SLE patients using older assessment modalities such as the Schirmer's test and Rose Bengal staining [6].