LTA-POC is a rapid test for the measurement of Lymphotoxin-α (LTA) in human tears. It is intended for monitoring ocular surface immune homeostasis and facilitating clinical diagnosis of dry eye disease. LTA is a valuable biomarker for the assessment of immune homeostasis, which is an important factor in dry eye pathogenesis.

The lack of correlation between clinical signs and symptoms of dry eye makes quick and accurate diagnosis difficult. Currently, Schirmer's test, tear break-up time, keratoconjunctival staining, tear osmolarity are the commonly used clinical tests for dry eye diagnosis. However, without objective, quantitative diagnostic tests that correlate well with and the severity of dry eye, the objective differentiation of dry eye symptoms from other eye diseases that present similar symptoms, such as ocular allergies, conjunctivochalasis or infectious bacterial or viral diseases, poses a significant challenge to timely diagnosis and treatment.

Biomarker profiling with tear fluid indicates that immune homeostasis is lost in the ocular surface in dry eye disease, with patients suffering from dry eye have significantly lower LTA levels in their tears as compared with control groups¹.

Regulation of ocular immune tolerance is important for the homeostasis and protection of the ocular tissues from pathogen invasion and immune-medicated inflammation and immune-mediated injury. Immune homeostasis is critical for the protection of ocular surface health, and the loss of immune homeostasis can lead to immunopathology¹. Regulatory T cells (Tregs) are suppressive T cells that play an essential role in maintaining the balance between immune activation and tolerance². The quantity and activity of Tregs are critical in maintaining the immune homeostasis of ocular surface³. Tumor necrosis factor receptor 2 (TNFR2) is expressed highly and selectively in Treg, and the activation of TNFR2 is essential for the activity and function of Tregs⁴. Lymphotoxin-α (LTA) is a ligand for TNFR2. The binding of LTA to TNFR2 activates the proliferation and function of Tregs; therefore, the levels of LTA reflect the status of immune homeostasis in the ocular surface.

LTA-POC measures the levels of LTA to monitor ocular immune homeostasis and facilitate rapid, accurate diagnosis of dry eye.

References

IgE POC is a rapid test for the measurement of Immunoglobulin E (IgE) in human tears. It is intended to facilitate clinical diagnosis of allergic conjunctivitis. IgE is a valuable biomarker for diagnosing allergic conjunctivitis related to the type I hypersensitivity response.

Currently, the diagnosis of allergic conjunctivitis is usually based on clinical history, symptoms and signs. However, because of the overlapping symptoms between allergic conjunctivitis and other eye diseases such as dry eye, objective, quantitative diagnostic testing for allergic conjunctivitis is greatly needed to avoid inaccurate diagnosis and treatments.

IgE concentration in human tears is normally very low in the absence of disease. Elevated total IgE levels in the tears are seen in patients with allergic conjunctivitis.

IgE mediates type I hypersensitivity response and plays a key role in the pathogenesis of allergic conjunctivitis. Type I hypersensitivity is characterized by the occurrence of allergic reactions immediately following re-exposure to an allergen. The ocular hypersensitivity response results from exposure of the conjunctiva to environmental allergens that stimulate the IgE production. Binding of allergens and cross-linking of IgE on the surface of sensitized mast cells and basophils results in cell degranulation, leading to the release of inflammatory mediators and the development of allergic diseases.

IgE POC measures the total IgE levels to facilitate rapid, accurate diagnosis of type I allergic conjunctivitis.

MMP-9 POC is a rapid test for the measurement of Matrix Metallopeptidase 9 (MMP-9) in human tears. It is intended to monitor inflammation of the ocular surface and facilitate diagnosis of dry eye disease. MMP-9 is a valuable biomarker for monitoring ocular surface inflammation, a core underlying mechanism in chronic dry eye, and for stratification of dry eye subtypes.

Currently, Schirmer's test, tear break-up time, keratoconjunctival staining, tear osmolarity are the commonly used clinical tests for dry eye diagnosis; however, these tests cannot identify the exact pathological mechanisms of the kind of dry eye subtype. Understanding the pathogenesis and pathological processes of dry eye is critical in clinical practice.

The MMP-9 activity in tears and MMP-9 gene expression were reported as relatively low in normal subjects and elevated in the patients with dry eye.

MMP-9, an inflammatory marker, is a zinc-binding proteolytic enzyme produced by stressed basal corneal epithelial cells and neutrophils. Proteolytic activities of MMPs play an important role in vascular remodeling, cellular migration, and the processing of ECM proteins and adhesion molecules. MMP-9 consists of a prodomain, catalytic domain, hinge region, and a hemopexin domain, and is secreted as an inactive zymogen that becomes activated extracellularly. The most relevant natural activators of proMMP-9 are unknown. MMP-9 activation may be mediated by removal of the prodomain by serine proteases or other MMPs, or it may be a direct response to oxidative stress that disrupts the cysteine switch. MMP-9 is capable of processing cytokines and chemokines.

MMP-9 POC measures the levels of MMP-9 to assess ocular inflammation and facilitate rapid, accurate diagnosis of dry eye, as well as the stratification of dry eye subtypes.