Multiplex assays in profiling biomarkers in eye disease
Today, our spotlight is set on eye diseases. A recent publication by Nassar et al. depicts the importance of serum cytokines as biomarkers for age-related macular degeneration. Serum samples from 30 age-related macular degeneration (AMD) patients and 15 age-matched controls were examined for 16 inflammatory cytokines using multiplex ELISA. Patients were divided into three subgroups (improvement/no change/deterioration during anti-VEGF treatment) by OCT and funduscopy, and correlated to the cytokine levels.
It was seen that elevation of IL-1α, IL-1β, IL-4, IL-5, IL-10, IL-13, and IL-17 in the serum of AMD patients supports the hypothesis of AMD as an inflammatory disease. Patients with high IL-17 and TNF-α serum levels were more likely to have a favourable course under VEGF therapy, allowing to use these cytokines both as diagnostic and prognostic biomarkers.
Another process where cytokines seem to play a role is Dry Eye Disease (DED). The main problem for analysis of cytokines in this case is that the ideal sample are tears… and in dry eye disease, obtaining high volumes of tears is quite challenging. So, for studies on cohorts of patients, oftentimes we have to work with tear samples volumes of maximum 1 or 2 microlitres.
The multiplex ELISA technology used in Nassar’s study has also been validated for its use in tears, using modified buffers. There are also tools allowing to perform a broader profiling (up to 40 by cytokines) in limited amounts of tear samples.
It is important to check that whatever tool we choose, it has been validated with tears, and especially, with small amounts!
Are you studying biomarkers on tears, or does your research on biomarkers make you cry?
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