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Gauri Shankar Shrestha, Ajay Kumar Vijay, Fiona Stapleton, Nicole Ann Carnt; The effect of collection method on tear interleukin-6 levels in healthy individuals: A pilot study. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5370.
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Interleukin-6 (IL-6) is an important cytokine associated with ocular inflammation in certain ocular surface diseases and contact lens wear. The Schirmer strip and the capillary tube techniques of tear collection are commonly used in biomarker studies of eye infection and inflammation. This study measured and compared the level of IL-6 in tear fluid collected from healthy individuals using Schirmer’s strips and the microcapillary tubes, with and without anesthesia.
Methods: Six subjects (33.5 ± 2.9 years) were recruited, and four tear samples were collected in a random order on four different days between 12:00 pm and 4:00 pm. Samples were collected using Schirmer’s strips without anesthesia (S1), with anesthesia (S2), and microcapillary tubes without anesthesia (M1) and with anesthesia (M2). The levels of IL-6 was quantified by enzyme-linked immunosorbent assay (ELISA). Tears collected using Schirmer’s strips were extracted and diluted 1:10 using 1x Standard Diluent Buffer (SDB), while the tears collected using microcapillary tubes were diluted 1:20 using SDB and adjusted for the dilution factor.
The median levels of IL-6 were 1.51 (Interquartile range (IQR), 0.87-2.20) pg/ml, 1.45 (IQR, 0.67-2.46) pg/ml, 2.98 (IQR, 1.37-3.24) pg/ml, and 0.37 (IQR, 0.25-4.98) pg/ml in S1, S2, M1 and M2 respectively. There was no significant difference in IL-6 levels of tears collected with and without topical anaesthesia using Schirmer’s strips (p = 0.94) and microcapillary tubes (p = 0.55) or between using the 2 tear collection methods (p = 0.63).
Neither the tear collection method nor anesthesia affects IL-6 levels in the tear fluid of healthy individuals. The level of IL-6 in the present study is lower than the levels reported in the literature where mostly unstimulated tears were collected with microcapillary tubes.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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