Cytokine biomarkers in tear film for primary open-angle glaucoma

Figures & data

Table 1 Number and percentage of samples below the LLOD and mean IC

Cytokine	<LLOD (%)	IC %	<LLOD and POAG (%)
IFNγ	11 (28.9)	6.0	2 (12.5)
IL-10	13 (34.2)	3.8	4 (25.0)
IL-12p70	11 (28.9)	8.5	3 (18.8)
IL-13	10 (26.3)	7.7	4 (25.0)
IL-1β	0 (0.0)	3.0	0 (0.0)
IL-2	0 (0.0)	3.4	0 (0.0)
IL-4	24 (63.2)	7.3	10 (62.5)
IL-6	0 (0.0)	4.9	0 (0)
IL-8	0 (0.0)	2.1	0 (0)
TNF-α	0 (0.0)	3.2	0 (0)

Note: The final column reports the number and percentage of subjects with POAG whose samples were below the LLOD.

Abbreviations: LLOD, lower limit of detection; POAG, primary open-angle glaucoma; IC, intraassay coefficients; IFNγ, interferon γ; IL, interleukin; TNFα, tumor necrosis factor α.

Table 2 Demographic and patient characteristic data of control and POAG patients

Demographics	Control (n=9), mean ± SD	POAG (n=10), mean ± SD	P-value
Age (years)	62.4±8.7	61.5±15.2	0.949a
Female n (%)	8 (89%)	6 (60%)	0.525b
Ethnicity
African American	0 (0%)	3 (30%)	0.142b
Caucasian	9 (100%)	6 (60%)
Middle Eastern	0 (0%)	1 (10%)
Patient characteristics	Control (n=18), mean ± SD	POAG (n=16), mean ± SD	P-valuec
logMAR visual acuity	0.02±0.9	0.17±0.32	0.094
Intraocular pressure	14.9±3.8	17.7±4.3	0.191
Cup-to-disc ratio	0.31±0.9	0.75±0.15	<0.001*

Notes:

a P-value based on two-tailed t-test of difference among means;

b P-value based on Fisher’s exact test of difference among proportions;

c P-value based on score statistic from GEE analysis of difference between means accounting for correlation between eyes;

* P<0.05. Bold figure indicates value was <0.05.

Abbreviations: POAG, primary open-angle glaucoma; SD, standard deviation; GEE, generalized estimating equations.

Table 3 Cytokine levels of control and glaucoma POAG patients

Cytokine	Control (n=18)	POAG (n=16)	P-value*
	Mean ± SD (range) pg/mL	Mean ± SD (range) pg/mL
IFNγ	16.85±20.10 (1.18–66.83)	14.76±13.99 (2.79–54.72)	0.910
IL-10	1.35±1.69 (0.10–5.75)	1.46±1.73 (0.20–7.14)	0.521
IL-12p70	3.94±2.19 (1.03–8.67)	2.31±1.16 (0.53–4.74)	0.035
IL-13	30.94±26.92 (2.98–91.39)	18.18±11.23 (3.83–36.46)	0.328
IL-1β	19.22±16.71 (2.87–60.46)	9.00±6.08 (1.37–23.98)	0.063
IL-2	5.06±4.59 (0.85–16.53)	3.38±1.66 (1.02–5.81)	0.482
IL-4	0.38±0.34 (0.06–1.18)	0.25±0.26 (0.03–1.10)	0.162
IL-6	86.71±88.45 (8.07–356.78)	54.62±67.09 (7.39–270.65)	0.173
IL-8	4,326.52±5,766.80 (625.19–25,596.07)	2,021.11±1,584.43 (269.25–6,615.59)	0.167
TNFα	4.86±2.96 (1.89–12.40)	4.91±1.91 (1.19–8.06)	0.727

Notes:

* P-value based on score statistic from GEE analysis of difference between means accounting for correlation between eyes. The log transformation of cytokines rendered the distributions normal and was used in the analysis. IL12p70 cytokine values were significantly lower in POAG patients. Bold figure indicates value was <0.05.

Abbreviations: POAG, primary open-angle glaucoma; IFNγ, interferon γ; IL, interleukin; TNFα, tumor necrosis factor α; SD, standard deviation; GEE, generalized estimating equations.