Abstract
BACKGROUND: Interleukin detection is helpful in screening vitreoretinal lymphoma (VRL). However, the levels of interleukin in aqueous humor (AqH) can be abnormally low in some cases, leading to underdiagnosis of VRL merely dependent on AqH. The purpose of this study was to investigate the correlation of interleukins between paired AqH and vitreous humor (VH) samples in VRL cases, and to explore potential factors affecting interleukin levels and diagnostic parameters. METHODS: This was a case series study. Reviewed were consecutive biopsy-proven B-cell VRL cases of which adequate paired AqH and VH samples were obtained for the measurement of interleukin 10 (IL-10) and interleukin 6 (IL-6). The correlations of IL-10 and IL-6 between AqH and VH were analyzed. Influences of clinical manifestations on IL levels and positive rates of IL-related parameters in AqH and VH were evaluated, which included AqH IL-10 > 30 pg/mL, VH IL-10 > 65 pg/mL, IL-10/IL-6 ratio > 1, and Interleukin Score for Intraocular Lymphoma Diagnosis (ISOLD) > 0 in both the AqH and VH. RESULTS: Seventy-four eyes of 64 patients with VRL were included. IL-10 in VH was significantly higher than in AqH (median: 1159.77 vs. 225.74 pg/mL, P < 0.001). For both IL-10 and IL-6, the AqH concentrations were positively correlated with VH concentrations in the form of power functions (P < 0.001 and P < 0.001, respectively). The positive rate of AqH IL-10/IL-6 > 1 (77%) was lower than that of VH IL-10 > 65 pg/mL (91%), VH IL-10/IL-6 > 1 (89%) and VH ISOLD > 0 (91%). Eyes without intraretinal infiltration tended to have lower IL-10 levels in the AqH and VH (median: 141.08 pg/mL vs. 449.10 pg/mL, 825.48 pg/mL vs. 2285.77 pg/mL; P = 0.001 and P < 0.001, respectively), and lower positive rates of AqH IL-10 > 30 pg/mL (78% vs. 97%, P = 0.018) and AqH ISOLD > 0 (76% vs. 97%, P = 0.033). CONCLUSIONS: IL-10/IL-6 in AqH may not be as sensitive as the parameters (including IL-10, IL-10/IL-6 and ISOLD) in VH for VRL screening. Cases without intraretinal involvement were less likely to be positive for IL-10 > 30 pg/mL and ISOLD > 0 in AqH; the possibility of VRL should be ruled out more cautiously in these cases.