Abstract
Abstract: :
Purpose: Primary intraocular lymphoma (PIOL) often masquerades as chronic uveitis.The diagnosis of PIOL is made by identifying malignant lymphoid cells in the eye, in particular the vitreous. Because these cells may be few and are often degenerated, misdiagnosis can occur. Recent data has shown that levels of interleukin (IL)-10 and IL-6 are elevated in the vitreous of patients with PIOL and uveitis, respectively. In PIOL, an IL-10 to IL-6 ratio greater than 1 has been reported to support the diagnosis of PIOL. Controversial data regarding the usefulness of measuring cytokine levels in the vitreous for the diagnosis of PIOL have been reported. We investigated the benefit of cytokine analysis to differentiate PIOL and uveitis. Methods: From 1993 to 2001 diagnostic vitrectomy specimens were collected from patients with PIOL and patients with uveitis including infectious and non-infectious uveitis. Levels of IL-10 and IL-6 were measured by ELISA (Endogen, Cambridge, Mass). Geometric mean IL-10 to IL-6 ratios for the PIOL and uveitis groups were compared by t-test, and the fraction of patients with ratios at or above unity were calculated for the two groups to determine how well this cutoff point differentiated the patient groups. Results: Thirty-five PIOL patients and 64 uveitic patients had sufficiently complete data for analysis. The geometric mean IL-10 to IL-6 ratio for the PIOL group was 5.23 with 95% confidence interval (2.13, 12.86). For the uveitis group it was 0.23 with interval (0.15, 0.36). The difference in geometric means was significant with p < 0.001. The cutoff rule correctly classified these patients 74.7% of the time. The sensitivity was 74.3%, and the specificity was 75.0%. Conclusion: PIOL is associated with the elevation of IL-10 expression in the vitreous relative to that of IL-6. In contrast, uveitis is associated with the reverse relationship between IL-10 and IL-6. These results are consistent with previous findings of high IL-10 production by PIOL cells and high IL-6 production by inflammatory cells. The ratio of vitreal IL-10 and IL-6 levels is a useful index for differential diagnosis of PIOL and uveitis.
Keywords: 380 cytokines/chemokines • 437 inflammation • 610 tumors