Elevated vitreous interleukin-10 level is not diagnostic of intraocular-central nervous system lymphoma

OBJECTIVE: Diagnosis of intraocular-central nervous system (CNS) lymphoma is commonly made by identifying malignant lymphocytes in the vitreous. However, such cells are in the minority in the vitreous cellular infiltrate (most are reactive lymphocytes), and therefore lack of cytologic support from biopsied vitreous samples in patients suspected of having intraocular-CNS lymphoma may occur. Recent data suggest that interleukin-10 (IL-10) levels are elevated in the serum and vitreous of patients with non-Hodgkin's lymphoma, whereas IL-12 and IL-6 levels are elevated in patients with uveitis of non-neoplastic etiology. The authors evaluated the usefulness of measuring vitreous levels of IL-6, -10, and -12 in the diagnosis of intraocular-CNS lymphoma. DESIGN: Prospective case series. PARTICIPANTS: Seventeen patients with intraocular inflammation who underwent a diagnostic or therapeutic vitrectomy: 4 patients with intraocular-CNS lymphoma and 13 patients with uveitis unrelated to a neoplasm. INTERVENTION: Eighteen vitreous specimens were obtained prospectively. Concentrations of IL-6, -10, and -12 were measured by enzyme immunosorbent assay, and relative ratios of the interleukins were calculated. Cytopathologic examination and flow cytometry of vitreous cells were also performed. MAIN OUTCOME MEASURES: The ratio of IL-10/IL-12 and IL-10/IL-6 was calculated to assess any association of intraocular-CNS lymphoma and high vitreous IL-10 relative to IL-6 and IL-12 levels. RESULTS: The IL-10/IL-6 and IL-10/IL-12 ratio was greater than 1 in 8 of 14 vitreous specimens obtained from 13 patients with non-neoplastic uveitis. One of the four specimens from patients with cytologically proven intraocular-CNS lymphoma had vitreous IL-10/IL-6 and IL-10/IL-12 ratios of less than 1. CONCLUSION: Although a helpful diagnostic tool, an elevated vitreous IL-10 to IL-6 or IL-12 ratio is not always associated with intraocular-CNS lymphoma.