Purpose: To determine whether a diagnosis of intraocular lymphoma (IOL) can be made using a combination of polymerase chain reaction (PCR) analysis to detect gene rearrangement of immunoglobulin and cytokine concentrations in the vitreous fluid.
Methods: Vitreous samples from 22 patients with clinically suspected IOL and ten control patients with acute retinal necrosis or cytomegalovirus retinitis were examined by PCR analysis and cytokine measurements. Genomic DNA was extracted from the cells in the vitreous, and the immunoglobulin heavy chain (IgH) gene was amplified by two PCR procedures: (1) microdissection and PCR to detect IgH gene rearrangement and (2) qualitative PCR to detect IgH VDJ gene rearrangement. The supernatants of the vitreous samples were used for enzyme-linked immunosorbent assay to determine interleukin (IL)-10 and IL-6 levels.
Results: PCR examinations detected IgH rearrangement in the vitreous in 21 of the 22 IOL patients (95.5%) and in none of the ten control patients. Elevated IL-10 concentrations (>100 pg/ml) and the IL-10/IL-6 ratio (>1.0) were positive in 18 of the 22 IOL patients (81.8%), but negative in all of the control patients. Sensitivity, specificity, positive predictive value, and negative predictive value of PCR for the diagnosis of IOL were calculated to be 0.955, 1.000, 1.000, and 0.909, respectively, and those of the cytokine concentration assay to be 0.818, 1.000, 1.000, and 0.714, respectively. When both the intravitreal cytokine assay and PCR analysis of the vitreous samples are used, as well as diagnostic criteria of IOL defined as a positive outcome from one of the two assays together with clinical signs, the sensitivity and specificity of the criteria were 1.000.
Conclusions: A combination of PCR assay to detect gene rearrangement of IgH and cytokine profiling (IL-10 and IL-6) is extremely useful for the diagnosis of intraocular lymphoma.