Interest of regular assays of aqueous humor Interleukin-10 levels in monitoring of Vitreoretinal Lymphoma

To investigate the variation of interleukin-10 (IL-10) levels in the aqueous humor (AH) of patients with vitreoretinal lymphoma (VRL) throughout therapy and follow-up, and analyze the relation of these variations with VRL clinical course and relapse. We retrospectively included consecutive patients diagnosed with VRL in a single center. AH IL-10 samples, as well as patient clinical course were evaluated. The response to treatment was evaluated according to the criteria set by the International Primary CNS Lymphoma Collaborative Group. A total of 59 eyes of 34 patients were included. IL-10 levels decreased significantly at first AH sample after therapy induction (median [IQR] 3.0 [2.8-3.6] months) among patients in complete clinical remission (CCR) (p<0.001). Among patients in CCR with residual detectable IL-10 in AH after therapy induction (85.3% systemic chemotherapy, 11.8% intravitreal methotrexate, 2.9% palliative care), 87.5% experienced ocular relapse within 5 years. The detection of IL-10 in AH at the first visit post-induction for CCR obtained a sensitivity of 77.8% [95%CI 0.45-0.96] and a specificity of 96.4% [95%CI 0.82-0.99] to predict ocular relapse. For relapsing eyes (N=26), IL-10 significantly increased between the last IL-10 measurement and the time of the first ocular relapse (p<0.001). In 76.0% of cases, increase in IL-10 was detected earlier than clinical relapse with a mean (SD) of 4.0 (2.4) months. The present study suggested the usefulness of IL-10 in the prognosis of VRL. We showed a relation between IL-10 in AH and tumoral activity, and for the first time with disease relapse.