Study links immune status to herpesvirus retinitis progression

The clinical progression and outcomes of two major herpesvirus retinitis forms are associated with patients' immune status, reveal Institute of Science Tokyo scientists. They evaluated the clinical symptoms at presentation, retinal detachment (RD) patterns, treatment strategies, and clinical outcomes of acute retinal necrosis (ARN) and cytomegalovirus retinitis (CMVR). They found that ARN was strongly associated with RD whereas CMVR followed an indolent course. These findings may help in early diagnosis and management of viral retinitis.

Herpesviruses are a family of DNA viruses that cause a range of infections in human and animals. Their unique character is that they can remain dormant in the body for prolonged periods and reactivation may lead to conditions such as keratitis, uveitis, or viral retinitis. Herpesvirus retinitis or necrotizing retinitis is an eye infection causing significant visual impairment, characterized by retinal tissue destruction and vascular inflammation. It often leads to a complication called retinal detachment or RD that significantly affects the disease prognosis and treatment options.

Two major clinical forms of necrotizing viral retinitis are acute retinal necrosis (ARN), typically affecting immunocompetent individuals, and cytomegalovirus retinitis (CMVR), common in immunocompromised patients. Accurate differentiation between these phenotypes at presentation is essential for optimizing treatments and visual outcomes. However, their distinct clinical differences, specific association with RD and associated visual outcomes remain poorly characterized.

To address this gap, researchers at Institute of Science Tokyo (Science Tokyo), Japan, conducted a retrospective longitudinal cohort study between 2013 and 2025. The research team, led by Associate Professor Koju Kamoi, graduate student Ms. Yaru Zou, and Professor Kyoko Ohno-Matsui from the Department of Ophthalmology and Visual Science, Graduate School of Medical and Dental Sciences, Science Tokyo, explored how host immune status influences the clinical phenotype as well as the risk of RD and severe visual impairment caused by herpesvirus retinitis. Their study was published online in the journal Ophthalmology Retina on June 6, 2026.

The study included 64 patients with ARN and 56 with CMVR. "We comprehensively analyzed the clinical course of herpesvirus retinitis, including immune status, disease subtype, visual acuity at presentation, extent of retinal lesions, severity of inflammation, findings from intraocular fluid testing, timing of retinal detachment diagnosis, therapeutic interventions, and final visual outcomes," says Kamoi.

The analyses revealed clear differences in the systemic profiles of the two conditions. CMVR was strongly associated with immunocompromised conditions, particularly lymphoma, autoimmune disease, transplantation history, and prior immunosuppressive therapy and followed an indolent progression course. In contrast, ARN was more common in immunocompetent individuals, frequently unilateral and showed a more rapidly progressive clinical phenotype. These findings highlighted the importance of host immune status in the assessment of herpesvirus retinitis.

At the ocular level, ARN showed more extensive retinal involvement and was associated with severe vitreous inflammation and peripheral necrosis. ARN and CMVR differed significantly in the incidence and timing of RD development as well. Eyes affected by ARN were more likely to develop RD and detachment tended to occur soon after the diagnosis. Statistical analysis confirmed ARN as an independent risk factor for RD, while poor visual acuity at presentation was also associated with an elevated risk.

Patients with late-onset RD had poorer visual outcomes compared to those with concurrent RD. The finding suggests that late detachment may occur after extensive retinal damage and scarring, limiting opportunities to preserve retinal function. Surgical treatments, such as pars plana vitrectomy, were associated with better visual outcomes. This highlights the importance of timely intervention, while emphasizing that the study does not establish a causal benefit of surgery.

The findings emphasize that herpesvirus retinitis should not be assessed based just on the clinical phenotypes. Differences in host immune status may contribute to distinct patterns of viral replication, inflammation, and retinal damage. The findings from this study may help in the construction of a disease risk assessment model combining multiple factors, enabling early identification of high-risk patients and appropriate therapeutic management of the condition.

A comprehensive evaluation of patients' immune status and ocular findings at the initial presentation may allow more accurate prediction of the risk of severe disease progression and visual impairment, which can further guide monitoring and management."

Koju Kamoi, Associate Professor, Institute of Science Tokyo