Human Adenovirus: An Unusual Causative Agent for Acute Retinal Necrosis Presented with Central Retinal Vascular Occlusion

Phylogenetic and Recombination Analysis of Clinical Vitreous Humor-Derived Adenovirus Isolates Reveals Discordance Between Serotype and Phylogeny

Purpose

To sequence, identify, and perform phylogenetic and recombination analysis on three clinical adenovirus samples taken from the vitreous humor at the Bascom Palmer Eye Institute.

Methods

The PacBio Sequel II was used to sequence the genomes of the three clinical adenovirus isolates. To identify the isolates, a full genome-based multiple sequence alignment (MSA) of 722 mastadenoviruses was generated using multiple alignment using fast Fourier transform (MAFFT). MAFFT was also used to generate genome-based human adenovirus B (HAdV-B) MSAs, as well as HAdV-B fiber, hexon, and penton protein-based MSAs. To examine recombination within HAdV-B, RF-Net 2 and Bootscan software programs were used.

Results

In the course of classifying three new atypical ocular adenovirus samples, taken from the vitreous humor, we found that all three isolates were HAdV-B species. The three Bascom Palmer HAdV-B genomes were then combined with over 300 HAdV-B genome sequences, including nine ocular HAdV-B genome sequences. Attempts to categorize the penton, hexon, and fiber serotypes using phylogeny of the three Bascom Palmer samples were inconclusive due to incongruence between serotype and phylogeny in the dataset. Recombination analysis using a subset of HAdV-B strains to generate a hybridization network detected recombination between nonhuman primate and human-derived strains, recombination between one HAdV-B strain and the HAdV-E outgroup, and limited recombination between the B1 and B2 clades.

Conclusions

The discordance between serotype and phylogeny detected in this study suggests that the current classification system does not accurately describe the natural history and phylogenetic relationships among adenoviruses.

Acute retinal necrosis in a patient with cervical malignant tumor treated with sintilimab: a case report and literature review

Acute retinal necrosis (ARN) is an inflammatory disease that is primarily caused by herpesvirus infection, most commonly varicella-zoster virus (VZV), followed by herpes simplex virus (HSV) and occasionally cytomegalovirus (CMV). Sintilimab is an immune checkpoint inhibitor (ICI) that can enhance the body's anti-tumor immune response. However, treatment with ICIs may lead to reactivation of the VZV. Here, we present a case of ARN caused by VZV infection in a patient receiving sintilimab for cervical cancer. A 64-year-old female patient developed vision loss and floaters with left eye redness for one week after 22 cycles of sintilimab for cervical cancer. Based on clinical manifestations, ophthalmological examination, and vitreous humor biopsy, the patient was diagnosed with acute retinal necrosis syndrome secondary to VZV. After receiving systemic antiviral and anti-inflammatory therapy, retinal necrosis lesions and visual function improved. In conclusion, clinicians should be aware of the risk of ARN when using sintilimab and should actively monitor patients for prompt diagnosis and optimal management of this rare adverse drug reaction.

Acute retinal necrosis caused by co-infection with multiple viruses in a natalizumab-treated patient: a case report and brief review of literature

Background

Acute retinal necrosis is considered a rare infectious uveitis. This condition is usually caused by varicella-zoster virus or herpes simplex virus. Acute retinal necrosis caused by co-infection with multiple viruses is extremely rare. Herein, we report a case of acute retinal necrosis caused by co-infection with herpes simplex virus (type I and II) and varicella-zoster virus (VZV) in a natalizumab-treated patient due to multiple sclerosis.

Case presentation

An adult man presented with a complaint of decreased vision of the right eye from 12 days ago. He was a known case of multiple sclerosis receiving natalizumab. Examination of the right eye revealed severe conjunctival injection, fine diffuse keratic precipitates, 3 + anterior chamber and vitreous cells, elevated intraocular pressure (26 mmHg), a blurred optic disk with hemorrhagic patches, and occlusive vasculitis plus confluent necrotizing patches in the peripheral retina compatible with diagnosis of acute retinal necrosis. He underwent anterior chamber and vitreous tap, and real-time PCR detected HSV I & II and VZV on the vitreous specimen. A second PCR showed the same result. After neurological consultation, natalizumab was discontinued and intravenous acyclovir was started followed by oral acyclovir and oral prednisolone to control the disease, which was successful.

Conclusions

Although rare, multiple-viral infection should be considered in the physiopathology of acute retinal necrosis, especially in immunosuppressed patients.