Bilateral retinitis after influenza virus infection in a case report

Response of Human Retinal Microvascular Endothelial Cells to Influenza A (H1N1) Infection and the Underlying Molecular Mechanism

Purpose

Whether H1N1 infection-associated ocular manifestations result from direct viral infections or systemic complications remains unclear. This study aimed to comprehensively elucidate the underlying causes and mechanism.

Method

TCID50 assays was performed at 24, 48, and 72 hours to verify the infection of H1N1 in human retinal microvascular endothelial cells (HRMECs). The changes in gene expression profiles of HRMECs at 24, 48, and 72 hours were characterized using RNA sequencing technology. Differentially expressed genes (DEGs) were validated using real-time quantitative polymerase chain reaction and Western blotting. CCK-8 assay and scratch assay were performed to evaluate whether there was a potential improvement of proliferation and migration in H1N1-infected cells after oseltamivir intervention.

Results

H1N1 can infect and replicate within HRMECs, leading to cell rounding and detachment. After H1N1 infection of HRMECs, 2562 DEGs were identified, including 1748 upregulated ones and 814 downregulated ones. These DEGs primarily involved in processes such as inflammation and immune response, cytokine-cytokine receptor interaction, signal transduction regulation, and cell adhesion. The elevated expression levels of CXCL10, CXCL11, CCL5, TLR3, C3, IFNB1, IFNG, STAT1, HLA, and TNFSF10 after H1N1 infection were reduced by oseltamivir intervention, reaching levels comparable to those in the uninfected group. The impaired cell proliferation and migration after H1N1 infection was improved by oseltamivir intervention.

Conclusions

This study confirmed that H1N1 can infect HRMECs, leading to the upregulation of chemokines, which may cause inflammation and destruction of the blood-retina barrier. Moreover, early oseltamivir administration may reduce retinal inflammation and hemorrhage in patients infected with H1N1.

Intraocular Viral Communities Associated With Post-fever Retinitis

The virome of ocular fluids is naive. The results of this study highlight the virome in the vitreous fluid of the eye of individuals without any ocular infection and compare it with the virome of the vitreous fluid of individuals with retinitis. A total of 1,016,037 viral reads were generated from 25 vitreous fluid samples comprising control and post-fever retinitis (PFR) samples. The top 10 viral families in the vitreous fluids comprised of Myoviridae, Siphoviridae, Phycodnaviridae, Herpesviridae, Poxviridae, Iridoviridae, Podoviridae, Retroviridae, Baculoviridae, and Flaviviridae. Principal coordinate analysis and heat map analysis clearly discriminated the virome of the vitreous fluid of the controls from that of the PFR virome. The abundance of 10 viral genera increased significantly in the vitreous fluid virome of the post-fever retinitis group compared with the control group. Genus Lymphocryptovirus, comprising the human pathogen Epstein-Barr virus (EBV) that is also implicated in ocular infections was significantly abundant in eight out of the nine vitreous fluid viromes of post-fever retinitis group samples compared with the control viromes. Human viruses, such as Hepacivirus, Circovirus, and Kobuvirus, were also significantly increased in abundance in the vitreous fluid viromes of post-fever retinitis group samples compared with the control viromes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analysis and the network analysis depicted an increase in the immune response by the host in the post-fever retinitis group compared with the control group. All together, the results of the study indicate changes in the virome in the vitreous fluid of patients with the post-fever retinitis group compared to the control group.

Bilateral optic neuritis with spine demyelination associated with influenza A H1N1 infection

Purpose

To report a rare case of optic neuritis with spine demyelination following H1N1 virus infection.

Observation

A 66-year-old female presented with decreased vision in both eyes (left > right) following a recent episode of fever and flu. She was diagnosed as H1N1 infection confirmed by viral antigen analysis of throat swab. On examination, she had a profound vision drop in the left eye with optic disc edema. MRI brain and orbit revealed bilateral optic nerve and frontal dural thickening with a ring-enhancing lesion in the right frontal lobe. MRI spine showed long cord signals at T1-T7 suggestive of demyelination. The patient had a complete recovery of vision and visual fields after intravenous and oral steroids.

Conclusion/Importance

Influenza A virus can manifest with a wide range of symptoms including flu-like illness to neurological complications. This case highlights optic neuritis as a presenting feature of H1N1 infection.

Neuro-ophthalmological consequences of acute influenza A encephalitis in a genetically predisposed child

Acute necrotising encephalopathy (ANE) is a rare disease that corresponds to a rapidly progressive encephalopathy induced by a viral infection. It is frequently associated with a mutation on the RAN-binding protein 2 (RANBP2) gene-ANE1. We present a case of a 5-year-old boy with a clinical picture of influenza aggravated to an acute encephalopathy picture after the 3rd day. Complementary examinations came back positive for the influenza A virus, and MRI showed aspects compatible with ANE. He was treated accordingly with subsequent improvement of the clinical picture. During ambulatory follow-up, a mutation was detected on the RANBP2 gene and, at the ophthalmological level, bilateral peripheral constriction on the campimetry and a significant reduction of bilateral peripapillary retinal nerve fibre layer was reported. Our case contributes to the enrichment of the neuro-ophthalmological literature and expands the spectrum of sequelae of this rare entity in the Caucasian population.