Mucosal signatures of pathogenic T cells in HLA-B*27+ anterior uveitis and axial spondyloarthritis.

HLA-B*27 was one of the first HLA alleles associated with an autoimmune disease, i.e., axial spondyloarthritis (axSpA) and acute anterior uveitis (B27AAU), which cause joint and eye inflammation, respectively. Gastrointestinal inflammation has been suggested as a trigger of axSpA. We recently identified a bacterial peptide (YeiH) that can be presented by HLA-B*27 to expanded public T cell receptors in the joint in axSpA and the eye in B27AAU. While YeiH is present in enteric microbiota and pathogens, additional evidence that pathogenic T cells in HLA-B*27-associated autoimmunity may have had a prior antigenic encounter within the gastrointestinal tract remains lacking. Here, we analyzed ocular, synovial, and blood T cells in B27AAU and axSpA, showing that YeiH-specific CD8+ T cells express a mucosal gene set and surface proteins consistent with intestinal differentiation, including CD161, integrin α4ß7, and CCR6. In addition, we found an expansion of YeiH-specific CD8+ T cells in axSpA and B27AAU blood compared with that from individuals acting as healthy controls, whereas influenza-specific CD8+ T cells were equivalent across groups. Finally, we demonstrated the dispensability of TRBV9 for antigen recognition. Collectively, our data suggest that, in HLA-B27-associated autoimmunity, early antigen exposure and differentiation of pathogenic CD8+ T cells may occur in enteric organs.

Intraocular Immune Response in Human Uveitis: Time to Look Beyond Animal Models.

PURPOSE: To review the current and future approaches to investigating the intraocular immune response in human uveitis. DESIGN: Perspective. METHODS: Review of currently available methods for investigating the immune response in ocular tissues and fluids in patients with intraocular inflammation/ uveitis. The advantages and disadvantages of human studies have been compared to those of animal models of uveitis. RESULTS: Animal models, while being excellent tools for mechanistic studies, do not replicate the clinical and immunologic heterogeneity of human uveitis. Opportunities for immunological studies in human uveitis are mostly limited to histological studies, or sampling of intraocular fluids and peripheral blood. Histopathological studies can be enhanced by revisiting published historical data, tissue repositories, or autopsy specimens. Intraocular fluids can be investigated by a variety of techniques. Among these, flow cytometry and single-cell RNA sequencing (scRNAseq) provide single-cell resolution. While the current technology is costly and labor-intensive, scRNAseq is less limited by the low cellular yield from intraocular fluids and allows unbiased immune profiling enabling discovery of new cellular subsets. Immunological phenotypes uncovered from human data can be further investigated in animal studies. CONCLUSION: The diversity of the intraocular immune response in uveitis patients remains challenging but can be studied by multiple techniques including histopathology, flow cytometry, and scRNAseq. Human data can be combined with animal studies for translating uveitis research into novel therapies.

Aqueous Macrophages Contribute to Conserved CCL2 and CXCL10 Gradients in Uveitis.

Purpose: Uveitis is a heterogenous group of inflammatory eye disease for which current cytokine-targeted immune therapies are effective for only a subset of patients. We hypothesized that despite pathophysiologic nuances that differentiate individual disease states, all forms of eye inflammation might share common mechanisms for immune cell recruitment. Identifying these mechanisms is critical for developing novel, broadly acting therapeutic strategies. Design: Experimental study. Subjects: Biospecimens from patients with active or inactive uveitis and healthy controls. Methods: Protein concentration and single cell gene expression were assessed in aqueous fluid biopsies and plasma samples from deidentified patients with uveitis or healthy controls. Main Outcome Measures: The concentration of 31 inflammatory proteins was measured in all aqueous samples, as well as plasma samples from patients with active uveitis. Chemokine and cytokine ligand and receptor expression were assessed in individual cell types from aqueous biopsies obtained from patients with active uveitis. Results: We identified 6 chemokines that were both elevated in active uveitis compared with controls and enriched in aqueous compared with plasma during active uveitis (C-C motif chemokine ligand [CCL]2, C-X-C motif chemokine ligand [CXCL]10, CXCL9, CXCL8, CCL3, and CCL14), forming potential gradients for migration of immune cells from the blood to the eye. Of these, CCL2 and CXCL10 were consistently enriched in the aqueous of all patients in our cohort, as well as in a larger cohort of patients from a previously published study. These data suggest that CCL2 and CXCL10 are key mediators in immune cell migration to the eye during uveitis. Next, single cell RNA sequencing suggested that macrophages contribute to aqueous enrichment of CCL2 and CXCL10 during human uveitis. Finally, using chemokine ligand and receptor expression mapping, we identified a broad signaling network for macrophage-derived CCL2 and CXCL10 in human uveitis. Conclusions: These data suggest that ocular macrophages may play a central role, via CCL2 and CXCL10 production, in recruiting inflammatory cells to the eye in patients with uveitis. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Optic Disc Edema Is an Under-Recognized Feature of Birdshot Chorioretinitis.

BACKGROUND: Optic disc edema is a feature of many ophthalmic and neurologic conditions. It remains an underappreciated feature of birdshot chorioretinitis (BSCR), leading to delay in diagnosis and treatment. The purpose of our study was to identify clinical features that are concomitant with optic disc edema and suggest a diagnosis of BSCR. METHODS: Retrospective multicenter case series of 29 patients who were referred to a neuro-ophthalmologist or uveitis specialist for evaluation of disc edema and were ultimately diagnosed with BSCR. RESULTS: Fifty-four eyes of 30 patients, from the practices of 15 uveitis specialists, met the eligibility criteria. In addition to disc edema, concomitant features in all patients included vitritis, chorioretinal lesions, and retinal vasculitis. Visual recovery to 20/40 or better occurred in 26 of 29 patients. Visual acuity remained 20/100 or worse in 2 patients previously diagnosed with idiopathic intracranial hypertension, 1 patient previously diagnosed with optic neuritis, and 1 patient for whom treatment was delayed for years, leading to optic disc atrophy. CONCLUSIONS: Optic disc edema is a presenting feature in some cases of BSCR. A diagnosis of BSCR should be considered when disc edema occurs with vitritis, chorioretinal inflammation, and retinal vasculitis. Patients should be referred to a uveitis specialist for treatment.

The spectrum of COVID-19-associated chorioretinal vasculopathy.

Purpose: Although conjunctivitis represents the most common ocular manifestation of COVID-19 infection, sight-threatening retinal involvement has been reported. Herein, we report and characterize with multimodal retinal imaging 5 cases of acute vision loss secondary to presumed chorioretinal vasculopathy temporally associated with COVID-19 infection with varying severity, visual morbidity, and treatment response, and review the available literature on the association between COVID-19 infection and retinal microvascular changes. Design: Observational case series and literature review. Methods: Multicenter case series of 5 patients who presented to academic centers and private offices with acute vision loss temporally associated with COVID-19 infection. A review of the literature was conducted using online databases. Results: 10 eyes of 5 patients, 3 men and 2 women, with a mean age of 30.8 years (median 33, range 16-44) were described. All patients had a recently preceding episode of COVID-19, with symptomatology ranging from mild infection to life-threatening encephalopathy. Treatment for their retinal disease included topical, oral, intravitreal, and intravenous steroids, steroid-sparing immunosuppression, retinal photocoagulation, antivirals, and antiplatelet and anticoagulant agents. Treatment response and visual recovery ranged from complete recovery of baseline acuity to permanent vision loss and need for chronic immunosuppression. Conclusions and Importance: Clinicians should be mindful of the potential for vision-threatening retinal involvement after COVID-19 infection. If found, treatment with both anti-inflammatory therapy and anticoagulation should be considered, in addition to close monitoring, as some patients with this spectrum of disease may require chronic immune suppression and/or anti-VEGF therapy.

Autoimmunity-associated T cell receptors recognize HLA-B*27-bound peptides.

Human leucocyte antigen B*27 (HLA-B*27) is strongly associated with inflammatory diseases of the spine and pelvis (for example, ankylosing spondylitis (AS)) and the eye (that is, acute anterior uveitis (AAU))1. How HLA-B*27 facilitates disease remains unknown, but one possible mechanism could involve presentation of pathogenic peptides to CD8+ T cells. Here we isolated orphan T cell receptors (TCRs) expressing a disease-associated public ß-chain variable region-complementary-determining region 3ß (BV9-CDR3ß) motif2-4 from blood and synovial fluid T cells from individuals with AS and from the eye in individuals with AAU. These TCRs showed consistent α-chain variable region (AV21) chain pairing and were clonally expanded in the joint and eye. We used HLA-B*27:05 yeast display peptide libraries to identify shared self-peptides and microbial peptides that activated the AS- and AAU-derived TCRs. Structural analysis revealed that TCR cross-reactivity for peptide-MHC was rooted in a shared binding motif present in both self-antigens and microbial antigens that engages the BV9-CDR3ß TCRs. These findings support the hypothesis that microbial antigens and self-antigens could play a pathogenic role in HLA-B*27-associated disease.

The CSF in neurosarcoidosis contains consistent clonal expansion of CD8 T cells, but not CD4 T cells.

The tissue-specific drivers of neurosarcoidosis remain poorly defined. To identify cerebrospinal fluid (CSF) specific, antigen-driven T and B cell responses, we performed single-cell RNA sequencing of CSF and blood cells from neurosarcoid participants coupled to T and B cell receptor sequencing. In contrast to pulmonary sarcoidosis, which is driven by CD4 T cells, we found CD8 T cell clonal expansion enriched in the neurosarcoid CSF. These CSF-enriched CD8 T cells were composed of two subsets with differential expression of EBI2, CXCR3, and CXCR4. Lastly, our data suggest that IFNγ signaling may distinguish neurosarcoidosis from other neurological disorders.

Vitreous microparticles contain apoptotic signals suggesting a diabetic vitreopathy.

AIM: To evaluate differences in microparticle profiles in vitreous samples between diabetic and non-diabetic eyes undergoing vitrectomy. METHODS: Un-masked cross-sectional series of 34 eyes undergoing vitrectomy. Vitreous specimens were collected and processed to evaluate for membrane integrity (DAPI), apoptosis (Annexin-V), and endothelial-cell origin (V-Cadherin). A BD LSR II flow cytometer was used for analysis and standardized sub-micron-sized beads were used for size comparison. RESULTS: Thirty-four specimens underwent analysis. Greater levels of Annexin-V were found on microparticles from specimens in which blood had entered the vitreous (n=12) compared to those without blood (n=22; 52.3%±30.7% vs 19.6%±27.2%, P=0.002). Patients with diabetes having surgery with hemorrhage (n=7) had greater expression of Annexin-V than those without hemorrhage (n=8; 62.1%±31.7% vs 18.9%±20.9%, P=0.009). However, in patients with non-diabetic vitreous hemorrhage, the level of Annexin-V expression was not significantly different compared to other disease processes (38.6%±25.7%, n=5 vs 20.0%±30.9%, n=14, P=0.087). CONCLUSION: Increased expression of the apoptotic marker, Annexin-V is detected on vitreous microparticles in diabetes-related vitreous hemorrhage. When evaluating vitreous hemorrhage in patients without diabetes, the apoptotic signal is not significantly different. Vitrectomy in patients with diabetes, and improvement in visual outcomes, may be related to the removal of a serum-derived, pro-apoptotic vitreous. Further investigation is warranted in order to identify the molecular characteristics of microparticles that regulate disease.

Update on ophthalmic manifestations of systemic lupus erythematosus: pathogenesis and precision medicine.

PURPOSE OF REVIEW: Systemic lupus erythematosus (SLE) is an autoimmune disease with manifestations in multiple organs including the eyes. Several ocular manifestations like dry eye, retinopathy, and choroidopathy have been linked with specific systemic manifestations like lupus nephritis or CNS disease. Furthermore, the presence of ocular manifesattions can correlated with the severity of SLE. Finally, some medications used in the treatment of uveitis can present with lupus-like disease. Therefore, communication between the ophthalmologist and rheumatologist is vital. RECENT FINDINGS: Ocular and systemic manifestations of SLE can be linked by common pathological processes including immune complex deposition, complement fixation, and vascular injury. Recent research correlating ophthalmic imaging with SLE disease has yielded heterogeneous results likely due to the clinical heterogeneity of SLE, but molecular technologies have and will continue to yield contributions to the emergence of new therapeutics for the treatment of SLE. SUMMARY: Ocular manifestations are prevalent in patients with SLE. The association with certain manifestations and other disease manifestations highlights the importance of collaboration between the ophthalmologist and rheumatologist. Additional research utilizing clinico-molecular techniques will likely continue to improve our knowledge in the treatment of SLE in the future.

Loss of Mir146b with aging contributes to inflammation and mitochondrial dysfunction in thioglycollate-elicited peritoneal macrophages.

Macrophages undergo programmatic changes with age, leading to altered cytokine polarization and immune dysfunction, shifting these critical immune cells from protective sentinels to disease promoters. The molecular mechanisms underlying macrophage inflammaging are poorly understood. Using an unbiased RNA sequencing (RNA-seq) approach, we identified Mir146b as a microRNA whose expression progressively and unidirectionally declined with age in thioglycollate-elicited murine macrophages. Mir146b deficiency led to altered macrophage cytokine expression and reduced mitochondrial metabolic activity, two hallmarks of cellular aging. Single-cell RNA-seq identified patterns of altered inflammation and interferon gamma signaling in Mir146b-deficient macrophages. Identification of Mir146b as a potential regulator of macrophage aging provides novel insights into immune dysfunction associated with aging.