Intraretinal hyperreflective foci (HRF) are significant biomarkers for diabetic macular edema. However, HRF at the vitreoretinal interface (VRI) have not been examined in diabetic retinopathy (DR). A prospective observational clinical study with 162 consecutive eyes using OCT imaging showed significantly increased HRF at the VRI during DR progression (P<0.01), which was reversed by anti-VEGF therapy. F4/80+ macrophages increased significantly at the VRI in Kimba (vegfa+/+) or Akimba (Akita × Kimba) mice (both P<0.01), but not in diabetic Akita (Ins2+/−) mice, indicating macrophage activation was modulated by elevated VEGF rather than the diabetic milieu. Macrophage depletion significantly reduced HRF at the VRI (P<0.01). Furthermore, BrdU administration in Ccr2rfp/+Cx3cr1gfp/+vegfa+/− mice identified a significant contribution of M2-like tissue-resident macrophages (TRMs) at the VRI. Ki-67- and CD11b-positive cells were observed in preretinal tissues of DR patients while exposure of vitreal macrophages to vitreous derived from PDR patients induced a significant proliferation response in vitro (P<0.01). Taken together, the evidence suggests that VEGF drives a local proliferation of vitreous resident macrophages (VRMs) at the VRI during DR. This phenomenon helps to explain the derivation and disease-relevance of the HRF lesions observed through OCT imaging in patients.

Cytomegalovirus (CMV) causes clinical issues primarily in immune-suppressed conditions. CMV-associated anterior uveitis (CMV-AU) is a notable new disease entity manifesting recurrent ocular inflammation in immunocompetent individuals. As patient demographics indicated contributions from genetic background and immunosenescence as possible underlying pathological mechanisms, we analyzed the immunogenetics of the cohort in conjunction with cell phenotypes to identify molecular signatures of CMV-AU. Among the immune cell types, natural killer (NK) cells are main responders against CMV. Therefore, we first characterized variants of polymorphic genes that encode differences in CMV-related human NK cell responses (Killer cell Immunoglobulin-like Receptors (KIR) and HLA class I) in 122 CMV-AU patients. The cases were then stratified according to their genetic features and NK cells were analyzed for human CMV-related markers (CD57, KLRG1, NKG2C) by flow cytometry. KIR3DL1 and HLA class I combinations encoding strong receptor–ligand interactions were present at substantially higher frequencies in CMV-AU. In these cases, NK cell profiling revealed expansion of the subset co-expressing CD57 and KLRG1, and together with KIR3DL1 and the CMV-recognizing NKG2C receptor. The findings imply that a mechanism of CMV-AU pathogenesis likely involves CMV-responding NK cells co-expressing CD57/KLRG1/NKG2C that develop on a genetic background of KIR3DL1/HLA-B allotypes encoding strong receptor–ligand interactions.

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<p>Intraretinal hyperreflective foci (HRF) are significant biomarkers for diabetic macular edema. However, HRF at the vitreoretinal interface (VRI) have not been examined in diabetic retinopathy (DR). A prospective observational clinical study with 162 consecutive eyes using OCT imaging showed significantly increased HRF at the VRI during DR progression (<em>P</em><0.01), which was reversed by anti-VEGF therapy. F4/80+ macrophages increased significantly at the VRI in Kimba (<em>vegfa</em>+/+) or Akimba (Akita × Kimba) mice (both <em>P</em><0.01), but not in diabetic Akita (<em>Ins2</em>+/-) mice, indicating macrophage activation was modulated by elevated VEGF rather than the diabetic milieu. Macrophage depletion significantly reduced HRF at the VRI (<em>P</em><0.01). Furthermore, BrdU administration in <em>Ccr2</em>rfp/+<em>Cx3cr1</em>gfp/+ <em>vegfa</em>+/- mice identified a significant contribution of M2-like tissue-resident macrophages (TRMs) at the VRI. Ki-67- and CD11b-positive cells were observed in preretinal tissues of DR patients while exposure of vitreal macrophages to vitreous derived from PDR patients induced a significant proliferation response <em>in vitro</em> (<em>P</em><0.01). Taken together, the evidence suggests that VEGF drives a local proliferation of vitreous resident macrophages (VRMs) at the VRI during DR. This phenomenon helps to explain the derivation and disease-relevance of the HRF lesions observed through OCT imaging in patients.<br>  </p>

Human cytomegalovirus (HCMV) infections develop into CMV diseases that result in various forms of manifestations in local organs. CMV-retinitis is a form of CMV disease that develops in immunocompromised hosts with CMV-viremia after viruses in the peripheral circulation have entered the eye. In the HCMV genome, extensive diversification of the UL40 gene has produced peptide sequences that modulate NK cell effector functions when loaded onto HLA-E and are subsequently recognized by the NKG2A and NKG2C receptors. Notably, some HCMV strains carry UL40 genes that encode peptide sequences identical to the signal peptide sequences of specific HLA-A and HLA-C allotypes, which enables these CMV strains to escape HLA-E-restricted CD8+T cell responses. Variations in UL40 sequences have been studied mainly in the peripheral blood of CMV-viremia cases. In this study, we sought to investigate how ocular CMV disease develops from CMV infections. CMV gene sequences were compared between the intraocular fluids and peripheral blood of 77 clinical cases. UL40 signal peptide sequences were more diverse, and multiple sequences were typically present in CMV-viremia blood compared to intraocular fluid. Significantly stronger NK cell suppression was induced by UL40-derived peptides from intraocular HCMV compared to those identified only in peripheral blood. HCMV present in intraocular fluids were limited to those carrying a UL40 peptide sequence corresponding to the leader peptide sequence of the host’s HLA class I, while UL40-derived peptides from HCMV found only in the peripheral blood were disparate from any HLA class I allotype. Overall, our analyses of CMV-retinitis inferred that specific HCMV strains with UL40 signal sequences matching the host’s HLA signal peptide sequences were those that crossed the blood–ocular barrier to enter the intraocular space. UL40 peptide repertoires were the same in the intraocular fluids of all ocular CMV diseases, regardless of host immune status, implying that virus type is likely to be a common determinant in ocular CMV disease development. We thus propose a mechanism for ocular CMV disease development, in which particular HCMV types in the blood exploit peripheral and central HLA-E-mediated tolerance mechanisms and, thus, escape the antivirus responses of both innate and adaptive immunity.