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Age-related macular degeneration (AMD) involves degenerative and neovascular alteration in the macular region of the retina resulting in central vision loss. AMD can be classified into dry (dAMD) and wet AMD (wAMD). There is no established treatment for dAMD, and therapies available for wAMD have limited success. Diagnosis in early AMD stages is difficult due to the absence of clinical symptoms. Currently, imaging tests are used in the diagnosis of AMD, but cannot predict the clinical course. The clinical limitations to establishing a diagnosis of AMD have led to exploration for innovative and more sensitive tests to support the diagnosis and prognosis of the disease. MicroRNAs (miRNAs) are small single-stranded non-coding RNA molecules that negatively regulate genes by post-transcriptional gene silencing. Because these molecules are dysregulated in various processes implicated in the pathogenesis of AMD, they could contribute to the early detection of the disease and monitoring of its progression. Studies of miRNA profiling have indicated several miRNAs as potential diagnostic biomarkers of AMD, but no approved biomarker is available at present for early AMD detection. Thus, understanding the function of miRNAs in AMD and their use as potential biomarkers may lead to future advances in diagnosis and treatment. Here we present a brief review of some of the miRNAs involved in regulating pathological processes associated with AMD and discuss several candidate miRNAs proposed as biomarkers or therapeutic targets for AMD.

A key aspect of the inflammatory phenomenon is the involvement of costimulatory molecules expressed by antigen-presenting cells (APCs) and their ability to secrete cytokines to set instructions for an adaptive immune response and to generate tolerance or inflammation. In a novel integrative approach, we aimed to evaluate the kinetic expression of the membrane and soluble B7 costimulatory molecules CD86, ICOS-L, PDL1, PDL2, the transcription factor Interferon Regulatory Factor 4 (IRF4), and the cytokines produced by monocyte-derived dendritic cells (Mo-DCs) after challenging them with different concentrations of stimulation with E. coli lipopolysaccharide (LPS) for different lengths of time. Our results showed that the stimuli concentration and time of exposure to an antigen are key factors in modulating the dynamic expression pattern of membrane and soluble B7 molecules and cytokines.

The implementation and validation of anti-SARS-CoV-2 IgG serological assays are reported in this paper. S1 and RBD proteins were used to coat ELISA plates, and several secondary antibodies served as reporters. The assays were initially validated with 50 RT-PCR positive COVID-19 sera, which showed high IgG titers of mainly IgG1 isotype, followed by IgG3. Low or no IgG2 and IgG4 titers were detected. Then, the RBD/IgG assay was further validated with 887 serum samples from RT-PCR positive COVID-19 individuals collected at different times, including 7, 14, 21, and 40 days after the onset of symptoms. Most of the sera were IgG positive at day 40, with seroconversion happening after 14–21 days. A third party conducted an additional performance test of the RBD/IgG assay with 406 sera, including 149 RT-PCR positive COVID-19 samples, 229 RT-PCR negative COVID-19 individuals, and 28 sera from individuals with other viral infections not related to SARS-CoV-2. The sensitivity of the assay was 99.33%, with a specificity of 97.82%. All the sera collected from individuals with infectious diseases other than COVID-19 were negative. Given the robustness of this RBD/IgG assay, it received approval from the sanitary authority in Mexico (COFEPRIS) for production and commercialization under the name UDISTEST-V2G®.

Allergic conjunctivitis (AC) is one of the most common ophthalmological disorders seen in clinical practice. Growing evidence from recent years suggests that a subset of IL-10-expressing B cells is involved in inflammatory allergic diseases. In this study, we aimed to evaluate the potential involvement of blood Bregs cells in perennial allergic conjunctivitis (PAC), and interleukins (IL)-1β, IL-6, IL-8, IL-10, and IL-12, and tumor necrosis factor (TNF)-α, were measured in tear samples and compared with healthy controls (HC) using flow cytometry. Non-significant differences in CD19+IL-10+ cell frequency between PAC patients and healthy controls (HC) were observed. Nevertheless, when we analyzed the mean fluorescence intensity (MFI) of IL-10 on CD19+CD38Lo/Med/Hi-gated cells, we observed a significant decrease in MFI in all Bregs subsets in PAC patients. Additionally, tear cytokines showed 2.8 times lower levels of IL-10 than TNF-α in PAC patients when compared to HC. Our findings demonstrate an immunological dysregulation in patients with allergic conjunctivitis, characterized by the low expression of IL-10 in circulating CD19+CD38+ Bregs subsets and an inverted tear IL-10/TNF-α ratio, promoting a local pro-inflammatory microenvironment. These findings highlight the novel pathologic changes involved in ocular allergic diseases. Understanding systemic and local mechanisms will aid the design of immunomodulating therapeutics at different levels.

O-glycosidically-linked glycans have been involved in development, maturation, homing, and immune regulation in T cells. Previous reports indicate that Amaranthus leucocarpus lectin (ALL), specific for glycans containing galactose-N-acetylgalactosamine and N-acetylgalactosamine, recognizes human naïve CD27+CD25+CD4+ T cells. Our aim was to evaluate the phenotype of CD4+ T cells recognized by ALL in peripheral blood mononuclear cells obtained from healthy volunteers. CD4+ T cells were isolated by negative selection using magnetic beads-labeled monoclonal antibodies; the expression of T regulatory cell phenotypic markers was assessed on ALL-recognized cells. In addition, IL-4, IL-10, IFN-γ, and TGF-β intracellular production in ALL+ cells was also evaluated. The analyses of phenotypic markers and intracellular cytokines were performed through flow cytometry. ALL-recognized CD4+ T cells were mainly CD45RA+, CCR7+ cells. Although 52±10% CD25+Foxp3+ cells were positive to ALL, only 34±4% of ALL+ cells corresponded to CD25+Foxp3− cells. Intracellular cytokines in freshly obtained ALL+CD4+ T cells exhibited 8% of IL-4, 15% of IL-10, 2% of IFN-γ, and 15% of TGF-β, whereas ALL−CD4+ T cells depicted 1% of IL-4, 2% of IL-10,

A 43-year-old man with linear immunoglobulin A (IgA) dermatosis associated with gluten intolerance presented with progressive vision loss, pain and photosensitivity in both eyes. His visual acuity was light perception (LP) in both eyes. A physical examination revealed bullous, papular lesions with erythematous borders in periocular tissues, limbs, and thorax. Slit-lamp examination showed conjunctival hyperemia, fibrosis, corneal opacification, and vascularization with epithelial defects. Immunofluorescent skin and corneal surface biopsy studies showed linear IgA deposits. The patient was treated with keratolimbal allogenic transplantation and cryopreserved amniotic membrane in the right eye. Regardless of the treatment he persisted with torpid evolution developing retinal and choroidal detachments. After these events he was started on intravenous immune globulin (IVIG) and showed very slight improvement in ocular surface. These types of blistering diseases are rare in the eye. Even when adequate local treatment is given, systemic treatment is mandatory and ocular prognosis can be unsatisfactory.

Abdala is a recently released RBD protein subunit vaccine against SARS-CoV-2. A few countries, including Mexico, have adopted Abdala as a booster dose in their COVID-19 vaccination schemes. Despite that, most of the Mexican population has received full-scheme vaccination with platforms other than Abdala; little is known regarding Abdala’s immunological features, such as its antibody production and T- and B-cell-specific response induction. This work aimed to study antibody production and the adaptive cellular response in the Mexican population that received the Abdala vaccine as a booster. We recruited 25 volunteers and evaluated their RBD-specific antibody production, T- and B-cell-activating profiles, and cytokine production. Our results showed that the Abdala vaccine increases the concentration of RBD IgG-specific antibodies. Regarding the cellular response, after challenging peripheral blood cultures with RBD, the plasmablast (CD19+CD27+CD38High) and transitional B-cell (CD19+CD21+CD38High) percentages increased significantly, while T cells showed an increased activated phenotype (CD3+CD4+CD25+CD69+ and CD3+CD4+CD25+HLA-DR+). Also, IL-2 and IFN-γ increased significantly in the supernatant of the RBD-stimulated cells. Our results suggest that Abdala vaccination, used as a booster, evokes antibody production and the activation of previously generated memory against the SARS-CoV-2 RBD domain.

Age-related macular degeneration (AMD) is a complex, progressive degenerative retinal disease. Retinal pigment epithelial (RPE) cells play an important role in the immune defense of the eye and their dysfunction leads to the progressive irreversible degeneration of photoreceptors. Genetic factors, chronic inflammation, and oxidative stress have been implicated in AMD pathogenesis. Oxidative stress causes RPE injury, resulting in a chronic inflammatory response and cell death. The Y402H polymorphism in the complement factor H (CFH) protein is an important risk factor for AMD. However, the functional significance of CFH Y402H polymorphism remains unclear. In the present study, we investigated the role of CFH in the pro-inflammatory response using an in vitro model of oxidative stress in the RPE with the at-risk CFH Y402H variant. ARPE-19 cells with the at-risk CFH Y402H variant were highly susceptible to damage caused by oxidative stress, with increased levels of inflammatory mediators and pro-apoptotic factors that lead to cell death. Pretreatment of the ARPE-19 cell cultures with exogenous CFH prior to the induction of oxidative stress prevented damage and cell death. This protective effect may be related to the negative regulation of pro-inflammatory cytokines. CFH contributes to cell homeostasis and is required to modulate the pro-inflammatory cytokine response under oxidative stress in the ARPE-19 cells with the at-risk CFH Y402H variant.

Vaccines have been recognized as having a central role in controlling the COVID-19 pandemic; however, most vaccine development research is focused on IgG-induced antibodies. Here, we analyzed the generation of IgGs related to SARS-CoV-2 and the changes in B- and T-lymphocyte proportions following vaccination against COVID-19. We included samples from 69 volunteers inoculated with the Pfizer-BioNTech (BNT162b2), Astra Zeneca (AZD1222 Covishield), or Sputnik V (Gam-COVID-Vac) vaccines. IgGs related to SARS-CoV-2 increased after the first vaccine dose compared with the nonvaccinated group (Pfizer, p = 0.0001; Astra Zeneca, p < 0.0001; Sputnik V, p = 0.0089). The results of the flow cytometry analysis of B- and T-lymphocytes showed a higher proportion of effector-memory B-lymphocytes in both first and second doses when compared with the nonvaccinated subjects. FcRL4+ cells were increased in second-dose-vaccinated COVID-19(−) and recovered COVID-19(+) participants when compared with the nonvaccinated participants. COVID-19(−) participants showed a lower proportion of follicular helper T-lymphocytes (TFH) in the second dose when compared with the first-vaccine-dose and nonvaccinated subjects. In conclusion, after the first vaccine dose, immunization against SARS-CoV-2 induces IgG production, and this could be mediated by TFH and effector-memory B-lymphocytes. Our data can be used in the design of vaccine schedules to evaluate immuno-bridging from a cellular point of view.

Ocular allergic diseases are frequently seen in ophthalmological clinical practice. Immunological damage is mediated by a local Th2 inflammatory microenvironment, accompanied by changes in circulating cell subsets, with more effector cells and fewer T regulatory cells (Tregs). This study aimed to evaluate the involvement of toll-like receptor 4 (TLR4) and α-melanocyte stimulating hormone (α-MSH) in the immune regulation associated with perennial allergic conjunctivitis (PAC). We performed an Ag-specific stimulation during 72 h of culturing with or without lipopolysaccharide (LPS) or α-MSH in peripheral blood mononuclear cells (PBMC), analyzing the cell subsets and cytokines induced by the stimuli. We also determined α-MSH in tear samples from healthy donors (HD) or PAC patients. Our findings demonstrate an immunological dysregulation characterized by an increased frequency of CD4+TLR4+ in the PBMC of patients with PAC, compared to HD. Most of these CD4+TLR4+ cells were also CD25+, and when α-MSH was added to the culture, the percentage of CD4+CD25+FoxP3+ increased significantly, while the percentage of CD69+ cells and cytokines IL-4 and IL-6 were significantly decreased. In tears, we found an increased concentration of α-MSH in PAC patients, compared with HD. These findings indicate a novel mechanism involved in controlling ocular allergic diseases, in which α-MSH diminishes the concentration of IL-6 and IL-4, restoring the frequency of Tregs and down-regulating CD4 activation. Moreover, we demonstrated the involvement of CD4+TLR4+ cells as an effector cell subset in ocular allergy.

Corneal infections are frequent and potentially vision-threatening diseases, and despite the significance of the immunological response in animal models of microbial keratitis (MK), it remains unclear in humans. The aim of this study was to describe the cytokine profile of tears in patients with MK. Characteristics of ocular lesions such as size of the epithelial defect, stromal infiltration, and hypopyon were analyzed. Immunological evaluation included determination of interleukine (IL)-1β, IL-6, IL-8, IL-10, IL-12 and tumor necrosis factor (TNF)-α in tear samples obtained from infected eyes of 28 patients with MK and compared with their contralateral non-infected eyes. Additionally, frequency of CD4+, CD8+, CD19+ and CD3−CD56+ cells was also determined in peripheral blood mononuclear cells in patients with MK, and compared with 48 healthy controls. Non-significant differences were observed in the size of the epithelial defect, stromal infiltration, and hypopyon. Nevertheless, we found an immunological profile apparently related to MK etiology. IL-8 > IL-6 in patients with bacterial keratitis; IL-8 > IL-6 > IL-1β and increased frequency of circulating CD3−CD56+ NK cells in patients with gram-negative keratitis; and IL-8 = IL-6 > IL-1β in patients with fungal keratitis. Characterization of tear cytokines from patients with MK could aid our understanding of the immune pathophysiological mechanisms underlying corneal damage in humans.