Tear Inflammatory Cytokines Research Articles

Clinical Characteristic and Tear Film Biomarkers After Myopic FS-LASIK: 1-Year Prospective Follow-up.

To assess the long-term (1-year) effect of myopic femtosecond laser-assisted in situ keratomileusis (FSLASIK) on clinical characteristics and tear film biomarkers. Eighty eyes from 80 patients who underwent FSLASIK were evaluated. Ocular surface symptoms and signs were evaluated using specific questionnaires and tests. The corneal nerves and dendritic cells were examined using in vivo confocal microscopy. Corneal sensitivity was evaluated using a Cochet-Bonnet esthesiometer. Tear inflammatory cytokines and neuropeptides were evaluated using Luminex immunoassay. These examinations were performed preoperatively and at 1, 3, 6, and 12 months postoperatively. Seventy-three participants completed all follow-up visits. Following FS-LASIK, ocular symptoms and signs (except Schirmer I test) worsened at 1 month but corneal and conjunctival stainings improved by 3 months. The numbers of dendritic cells and activated dendritic cells increased at the 3-month postoperative visit and recovered to preoperative levels by the 6-month visit. Ocular symptoms and corneal sensitivity recovered to preoperative levels at the 12-month visit. Tear break-up time and corneal nerve morphology were not recovered to preoperative status at the 12-month visit. Interleukin (IL)-1β, IL-17A, tumor necrosis factor-α, and substance P tear levels significantly increased at all postoperative visits compared to preoperative levels. Corneal staining scores positively correlated with tear IL-1β and IL-17A levels, whereas corneal nerve morphology positively correlated with corneal sensitivity and negatively correlated with substance P levels. Although most clinical variables improved at 12 months postoperatively, some tear inflammatory cytokines and substance P remain altered beyond 12 months, indicating that ocular homeostasis is not completely recovered. [J Refract Surg. 2024;40(8):e508-e519.].

The Role of IL-6, IL-10, and TNF-α in Ocular GVHD Following Allogeneic Transplantation

ABSTRACT Purpose To figure out the roles of tear inflammatory cytokines in Ocular graft-versus-host disease (oGVHD) symptoms by analyzing tear cytokine levels and related factors. Methods This prospective study involved 27 post-HSCT patients and 19 controls with dry eye disease. Analyses included tear cytokine (IL-6, IL-10, and TNF-α), ocular surface evaluation, and conjunctival impression cell examination. Tear cytokine levels were evaluated in three grades of corneal epithelial lesions. The study also analyzed the correlation between tear cytokine levels and ocular surface parameters. Tear cytokine levels were then used in a Receiver Operating Characteristic (ROC) curve and linear regression model to predict oGVHD related factors. Results IL-6 has good diagnostic efficacy in oGVHD related dry eye. Elevated levels of tear IL-6 and TNF-α were observed in the group with severe corneal epithelial lesions. IL-6 levels were positively correlated with corneal fluorescein staining (CFS), eyelid margin hyperemia, conjunctival lesions, and meibum secretion. IL-6 showed excellent predictive ability with Area Under the Curve (AUC) values all greater than 0.70 (p < 0.05). IL-10 and TNF-α were negatively correlated with the meibomian gland proportion and conjunctival goblet cell (GC) density, while TNF-α was positively correlated with CFS and eyelid margin hyperemia. Conclusion Dry eye symptoms related to ocular GVHD, can be partly diagnosed and assessed using various tear cytokine level detection methods.

Association of Tear Cytokine Ratios with Symptoms and Signs of Dry Eye Disease: Biomarker Data from the Dry Eye Assessment and Management Study

Purpose To assess the relationship between tear inflammatory cytokine ratios (CRs) and signs and symptoms of dry eye disease (DED) to investigate the possible use of tear CRs, which may better address the complexity of cytokine interactions than absolute cytokine levels, as a DED biomarker. Methods Tear concentrations of IL-1b, IL-6, IL-8, IL-10, IL-17A, IFN-g, and TNF-a were measured using standardized procedures, as were DED signs (corneal and conjunctival staining scores, tear break-up time, Schirmer test, Meibomian gland plugging, tear osmolarity, composite sign severity score) and symptoms [Ocular Surface Disease Index (OSDI)]. Ratios between pro-inflammatory (IL-1b, IL-8, IL-17A, IFN-g, and TNF-a) and anti-inflammatory (IL-10) cytokines were calculated. Given its opposing roles in inflammation, IL-6 was tested as both a pro- and anti-inflammatory cytokine. Correlations between CR and DED symptoms and signs were calculated using Spearman correlation coefficients (rho). Results At baseline, 131 patients, 80.2% female and mean age 54.2 years (SD 14.1, range 20–82), from 10 sites of the Dry Eye Assessment and Management study had sufficient tear volumes ≥4 μL for analysis. IL-6:IL-10, IL-8:IL-10, and TNF-a:IL-10 had some significant correlations, mostly with conjunctival or corneal staining or the composite sign severity score (IL-8:IL-10 and conjunctival staining: rho = 0.19, p = 0.03; IL-6:IL-10 and corneal staining: rho = 0.31, p < 0.001; IL-8:IL-10 and corneal staining: rho = 0.21, p = 0.01; IL-6:IL-10 and composite sign severity score: rho = 0.26, p = 0.003; IL-8:IL-10 and composite sign severity score: rho = 0.26, p = 0.003; TNF-a:IL-10 and corneal staining: rho = 0.29, p < 0.001; TNF-a:IL-10 and Schirmer test: rho = −0.23, p = 0.009). CRs had no significant correlation with DED symptoms. All significant correlations using IL-6 in the denominator (anti-inflammatory) produced counterintuitive results based on clinical understanding of the disease. Conclusions Pro- to anti-inflammatory CR was weakly correlated with some DED signs and not with symptoms, as measured by OSDI. Future studies in different dry eye populations are needed and should address sampling biases and tear collection techniques.

Tear inflammatory cytokines as potential biomarkers for myopic macular degeneration

Previous studies have reported that inflammatory cytokine levels increase in the intraocular fluids (aqueous humor and vitreous) of highly myopic eyes, However, there has been currently no study revealing the levels of inflammatory cytokines in tear. Therefore, this study aimed to determine tear cytokine levels of highly myopic eyes, and their relationships with myopic macular degeneration (MMD).This case-control study screened inflammatory cytokines of tear samples from 132 highly myopic and 105 emmetropic eyes using a multiplex cytokine antibody array, and cytokines showing significant intergroup differences were further validated using ProQuantum immunoassays in tear samples from another 60 highly myopic and 60 emmetropic eyes. Ultra-widefield fundus photographs of eyes were classified according to the meta-analyses of the Pathologic Myopia Classification. Associations between tear cytokine levels and MMD category were investigated.As a result, tear levels of interleukin (IL)-6, IL-13 and monocyte chemoattractant protein (MCP)-1 were screened significantly higher in highly myopic eyes than in emmetropic controls (IL-6: 11.70 ± 16.81 versus 8.22 ± 10.76 pg/mL; MCP-1: 63.60 ± 54.40 versus 33.87 ± 43.82 pg/mL; both P < 0.05). Validation assays further demonstrated the elevated concentrations of IL-6 and MCP-1 (IL-6: 13.97 ± 8.41 versus 8.06 ± 7.94 pg/mL, P < 0.001; MCP-1: 32.69 ± 8.41 versus 18.07 ± 8.41 pg/mL, P = 0.003). Tear levels of IL-6 and MCP-1 differed significantly among MMD categories (both P < 0.05). The area under receiver operating characteristic curve were 0.783 and 0.682 respectively (both P < 0.05), when using tear IL-6 and MCP-1 levels to predict the presence of MMD (category ≥2). The ordered logistic regression model also indicated that longer axial length, and higher IL-6 and MCP-1 tear levels were independent predictors of higher MMD category. In our study, highly myopic eyes presented significantly higher levels of tear IL-6 and MCP-1, which may also serve as potential biomarkers for MMD.

Clinical Characteristics and Tear Film Biomarkers in Patients With Chronic Dry Eye Disease After Femtosecond Laser-Assisted Laser in Situ Keratomileusis.

To investigate clinical characteristics and tear film biomarkers of patients with chronic dry eye disease (DED) following femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). Patients were divided into the chronic DED after FS-LASIK (n = 36), DED without FS-LASIK (n = 39), and normal control (without FS-LASIK; n = 34) groups. Dry eye, pain, and psychological-related symptoms were evaluated using the Ocular Surface Disease Index (OSDI), Numerical Rating Scale (NRS), Neuropathic Pain Symptom Inventory Modified for the Eye (NPSI-Eye), and Hamilton Anxiety Rating Scale (HAMA) questionnaires. Ocular surface parameters, tear cytokines, and neuropeptide concentrations were evaluated with specific tests. The DED after FS-LASIK group showed higher corneal fluorescein staining scores, but lower OSDI and NPSI-Eye scores than the DED without FS-LASIK group (all P < .05). Corneal sensitivity and nerve density decreased in the DED after FS-LASIK group (all P < .01). Granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-17A, IL-23, alpha-melanocyte stimulating hormone (α-MSH), oxytocin, and substance P levels were highest in the DED after FS-LASIK group, followed by the DED without FS-LASIK and normal control groups (all P < .05). Interferon-γ and neurotensin levels were only significantly higher in the DED after FS-LASIK group (all P < .05). Patients with chronic DED after FS-LASIK showed milder ocular symptoms, greater epithelial damage, and higher levels of tear inflammatory cytokines and neuropeptides than patients with DED without FS-LASIK, indicating that the nervous and immune systems may play significant roles in FS-LASIK-related chronic DED development. [J Refract Surg. 2023;39(8):556-563.].

IgA-Based Secretory Response in Tears of COVID-19 Patients: A Potential Biomarker of Pro-Inflammatory State in Course of SARS-CoV-2 Infection.

Mucosal immunity, including secretory IgA (sIgA), plays an important role in the early defence against SARS-CoV-2 infection. However, a comprehensive evaluation of the local immune response in tears in relation to blood antibody reservoirs has not yet been conducted. A total of 179 symptomatic laboratory-confirmed COVID-19 patients were included in this single-centre study. Conjunctival swabs were analysed by a reverse transcription polymerase chain reaction for the detection of SARS-CoV-2 RNA. In parallel, tear samples collected by Schirmer test strips and plasma samples were analysed by ELISA to detect anti-S1 IgA levels. The concentrations of selected inflammatory cytokines in tears were determined by a magnetic bead assay. Anti-SARS-CoV-2 sIgA was present in the tears of 81 (45.25%) confirmed COVID-19 patients, and the tear IgA levels were correlated with the plasma IgA levels (Rs = +0.29, p = 0.0003). SARS-CoV-2 RNA in the conjunctival sac was identified in 18 COVID-19 patients (10%). Positive correlations between the tear IgA level and the concentrations of several cytokines TNF-α (Rs = +0.23, p = 0.002), IL-1β (Rs = +0.25, p < 0.001), IL-2 (Rs = +0.20, p = 0.007), IL-4 (Rs = +0.16, p = 0.04), IL-5 (Rs = +0.36, p < 0.001), IL-6 (Rs = +0.32, p < 0.001), IL-8 (Rs = +0.31, p < 0.001), VEGF (Rs = +0.25, p < 0.001) and GM-CSF (Rs = +0.27, p < 0.001) were also found. Quantitative tear film-based sIgA could potentially serve as a rapid and easily accessible biomarker of external mucosal immunity to SARS-CoV-2. The concentration of sIgA is directly related to individual host immune responses to SARS-CoV-2 infection.

Response of tear cytokines following intense pulsed light combined with meibomian gland expression for treating meibomian gland dysfunction-related dry eye.

PurposeThis study compared the changes in tear inflammatory cytokine levels after intense pulsed light (IPL) combined with meibomian gland expression (MGX) (IPL group) and instant warm compresses combined with MGX (physiotherapy group) as treatments for meibomian gland dysfunction (MGD)-related dry eye disease (DED) to explore their similarities and differences in therapeutic mechanisms.MethodsThis study was a post-hoc analysis of a randomized controlled trial. Thirteen patients with MGD-related DED were enrolled in each group and received three treatments correspondingly with 3-week intervals. The levels of 20 tear cytokines, namely, TNF-α, IL-6, MMP-9, CXCL8/IL-8, CXCL10/IP-10, IL-10, EGF, IL-6R, IL-1β, IFN-γ, lactoferrin, Fas ligand, IL-17A, LT-α, S100A9, LCN2/NGAL, IL-13, IL-12/IL-23p40, Fas, and CCL11/Eotaxin, were measured at baseline, before the second and third treatments, and 3 weeks after the third treatment. The primary outcome was the difference in cytokine levels between baseline and the last measurement, and the trends were analyzed at each measurement point.ResultsAt the last measurement, a significant decrease was observed in all tear cytokines for both IPL and physiotherapy groups compared with baseline. The IPL group showed greater reductions in IL-6, IL-6R, IL-1β, IL-13, and CCL11/Eotaxin than the physiotherapy group. TNF-α, CXCL8/IL-8, CXCL10/IP-10, IL-10, EGF, IL-1β, IFN-γ, and Lipocalin-2/NGAL levels continued to decrease with treatment time. Important interactions were found in the changes of IL-6 and IL-13 levels, where the levels first decreased and then slightly increased in the physiotherapy group after treatment, while they continued to decrease in the IPL group.ConclusionsThe mechanisms of IPL and physiotherapy in treating MGD-related DED were both associated with reducing inflammation, and the superiority of IPL could be attributed to its better inhibitory effect on inflammatory cytokines like IL-6. In addition, several cytokines were on a downward trend during treatment, suggesting that the vicious cycle of DED was suppressed.

Assessment of tear inflammatory cytokines concentration in patients with diabetes with varying severity of involvement

Diabetic retinopathy (DR), as one of the most important causes of blindness in Western societies, is a common micro-vasculopathy associated with diabetes. There is growing evidence of the role of inflammation in its development. This study was designed to measure cytokines in patients with diabetes with different stages of retinopathy .In this study, tear concentrations of three types of cytokines with different angiogenic properties including IL-1RA, IL-8, and TNF-α were measured in patients with diabetes without retinopathy, with non-proliferative retinopathy, with proliferative retinopathy, and in a healthy control group.The results showed that concentrations of TNF-α and IL-8 were higher in the tear sample of diabetics than in the control group and the concentrations of these cytokines were higher in patients with more advanced stages of diabetes, while the tear level of IL-1RA was significantly lower in diabetics.Based on these findings, it can be concluded that diabetes and its progression of severity affects the tear levels of IL-1RA, IL-8, and TNF-α inflammatory cytokines.

Increased proinflammatory cytokines in tears correspond with conjunctival SARS-CoV-2 positivity in symptomatic COVID-19 patients

Tear fluid cytokine levels may serve as biomarkers of innate immune system response against SARS-CoV-2 infection. Therefore, our aim was to analyze panel of selected inflammatory cytokines in tears of COVID-19 patients in relation to presence of SARS-CoV-2 viral load in conjunctival secretions. In this study concentrations of TNF-α, IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12 p70, GM-CSF, and IFN-γ were determined by a magnetic bead assay in tear film collected from 232 symptomatic COVID-19 patients. SARS-CoV-2 ocular infection was confirmed based on positive conjunctival swab-based RT-PCR testing. Viral RNA in conjunctival sac was detected in 21 patients (9%). No relation between presence and the duration of ophthalmic symptoms and SARS-CoV-2 infection detected in conjunctival secretions was found. The tear film concentrations of IFN-γ, TNF-α, IL-5, IL-8 and GM-CSF were found to be significantly greater among patients with positive conjunctival swab results as compared to the group negative for SARS-CoV-2 in conjunctival sac. Our current data depict a group of inflammatory mediators in human tears, which may play a significant role in ocular pathology of SARS-CoV-2 conjunctival infection.

Changes of Dry Eye Related Markers and Tear Inflammatory Cytokines After Upper Blepharoplasty.

Objectives: To investigate the changes of dry eye-related clinical manifestations, ocular surface parameters, and tear inflammatory cytokines after upper blepharoplasty.Methods: Forty eyes of 20 who underwent upper blepharoplasty were divided into either the group with or the group without preexisting dry eye before upper blepharoplasty. Ocular Surface Disease Index (OSDI), Schirmer I test, tear meniscus height, lipid layer thickness, non-invasive tear break-up time (NIKBUT), fluorescein tear film break-up time (FBUT), corneal fluorescein staining, meibum expression, lid margin changes, and tear inflammatory cytokines were assessed preoperatively and at 1, 3, and 6 months postoperatively. Correlations between inflammatory cytokines and dry eye-related parameters were determined.Results: The OSDI scores increased significantly at 1 month (p = 0.040) and subsequently decreased to the preoperative levels at 6 months postoperatively in subjects with dry eye. First (f)-NIKBUT and FBUT were significantly shortened at 1, 3, and 6 months postoperatively in subjects with dry eye (f-NIKBUT: p <0.001, p = 0.010, p = 0.042; FBUT: p = 0.002, p = 0.005, p = 0.037, respectively), but were only shortened at 1 month (p = 0.028, p = 0.005) and returned to baseline levels at 6 months postoperatively in subjects without preexisting dry eye. A significant increasing trend of interleukin (IL)-6 was found in both dry eye and subjects without preexisting dry eye (p = 0.016, p = 0.008), while IL-8 and tumor necrosis factor alpha (TNF-α) were only found to be increased in subjects with dry eye postoperatively (p = 0.031, p = 0.031). The levels of IL-8 and TNF-α were positively correlated with OSDI scores (p = 0.046, p = 0.043, respectively) and negatively correlated with f-NIKBUT and FBUT (p = 0.026, p = 0.006, respectively).Conclusions: Upper blepharoplasty might increase the release of tear inflammatory cytokines and tear film instability that contribute to the development of postoperative dry eye in the early postoperative period and the changes most relieved in 6 months. Preexisting dry eye is a higher risk factor for worse and persistent ocular surface damage after upper blepharoplasty.

Detection & analysis of inflammatory cytokines in tears of patients with lacrimal duct obstruction.

Background & objectives:Tear proteomic changes can be a candidate etiopathogenesis of lacrimal duct obstruction diseases (LDODs). Studies on proteomics have focused primarily on nasolacrimal duct obstruction, and some specific inflammatory cytokines such as interferon (IFN)-α2a, interleukin (IL)-8 and IL-10, have not been investigated. In addition, differences in inflammatory cytokines in tears according to the LDOD subtype have not been reported. This study aimed to quantitatively compare inflammatory cytokines in tears from patients with LDOD and investigate tear-cytokine differences among different LDOD subtypes.Methods:Tear samples were collected from both eyes of 30 patients with unilateral LDOD five patients with prelacrimal obstruction, five with acute dacryocystitis and 20 with chronic dacryocystitis. The contralateral eyes were used as controls. IFN-α2a, IFN-β, IFN-γ, IL-17A, IL-6, IL-8, tumour necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF)-A, induced protein-10 (IP-10) and monocyte chemotactic protein-1 (MCP-1) were quantified in all samples.Results:The expression of eight cytokines (except for IP-10 and MCP-1) were significantly increased in the affected eyes compared with those in the control eyes. The levels of nine inflammatory cytokines (except for IP-10) in the affected eyes of patients with chronic dacryocystitis were higher than those in the affected eyes of patients with prelacrimal obstruction. In addition, patients with chronic dacryocystitis presented significantly higher IFN-γ level than those with prelacrimal obstruction or acute dacryocystitis.Interpretation & conclusions:Specific pro-inflammatory cytokines were increased in tears of patients with LDOD compared with those in the controls. The specific cytokine profiles observed in the tears of individuals with different LDOD subtypes may be associated with the unique aetiopathogenesis of these conditions.

High Level of Inflammatory Cytokines in the Tears: A Bridge of Patients with Concomitant Exotropia and Dry Eye.

Concomitant exotropia have obvious symptoms of eye discomfort in adults, and the presence of ocular surface inflammation in patients may be important mediators between concomitant exotropia and dry eye. Oculus Keratograph eye comprehensive analyzer was performed to detect noninvasive tear break time, noninvasive tear height, and eye red index, while the ocular surface disease index and schirmer I testing were made. The levels of IL-6, IL-10, IL-17A, IL-12P70, INF-γ, and TNF-α were detected in tears in patients with concomitant exotropia and healthy controls matched by age and gender through the Simoa technology. IL-6 was significantly higher in patients with concomitant exotropia (4.683 ± 1.329) pg/mL than that in normal group (1.455 ± 0.391) pg/mL, p = 0.0304. TNF-α was also significantly higher in patients (0.2095 ± 0.0703) pg/mL than normal group (0.0513 ± 0.0149) pg/mL, p = 0.0397. The levels of inflammatory factors in strabismic patients vs. normal controls were as follows: IL-17A (0.1551 pg/mL︰0.0793 pg/mL), IL-10 (0.3358 pg/mL︰0.0513 pg/mL), IL-12p70 (0.0253 pg/mL︰0.0099 pg/mL), and INF-γ (0.0284 pg/mL︰0.009 pg/mL) were detected, and the median of them in concomitant strabismus was 1.96-6.55-fold as much as the control group. High levels of inflammatory cytokines in tears of patients with concomitant exotropia, which may be a potentially factor promoted the occurrence of dry eye in the patients with concomitant exotropia.

Meibum Expressibility Improvement as a Therapeutic Target of Intense Pulsed Light Treatment in Meibomian Gland Dysfunction and Its Association with Tear Inflammatory Cytokines

Many recent studies have demonstrated the efficacy of intense pulsed light (IPL) for the treatment of meibomian gland dysfunction (MGD); however, its effective treatment targets have not yet been elucidated. This study aimed to investigate the baseline characteristics associated with an improvement in symptoms after IPL treatment; to examine the course of change in inflammatory tear cytokines, meibomian gland function, and tear stability; and to investigate the correlation between cytokines and ocular surface parameters. Thirty participants underwent three sessions of IPL treatment. During each examination, tear film lipid layer interferometry, meibography, tear meniscus height measurement, tear sampling, and slit-lamp examination were performed, and the Ocular Surface Disease Index (OSDI) questionnaire was administered. Meibum quality, meibum expressibility, lid margin abnormality, tear film break-up time (TBUT), ocular surface staining, and the OSDI significantly improved after treatment. Poor meibum expressibility and short TBUT were associated with greater recovery in the OSDI after IPL. Tear levels of IL-4, IL-6, IL-10, IL-17A, and TNF-α decreased after IPL, and IL-6, and TNF-α were correlated with the improvement in meibum expressibility. Therefore, IPL treatment improved meibomian gland function, stabilized the tear film, and decreased ocular surface inflammation. Patients with obstructive MGD and tear instability were more likely to experience an improvement in ocular discomfort after IPL treatment.

Tear Inflammatory Cytokines Analysis and Clinical Correlations in Diabetes and Nondiabetes With Dry Eye

To enhance the understanding of dry eye (DE) in diabetes by evaluating the ocular surface characteristics and the levels of tear inflammatory cytokines. Cross-sectional study. Subjects were divided into 4 groups: 32 patients in the diabetes with DE group; 24 patients in the diabetes without DE group; 28 patients in the nondiabetes with DE group; and 29 volunteers in the normal group. Ocular surface disease index (OSDI) was self-answered and ocular surface characteristics including tear film break-up time (BUT), Schirmer I test, corneal fluorescein staining (CFS), and corneal sensitivity were evaluated. Concentrations of epidermal growth factor (EGF), IL-17A, IL-1β, and tumor necrosis factor alpha (TNF-α) were measured by mutiplex bead analysis. Spearman correlations between cytokines and ocular surface parameters were calculated. The level of EGF in tears significantly increased in the diabetes with DE group and positively correlated with the CFS and negatively correlated with the Schirmer I test in this group (P < .05). No differences were found in the levels of IL-17A, IL-1β, and TNF-α in the diabetes with DE and diabetes without DE groups compared to the normal group (P> .05). The nondiabetes with DE group showed increased levels of IL-17A, IL-1β, and TNF-α in tears compared to the normal group and the levels of IL-1β and TNF-α in tears positively correlated with CFS (P<.05). Our study showed that levels of EGF in tears have potential to be the diagnostic biomarker of DE in diabetes. No differences of IL-17A, IL-1β, and TNF-α in tears were found between the diabetes with DE and normal group, suggesting different pathogenesis of diabetes DE vs nondiabetes DE.

Inflammatory Response in Dry Eye.

Dry eye is a major ocular pathology worldwide. Although dry eye is a multifactorial disease, recent studies have shown that chronic immunologic processes have a pivotal role in its pathogenesis, characterized by the infiltration of immune cells in the lacrimal glands, elevated levels of tear inflammatory cytokines, and increased density of immune cells in the cornea and conjunctiva. This review describes the recent advances in understanding the relationship between dry eye and inflammation. This narrative review is based on searches of recent international literature using terms related to the immune response in dry eye, and includes clinical trials, animal experiments, and expert reviews. Although dry eye presents clinically as tear film instability associated with corneal/conjunctival epithelial disorders, Meibomian gland dysfunction, and decreased visual function, recent laboratory and clinical studies have indicated inflammation in the lacrimal glands, Meibomian glands, conjunctiva, cornea, and aqueous tears. Furthermore, inflammation at these locations leads to conjunctival goblet cell apoptosis, corneal epithelial barrier disruption, and corneal nerve damage. These inflammatory outcomes can be exacerbated by intrinsic and extrinsic factors, such as aging, sex steroid hormone, autoimmune diseases, contact lens use, visual display terminals, and dry environment. Recent advances in dry eye research have revealed the inflammatory process and its pathogenesis, which has been proposed as an "inflammatory vicious cycle" of dry eye. Comprehensive assessment of dry eye based on inflammation will improve the selection of treatments and help break the inflammatory cycle in clinical settings.

Tear Luminex Analysis in Dry Eye Patients.

BackgroundThe purpose of this study was to analyze tear inflammatory cytokines of different subclasses of dry eye disease (DED) patients using Luminex technology.Material/MethodsForty-five DED patients including 20 Sjogren syndrome aqueous tear deficiency (SS-ATD) patients, 20 non-Sjogren syndrome aqueous tear deficiency (NSS-ATD) patients, 15 meibomian gland dysfunction (MGD) patients, and 15 normal participants were enrolled in this study. Concentrations of 11 inflammatory cytokines in tear samples of study participants were measured by Luminex assay; ELISA assay was further applied for validation.ResultsThe levels of cytokines were mostly increased (TNF-α, IL-1α, IL-1β, IL-6, IL-8, IL-12P70, IL-13, IFN-γ, and MIP-1α) in DED patients compared with normal participants. And the levels of TNF-α, IL-6, IL-8, and IL-12P70 were significantly elevated in tears of the patient groups compared to tears of participants in the normal group (P<0.05). Statistical differences were also observed among the patient groups (SS-ATD, NSS-ATD, and MGD) for the level of IL-8 and TNF-α. The results of ELISA assay demonstrated the consistence with Luminex assay, confirming the practicality of Luminex technology for the analysis of multiple cytokines in DED patient tears.ConclusionsThe levels of inflammatory cytokines were mostly elevated in DED patients, and statistical differences of some cytokines were also found between SS-ATD, NSS-ATD, and MGD groups, suggesting that inflammatory cytokines could be potential supplements for the diagnosis of DED subclasses and therapeutic targets for DED patients.

Overexpression of Tear Inflammatory Cytokines as Additional Finding in Keratoconus Patients and Their First Degree Family Members.

Keratoconus is a progressive corneal ectasia that may lead to severe visual impairment due to the irregular astigmatism caused by corneal thinning. In addition to its association with atopy, eye rubbing, or genetic component, late reports suggest the involvement of inflammation in the pathogenesis of the disease. Our aim was to determine the concentration of IL-4, IL-6, IL-10, RANTES, IFN gamma, and TNF alpha in the tear film of patients with keratoconus and their first degree family members. We analyzed forty-eight participants in an observational cross-sectional study. The diagnosis of keratoconus had to be confirmed in addition to a minimum of 47 D corneal refractive power by corneal topography readings provided by a Placido-based topography system and analysis of the pattern: irregular astigmatism with an asymmetric “bow-tie.” As for the other groups, the most important diagnosis criteria were a normal topographic pattern with a regular astigmatism. 17 keratoconus patients, 16 relatives, and 15 controls were recruited after clinical assessment as part of the research. The cytokine's mean values were similar in the keratoconus group and the relatives' samples but significantly higher compared to the controls. Important differences were found in IL-4 levels between keratoconus patients and relatives and between relatives and controls (mean difference of 302.42, p < 0.0016 and 219.16, p < 0.033, Tukey's HSD procedure). In the keratoconus group, using the CORR procedure, we found statistically strong correlations of IL-6 lacrimal concentrations with the disease stage (r = 0.56, p < 0.01), keratometry (r = 0.55, p < 0.02), pachymetry (r = −0.64, p < 0.048), and corneal hysteresis (r = −0.53, p < 0.02). Cytokine overexpression may be relevant for the inflammatory etiology of keratoconus. In conclusion, in the case of some first degree family members, the elevated tear biomarkers may represent a supplementary risk factor.

The Level of Inflammatory Tear Cytokines is Elevated in Congenital Aniridia and Associated with Meibomian Gland Dysfunction.

To investigate the tear cytokine profile in congenital aniridia, and correlate cytokine levels with ophthalmologic findings. We examined 35 patients with aniridia and 21 healthy controls. Tear fluid was collected with Schirmer I test and capillary tubes from each eye, and the concentration of 27 inflammatory cytokines determined using multiplex bead assay. Eyes of all participants were examined with tests for dry eye disease, including evaluation of meibomian glands (meibography). Differences in cytokine levels between the two groups were analyzed, and correlations between cytokine concentrations and ophthalmologic findings in the aniridia group investigated. The concentrations of six tear cytokines were significantly higher in aniridia patients than controls in both eyes, and included interleukin 1β (IL-1β), IL-9, IL-17A; eotaxin; basic fibroblast growth factor (bFGF/FGF2); and macrophage inflammatory protein 1α (MIP-1α/CCL3). The ratio between the anti-inflammatory IL-1RA and the proinflammatory IL-1β was significantly lower in patients than controls in both eyes (P = 0.005 right eye and P = 0.001 left eye). Increasing concentration of IL-1β, IL-9, IL-17A, FGF2, and MIP-1α correlated with parameters for meibomian gland dysfunction (MGD) in the aniridia group, including increasing atrophy of meibomian glands, and shorter break-up time of the tear film. A number of pro-inflammatory cytokines are significantly elevated in tear fluid from aniridia patients, and correlate with parameters for MGD in aniridia. Increased inflammation of the ocular surface may be a factor in the development of MGD in aniridia patients, and explain the high prevalence of MGD and dry eye disease in these patients.

Preinflammatory Signs in Established Reusable and Disposable Contact Lens Wearers.

Established reusable contact lens (CL) wearers show higher tear inflammatory cytokine concentrations and greater conjunctival metaplasia in the region covered by standard soft CLs. The balance of proinflammatory to anti-inflammatory cytokines, but not individual tear cytokine concentrations, was associated with self-reported CL discomfort. Daily disposable (DD) lenses are often used to improve CL discomfort, but the effect on ocular inflammatory responses has not been fully investigated. This study aimed to compare the concentrations of tear cytokines and conjunctival cell morphology in healthy habitual DD and reusable soft CL wearers. Thirty-six established daily CL wearers, including 14 DD and 24 reusable wearers, were enrolled. Symptoms and ocular surface integrity were evaluated. The concentration of tear cytokines (interleukin 1β [IL-1β], IL-6, IL-10, IL-12(p70), IL-17A, and tumor necrosis factor α) were determined using Multiplex assays. The ratios of proinflammatory and anti-inflammatory cytokines were calculated. Impression cytology was performed on the conjunctiva, and goblet cell density and epithelial squamous metaplasia were quantified. Differences in variables by CL replacement schedules and the associations between variables were analyzed. Reusable CL wearers had higher concentrations (in pg/mL) of IL-1β (26 ± 7 vs. 16 ± 11), IL-6 (42 ± 14 vs. 25 ± 20), IL-10 (83 ± 23 vs. 49 ± 36), IL-12(p70) (145 ± 44 vs. 91 ± 68), IL-17A (93 ± 26 vs. 54 ± 44), and tumor necrosis factor α (312 [171 to 468] vs. 189 [6 to 447]) (all P < .01) and greater conjunctival metaplasia in the region covered by CLs (0.7 [0.2 to 1.6] vs. 0.4 [0.04 to 1.2], P = .01) compared with DD wearers. There was a positive association between CL discomfort and ratios of IL-1β to IL-10 and IL-12(p70) to IL-10 (ρ = 0.42 and ρ = 0.33, P < .05). Higher ocular inflammatory responses, as indicated by higher tear cytokine concentrations and higher conjunctival epithelial metaplasia, were found in reusable CL wearers than in DD CL wearers. The balance of proinflammatory and anti-inflammatory cytokines may be helpful to assess the inflammatory status of the eye.

Effects of Exposure to Ozone on the Ocular Surface in an Experimental Model of Allergic Conjunctivitis.

Based on previous findings that ozone can induce an inflammatory response in the ocular surface of an animal model and in cultured human conjunctival epithelial cells, we investigated whether exposure to ozone exacerbates symptoms of allergic conjunctivitis. We evaluated the effects of exposure to ozone on conjunctival chemosis, conjunctival injection, corneal and conjunctival fluorescein staining scores, production of inflammatory cytokines in tears, and aqueous tear production in a mouse model of allergic conjunctivitis. To validate our in vivo results, we used interleukin (IL)-1α-pretreated conjunctival epithelial cells as an in vitro substitute for the mouse model. We evaluated whether exposure to ozone increased the inflammatory response and altered oxidative status and mitochondrial function in IL-1α-pretreated conjunctival epithelial cells. In the in vivo study, ozone induced increases in conjunctival chemosis, conjunctival injection, corneal and conjunctival fluorescein staining scores, and production of inflammatory cytokines, accompanied by a decrease in tear volume. In the in vitro study, exposure to ozone led to additional increases in IL-6 and tumor necrosis factor-α mRNA levels, which were already induced by treatment with IL-1α. Ozone did not induce any changes in cell viability. Pretreatment with IL-1α increased the expression of manganese superoxide dismutase, and exposure to ozone led to additional increments in the expression of this antioxidant enzyme. Ozone did not induce any changes in mitochondrial activity or expression of mitochondrial enzymes and proteins related to mitochondrial function, with the exception of phosphor-mammalian target of rapamycin. Treatment with butylated hydroxyanisole, a free radical scavenger, attenuated the ozone-induced increases in IL-6 expression in IL-1α-pretreated conjunctival epithelial cells. Therefore, we conclude that exposure to ozone exacerbates the detrimental effects on the integrity of the ocular surface caused by conjunctival allergic reactions, and further increases the inflammatory response in IL-1α-pretreated conjunctival epithelial cells.