Immunologic basis for development of keratoconjunctivitis sicca in systemic autoimmune diseases: Role of innate immune sensors

The literature is filled with citations reporting an increased incidence of chronic dry eye disease, also known as keratoconjunctivitis sicca, in patients with systemic autoimmune diseases such as rheumatoid arthritis, Sjögren's Syndrome, systemic sclerosis and lupus. As the most environmentally exposed mucosal surface of the body, the conjunctiva constantly responds to environmental challenges which are typically self limited, but when persistent and unresolved may provoke pathogenic innate and adaptive immune reactions. Our understanding of the pathophysiological mechanisms by which systemic autoimmune diseases cause dry eye inducing ocular surface inflammation continues to evolve. Conjunctival immune tone responds to self or foreign danger signals (including desiccating stress) on the ocular surface with an initial non-specific innate inflammatory response. If unchecked, this can lead to activation of dendritic cells that present antigen and prime T and B cells resulting in an adaptive immune reaction. These reactions generally resolve, but dysfunctional, hyper-responsive immune cells found in systemic autoimmune diseases that are recruited to the ocular surface can amplify inflammatory stress responses in the ocular surface and glandular tissues and result in autoimmune reactions that disrupt tear stability and lead to chronic dry eye disease. We here propose that unique features of the ocular surface immune system and the impact of systemic immune dysregulation in autoimmune diseases, can predispose to development of dry eye disease, and exacerbate severity of existing dry eye.

Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19

BACKGROUND

Whereas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody tests are increasingly being used to estimate the prevalence of SARS-CoV-2 infection, the determinants of these antibody responses remain unclear.

OBJECTIVES

Our aim was to evaluate systemic and mucosal antibody responses toward SARS-CoV-2 in mild versus severe coronavirus disease 2019 (COVID-19) cases.

METHODS

Using immunoassays specific for SARS-CoV-2 spike proteins, we determined SARS-CoV-2-specific IgA and IgG in sera and mucosal fluids of 2 cohorts, including SARS-CoV-2 PCR-positive patients (n = 64) and PCR-positive and PCR-negtive health care workers (n = 109).

RESULTS

SARS-CoV-2-specific serum IgA titers in patients with mild COVID-19 were often transiently positive, whereas serum IgG titers remained negative or became positive 12 to 14 days after symptom onset. Conversely, patients with severe COVID-19 showed a highly significant increase of SARS-CoV-2-specific serum IgA and IgG titers after symptom onset. Very high titers of SARS-CoV-2-specific serum IgA were correlated with severe acute respiratory distress syndrome. Interestingly, some health care workers with negative SARS-CoV-2-specific serum antibody titers showed SARS-CoV-2-specific IgA in mucosal fluids with virus-neutralizing capacity in some cases. SARS-CoV-2-specific IgA titers in nasal fluids were inversely correlated with age.

CONCLUSIONS

Systemic antibody production against SARS-CoV-2 develops mainly in patients with severe COVID-19, with very high IgA titers seen in patients with severe acute respiratory distress syndrome, whereas mild disease may be associated with transient production of SARS-CoV-2-specific antibodies but may stimulate mucosal SARS-CoV-2-specific IgA secretion.

Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19

BACKGROUND

Whereas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody tests are increasingly being used to estimate the prevalence of SARS-CoV-2 infection, the determinants of these antibody responses remain unclear.

OBJECTIVES

Our aim was to evaluate systemic and mucosal antibody responses toward SARS-CoV-2 in mild versus severe coronavirus disease 2019 (COVID-19) cases.

METHODS

Using immunoassays specific for SARS-CoV-2 spike proteins, we determined SARS-CoV-2-specific IgA and IgG in sera and mucosal fluids of 2 cohorts, including SARS-CoV-2 PCR-positive patients (n = 64) and PCR-positive and PCR-negtive health care workers (n = 109).

RESULTS

SARS-CoV-2-specific serum IgA titers in patients with mild COVID-19 were often transiently positive, whereas serum IgG titers remained negative or became positive 12 to 14 days after symptom onset. Conversely, patients with severe COVID-19 showed a highly significant increase of SARS-CoV-2-specific serum IgA and IgG titers after symptom onset. Very high titers of SARS-CoV-2-specific serum IgA were correlated with severe acute respiratory distress syndrome. Interestingly, some health care workers with negative SARS-CoV-2-specific serum antibody titers showed SARS-CoV-2-specific IgA in mucosal fluids with virus-neutralizing capacity in some cases. SARS-CoV-2-specific IgA titers in nasal fluids were inversely correlated with age.

CONCLUSIONS

Systemic antibody production against SARS-CoV-2 develops mainly in patients with severe COVID-19, with very high IgA titers seen in patients with severe acute respiratory distress syndrome, whereas mild disease may be associated with transient production of SARS-CoV-2-specific antibodies but may stimulate mucosal SARS-CoV-2-specific IgA secretion.

Dry Eye Disease and Tear Cytokine Levels-A Meta-Analysis

Background—It is recognized that inflammation is an underlying cause of dry eye disease (DED), with cytokine release involved. We systematically reviewed literature with meta-analyses to quantitatively summarize the levels of tear cytokines in DED. Methods—The PubMed, Embase, Web of Science, Ovid, Cochrane, and Scopus databases were reviewed until September 2019, and original articles investigating tear cytokines in DED patients were included. Differences of cytokines levels of DED patients and controls were summarized by standardized mean differences (SMD) using a random effects model. Study quality was assessed by applying Newcastle-Ottawa-Scale and the GRADE quality score. Methods of analytical procedures were included as covariate. Results—Thirteen articles investigating 342 DED patients and 205 healthy controls were included in the meta-analysis. The overall methodological quality of these studies was moderate. Systematic review of the selected articles revealed that DED patients had higher tear levels of interleukin (IL)-1β, IL-6, chemokine IL-8, IL-10, interferon-γ, IFN-γ, and tumor necrosis factor-α, TNF-α as compared to controls. Evidence was less strong for IL-2 and IL-17A. Conclusions—Data show that levels of tear cytokines in DED and control display a great variability, and further studies of higher quality enrolling a higher number of subjects are needed, to define a cut-off value.

The Immunological Basis of Dry Eye Disease and Current Topical Treatment Options

Homeostasis of the lacrimal functional unit is needed to ensure a well-regulated ocular immune response comprising innate and adaptive phases. When the ocular immune system is excessively stimulated and/or immunoregulatory mechanisms are disrupted, the balance between innate and adaptive phases is dysregulated and chronic ocular surface inflammation can result, leading to chronic dry eye disease (DED). According to the Tear Film and Ocular Surface Society Dry Eye Workshop II definition, DED is a multifactorial disorder of the ocular surface characterized by impairment and loss of tear homeostasis (hyperosmolarity), ocular discomfort or pain, and neurosensory abnormalities. Dysregulated ocular immune responses result in ocular surface damage, which is a further contributing factor to DED pathology. Several therapeutics are available to break the vicious circle of DED and prevent chronic disease and progression, including immunosuppressive agents (steroids) and immunomodulators (cyclosporine and lifitegrast). Given the chronic inflammatory nature of DED, each of these agents is commonly used in clinical practice. In this study, we review the immunopathology of DED and the molecular and cellular actions of current topical DED therapeutics to inform clinical decision making.

Differential effects of specific cathepsin S inhibition in biocompartments from patients with primary Sjögren syndrome

OBJECTIVE

Primary Sjögren syndrome (pSS) is characterized by T and B cell infiltration of exocrine glands. The cysteine protease cathepsin S (CatS) is crucially involved in MHCII processing and T cell stimulation, and elevated levels have been found in patients with RA, psoriasis and pSS. However, little is known about the functional characteristics and mechanisms of SS-A- and SS-B-specific T cells in pSS patients. We herein investigated the inhibition of CatS activity in different biocompartments of pSS patients including antigen-specific T cell responses.

METHODS

Ex vivo CatS activity was assessed in tears, plasma and saliva of 15 pSS patients and 13 healthy controls (HC) and in the presence or absence of the specific CatS inhibitor RO5459072. In addition, antigen (SS-A (60kD), SS-B, influenza H3N2, tetanus toxoid and SEB)-specific T cell responses were examined using ex vivo IFN-γ/IL-17 Dual ELISPOT and Bromdesoxyuridin (BrdU) proliferation assays in the presence or absence of RO5459072. Supernatants were analysed for IL-1β, IL-6, IL-10, TNF-α, IL-21, IL-22 and IL-23, using conventional ELISA.

RESULTS

CatS activity was significantly elevated in tear fluid, but not other biocompartments, was inversely associated with exocrinic function in pSS patients and could significantly be suppressed by RO5459072. Moreover, CatS inhibition by RO5459072 led to strong and dose-dependent suppression of SS-A/SS-B-specific T cell effector functions and cytokine secretion by CD14+ monocytes. However, RO5459072 was incapable of suppressing SS-A/SS-B-induced secretion of cytokines in CD14+ monocytes when T cells were absent, confirming a CatS/MHCII-mediated mechanism of suppression.

CONCLUSION

CatS activity in tear fluid seems to be a relevant biomarker for pSS disease activity. Conversely, CatS inhibition diminishes T cell and associated monokine responses towards relevant autoantigens in pSS. Thus, CatS inhibition may represent a promising novel treatment strategy in pSS.

Immunization of cats to induce neutralizing antibodies against Fel d 1, the major feline allergen in human subjects

BACKGROUND

Cat allergy in human subjects is usually caused by the major cat allergen Fel d 1 and is found in approximately 10% of the Western population. Currently, there is no efficient and safe therapy for cat allergy available. Allergic patients usually try to avoid cats or treat their allergy symptoms.

OBJECTIVE

We developed a new strategy to treat Fel d 1-induced allergy in human subjects by immunizing cats against their own major allergen, Fel d 1.

METHODS

A conjugate vaccine consisting of recombinant Fel d 1 and a virus-like particle derived from the cucumber mosaic virus containing the tetanus toxin-derived universal T-cell epitope tt830-843 (CuMVTT) was used to immunize cats. A first tolerability and immunogenicity study, including a boost injection, was conducted by using the Fel-CuMVTT vaccine alone or in combination with an adjuvant.

RESULTS

The vaccine was well tolerated and had no overt toxic effect. All cats induced a strong and sustained specific IgG antibody response. The induced anti-Fel d 1 antibodies were of high affinity and exhibited a strong neutralization ability tested both in vitro and in vivo. A reduction in the endogenous allergen level and a reduced allergenicity of tear samples, were observed.

CONCLUSION

Vaccination of cats with Fel-CuMVTT induces neutralizing antibodies and might result in reduced symptoms of allergic cat owners. Both human subjects and animals could profit from this treatment because allergic cat owners would reduce their risk of developing chronic diseases, such as asthma, and become more tolerant of their cats, which therefore could stay in the households and not need to be relinquished to animal shelters.

Determination of inmune response and inflammation mediators in tears: Changes in dry eye and glaucoma as compared to healthy controls

OBJECTIVE

To determine the expression profile of immune response and inflammation (IRI) mediator molecules in tears from patients with dry eye (DE), and those suspected of having or have primary open-angle glaucoma (POAG) under treatment and compare them with healthy controls.

METHODS

A prospective observational cohort study including 107 participants sub-divided into: healthy controls (CG; n=30), patients with DE (DEG; n=41) and patients suspected of having or have POAG and on hypotensive treatment (POAG-G; n=36). Tear samples were collected by capillary to be processed using a multi-immunoassay system based on flow cytometry (Luminex R-200 ®), in order to determine the interleukins (IL): 1β, 2, 4, 5, 6, and 10, and the growth factors: Tumour necrosis alpha (TNF-α), vascular endothelial (VEGF), and granulocyte-macrophage colony stimulating- (GM-CSF). Data were processed using the SPSS 20.0 program.

RESULTS

Molecules that significantly increased in tears from DEG vs. POAG-G patients were: IL-1 (P=.01), IL-6 (P=.004), IL-10 (P=.04), whereas VEGF significantly decreased in the DEG. The POAG-G showed significantly higher IL-6 values (P<.0001) as compared to the CG. When comparing both the DEG and POAG-G, significant differences were observed in tear expression of IL-4 (P=.004), IL-6 (P=.002), TNF-α (P=.03), GM-CSF (P=.03), and VEGF (P=.002).

CONCLUSIONS

The increased expression of IRI mediators in tears from patients with DE or POAG strongly demonstrated the importance of immune response in both pathologies. However, the different molecules involved also suggest distinct signalling pathways for these processes that still require further research.

Increased serum IgA concentration and plasmablast frequency in patients with age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness among senior citizens of developed countries, with currently unknown etiology. Despite the close associations between AMD development and inhibitory complement factor H mutations, the first step of complement activation, which is the antibody response in AMD patients, has not been studied. Here, we obtained blood and tear samples from AMD patients and Non-AMD controls. We found that compared to Non-AMD controls, AMD subjects had increased IgA titers in serum and tear, and had elevated levels of circulating antibody-secreting plasmablasts. The increase in antibody titer was limited to the IgA isotype, since no significant differences were observed in IgM and IgG isotypes between AMD patients and Non-AMD controls. Interestingly, this increased antibody response in AMD patients was correlated with disease severity, as late AMD patients had increased IgA titers in serum and tear, as well as elevated plasmablast frequency after staphylococcal enterotoxin B stimulation, compared to early AMD patients. Together, our results implicated a role of overreactive IgA responses in AMD pathogenesis.

Inflammatory cytokines regulate secretion of VEGF and chemokines by human conjunctival fibroblasts: Role in dysfunctional tear syndrome

Ocular surface inflammation is one of the primary mechanisms associated with dysfunctional tear syndrome (DTS), also known as dry eye disease. DTS, more prevalent in older populations, causes ocular discomfort and visual disturbance due to dryness on the surface layer in the eye. We used human conjunctival fibroblast cultures (HCJVF) to investigate the effects of inflammatory cytokines IFN-γ, TNF-α and IL-1β (ITI) on the secretions of VEGF and chemokines. Our results demonstrate the elevated secretion of angiogenic VEGF molecules by ITI without affecting anti-angiogenic molecules, PEDF, endostatin, thrombospondin and sVEGF-R1. The secretion of interferon-γ inducible chemokines, CXCL9, -10, -11 by HCJVF were significantly enhanced by ITI. Our in vitro study supports previously reported observations of elevated VEGF and chemokines in tear fluids of DTS patients, reiterating the role of inflammatory reactions in DTS.

Lacrimal Cytokines Assessment in Subjects Exposed to Different Levels of Ambient Air Pollution in a Large Metropolitan Area

Background

Air pollution is one of the most environmental health concerns in the world and has serious impact on human health, particularly in the mucous membranes of the respiratory tract and eyes. However, ocular hazardous effects to air pollutants are scarcely found in the literature.

Design

Panel study to evaluate the effect of different levels of ambient air pollution on lacrimal film cytokine levels of outdoor workers from a large metropolitan area.

Methods

Thirty healthy male workers, among them nineteen professionals who work on streets (taxi drivers and traffic controllers, high pollutants exposure, Group 1) and eleven workers of a Forest Institute (Group 2, lower pollutants exposure compared to group 1) were evaluated twice, 15 days apart. Exposure to ambient PM_2.5 (particulate matter equal or smaller than 2.5 μm) was 24 hour individually collected and the collection of tears was performed to measure interleukins (IL) 2, 4, 5 and 10 and interferon gamma (IFN-γ) levels. Data from both groups were compared using Student’s t test or Mann- Whitney test for cytokines. Individual PM_2.5 levels were categorized in tertiles (lower, middle and upper) and compared using one-way ANOVA. Relationship between PM_2.5 and cytokine levels was evaluated using generalized estimating equations (GEE).

Results

PM_2.5 levels in the three categories differed significantly (lower: ≤22 μg/m³; middle: 23–37.5 μg/m³; upper: >37.5 μg/m³; p<0.001). The subjects from the two groups were distributed unevenly in the lower category (Group 1 = 8%; Group 2 = 92%), the middle category (Group 1 = 89%; Group 2 = 11%) and the upper category (Group 1 = 100%). A significant relationship was found between IL-5 and IL-10 and PM_2.5 levels of the group 1, with an average decrease of 1.65 pg/mL of IL-5 level and of 0.78 pg/mL of IL-10 level in tear samples for each increment of 50 μg/m3 of PM_2.5 (p = 0.01 and p = 0.003, respectively).

Conclusion

High levels of PM_2.5 exposure is associated with decrease of IL-5 and IL-10 levels suggesting a possible modulatory action of ambient air pollution on ocular surface immune response.

Upregulation of NLRP3 Inflammasome in the Tears and Ocular Surface of Dry Eye Patients

PURPOSE

To evaluate the mRNA and protein expressions of NLRP3 inflammasome and its downstream inflammatory factors in human dry eye.

METHODS

We recruited 54 patients with Sjögren's syndrome dry eye (SSDE), 50 patients with non-Sjögren's syndrome dry eye (NSSDE), and 46 healthy controls. Tear film breakup time (TBUT), Schirmer I test, and fluorescein staining (FL) were performed on all subjects. Tear samples were obtained to analyze the inflammatory cytokine levels of IL-1β and IL-18 via enzyme-linked immunosorbent (ELISA). Conjunctival impression cytology (CIC) specimens were collected to detect the mRNA expression of NLRP3, caspase-1, IL-1β, and IL-18 using quantitative RT-PCR, and the protein expression of NLRP3 and caspase-1 by Western blotting.

RESULTS

NLRP3 mRNA expression showed higher levels in both dry eye groups compared with controls, with a comparably significant elevation in the SSDE group (relative 2.47-fold upregulation, p<0.05). NLRP3 protein expression was also increased in SSDE group (relative1.94-fold upregulation) compared with the controls. mRNA expression of caspase-1 was significantly upregulated in both SSDE (relative 1.44-fold upregulation, p<0.05) and NSSDE (relative 1.32-fold upregulation, p<0.05). Procaspase-1 protein level was increased in SSDE (relative 1.84-fold upregulation) and NSSDE (relative 1.12-fold upregulation) versus controls; and caspase-1 protein expression was also increased in SSDE (relative 1.49-fold upregulation) and NSSDE (relative 1.17-fold upregulation) compared with the controls. The patients with SSDE and NSSDE had higher IL-1β and IL-18 mRNA values and protein expressions than the controls did. The relative mRNA expression of IL-1β upregulated 3.59-fold (p<0.001) in SSDE and 2.13-fold (p<0.01) in NSSDE compared with the controls. IL-1β protein level also showed significant upregulation in SSDE (p=0.01; vs. controls groups). IL-18 mRNA expression levels were significantly upregulated in the SSDE (relative 2.97-fold upregulation, p=0.001) and NSSDE (relative 2.05-fold upregulation, p=0.001) groups compared with the controls; tear IL-18 concentrations were also significantly increased in the SSDE (p<0.001) and NSSDE (p<0.05) groups.

CONCLUSIONS

In the current study, we found that mRNA and protein expressions of NLRP3 inflammasome were upregulated in human dry eyes, especially in SSDE; the downstream inflammatory factors caspase-1, IL-1β, and IL-18 were also elevated in dry eye patients. These observations suggest the involvement of NLRP3 inflammasome in the onset and development of the inflammation in dry eye.

Expression of IL-8, IL-6 and IL-1β in tears as a main characteristic of the immune response in human microbial keratitis

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.

Antibody detection in tear samples as a surrogate to monitor host immunity against papillomavirus infections in vaccinated and naturally infected hosts

Monitoring serum antibodies against natural infections or after immunizations has been a standard clinical diagnostic procedure. However, collecting blood samples requires trained personnel, and may cause discomfort and increase the risk of complications. In this study, we investigated whether tear samples could serve as a surrogate for serum samples to measure specific antibodies. A widely used preclinical cottontail rabbit papillomavirus (CRPV)/rabbit model has been a surrogate model for high-risk human papillomavirus (HPV) infections. New Zealand white rabbits, either naturally infected with CRPV or immunized with two clinically available HPV vaccines (Gardasil and Cervarix), were examined for antibody generation in both tear and serum samples. We demonstrated that antibodies were detectable in tears from both naturally infected as well as vaccinated animals. Overall, the antibody levels in tears were ~10-fold lower than those from the corresponding serum samples, but background noise was lower in tear samples. The isotypes of antibodies in tears were predominantly IgA and IgG. These findings showed clearly that tears could be a surrogate for serum samples for monitoring antibody responses. As collecting tears causes no discomfort and poses no risk to patients, it represents a novel and promising method for monitoring future HPV epidemiological studies as well as for use in clinical practice.

[Clinical and immunological factors of the onset and development of age-related macular degeneration]

The purpose of the study is to determine the role of certain clinical and immunological factors of the onset and development of age-related macular degeneration (AMD).

MATERIALS AND METHODS

Retrospective analysis of patients records; determination of IFNalpha IFNgamma, IL-1beta, and TNFalpha cytokines levels as well as extracellular peroxidase activity (EPA) in blood serum and tear; measuring frequency of occurrence of intraocular infectious antigens with predominantly intracellular localization, such as Herpesviridae spp. (Herpes simplex, Cytomegalovirus, Epstein-Barr virus) and Chlamydiaceae spp. (Chlamydia pneumoniae, Chlamydia trachomatis) in lens matter and aqueous humor by means of polymerase chain reaction (PCR). The new evidence strongly suggests a relationship between AMD development and hypertension (p < 0.001; r = +0.30, P < 95%) as well as between AMD progression and hypertension accompanied by chronic inflammation with predominantly intracellular localization of the infectious agent (p < 0.05 for the predisciform stage, p < 0.001 for the disciform and cicatrical stages; r = +0.30, P < 95%). "Dry" AMD is characterized by hypertension-associated systemic and then local increase of EPA. In "wet" AMD it is the interferon response that is impaired: IFNalpha and IFNgamma are systemically decreased, while local level of IFNalpha is increased. Intraocular Herpes simplex infection is pathogenically significant for AMD development (18.8% in the study group vs 0% in the control group).

CONCLUSION

AMD progression is associated with hypertension accompanied by chronic inflammation with predominantly intracellular localization of the infectious agent as well as impairment of the interferon response (systemic decrease of IFNalpha and IFNgamma with local increase of IFNalpha). Moreover, the presence of intraocular Herpes simplex infection leads to activation of the first line antiviral immunity (IFNgalpha) with decompensation of the local interferon response (IFNgamma).

[Evaluation of anti-Pseudomonas aeruginosa specific secretory IgA antibodies in tears of patients with Pseudomonas aeruginosa keratitis]

PURPOSE

To investigate the role of specific secretary IgA antibodies on lipopolysaccharide (LPS-sIgA) and exotoxin A (ETA-sIgA) in tear fluid produced by immunoresponse to P. aeruginosa.

SUBJECTS AND METHODS

Subjects were divided into 3 groups; 41 eyes of 41 normal volunteers without a history of using contact lenses (CL) as controls, 32 eyes of 32 CL users without adverse events as a healthy CL wearer group (CL group), and 12 eyes of 12 patients with CL-related corneal ulcers from which P. aeruginosa was isolated (ulcer group). Tear fluid was obtained using filter paper, and the concentration of LPS-sIgA and ETA-sIgA in samples was determined using enzyme-linked immunosorbent assay (ELISA).

RESULTS

The lower limit of concentration for LPS-sIgA and ETA-sIgA was 1.24 and 1.24 (U/mL), respectively. The positive eyes which exceeded this lower limit in LPS-sIgA were 17 of 22 eyes in the control group (median concentration 2.00U/ml, range 1.28 to 7.20), 15 of 25 eyes in the CL group (median 1.76 U/ml, range 1.24 to 6.92) and 1 of 12 eyes in the ulcer group (1.80 U/ml). The number of eyes which exceeded the lower limit in ETA-sIgA was 36 of 41 eyes in the control group (median concentration 6.56 U/ml, range 1.36 to 182), 28 of 32 eyes in the CL group (median 5.40 U/ml, range 1.56 to 29.20) and 5 of 12 eyes in the ulcer group (median 1.72 U/ml, range 1.40 to 2.16). There was no significant difference in LPS-sIgA and ETA-sIgA between the control group and the CL group, but they were significantly lower in the ulcer group than in the control group (p < 0.01, Steel's test).

CONCLUSION

Tear fluid in normal, healthy CL wearers contains LPS-sIgA and ETA-sIgA which acts as a barrier to P. aeruginosa infectious keratitis.

Antimicrobial compounds in tears

The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here.

The ocular surface: from physiology to the ocular allergic diseases

Allergic conjunctivitis (AC) is an inflammation of the conjunctiva secondary to an immune response to exogenous antigens, usually called allergens. In fact, AC is a syndrome that involves the entire ocular surface, including conjunctiva, lids, cornea, and tear film. The signs and symptoms of AC have a meaningful effect on comfort and patient health, and could be influenced by environment, genetics and immune regulation mechanisms, all of which work together in a complex immunological homeostasis. Dysregulation in such immune responses could turn into a variety of ocular allergic diseases (OAD). This review describes some of the current understanding of cellular and molecular pathways involved in different OAD.

[Functional tear production indices in thyroid eye disease]

Analysis of functional tear production indices in patients with Grave's disease and thyroid eye disease confirmed lacrimal gland involvement in inflammatory autoimmune process. Close direct correlation was found between tear production and main disease characteristics - severity and activity.

Secretory phospholipase A2 in dromedary tears: a host defense against staphylococci and other gram-positive bacteria

The best known physiologic function of secreted phospholipase A2 (sPLA2) group IIA (sPLA2-IIA) is defense against bacterial infection through hydrolytic degradation of bacterial membrane phospholipids. In fact, sPLA2-IIA effectively kills Gram-positive bacteria and to a lesser extent Gram-negative bacteria and is considered a major component of the eye's innate immune defense system. The antibacterial properties of sPLA2 have been demonstrated in rabbit and human tears. In this report, we have analyzed the bactericidal activity of dromedary tears and the subsequently purified sPLA2 on several Gram-positive bacteria. Our results showed that the sPLA2 displays a potent bactericidal activity against all the tested bacteria particularly against the Staphylococcus strains when tested in the ionic environment of tears. There is a synergic action of the sPLA2 with lysozyme when added to the bacteria culture prior to sPLA2. Interestingly, lysozyme purified from dromedary tears showed a significant bactericidal activity against Listeria monocytogene and Staphylococcus epidermidis, whereas the one purified from human tears displayed no activity against these two strains. We have also demonstrated that Ca(2+) is crucial for the activity of dromedary tear sPLA2 and to a less extent Mg(2+) ions. Given the presence of sPLA2 in tears and intestinal secretions, this enzyme may play a substantial role in innate mucosal and systemic bactericidal defenses against Gram-positive bacteria.

[Evaluation of the efficacy of subjective symptoms, objective findings, and of a total tear IgE detection kit in diagnosis of allergic conjunctival diseases]

PURPOSE

To evaluate the efficacy of subjective symptoms, objective findings, and of a total tear IgE test kit in the diagnosis of allergic conjunctival diseases (ACD).

SUBJECTS AND METHODS

The subjects were 223 patients with ACD, diagnosed according to the clinical practice guidelines for allergic conjunctival diseases in 28 medical facilities in Japan. The ACD patients were divided into the following five groups: 84 patients with seasonal allergic conjunctivitis (SAC), 52 patients with perennial allergic conjunctivitis (PAC), 41 patients with atopic keratoconjunctivitis (AKC), 38 patients with vernal keratoconjunctivitis (VKC) and 8 patients with giant papillary conjunctivitis (GPC). All cases were examined for clinical ACD, subjective symptoms, objective findings by the clinical score and by a total tear IgE test. An eosinophil examination by conjunctival smear was also performed in 87 ACD patients.

RESULTS

The most prevalent subjective symptoms were itching (81.6%) and hyperemia (77.6%). The clinical scores of the objective findings in the patients with SAC, PAC, AKC, VKC and GPC were 16.3 +/- 3.8 (mean +/- SD) points, 16.2 +/- 2.8, 19.8 +/- 6.5, 23.1 +/- 5.3, and 21.4 +/- 3.9, respectively. In the total tear IgE test 72.2% of the ACD patients were positive; i.e., the ratios were 61.9% in SAC, 65.4% in PAC, 80.5% in AKC, 94.7% in VKC, and 75.0% in GPC. In the examination of eosinophils in the 87 ACD patients, 42.5% (37 eyes) were positive, i.e., the ratio was 20.0% in SAC, 36.8% in PAC, 53.3% in AKC, 75.0% in VKC and 33.3% in GPC. The rate of agreement between the total tear IgE test and the examination of eosinophils was kappa = 0.28 (Cohen kappa coefficient).

CONCLUSION

Because of the high positive ratio in patients quasi-definitively diagnosed with ACD, we conclude that the total tear IgE test is useful as an auxiliary method for diagnosing ACD.

[Changes in various immunological parameters of lacrimal fluid in excessive scarring after antiglaucoma surgery in patients with primary open-angle glaucoma]

Twenty-two patients in whom the expression of the human beta-defensin-2 (HBD-2) gene and the concentrations of human neutrophil peptides (HNP 1-3) and interleukin-17 (IL-17) were determined in the conjunctiva and lacrimal fluid were followed. In patients with primary open-angle glaucoma, the baseline concentrations of HNP 1-3 and IL-17 in lacrimal fluid and the expression of the HBD-2 gene in the conjunctival epithelial cells were higher than those in healthy individuals. The appearance of signs of pathological scarring was observed when HBD-2 expression in the conjunctival epithelial cells was lower and the rate of changes in the lacrimal fluid concentrations of HNP 1-3 and IL-17 was stable.

Clinical evaluation of total IgE in tears of patients with allergic conjunctivitis disease using a novel application of the immunochromatography method

BACKGROUND

The determination of total IgE in tears is useful as a diagnostic tool in allergic conjunctivitis disease (ACD). We evaluated the efficacy of this diagnostic tool for ACD, which is a clinically applicable novel immunochromagraphic method to determine total IgE in tears.

METHODS

The subjects comprised 4 groups: 15 patients with vernal keratoconjunctivitis (VKC group), 8 patients with atopic keratoconjunctivitis (AKC group), 18 patients with allergic conjunctivitis (AC group), and 7 normal healthy volunteers as a control (control group). Tears were sampled using filter paper, and the total IgE in tears was determined by immunochromatography assay. Semiquantitative determination was carried out by examining the intensity of the colored line using an immunochromatoreader (IgE index). The relationship between IgE indices in tears and total IgE levels in serum or between IgE indices and the clinical scores of ACD was examined.

RESULTS

The positive ratio obtained by this novel application of the immunochromatography assay was 38 of the 41 in the patients with ACD and none in the 7 controls. IgE indices for the VKC group, AKC group and AC group were 27.5 +/- 15.6, 19.8 +/- 15.8, and 4.0 +/- 3.1 (mean +/- SD), respectively. IgE indices in tears showed significant correlation with both total IgE levels in serum (P < 0.001, r = 0.76) and clinical scores of ACD (P < 0.001, r = 0.57).

CONCLUSIONS

The novel application of the immunochromatography assay to assess the total IgE in tears is a useful clinical tool to investigate ACD.

Cytokines, matrix metalloproteases, angiogenic and growth factors in tears of normal subjects and vernal keratoconjunctivitis patients

BACKGROUND

To detect the presence of multiple mediators and growth factors in tears of vernal keratoconjunctivitis (VKC) patients with active disease using stationary phase antibody arrays.

METHODS

Tears were collected from 12 normal subjects (CT) and 24 active VKC patients. Tears were centrifuged and successively probed using three microwell plate arrays specific for: (i) cytokines: interleukin (IL)-2, IL-4, IL-5, IL-8, IL-10, IL-12, IL-13, interferon-gamma and tumour necrosis factor-alpha; (ii) growth factors: basic fibroblast growth factor (bFGF), platelet-derived growth factor, thrombopoietin, angiopoietin-2, vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), keratocyte growth factor, tissue inhibitor of metalloprotease (TIMP)-1 and heparin-binding epithelial growth factor (HB-EGF) and (iii) matrix metalloprotease (MMP)-1, MMP-2, MMP-3, MMP-8, MMP-9, MMP-10, MMP-13, TIMP-1 and TIMP-2.

RESULTS

Interleukin-8 signals were detected in all CT and highly detected in all VKC samples. The Th2-type cytokines, IL-4, IL-5 and IL-10 were detected only in tears of VKC patients. Signals for bFGF, HB-EGF, VEGF and HGF were detected in 41-87% of VKC samples and in few CT samples. Only TIMP-1 and TIMP-2 were found in all normal and patient tear samples, whereas MMP-1, MMP-2, MMP-3, MMP-9 and MMP-10 were highly present in all VKC samples.

CONCLUSIONS

Stationary phase antibody array methodology was useful for the screening of various cytokines, growth factors and MMPs in tears. These analyses identified in tears of VKC patients previously unreported factors including MMP-3 and MMP-10 and multiple proteases, growth factors and cytokines, which may all play an important role in the pathogenesis of conjunctival inflammation.

[Lacrimal assessment of lg E in cases with allergic conjunctivitis]

PURPOSE

To present the study regarding Ig E tears dosation in cases with allergic conjunctivitis.

METHOD

The Ig E tear dosation was done on two study groups--group A with 124 patients presenting allergic conjunctivitis symptoms (58 with seasonal allergic conjunctivitis, 43 with atopic allergic ocular symptoms, 23 treated with olopatadina 0.1% for 10 days) and compare group B consisting of 40 healthy patients (no local or general allergic symptoms) evaluated in the the Ophthalmology Clinic Arad between 2002-2008. The biological material used in the study was that of tears samples. For the determination of Ig E we used ELISA method, HUMAN IMUNO IG E QUANTITATION (Bethyl Laboratoires, Montgomery, TX) test.

RESULTS

Significant statistic high levels of IgE concentration were observed in study group A in patients with allergic seasonal conjunctivitis (331.11 +/- 125.22 ng/ml) and patients with atopic terrain (177.18 +/- 56.70) compared to group B (67.25 +/- 8.89 ng/ml) with healthy patients. In the study group with allergic seasonal conjunctivitis there have been significant diminished IgE levels (71.70 +/- 9.94) after treatment.

CONCLUSION

The method of IgE tears dosation proved to be efficient in establishing the ethiology of ocular allergies and in the screening of new cases with allergic conjunctivitis.

Induction of mucosal immunity in the avian Harderian gland with a replication-deficient Ad5 vector expressing avian influenza H5 hemagglutinin

The chicken Harderian gland (HG) plays an important role in adaptive immune responses upon ocular exposure to avian pathogens such as avian influenza (AI). To determine the role of HGs in generating immunity, chickens were immunized ocularly with an adenovirus (Ad5) vector expressing the AI hemagglutinin H5 gene. The Ad5-H5 vector induced H5 transgene expression and induced H5- and Ad5-specific IgA and IgG spot-forming cells (SFCs) in the HGs. The IgA and IgG SFC peaked on day 9 forAd5 and day 11 for the H5 protein. In addition, Ad5- and H5-specific antibodies were induced in serum. IgA in chicken tears was predominantly dimeric, while in serum monomeric IgA was most abundant. Analysis of HG mRNA confirmed expression of the polymeric immunoglobulin receptor (plgR). These data demonstrated the importance of HGs to generate mucosal and systemic immunity to AI following ocular Ad5-H5 administration to chickens.

[Dry eye syndrome and allergic conjunctivitis--epidemics of XXI century--diagnostic problems and management]

Recently, allergic conjunctivitis and dry eye syndrome have been thought to be the epidemics of XXI century. Allergic conjunctivitis is the commonest form of allergy worldwide. Clinical symptoms of dry eye are the most common cause of patients complains in out-patient ophthalmological clinics. Both, allergic conjunctivitis and dry eye syndrome, may be associated with some systemic diseases. Thus, it is crucial to perform complete allergic tests in patients suspected of allergic conjunctivitis. The assessment of IgE in tears is a very sensitive test in these cases because physiologically this immunoglobulin is not detectable in tear film. In cases of dry eye syndrome the measurement of tear osmolarity has been is thought to be the most specific and sensitive test, recently.

The natural history of trachoma infection and disease in a Gambian cohort with frequent follow-up

Background

The natural history of ocular Chlamydia trachomatis infections in endemic communities has not been well characterised and is an important determinant of the effectiveness of different mass treatment strategies to prevent blindness due to trachoma.

Methodology/Principal Findings

A multistate hidden Markov model was fitted to data on infection and active disease from 256 untreated villagers in The Gambia who were examined every 2 weeks over a 6-month period. Parameters defining the natural history of trachoma were estimated, and associations between these parameters, demographic and baseline immune measurements examined. The median incubation period following infection was estimated at 17 days (95% confidence interval: 11–28). Disease persisted for longer than infection (median 21 (15–32) weeks) versus 17 (12–24) weeks), with an estimated median duration of post-infection inflammation of 5 (3–8) weeks. The duration of active disease showed a significant decline with age even after accounting for lower rates of re-infection and disease at older ages (p = 0.004). Measurements of levels of baseline IgA to epitopes in the major outer membrane protein of Chlamydia trachomatis were not significantly correlated with protection or more rapid clearance of infection.

Conclusions

The average duration of infection with Chlamydia trachomatis especially at younger ages is long. This contributes to the persistence and gradual return of trachoma after community-wide treatment with antibiotics.

Trachoma is an infectious disease of the eye that causes blindness in many of the poorest parts of the world. In this paper, we use a novel statistical approach to estimate the characteristics of this disease among people living in The Gambia who were examined every 2 weeks over a 6-month period. We found that the typical duration of infection with Chlamydia trachomatis and of clinically active disease were significantly longer than previously estimated. We tested different hypotheses about the natural history of trachoma that explain the relationship between infection and disease observed in the field. We also confirmed that disease lasts significantly longer among young children under 5 years old compared with older children and adults, even after accounting for high rates of re-infection in this age group, consistent with the development of immunity with age. The long duration of infection, especially among younger children, contributes to the persistence and gradual return of trachoma after community-wide treatment with azithromycin. This implies the need for high treatment coverage if infection is to be eliminated from a community, even where the return of infection after treatment is seen to be slow.

[Imbalance of alpha- and gamma-interferon levels in patients with herpetic keratitis]

The paper presents data on elevated serum and lacrimal fluid alpha- and gamma-interferon (INF) levels in patients with herpetic keratitis (HK) in the course of the disease depending on its clinical form and stage. A more significant increase in the levels of alpha- and gamma-INF was noted in the lacrimal fluid, which was indicative of the important role of local antiherpetic corneal and conjunctival protection. The determination of serum and lacrimal fluid IFN levels in patients with HK may be used to predict the clinical course of the disease.

Tear IgA-ELISA: a novel and sensitive method for diagnosis of ophthalmic cysticercosis

For the first time, presence of locally secreted specific IgA antibodies in tear specimen from human with ophthalmic cysticercosis is documented in the present study. The ELISA using Taenia solium metacestode excretory secretory (ES) antigen demonstrated a diagnostic level of IgA antibodies in tears with 100% sensitivity (6 out of 6 confirmed cases of ophthalmic cysticercosis) whereas, 25 of 34 (73.52%) clinically suspected cases were diagnosed positive. The ELISA using T. solium metacestode somatic antigen detected a diagnostic titre of IgA antibody in tears with a sensitivity of 50% (3 out of 6 confirmed cases). The specificity of the tear IgAELISA using T. solium metacestode somatic and ES antigens is observed to be 94.87% and 92.3%, respectively. Overall in tears, the ELISA using T. solium metacestode ES antigens for detection of IgA antibodies shows a higher diagnostic efficiency (93.33%) compared to that using T. solium metacestode somatic antigen (88.88%). The sensitivities of the ELISA for detection of IgA antibodies in tears is observed to be higher than that for detection of IgG antibodies in serum using either somatic or ES antigens of the parasite.

Multiple Chlamydiaceae species in trachoma: implications for disease pathogenesis and control

BACKGROUND

Chlamydia trachomatis is a unique obligate intracellular bacterium that remains the leading cause of sexually transmitted bacterial diseases and preventable blindness worldwide. Chronic ocular infections are referred to as trachoma, and predominate in developing countries. Since 2001, the World Health Organization has promoted control strategies including antibiotics, improved hygiene, and environmental measures with limited success. Consequently, a vaccine is urgently needed. Integral to vaccine design is an understanding of the interactions of the pathogen and host immune response. Various animal models of trachoma show that urogenital C. trachomatis strains and other species of the family Chlamydiaceae produce severe conjunctival inflammation and scarring similar to that of the ocular C. trachomatis strains. However, we do not know the extent of organisms that may be involved in human trachoma. Furthermore, C. trachomatis heat shock protein 60 (Hsp60) has been implicated in inflammation and conjunctival scarring but the role of other Chlamydiaceae Hsp60 in disease pathogenesis has not been examined. In this study, we set out to identify whether other Chlamydiaceae species are present in trachoma, and determine their association with severity of clinical disease and with mucosal and systemic immune responses to Chlamydiaceae species-specific Hsp60 to further investigate the immunopathogenesis of this blinding disease.

METHODS AND FINDINGS

We randomly selected nine of 49 households in a trachoma-endemic region of Nepal. Trachoma was graded, and real-time, quantitative (k)PCR was used to detect genomic DNA and cDNA (from RNA) for Chlamydiaceae ompA and 16S rRNA genes, respectively, from conjunctival swabs. IgG antibody responses to recombinant (r) Chlamydiaceae species-specific Hsp60 were determined for tears and sera. Surprisingly, all three species-C. trachomatis, Chlamydophila psittaci, and Chlamydophila pneumoniae-were detected in eight (89%) study households; one household had no members infected with C. pneumoniae. Of 80 (63%; n = 127) infected individuals, 28 (35%) had infection with C. psittaci, or C. pneumoniae, or both; single and dual infections with C. psittaci and C. pneumoniae were significantly associated with severe conjunctival inflammation (OR 4.25 [95% confidence interval (CI), 2.9-11.3], p = 0.009] as were single infections with C. trachomatis (OR 5.7 [95% CI, 3.8-10.1], p = 0.002). Of the 80 infected individuals, 75 (93.8%) were also positive for 16S rRNA by kPCR for the same organism identified by ompA. Individuals with tear IgG immunoreactivity to Chlamydiaceae rHsp60 were eight times more likely than individuals without tear immunoreactivity to be infected (95% CI 6.4-15.1; p = 0.003), 6.2 times more likely to have severe inflammation (95% CI 4.4-12.6; p = 0.001), and 5.7 times more likely to have scarring (95% CI 3.9-11.1; p = 0.019) while individuals with serum IgG immunoreactivity were 4.1 times more likely to be infected (95% CI 3.1-10.1; p = 0.014).

CONCLUSIONS

We provide substantial evidence for the involvement of C. psittaci and C. pneumoniae, in addition to C. trachomatis, in trachoma. The distribution of Chlamydiaceae species by household and age suggests that these infections are widespread and not just sporadic occurrences. Infection with multiple species may explain the failure to detect chlamydiae among active trachoma cases, when only C. trachomatis is assayed for, and the failure of clinically active cases to resolve their disease following what would be considered effective C. trachomatis treatment. The evidence for viable (RNA-positive) organisms of all three species in single and coinfections, the significant association of these infections with severe inflammation, and the significant association of tear and serum IgG responses to Chlamydiaceae Hsp60 with inflammation and scarring, support the role of all three species in disease pathogenesis. Thus, while our findings should be confirmed in other trachoma-endemic countries, our data suggest that a reevaluation of treatment regimens and vaccine design may be required. Understanding the full impact of Chlamydiaceae species on the epidemiology, immunopathology, and disease outcome of trachoma presents a new challenge for Chlamydiaceae research.

[The role of chemokines CCL3/ MIP-1 alfa and CCL4/ MIP-1 beta in pathogenesis of dry eye syndrome]

PURPOSE

To evaluate the concentration of chemokines CCL3/ MIP-1 alfa and CCL4/ MIP-1 beta in film tears in patients with dry eye syndrome.

MATERIAL AND METHODS

Tears samples were collected from 62 patients with dry eye syndrome and 18 patients from control group. The concentration of chemokines in film tears were determined by immunoenzymatic assay ELISA.

RESULTS

We found statistically increased levels of chemokines CCL3/ MIP-1 alfa and CCL4/ MIP-1 beta in film tears of patients with dry eye syndrom compared with control group.

CONCLUSION

Inflammation may play role in pathogenesis of dry eye syndrome.

The differences of tear function and ocular surface findings in patients with atopic keratoconjunctivitis and vernal keratoconjunctivitis

BACKGROUND

The pathogenesis of the ocular surface disease in atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC) has not been fully understood. We tried to clarify the differences in the ocular surface status in patients with AKC, VKC, and healthy control subjects.

METHODS

Twenty-four eyes of 12 AKC patients, 12 eyes of six VKC patients, and 20 eyes of 10 normal control subjects were studied. The subjects underwent corneal sensitivity measurements, Schirmer test, tear film break-up time (BUT), vital staining of the ocular surface, conjunctival impression and brush cytology. Impression cytology samples underwent periodic acid Schiff staining for goblet cell density, squamous metaplasia grading, and immunohistochemical staining for MUC1, 2, 4, and 5AC. Brush cytology specimens underwent staining for inflammatory cell counting and Real Time PCR for MUC1, 2, 4, and 5AC mRNA expression.

RESULTS

The mean BUT, corneal sensitivity, and conjunctival goblet cell density values in AKC patients were significantly lower compared with VKC patients and control subjects. The squamous metaplasia grades in eyes with AKC were significantly higher compared to eyes with VKC and controls. The inflammatory cell response in brush cytology specimens was different between patients with AKC and VKC. Eyes with AKC showed significantly higher MUC1, 2 and 4 and lower MUC5AC mRNA expression compared to eyes with VKC.

CONCLUSIONS

Differences of the infiltrates, higher level of tear instability, lower corneal sensitivity, up-regulation of MUC1, 2, and 4, and down regulation of MUC5AC were important differential features of the ocular surface disease in AKC compared with VKC.

Human tear fluid protects against Pseudomonas aeruginosa keratitis in a murine experimental model

Pseudomonas aeruginosa keratitis is an acute sight-threatening infection. We previously reported that human tear fluid could protect individual human corneal epithelial cells in vitro against invasion by and cytotoxicity due to clinical and laboratory isolates of P. aeruginosa and that the protective mechanism was independent of bacteriostatic activity. In the present study, we examined the effects of human tear fluid in vivo. Tears were collected from healthy human volunteers and were studied in vivo in mice. The effects on the virulence of both invasive and cytotoxic clinical isolates of P. aeruginosa were examined. Tear fluid was found to reduce the severity of disease when corneas were challenged with cytotoxic bacteria immediately after scratch injury, and it completely protected against susceptibility to infection by a cytotoxic strain in a model in which corneas were infected during the healing process 6 h after scratching. Visible protection correlated with the inhibition of bacterial colonization 1, 4, and 48 h postinoculation. Tear fluid also significantly reduced the severity of infections caused by invasive P. aeruginosa in the 6-h-healing model. This result also coincided with significantly reduced bacterial colonization at 48 h. In vitro, human tear fluid significantly reduced the ability of invasive and cytotoxic bacteria to translocate across corneal epithelia and increased transepithelial resistance with or without bacterial inoculation. These data show that human tear fluid can protect against P. aeruginosa corneal infection in vivo and that the mechanism likely involves enhanced epithelial barrier function in addition to protection of individual epithelial cells against bacterial internalization and cytotoxicity.

Ocular surface and intraocular inflammation are related in SS-I and rheumatoid arthritis patients

The purpose of this study is to evaluate the intraocular inflammation at a sub clinical level, in patients suffering from Sjogren's syndrome (SS-I) and Rheumatoid Arthritis (RA), to relate it with the ocular surface status and to verify the diagnostic performance of the method. Twenty-eight patients suffering from SS-I, 31 patients suffering from RA and 31 normal subjects matched in age and gender were included in the study. A Kowa 500F laser cell flare meter was utilized to quantify the aqueous cells and flare in vivo, ocular surface inflammation was graded by conjunctival cytology and dosage of serum albumin in tears, eye dryness was scored with Tear Function Index. All data resulted significantly different in both SS-I and RA patients vs. control group and also different comparing SS-I vs. RA patients group, except for the Flare values. A blood-aqueous barrier breakdown occurs either in SS-I and RA patients; the degree of the damage is related with ocular surface inflammation and dryness. We recommend the aqueous flare be analysed in those rheumatic patients where an ocular surface inflammation has been documented.

[A systemic approach to the diagnosis and treatment of allergic conjunctivitis]

The diagnosis of allergic conjunctivis begins by a meticulous questioning emphasizing the existence of ocular itching, the way of evolution of the signs and allergic preceeding. The examination searchs after follicles and papillae of the conjunctiva who usually go with serous discharges, blepharitis and keratitis. So four clinical forms may be described the chronic conjunctivitis, the vernal kerato-conjunctivitis, the atopic conjunctivitis and the giganto-papillar conjunctivitis. For the treatment, all non specific signs of allergy must be eliminated, the focal infections also and allergic substance isolated. If evolution is worse, an antiallergic eye drop is given until the disappearance of all the physical signs. In the same time, steroids and anti H1 drugs must be avoided. In case of failure, the specialist in allergy will be helpful to exam the patient.

Multiple cytokines in human tear specimens in seasonal and chronic allergic eye disease and in conjunctival fibroblast cultures

BACKGROUND

Several cytokines are involved in the recruitment and activation of inflammatory cells in ocular allergic diseases. The purpose of the study was to assay multiple cytokines and chemokines in tears, to compare subgroups of allergic conjunctivitis (AC) with controls, and in culture supernatants to determine whether conjunctival fibroblasts produce some of these cytokines.

METHODS

Fifty to one hundred microlitre tears were obtained from patients with active seasonal allergic conjunctivitis (SAC; n=12), vernal keratoconjunctivitis (VKC; n=18), atopic keratoconjunctivitis (AKC; n=6) and non-atopic controls (n=14). Primary conjunctival fibroblasts grown in vitro were stimulated with IL-4, IL-13 or TNF-alpha for 24 h. Cell-free tear and culture supernatants were assayed for IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IFN-gamma, TNF-alpha, eotaxin, MCP-1 and RANTES using multiplex bead analysis. Induction of chemokine gene expression was determined by PCR.

RESULTS

IL-1beta, IL-2, IL-5, IL-6, IL-12, IL-13, MCP-1 were increased in all tears groups compared with controls, with highly significant correlations between many of these molecules. In addition IL-4, IFN-gamma, and IL-10 were elevated in SAC and VKC, while eotaxin and TNF-alpha were only increased in VKC. IL-6, IL-8, MCP-1, RANTES and eotaxin were detected from fibroblasts cultures, and were all up-regulated by TNF-alpha. By PCR, fibroblasts expressed MCP-1 transcripts constitutively, whereas IP-10 and Mig were up-regulated by TNF-alpha.

CONCLUSIONS

Differential cytokine levels support tears as a useful indicator of immune mechanisms occurring during AC. The striking similarities in chemokine profiles between tears and fibroblasts suggest these cells as likely sources of chemokines in tears.

Oral immunization with Acanthamoeba castellanii mannose-binding protein ameliorates amoebic keratitis

Acanthamoeba castellanii mannose-binding protein (MBP) mediates adhesion of the amoebae to corneal epithelial cells, a key first step in the pathogenesis of Acanthamoeba keratitis (AK), a devastating corneal infection. In the present study, we demonstrate that oral immunization with recombinant MBP ameliorates AK in a hamster animal model and that this protection is associated with the presence of elevated levels of anti-MBP immunoglobulin A in the tear fluid of the immunized animals.

Measurement of inflammatory cytokines by multicytokine assay in tears of patients with glaucoma topically treated with chronic drugs

AIM

To investigate the ocular surface inflammatory response to chronic topical treatments in patients with glaucoma by measuring the cytokine level in tears using multiplex bead analysis.

METHODS

Tear samples were collected from 21 patients with glaucoma and 12 healthy volunteers. Tears were analysed for the presence of 17 cytokines: interleukin (IL)1beta, IL2, IL4, IL5, IL6, IL7, IL8, IL10, IL12, IL13, IL17, granulocyte-colony stimulating factor, granulocyte-macrophage stimulating factor, interferon (INF)gamma, monocyte chemotactic protein (MCP)1, macrophage inflammatory protein 1beta and tumour necrosis factor (TNF)alpha. The cytokines in each sample of tears were measured using multiplex bead analysis with microspheres as solid support for immunoassays.

RESULTS

In the tears of treated patients, proinflammatory cytokines (IL1beta, IL6, IL12, TNFalpha) were significantly increased compared with controls. T helper (Th)1 (INFgamma, IL2) and Th2 (IL5, IL10, IL4) type cytokines were also significantly higher (p<0.05); however, the most marked increase was observed with Th1 cytokines. The expression of chemokine IL8 and MCP1 was also increased in the treated group.

CONCLUSION

This study shows that pro-inflammatory cytokine secretion by conjunctival cells is increased in response to topical treatments for glaucoma. The characterisation of cytokines in tears was previously limited by the small volume attainable, a limitation that has been overcome by multiplex analysis.

Cytomegalovirus antibodies in tear fluid of patients with retinitis

The diagnosis of cytomegalovirus retinitis (CMV-R) is difficult and usually based on clinical criteria or invasive diagnostic procedures. The purpose of this study was to investigate a possible association between CMV-R and specific anti-CMV antibodies in tears. Paired tear and serum samples were obtained from 96 individuals, which included 20 children with congenital CMV infection and chorioretinitis, 56 adults with retinitis with clinical signs suggestive of viral infection, and 20 healthy control subjects, and were tested for CMV antibodies using ELISA. The prevalence of anti-CMV antibodies in tears was found to be 80% (16/20) in children, 35% (20/56) in adults, and 5% (1/20) in control subjects. Furthermore, high antibody levels were detected in 35% (7/20) of children and 10.7% (6/56) of adults with retinitis, and were not found in control subjects. There was a strong association between high tear levels of anti-CMV antibodies and active ocular infection. No correlations were found between tear and serum antibodies. ELISA sensitivity was 80% and specificity 95%. Further studies are needed to compare the tear and intraocular levels of CMV-specific antibodies in patients with retinitis to find out if CMV antibody testing in tear fluid could substitute for more invasive diagnostic procedures.

Comparative analysis of autoantibodies against a-fodrin in serum, tear fluid, and saliva from patients with Sjögren's syndrome

OBJECTIVE

To evaluate levels of IgA and IgG antibodies against a-fodrin in serum, tear fluid, and saliva and compare them with anti-Ro and anti-La antibody levels in the same samples of patients with Sjögren's syndrome (SS).

METHODS

Samples from 25 patients with SS (17 primary and 8 secondary), 8 patients with systemic lupus erythematosus (SLE), and 7 patients with rheumatoid arthritis (RA) as well as 20 healthy blood donor controls were collected. Antibodies were measured using ELISA.

RESULTS

Although 40% of patients with primary SS had IgG anti-a-fodrin in their sera, it was also found in 36% and 32% of samples of their tear fluid and saliva, respectively. IgA a-fodrin antibodies were detected in 32% of SS sera, 20% of tear fluid samples, and 32% of saliva samples. Although the level of IgG anti-a-fodrin was significantly greater in serum, tear fluid, and saliva of SS patients compared to controls (p < 0.001), a significant difference was observed only in serum and saliva. While anti-Ro was detected in 48%, 56%, and 24% of serum, tear fluid, and saliva samples, respectively, anti-La was found in 40%, 44%, and 28%. Significant association was observed between serum IgG antibodies against a-fodrin and dry eye symptom score and rose bengal staining score. A negative association was also noted between tear IgA antibodies against a-fodrin and Schirmer I test.

CONCLUSION

Correlation of IgG and IgA antibodies against a-fodrin with the severity of eye involvement suggests that these autoantibodies may be considered activation markers of SS.

Antibody Array-Generated Cytokine Profiles of Tears of Patients with Vernal Keratoconjunctivitis or Giant Papillary Conjunctivitis

PURPOSE

To investigate differences in the cytokine and chemokine profiles of patients with vernal keratoconjunctivitis (VKC) or giant papillary conjunctivitis (GPC).

METHODS

The study included six patients (six eyes) with VKC, five patients (five eyes) with GPC, and five healthy volunteers (five eyes) as controls. None of the patients had received any anti-allergic treatment prior to this study. One patient with VKC was given a tear examination to evaluate the effect of anti-inflammatory treatment with a steroid on the tear cytokine profile about the treatment. Tear samples were collected with the Schirmer I method, using filter paper. Tear samples were eluted and analyzed by an antibody array system for inflammation-related factors, including cytokines and chemokines.

RESULTS

In the patients with VKC, four inflammation-related factors, eotaxin, interleukin (IL)-11, monocyte chemoattractant protein (MCP)-1, and macrophage-colony stimulating factor (M-CSF) increased to four times the values in the control group, and seven inflammation-related factors, eotaxin-2, IL-4, IL-6, interleukin-6 soluble receptor (IL-6sR), IL-7, macrophage inflammatory protein (MIP)-1delta, and tissue inhibitor of metalloproteinases (TIMP)-2, increased to eight times the control values. In the patients with GPC, three inflammation-related factors, IL-6, M-CSF, and monokine-induced gamma interferon (MIG), increased to four times those in the control group, and five inflammation-related factors, eotaxin-2, IL-6sR, IL-11, MIP-1delta, and TIMP-2, increased to eight times the control values. The increase in IL-6sR relative to the controls was statistically significant in both the VKC and GPC groups. The increase in eotaxin-2 was significant only in the VKC group, and that in TIMP-2 was significant only in the GPC group, compared with the controls.

CONCLUSIONS

The present study demonstrated the presence of crucial cytokines, soluble cytokine receptors, and chemokines in tears of patients with VKC and GPC. In particular, IL-6sR increased significantly in both the VKC and GPC groups, whereas eotaxin-2 increased significantly only in the VKC group. Thus, IL-6sR may play an important pathophysiological role in giant papillary proliferation in VKC and GPC, and eotaxin-2 may play an important role in eosinophilic inflammation in VKC.

Mucins and TFF peptides of the tear film and lacrimal apparatus

The three-dimensional organization of the tear film, which is produced and drained by the different structures of the ocular adnexa, is essential for maintainance and protection of the ocular surface. This is facilitated by a class of large, highly glycosylated, hydrophilic glycoproteins, the mucins, which are usually expressed in association with a class of peptides having a well-defined, structurally conserved trefoil domain, the mammalian trefoil factor family (TFF) peptides. In this review, the latest information regarding mucin and TFF peptide function and regulation in the human lacrimal system, the tear film and the ocular surface is summarized with regard to mucous epithelia integrity, rheological and antimicrobial properties of the tear film and tear outflow, age-related changes and certain disease states such as dry eye, dacryostenosis and dacryolith formation.

Identification of tear lipocalin as a novel autoantigen target in Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration and tissue damage mainly confined to the salivary and lacrimal glands, resulting in dryness of mouth and eyes. Since different epithelial cells of exocrine and non-exocrine tissues are primarily affected, an autoimmune reaction against antigens commonly expressed in epithelial cells is believed to play a pathogenic role. To identify novel autoantigen targets associated with the systemic involvement in SS, we screened a random peptide library with pooled IgG immunoglobulins derived from patients with primary SS. Among the identified peptides, one was recognized by the majority of patients' sera, but not by sera of normal donors and of patients with other autoimmune diseases. The peptide showed homology with an Epstein-Barr Virus (EBV) derived protein and with tear lipocalin, a protein highly expressed in tears and saliva, and with alpha-fodrin, a cytoskeleton protein considered an important autoantigen target in SS. Anti-peptide antibodies affinity purified from patients' sera recognize the viral protein, tear lipocalin and alpha-fodrin. Our findings suggest that EBV infection may be linked to the pathogenesis of SS and that tear lipocalin can be considered a novel and yet unidentified autoantigen in SS.