Blockage of complement regulators in the conjunctiva and within the eye leads to massive inflammation and iritis

The open environment of the eye is continuously subject to an influx of foreign agents that can activate complement. Decay-accelerating factor (DAF), membrane cofactor protein (MCP) and CD59 are regulators that protect self-cells from autologous complement activation on their surfaces. They are expressed in the eye at unusually high levels but their physiological importance in this site is unstudied. In the rat, a structural analogue termed 5I2 antigen (5I2 Ag) has actions overlapping DAF and MCP. In this investigation, we injected F(ab')2 fragments of 5I2 mAb into the conjunctiva and aqueous humor, in the latter case with and without concomitant blockage of CD59. Massive neutrophilic infiltration of the stroma and iris resulted upon blocking 5I2 Ag activity. Frank necrosis of the iris occurred upon concomitant intraocular blockage of CD59. C3b was identified immunohistochemically, and minimal effects were seen in complement-depleted animals and in those treated with non-relevant antibody. The finding that blockage of 5I2 Ag function in periocular tissues and within the eye causes intense conjunctival inflammation and iritis demonstrates the importance of intrinsic complement regulators in protecting ocular tissues from spontaneous or bystander attack by autologous complement.

Pathogenesis of mousepox in H-2(d) mice: evidence for MHC class I-restricted CD8(+) and MHC class II-restricted CD4(+) CTL antiviral activity in the lymph nodes, spleen and skin, but not in the conjunctivae

Genetically sensitive mice (i.e. H-2(d) haplotype) infected with a natural mouse pathogen named ectromelia virus (EV) can develop a mousepox. Virus replicates well in the skin, next in the draining lymph nodes (DLNs) and then in the spleen and liver, where it may induce extensive necrosis with strong inflammatory reaction. It is well known from the studies defined on some other viruses that a correlation, functional link and powerful help exist between MHC class I-restricted CD8(+) and MHC class II-restricted CD4(+) virus-specific cytotoxic T lymphocytes (CTLs). However, in the case of mousepox the role of CD4(+) CTLs is still controversial and some reports support the notion that induction of EV-specific CD4(+) CTLs is nonessential for the generation of virus-specific immune response. Consequently, this study was designed to evaluate EV-specific CD8(+) and CD4(+) CTL activity in the DLNs, spleen, skin and conjunctivae of BALB/c (H-2(d)) mice at 7 and 14 days p.i. with Moscow strain of EV. By using bulk cytotoxicity assay and immunosurgery of effector T cells with mAb specific for CD4(+) and/or CD8(+) T cells our data show that EV-specific CD8(+) CTLs predominated in DLNs and spleen at 7 days (67 and 66% of total CTLs, respectively) and 14 days p.i. (63 and 69% of total CTLs, respectively). In contrast, we found that EV clearance from the cutaneous lesions during mousepox is CD4(+) CTL-dependent at 7 days p.i. (59% of total CTLs), whereas at 14 days p.i. CD8(+) CTLs predominated in the epidermis, accounting for 72% of the total EV-specific CTLs. Our studies showed that the population of EV-specific CTLs is heterogeneous and contains cells of both phenotypes: CD8(+) and CD4(+). However, these effector cells did not express a similar tendency in cytotoxic activity in the DLNs, spleen and skin in comparison to the conjunctivae where EV-specific CD8(+) and CD4(+) CTLs were not detected at 7 days p.i. and at peak of mousepox conjunctivitis (14 days p.i.). Our results are discussed in terms of the value of EV to study antiviral CTL responses in the genetically susceptible host.

Olopatadine inhibits anti-immunoglobulin E-stimulated conjunctival mast cell upregulation of ICAM-1 expression on conjunctival epithelial cells

BACKGROUND

Olopatadine is a clinically effective dual-action (antihistamine/mast cell stabilizer) ophthalmic antiallergic agent. We have previously demonstrated that olopatadine inhibits tumor necrosis factor alpha (TNF-alpha) release from purified human conjunctival mast cells and that supernates from stimulated mast cells upregulate intercellular adhesion molecule 1 (ICAM-1) expression on epithelial cells via TNF-alpha.

OBJECTIVE

To investigate the effect of olopatadine on the TNF-alpha-mediated mast cell upregulation of ICAM-1 expression on conjunctival epithelial cells.

METHODS

Human conjunctival mast cells and epithelial cells were purified (>95%) from cadaveric tissue. Conjunctival mast cells were preincubated with three doses (30, 300, or 3,000 microM) of olopatadine or buffer alone for 30 minutes followed by 90-minute challenge with anti-immunoglobulin E (10 microg/mL). The resulting supernates were incubated with conjunctival epithelial cell monolayers for 24 hours along with the following treatments: rTNF-alpha, mast cell supernate + anti-TNF-alpha, recombinant (r)TNF-alpha + anti-TNF-alpha, the three doses of olopatadine, olopatadine supernates, olopatadine supernates + rTNF-alpha. ICAM-1 expression was measured using flow cytometry.

RESULTS

Anti-IgE-stimulated human conjunctival mast cell supernates upregulated human conjunctival epithelial cell ICAM-1 expression to the same extent as rTNF-alpha. ICAM-1 upregulation could be completely blocked with anti-TNF-alpha. Preincubation of conjunctival mast cells with olopatadine significantly blocked the ability of supernates to upregulate ICAM-1 on conjunctival epithelial cells. ICAM-1 expression could be restored by adding rTNF-alpha to the olopatadine-preincubated mast cell supernates.

CONCLUSIONS

Olopatadine is able to significantly decrease the anti-immunoglobulin E mast cell supernate-mediated upregulation of ICAM-1 on human conjunctival epithelial cells in vitro. This seems to be mediated through an effect on a TNF-alpha-specific mechanism.

Immunology of trachomatous conjunctivitis

Trachoma, a chronic follicular conjunctivitis caused by infection with Chlamydia trachomatis, is a leading cause of preventable blindness. The blinding complications are associated with progressive conjunctival scarring. Our immunohistochemical studies of conjunctival biopsies from children with active trachoma demonstrated the presence of both humoral and cell-mediated immune responses. Antichlamydial antibodies can neutralize Chlamydiae, block attachment and internalization of the organism, and can produce partial immunity. Our observations suggest a role for T-lymphocytes and cell mediated immunity in the genesis of conjunctival scarring. Conjunctival epithelial cells expressed major histocompatibility complex (MHC) class II antigens which might allow conjunctival epithelial cells to present Chlamydial antigens to T-cells enhancing the immune response. The epithelial cells expressing MHC class II antigens might present autoantigens to T-cells leading to induction of an autoimmune reaction. We have demonstrated that the conjunctival epithelial cells from patients with trachoma expressed interleukin (IL)-1 alpha and IL-1 beta. In addition, we have detected cytoplasmic expression of IL-1 alpha, IL-1 beta, tumor necrosis factor alpha and platelet-derived growth factor by macrophages. These cytokines have the potential to influence the remodeling and fibrosis observed in trachoma. Alterations of extracellular matrix components and collagen metabolism occur in the conjunctival tissue from patients with trachoma. New collagen type V formation was noted in active trachoma and scarred trachoma. The conjunctival tissue from patients with active trachoma contained increased amounts of collagen types I, III and IV. Scarred trachoma is characterized by marked increase in basement membrane--collagen IV and marked decrease in collagen types I and III. In addition, we demonstrated increased activity of gelatinase B and numbers of inflammatory cells containing gelatinase B in trachoma patients suggesting that this enzyme might be involved in matrix degradation and promotion of conjunctival scarring in trachoma.

Chicken serum albumin (Gal d 5*) is a partially heat-labile inhalant and food allergen implicated in the bird-egg syndrome

BACKGROUND

Chicken serum albumin (alpha-livetin) has been implicated as the causative allergen of the bird-egg syndrome. However, the clinical relevance of sensitization to this allergen has not been confirmed by specific challenge tests and environmental sampling. We investigated whether chicken albumin can be detected in air samples collected in a home with birds, and whether sensitization to this protein may cause respiratory and food allergy symptoms. The heat resistance of chicken albumin and the possible cross-reactivity with conalbumin were also investigated.

METHODS

We studied eight patients with food allergy to egg yolk who also suffered from respiratory symptoms (rhinitis and/or asthma) caused by exposure to birds. Sensitization to egg yolk and bird antigens was investigated by skin and serologic tests. Hypersensitivity to chicken albumin was confirmed by specific bronchial, conjunctival, and oral provocation tests.

RESULTS

All patients had positive skin tests and serum IgE against egg yolk, chicken serum, chicken meat, bird feathers, and chicken albumin. The presence of airborne chicken albumin in the domestic environment was confirmed. Specific bronchial challenge to chicken albumin elicited early asthmatic responses in six patients with asthma. An oral challenge with chicken albumin provoked digestive and systemic allergic symptoms in the two patients challenged. IgE reactivity to chicken albumin was reduced by 88% after heating at 90 degrees C for 30 min. ELISA inhibition demonstrated only partial cross-reactivity between chicken albumin and conalbumin.

CONCLUSION

Chicken albumin (Gal d 5) is a partially heat-labile allergen that may cause both respiratory and food-allergy symptoms in patients with the bird-egg syndrome.

Autoantibodies to human alpha6 integrin in patients with oral pemphigoid

Mucous membrane pemphigoid or cicatricial pemphigoid is a mucocutaneous blistering disease characterized by autoantibodies to different molecules in the basement membrane zone. Our objectives were to identify the target antigen recognized by sera from 20 untreated patients with pemphigoid disease limited to the oral cavity, and to determine the pathogenicity of autoantibodies in oral pemphigoid, with an organ culture model. We conducted indirect immunofluorescence, immunoblot, and immunoprecipitation assays, with accompanying absorption experiments, using normal human skin, conjunctiva and gingiva, bovine gingiva and a tumor cell line, which were reacted with sera from patients with oral pemphigoid, anti-alpha6 antibody, and control sera. Sera of oral pemphigoid patients selectively and specifically bound to human alpha6 integrin, a 120-kDa protein present in gingiva and the tumor cell line. Oral pemphigoid sera and anti-alpha6 antibody produced separation of epithelium from basement membrane (blister formation) of normal human buccal mucosa, after 48 hours, in organ culture.

Cyclosporine effects on clinical findings and impression cytology specimens in severe vernal keratoconjunctivitis

PURPOSE

To investigate the possible effects of topical cyclosporine eye drops 2% (CsA) on conjunctival immune cells obtained by impression cytology technique and to determine the clinical relevance of this effect if present.

METHODS

Ten consecutive patients with severe, resistant, and active vernal keratoconjunctivitis (VKC) were included in this study. All of them were treated with 2% of topical CsA drops. Symptom and clinical scores and conjunctival impression cytology specimens were obtained both before and following treatment. Impression cytology specimens were stained with anti-CD8+, CD4+, CD45RA+, and CD23+ antibodies and the percentages of positive cells were counted. The results were compared and correlation analyses were performed between clinical and laboratory data.

RESULTS

Significant reductions were observed with respect to the percentages of CD4+ and CD23+ cells in the conjunctival impression cytology specimens and clinical and symptom scores following treatment with topical CsA, while no change occurred in the percentages of CD8+ and CD45RA+ cells. The percentages of CD4+ and CD23+ cells showed good correlations with symptom and clinical scores.

CONCLUSION

Topical CsA treatment is a very effective alternative in severe VKC cases in clinical ground and clinical efficacy of topical CsA treatment in severe, resistant VKC cases can be (at least partly) related to reduction of the CD23+ and CD4+ cell populations on the conjunctival surface.

[Zinsser-Engman-Cole syndrome (dyskeratosis congenita) with severe sicca syndrome, panuveitis and corneal perforation--a case report]

BACKGROUND

Zinsser-Engman-Cole syndrome (Z.E.C.) is a very rare type of ectodermal dysplasia, inherited in X-linked recessive manner and characterised by poikiloderma, nail dystrophy, lingual leucoplakia, bone marrow hypoplasia, hyperkeratosis and hyperhidrosis of planta and palms, dental anomalies and caries, premature grey hair.

PATIENT AND METHODS

We report on a 46-year-old man who presented with occlusion of lacrimal puncta, trichiasis, severe dry eye, recurrent corneal ulceration and perforation, uveitis. HLA typing, flow cytometry of peripheral lymphocytes, bone marrow biopsy, conjunctival biopsy and extensive laboratory evaluation towards autoimmune and infectious diseases were performed.

RESULTS

CD4+ T cells fraction was decreased, CD8+ and CD3+ HLA DR+ elevated. The patient was HLA-B27 positive. Laboratory studies revealed increased erythrocyte sedimentation rate and C-reactive protein level, hypochromic and hypoplastic anaemia, negative serum titers of antibodies to Epstein-Barr virus, HIV, HTLV-I, toxoplasma gondii and treponema pallidum, repeated titers to cytomegalovirus, herpes simplex and herpes zoster viruses--IgM negative, IgG positive. Corneal perforation was treated with amniotic membrane transplantation and corneal transplantation.

CONCLUSION

The defect in cell-mediated immune mechanisms in Z.E.C. syndrome explains the corneal perforation, sicca syndrome and uveitis, first reported in this syndrome.

Conjunctival mast cells in ocular allergic disease

Allergic eye disease is a common clinical problem adversely affecting the quality of life for millions of sufferers. This ocular process is associated with IgE-mediated conjunctival inflammation leading to signs of immediate hypersensitivity including redness, itching, and tearing. Pathologic studies have shown that the conjunctiva contains mast cells that when sensitized with IgE antibody and exposed to environmental allergens can release mediators of allergic inflammation. The type, release kinetics, and concentration of these mediators in the conjunctiva have not been completely characterized. The ability to isolate and purify mast cells and epithelial cells from human conjunctival tissue has permitted the study of mediator release and cell-to-cell signaling in this tissue. Our laboratory has developed in vitro and in vivo models to better understand how inflammatory cells are recruited to and infiltrate conjunctival tissues. These models demonstrate that mast cell activation may supply sufficient cytokine signaling to initiate and direct the well-orchestrated trafficking of eosinophils to the ocular surface, facilitate their adhesion, and cause release of potent mediators of ocular inflammation.

The relative contribution of mast cell subsets to conjunctival TH2-like cytokines

PURPOSE

To investigate the distribution of the T-helper (TH)2-like cytokines, interleukin (IL)-4, IL-5, IL-6, and IL-13 between mast cell subsets in conjunctival biopsy specimens from normal subjects and those with seasonal allergic conjunctivitis (SAC) during and outside of the grass pollen season.

METHODS

Sequential and double in situ hybridization (ISH) and immunohistochemistry (IHC) were performed on thin sections of human conjunctiva to determine the colocalization of the immunoreactivity of IL-4, IL-5, IL-6, and IL-13 to mast cell subsets in normal subjects and subjects with atopy and to detect IL-4 mRNA in conjunctival mast cells.

RESULTS

More than 90% of IL-4+-immunoreactive cells were observed to be mast cells in conjunctival biopsy specimens from all patient groups. The majority of IL-5+, IL-6+, and IL-13+ cells were also noted to be mast cells for each group. IL-4 preferentially colocalized to the tryptase+-chymase+ mast cell phenotype (MC(TC)) with MC(TC) cells comprising 93.3% of cytokine+ mast cells in symptomatic SAC (P = 0.0017), 89.2% in asymptomatic SAC (P = 0.0008), and 77.8% in normal subjects (P = 0.0472). IL-13 appeared to colocalize preferentially to the MC(TC) phenotype and IL-5 and IL-6 to the MC(T) phenotype. ISH showed that 75.8% of mast cells in normal subjects, 78.7% in subjects with symptomatic SAC, and 18.7% in subjects with asymptomatic SAC expressed mRNA for IL-4.

CONCLUSIONS

Conjunctival mast cells are an important source of IL-4, IL-5, IL-6, and IL-13 immunoreactivity, with preferential colocalization of IL-4 and IL-13 on the MC(TC) subset and IL-5 and IL-6 to the MC(T) subset. This evidence suggests that differences in protease phenotype may also reflect functional differences evidenced by the different patterns of cytokine distribution.

Inflammation and clearance of Chlamydia trachomatis in enteric and nonenteric mucosae

Immunization(s) fostering the induction of genital mucosa-targeted immune effectors is the goal of vaccines against sexually transmitted diseases. However, it is uncertain whether vaccine administration should be based on the current assumptions about the common mucosal immune system. We investigated the relationship between mucosal sites of infection, infection-induced inflammation, and immune-mediated bacterial clearance in mice using the epitheliotropic pathogen Chlamydia trachomatis. Chlamydial infection of the conjunctival, pulmonary, or genital mucosae stimulated significant changes in tissue architecture with dramatic up-regulation of the vascular addressin, VCAM, a vigorous mixed-cell inflammatory response with an influx of alpha4beta1+ T cells, and clearance of bacteria within 30 days. Conversely, intestinal mucosa infection was physiologically inapparent, with no change in expression of the local MAdCAM addressin, no VCAM induction, no histologically detectable inflammation, and no tissue pathology. Microbial clearance was complete within 60 days in the small intestine but bacterial titers remained at high levels for at least 8 months in the large intestine. These findings are compatible with the notion that VCAM plays a functional role in recruiting cells to inflammatory foci, and its absence from the intestinal mucosa contributes to immunologic homeostasis at that site. Also, expression of type 1 T cell-mediated immunity to intracellular Chlamydia may exhibit tissue-specific variation, with the rate and possibly the mechanism(s) of clearance differing between enteric and nonenteric mucosae. The implications of these data for the common mucosal immune system and the delivery of vaccines against mucosal pathogens are discussed.

In vitro organ culture model for mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP), also known as cicatricial pemphigoid, is a rare vesiculobullous disease of mucosal tissues, which involves the oral, ocular, and other mucous membranes. We have studied a group of patients with histologically and immunopathologically proven pemphigoid disease involving predominantly the conjunctiva and oral mucosa in addition to other mucosae. The purpose of our study was to (i) demonstrate the specific binding of autoantibodies present in the sera of patients with MMP to normal human oral mucosa by indirect immunofluorescence (IIF) and (ii) to study the role of these autoantibodies in the pathogenesis of subepithelial blister formation using normal human buccal mucosa in organ culture. Serum and IgG fractions from MMP patients showed homogeneous smooth linear binding along the basement membrane zone (BMZ) of the normal buccal mucosa on IIF. Serum from pemphigus vulgaris patients showed intercellular or keratinocyte cell surface staining. BMZ separation developed at 48 h after incubation of normal human buccal mucosa in organ culture, with serum or IgG from patients with MMP but not after addition of normal human serum. Addition of pemphigus vulgaris serum to the in vitro culture of normal human buccal mucosa showed acantholysis. This preliminary report suggests that circulating autoantibodies may have an important role in the pathogenesis of MMP. This in vitro organ culture model will facilitate enhancing our understanding of various molecular events during the process of blister formation in MMP and in the study of other mucosal diseases.

Presence and possible significance of immunohistochemically demonstrable metallothionein expression in pterygium versus pinguecula and normal conjunctiva

PURPOSE

To investigate metallothionein (MT) expression in pterygium, pinguecula and normal conjunctiva and define its possible significance in this area of the eye. In order to further elucidate the mechanism of MT expression we correlated it with lymphocyte subpopulations (T4, T8), macrophages (CD68), Langerhans' cells (S100) and the proliferation-associated indices (PCNA, Ki67).

METHODS

Eighty-five surgically excised pterygia, 15 pingueculae and 20 normal conjunctivae were immunohistochemically studied by the avidin-biotin (ABC) method. A monoclonal antibody (E9) against a conserved epitope of I and II isoforms of MT was used on formalin-fixed, paraffin-embedded tissues. Statistical analysis was performed using the SPSS statistical package.

RESULTS

Epithelial MT expression was detected in all 120 cases examined and in most of them both nuclear and cytoplasmic immunoreactivity was present. Nevertheless no statistically significant difference of MT expression was found between the three types of tissue. A statistically significant positive correlation between MT expression and lymphocyte subsets, macrophages and Langerhans' cells was found in pterygium. On the contrary, we did not find any statistical correlation in pinguecula and normal conjunctiva. In all three types of tissues MT expression was also positively correlated with the proliferation-associated indices.

CONCLUSION

The data suggest that there is immunohistochemically demonstrable MT expression in the epithelium of pterygium, but also of normal conjunctiva and pinguecula. MT may serve a photoprotective role in this region. In pterygium in particular, the biochemical pathway of MT synthesis seems interestingly to cross the pathways of cell proliferation, inflammation and immune activation.

Local ocular immunotherapy for experimental allergic conjunctivitis

PURPOSE

We studied the efficacy of eyedrops as local ocular immunotherapy against experimental allergic conjunctivitis.

METHODS

Guinea pigs were sensitized with an intraperitoneal injection of ovalbumin (OA). Three weeks after the sensitization, a low concentration (10 microg/mL) of OA eyedrops was administered once a day for 3 weeks. Six weeks after the sensitization, an allergic inflammation was provoked with 20 mg/mL of OA eyedrops.

RESULTS

In conjunctival clinical scores 30 minutes after the allergen challenge, there was no significant difference between the controls and the treated group. The total number of inflammatory cells in the conjunctiva 8 hours after the allergen challenge was significantly decreased in the treated group (60.8 +/- 23.2 cells/field) compared with the control group (199.1 +/- 83.4 cells/field). Eosinophils in the conjunctiva 24 hours after the allergen challenge were also significantly decreased in the treated group (22.1 +/- 15.5 cells/field) compared with the control group (50.3 +/- 15.0 cells/field).

CONCLUSIONS

In this study, local ocular immunotherapy mainly suppressed the late phase reaction of allergic inflammation. These results coincide with previous studies of immunotherapy in which a subcutaneous injection was used. Local ocular immunotherapy is effective against experimental allergic conjunctivitis.

Analysis of topical cyclosporine treatment of patients with dry eye syndrome: effect on conjunctival lymphocytes

OBJECTIVE

To study the effect of topical cyclosporine on lymphocyte activation within the conjunctiva of patients with moderate to severe dry eye syndrome (Sjögren and non-Sjögren).

METHODS

Biopsy specimens were obtained at baseline and after 6 months of cyclosporine treatment from eyes of 32 patients with moderate to severe dry eye syndrome; 19 were cyclosporine treated (0.05% cyclosporine, n = 13; 0.1% cyclosporine, n = 6) and 13 were vehicle treated. Within this group there were 12 with Sjögren syndrome and 20 with non-Sjögren syndrome. Biopsy tissue was analyzed using immunohistochemical localization of binding of monoclonal antibodies to lymphocytic markers CD3, CD4, and CD8 as well as lymphocyte activation markers CD11a and HLA-DR.

RESULTS

In cyclosporine-treated eyes, biopsy results of conjunctivae showed decreases in the number of cells positive for CD3, CD4, and CD8, while in vehicle-treated eyes, results showed increases in these markers, although these differences were not statistically significant. Following treatment with 0.05% cyclosporine, there was a significant decrease in the number of cells expressing the lymphocyte activation markers CD11a (P<.05) and HLA-DR (P<.05), indicating less activation of lymphocytes as compared with vehicle treatment. Within the Sjögren patient subgroup, those treated with 0.05% cyclosporine also showed a significant decrease in the number of cells positive for CD11a (P<.001) as well as CD3 (P<.03), indicating a reduction in number of activated lymphocytes.

CONCLUSION

Treatment of dry eye syndrome with topical cyclosporine significantly reduced the numbers of activated lymphocytes within the conjunctiva. Arch Ophthalmol. 2000;118:1489-1496

Specific immunotherapy with a standardized latex extract versus placebo in allergic healthcare workers

BACKGROUND

The prevalence of allergy to natural rubber latex proteins has increased over recent years among healthcare professionals but also in children undergoing multiple operations. Exposure to the antigen mainly occurs through the respiratory mucosa and the percutaneous route. Clinical manifestations range from urticaria to angioedema, rhinoconjunctivitis, bronchial asthma, or anaphylactic shock. Preventive measures have been proposed to reduce the risk of sensitization by using only powder-free or synthetic gloves and latex-free material in operating units, but this is not always possible.

OBJECTIVE

The aim of this study was to investigate the efficacy and safety of specific immunotherapy in sensitized workers.

METHODS

Seventeen patients with latex skin allergy and rhinitis (9 of whom also had asthma) were included in this randomized, double-blind, placebo-controlled trial (9 in the active group and 8 in the placebo group) for 1 year. Treatment started with a 2-day course of rush immunotherapy in hospital. Treatment efficacy was assessed after 6 and 12 months by means of symptom and medication scores recorded on diary cards. Conjunctival provocation tests were also performed.

RESULTS

Patients in the active treatment group had a significantly lower total rhinitis score after 6 (P <. 04) and 12 months (P <.05), conjunctivitis score after 6 months (P <. 02), and cutaneous score after 12 months (P <.03) than in the placebo group. Asthma symptoms after 6 or 12 months of treatment were not significantly different between the two groups after adjustment for baseline values. The global medication score was markedly decreased in the latex-treated group. A significant difference in conjunctival reactivity was observed in favor of the active group: the number of patients for whom the threshold dose was increased after 12 months of treatment was significantly greater in the active group than in the placebo group (P <.02). Most injections were well tolerated, but several adverse effects, including hypotension, urticaria, wheezing, and pharyngeal edema, were observed.

CONCLUSION

The clinical benefits observed during the present study included a significant improvement of rhinitis, conjunctivitis, and cutaneous symptoms. Immunotherapy also decreased allergen-specific conjunctival reactivity. Latex-specific immunotherapy may allow sensitized personnel to remain at work, but further trials need to be conducted in a larger number of patients.

Linear IgA bullous disease limited to the eye: a diagnostic dilemma: response to intravenous immunoglobulin therapy

PURPOSE

To report on a diagnostic dilemma and treatment challenge in a patient with chronic cicatrizing conjunctivitis without involvement of skin and other mucous membranes persisting for 6 years and not responding to topical and systemic steroids.

DESIGN

Interventional case report.

METHODS

We performed direct immunofluorescence of the conjunctiva with fluorescein-conjugated rabbit antihuman antibodies against immunoglobulin A, G, and M, complement 3 component, and fibrinogen. To investigate the presence of circulating antibodies in patient's serum, indirect immunofluorescence using normal human conjunctiva, normal human skin, and monkey esophagus as substrate was done. In addition, we did immunoblot analysis using normal human epidermis as substrate to determine the molecular weight of an antigen. The patient was treated with intravenous immunoglobulin (IVIg). The correlation between the titer of circulating antibodies and the activity of conjunctival inflammation at various intervals during the course of IVIg therapy was demonstrated by immunoblot assay with serial dilutions of the patient's serum. The highest dilution at which the binding was visible was considered the titer.

RESULTS

Direct immunofluorescence of the conjunctiva and indirect immunofluorescence with both salt split skin and conjunctiva as substrate disclosed linear deposition of immunoglobulin A (IgA) at the epithelial basement membrane. Immunoblot analysis demonstrated the presence of IgA circulating antibodies in patient's serum directed against a 97kDa protein in human epidermis. A continuous decrease in the titer of these antibodies correlating to improvement of clinical symptoms was observed during IVIg therapy.

CONCLUSIONS

Use of a nonconventional diagnostic tool (immunoblot analysis), in addition to conventional immunohistologic studies, might be helpful in establishing the diagnosis of patients with chronic cicatrizing conjunctivitis. On the basis of results of these laboratory tests and clinical presentation, we believe that this patient has linear IgA bullous disease limited to the eye. IVIg therapy decreased the titer of circulating antibodies and induced a remission in this patient.

The role of the immune system in conjunctival wound healing after glaucoma surgery

The immune system has a fundamental role in the development and regulation of ocular healing, which plays an important role in the pathogenesis of most blinding diseases. This review discusses the mechanisms of normal wound healing, describing the animal and fetal wound healing models used to provide further insight into normal wound repair. In particular, conjunctival wound repair after glaucoma filtration surgery will be used to illustrate the contributions that the different components of the immune system make to the healing process. The potential role of macrophages, the possible regulatory effect of lymphocytes, and the important role of growth factors and cytokines in the wound healing reaction are discussed. The significance of the immune system in the pathogenesis of aggressive conjunctival scarring is addressed, particularly assessing the predisposing factors, including drugs, age, and ethnicity. The rationale behind the pharmacological agents currently used to modulate the wound healing response and the effects these drugs have on the function of the immune system are described. Finally, potential new therapeutic approaches to regulating the wound healing response are reported.

Vernal keratoconjunctivitis revisited: a case series of 195 patients with long-term followup

OBJECTIVE

This study aimed at revisiting vernal keratoconjunctivitis (VKC) on the basis of anamnestic, clinical, immunologic, histopathologic, and followup data of 195 patients.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

One hundred and ninety-five patients with VKC.

METHODS

Clinical evaluation and outcome in 151 of 195 patients with a median followup of 47 months. Evaluation was by telephone survey in 69 patients.

MAIN OUTCOME MEASURES

(1) Demographic, clinical, and immunologic features of VKC and their influence on the course of the disease; (2) conjunctival and corneal complications and efficacy of treatment observed during the followup period.

RESULTS

VKC is a chronic disease. More than 60% of patients had repeated recurrences all year round. Males had an earlier presentation of symptoms than females and the male/female ratio decreased with age. Major (greater than 80%) and minor (up to 80%) diagnostic criteria were defined for clinical signs and symptoms of the disease. Negative skin test or radioallergosorbent test was present in approximately 50% of patients, whereas eosinophil infiltration was a constant histopathologic finding. A marked conjunctival sensitivity to nonspecific stimuli was noted in more than one third of patients. In 6% of cases, a reduction of visual acuity resulted from corneal scarring, and in 2% of patients, steroid-induced glaucoma was observed. The large size of giant papillae indicates poor prognosis for the persistence of the disease and its evolution into a chronic, perennial condition.

CONCLUSIONS

VKC is a chronic eosinophilic disease of the ocular surface involving IgE, non IgE-mediated mechanisms, and age-sex-related influences. Although the disease has a good prognosis, severe visual impairments may result from long-standing inflammation.

[A histochemical and immunohistochemical study of cornea and adjacent bulbar conjunctiva in Mooren's ulcer]

OBJECTIVE

To investigate immunopathologic changes of cornea and adjacent bulbar conjunctiva in Mooren's ulcer, and roles of macrophage, T lymphocyte, and VCAM-1 in the pathogeny of Mooren's ulcer.

METHODS

The specimens of the cornea lesions and their adjacent bulbar conjunctiva taken from 18 active Mooren's ulcer cases who received resection of conjunctiva and lamellar keratoplasty surgery were studied with histochemical and labelled streptavidin biotin (LSAB) immunohistochemical techniques to investigate the expressions of CD68, CD3, CD4, CD8, CD1a, VCAM-1, HSP70, and TNF in the affected cornea and adjacent conjunctiva.

RESULTS

Under the histochemical examination, infiltration of neutrophils, plasma cells, lymphocytes, and eosinophils were found in the affected cornea and conjunctiva. Degeneration and necrosis of corneal epithelium, Bowman's layer, collageneous fiber in stromal layer, and edema of conjunctiva were shown. Infiltration of a large number of macrophages and T lymphocytes in the affected cornea and adjacent conjunctiva were shown in LSAB immunohistochemical staining. The main infiltrating T lymphocytes were the CD4 positive cells. The CD4/CD8 ratio was significantly higher than that of normal contrals (P < 0.01). VCAM-1 was strongly expressed in the affected corneal and conjunctival epithelium. There were no significant differences for expressions of CD1a, HSP70, and TNF between the pathological specimens and normal contrals.

CONCLUSION

The large number of infiltrating macrophages are responsible for the immunopathological damage caused by T lymphocyte infiltration, aberrant production of cytokikens and aberrant expression of HLA-DR antigen of Mooren's ulcer. There is an aberrant expression of VCAM-1 in the affected corneal and conjunctival epithelium. The role of VCAM-1 in the immunopathogenesis of Mooren's ulcer needs to be studied.

Conjunctival epithelium expression of HLA-DR in glaucoma patients and its influence on the outcome of filtration surgery

AIMS

To analyse the expression of HLA-DR on conjunctival epithelial cells in patients with glaucoma taking topical antiglaucoma therapy.

METHODS

10 patients taking no topical medication and 30 patients with uncontrolled glaucoma taking medical therapy participated in the study. The specimens were obtained by impression cytology preoperatively, 3 months, and 6 months after filtration surgery. The expression of HLA-DR on T lymphocytes and epithelial cells was analysed by flow cytometry.

RESULTS

A significant increase in HLA-DR on epithelial cells was found preoperatively in patients with glaucoma. A significant increased expression of HLA-DR on epithelial cells was detected 3 months and 6 months after surgery.

CONCLUSIONS

The increased expression of HLA-DR on conjunctival epithelial cells still present 6 months after surgery indicates the increased ability of epithelial cells to induce immune inflammation with subsequent fibrosis.

A double-blind, placebo-controlled oral challenge study with lyophilized larvae and antigen of the fish parasite, Anisakis simplex

BACKGROUND

The third-stage larvae of Anisakis simplex may be a hidden source of allergens in fish. The objective was to determine whether the ingestion of lyophilized A. simplex larvae, or antigen, induces clinical symptoms in a group of A. simplex-sensitized patients.

METHODS

Double-blind, placebo-controlled oral challenges were conducted in 11 individuals who had experienced allergic reactions after eating fish. Another patient had chronic urticaria unrelated to the ingestion of fish. All patients had positive skin tests and specific IgE determinations for A. simplex and negative skin tests to a battery of fish species. Conjunctival tests with A. simplex extracts were conducted in all patients and in five controls. The 12 patients received capsules containing either lactose or one, five, or 25 lyophilized larvae of A. simplex at 2-h intervals in a double-blind fashion. The highest single dose was 100 larvae. ECP and tryptase levels in serum were measured before and after the last oral challenge. Lyophilized antigen was also given to five patients.

RESULTS

None of the 12 patients experienced a positive reaction after the ingestion of the placebo, the lyophilized larvae, or the antigen. Tryptase and ECP levels before and after challenges did not change significantly. Conjunctival provocation tests were positive in 11 out of the 12 patients and in none of the controls.

CONCLUSIONS

The ingestion of 100 lyophilized A. simplex larvae, or its equivalent in antigen, does not induce clinical symptoms in individuals with a clinical history and laboratory findings of hypersensitivity to A. simplex. The data suggest that only the ingestion of live larvae may be capable of inducing allergic manifestations.

In vivo behavior of peptide-specific T cells during mucosal tolerance induction: antigen introduced through the mucosa of the conjunctiva elicits prolonged antigen-specific T cell priming followed by anergy

The mucosa of the conjunctiva is an important site of entry for environmental Ags as well as Ags emanating from the eye itself. However, very little is known about T cell recognition of Ag introduced through this important mucosal site. We have characterized the in vivo process of CD4 T cell recognition of Ag delivered via the conjunctival mucosa. Application of soluble OVA to the conjunctiva of BALB/c mice induced potent T cell tolerance. APC-presenting OVA peptide in vivo was only found in the submandibular lymph node and not in other lymph nodes, spleen, or nasal-associated lymphoid tissue. Similarly, in TCR transgenic DO11. 10 adoptive transfer mice, OVA-specific CD4+ T cell clonal expansion was only observed in the submandibular lymph node following conjunctival application of peptide. These experiments thus define a highly specific lymphatic drainage pathway from the conjunctiva. OVA-specific T cell clonal expansion peaked at day 3 following initiation of daily OVA administration and gradually declined during the 10-day treatment period, but remained elevated compared with nontreated adoptive transfer mice. During this period, the T cells expressed activation markers, and proliferated and secreted IL-2 in vitro in response to OVA stimulation. In contrast, these cells were unable to clonally expand in vivo, or proliferate in vitro following a subsequent OVA/CFA immunization. These results suggest that Ag applied to a mucosal site can be efficiently presented in a local draining lymph node, resulting in initial T cell priming and clonal expansion, followed by T cell anergy.

Increase in CD45RO+ cells and activated eosinophils in chronic allergic conjunctivitis

We assessed the infiltration of CD45RO+ cells in conjunctival biopsies of fifteen subjects affected by seasonal allergic conjunctivitis by means of immunohistochemistry. Correlations between infiltration of CD45RO+ cells and serum and mucosal indices of eosinophilic activation were investigated. The study was performed in autumn and all selected patients showed <<red eyes>> also in absence of sensitising pollens. Fifteen healthy subjects were used as controls. The semi-quantitative count of CD45RO+ cells in biopsy specimens demonstrated that positive cells were higher in allergic patients than in controls (p < 0.001) and EG2+ eosinophils were present only in biopsies of allergic patients. Furthermore, a statistically significant positive correlation (r = 0.73; p < 0.001) between CD45RO+ lymphocytes and EG2 positive eosinophils, was observed in the biopsies of allergic patients. Total serum IgE significantly correlated with CD45RO+ cells (r = 0.61; p < 0.02) and EG2+ eosinophils (r = 0.67; p < 0.01) in the conjunctiva. On the other hand serum ECP did not correlate with any histological and immunohistochemical parameters in the conjunctival biopsies. The present study shows that mild symptoms in SCA patients out of pollen season are associated with inflammation of the conjunctiva as shown by an increased number of CD45RO and EG2 positive cells.

[Ocular cicatricial pemphigoid]

The scarry ocular pemphigoid, is an autoimmune disease, belonging to the category of the acquired oculo-muco-cutaneous bullous dermatosis. The ocular symptoms, during the acute stage are conjunctival bullae, which evolve quickly into ulcerous lesions. During the chronic stage, the disease consists of a chronic scarry conjunctivitis, accompanied by corneal lesions, ocular dryness syndrome, disturbances of the palpebral statics and dynamics. The immunopathological mechanism, is represented by a type II hypersensitiveness reaction, in which the antigen-antibody-complement interaction, takes place at the level of the conjunctival epithelium basement membrane. We have reviewed the structures with antigenic potential: the antigen of the bullous pemphigoid-2, 5-6 laminin, beta 4 integrin. The participation of the immunoregulating cells (eosinocytes, mast cells, neutrocytes, macrophages) during the acute stage of the disease, is displayed. The key role of the activated fibroblasts, in producing the subepithelial fibrosis, during the chronic stage of the scarry ocular pemphigoid, is also underlined.

[Experimental study of cytokines complex inhibitory effect on wound healing after glaucoma filtering operations: histopathological and immunochemical findings]

Experiments on a model of glaucoma filtering operation in 25 rabbits showed that the natural cytokine complex inhibited the operation wound healing in comparison with the control. The complex was prepared by an original method (culturing peripheral blood leukocytes) at Immunology Department of the Russian State Medical University. Histopathological study revealed delayed formation of cicatricial tissue under the effect of cytokines. Decreased proliferation of fibroblasts and their decreased functional activity (decreased synthetic activity of glycosaminoglycanes and collagen) was detected in cicatricial tissue. Immunohistochemical studies showed that in remote periods (after 3-8 months) type IV membrane collagen formed in new cicatricial tissue, while in the control, types III and I collagens predominated in cicatricial tissue. Immunohistochemical structure of the cicatrix in experiment correlated with fine fibrous structure of cicatricial tissue, characterized by high permeability. Possible mechanisms of the inhibitory effect of the natural cytokine complex on the course of operation wound healing after glaucoma-filtering surgery are discussed.

The role of antibody to human beta4 integrin in conjunctival basement membrane separation: possible in vitro model for ocular cicatricial pemphigoid

PURPOSE

To demonstrate the specific binding of autoantibodies present in the sera of patients with ocular cicatricial pemphigoid (OCP) to human beta4 integrin present in the normal human conjunctiva (NHC) and to study the role of OCP autoantibodies and antibody to human beta4 integrin in the pathogenesis of subepithelial lesion formation in OCP.

METHODS

Indirect immunofluorescence assay and in vitro organ culture method using NHC were used. Sera and IgG fractions from 10 patients with OCP; immunoaffinity-purified OCP autoantibody; antibodies to human beta4, beta1, alpha6, and alpha5 integrins; and sera from patients with pemphigus vulgaris, bullous pemphigoid (BP), and chronic atopic and chronic ocular rosacea cicatrizing conjunctivitis; and normal human serum (NHS) were used.

RESULTS

Nine of 10 OCP sera or IgG fractions, immunoaffinity-purified OCP autoantibody, antibodies to human beta4 and alpha6 integrins, and sera from patients with BP showed homogenous, smooth linear binding along the basement membrane zone (BMZ) of the NHC. NHS, antibodies to other integrins, and sera from patients with chronic cicatrizing conjunctivitis from other causes showed no such binding. When NHC was first absorbed with OCP sera and then reacted with anti-beta4 antibodies or vice versa, the intensity of the BMZ binding was dramatically reduced or completely eliminated, indicating that there were autoantibodies in OCP sera specific for the beta4 integrin. BMZ separation developed 48 to 72 hours after addition of total OCP sera, IgG fractions from OCP sera, immunoaffinity-purified autoantibodies from sera of patients with OCP, or anti-beta4 antibodies to the NHC cultures, but not after addition of normal control sera, sera from patients with chronic cicatrizing conjunctivitis from causes other than OCP, or sera from patients with OCP in clinical remission.

CONCLUSION

Circulating anti-beta4 integrin antibody may have an important role in the pathogenesis of OCP.

Anti VLA-4 monoclonal antibody inhibits eosinophil infiltration in allergic conjunctivitis model of guinea pig

PURPOSE

To determine the contribution of very late activation antigen-4 (VLA-4) molecule to eosinophil infiltration into the conjunctiva in an actively sensitized allergic conjunctivitis model of guinea pig, effects of a monoclonal antibody against VLA-4 was examined in vivo.

METHODS

A rat anti-mouse VLA-4 mAb (PS 2. 3), which cross-reacts with guinea pig VLA-4, inhibited the adhesion and transmigration of guinea pig eosinophils to /through human umbilical vein endothelial cells (HUVEC) in vitro. Hartley guinea pigs were actively sensitized by intraperitoneal injection of ovalbumin with aluminum hydroxide. Two weeks later, 2.5% ovalbumin was dropped into the eye for the antigen challenge. In the treatment group, 4 mg/kg (body weight) of the anti VLA-4 mAb (PS2.3), and in the control group, the same amount of a control Ab was intraperitoneally injected respectively at 4 hours before the antigen challenge. From both groups, the eyelids and eyeballs were excised at 2, 4, 10, and 24 hours after the antigen challenge, fixed, stained with Hansel solution and the number of the infiltrating eosinophils in the conjunctiva was counted.

RESULTS

In the control group, infiltration of eosinophils to the conjunctiva increased with time, peaked at 12 hours, and then gradually decreased until 24 hours after the antigen challenge. In the anti VLA4-mAb treated group, eosinophil infiltration was almost completely inhibited at least until 24 hours after the antigen challenge.

CONCLUSION

VLA-4 molecule was elucidated to play a critical roll in the eosinophil infiltration in experimentally-induced allergic conjunctivitis model of guinea pig.

Cluster versus conventional immunotherapy in patients allergic to Dermatophagoides pteronyssinus: a controlled study of in vivo and in vitro parameters

We designed a cluster schedule of immunotherapy for patients allergic to Dermatophagoides pteronyssinus which showed good safety and clinical efficacy. Here we compare the in vivo and in vitro changes with those of a conventional schedule in a controlled trial. Sixty-three patients were randomized as follows: 29 were treated with the cluster schedule, 15 with a conventional schedule and 19 received no immunotherapy. A standardized extract was used. Changes in in vivo parameters (skin prick test and conjunctival provocation test) and in in vitro parameters (IgE, IgG, IgG1 and IgG4 for the complete extract, Der p 1 and Der p 2) were measured before immunotherapy (T0), on reaching maintenance phase (T1), and after 6 (T2), 12 (T3) and 18 months of maintenance (T4). Cutaneous reactivity showed a significant decrease from T1 in both the cluster and conventional schedules, and conjunctival reactivity was also significantly lowered from T1 in these groups. Specific IgE decreased and specific IgG, IgG1 and IgG4 increased significantly from T1 in the cluster and conventional schedules. Neither of these parameters showed any changes in the group without immunotherapy. In conclusion, our cluster schedule induced changes in cutaneous and conjunctival reactivity and in immunological parameters that were similar to those achieved with the conventional schedule; these changes did not appear in patients who did not undergo immunotherapy.

Tumour necrosis factor alpha (TNFalpha) in tears of atopic patients after conjunctival allergen challenge

BACKGROUND

Proinflammatory cytokines, such as TNFalpha are involved in the pathogenesis of allergic rhinitis and asthma.

OBJECTIVE

Our aim was to study the tear fluid TNFalpha levels in atopic patients before and after topical ocular allergen challenge.

METHODS

Thirteen patients were first challenged with topical allergen in the left eye and then dilution buffer in the right eye. Tear fluid samples were collected before the challenges and after 5, 30 and 60 min. Clinical symptoms were scored. Tear fluid TNFalpha concentrations were measured using a double-antibody radioimmunoassay. TNFalpha release rates were calculated using the tear fluid flow in the collection capillary as an estimate for the tear secretion rate.

RESULTS

The mean baseline TNFalpha concentrations (ng/L) were 1310 (allergen-challenged eye) and 967 (control eye), and release rates (pg/min) 1.81 (allergen-challenged eye) and 1.39 (control eye), respectively. In the allergen-challenged eye, TNFalpha concentrations and release rates were 1479 and 4.30 (5 min), 1367 and 3.20 (30 min) and 1426 and 3.80 (60 min). In the control eye, TNFalpha concentrations and release rates were 746 and 0.67 (5 min), 1001 and 0.92 (30 min) and 1504 and 1.05 (60 min). The release rates of the allergen-challenged eye were significantly increased at all time points after the challenge when compared with the baseline or the control eye.

CONCLUSION

Increased TNFalpha release rates suggest that this cytokine is an early mediator of allergy after conjunctival challenge.

The immunomodulatory effect of topical cyclosporin A in atopic keratoconjunctivitis

PURPOSE

To perform a detailed examination of the immunomodulatory effects of topical cyclosporin A (CsA) in conjunctival tissue from patients with atopic keratoconjunctivitis (AKC).

METHODS

Patients with active AKC were randomly allocated into two groups of four patients. For 3 months one group received 2% CsA drops, and the other group received placebo drops. Superior tarsal conjunctival biopsy specimens were harvested before and after treatment and examined by one- and two-color immunohistochemistry to compare leukocyte counts, HLA-DR+ and IL-2R+ cell counts, HLA-DR positivity of conjunctival epithelial cells, and counts of T cells expressing the cytokines interleukin (IL)-2, IL-3, IL-4, IL-5, and interferon (IFN)-gamma.

RESULTS

Posttreatment values were significantly less than pretreatment values for the total number of leukocytes and in the numbers of CD3+ T cells, CD4+ cells, CD8+ cells, CD20+ B cells, neutrophils, and macrophages, and there was a decrease in the CD4-CD8 ratio (P = 0.03) in the CsA group. There was a reduction from before CsA treatment to after CsA-treatment in the numbers of HLA-DR+ and IL-2R+ cells (P = 0.03), but the reduction in the epithelial cell HLA-DR expression did not reach significance. The number of T cells staining for IL-3 and IL-5 was reduced, although not to statistical significance, but there was a significant reduction in the number of T cells expressing IL-2 and IFN-gamma (P = 0.03) after CsA treatment compared with initial values. There were no statistically significant differences between pretreatment and posttreatment values in the placebo group. There was a clinical improvement in the CsA group and a clinical worsening in the placebo group.

CONCLUSIONS

The in vitro effects of CsA translate into a reduction in T cells, a normalization of the CD4-CD8 ratio, a decrease in T-cell activation, and a reduction in T-cell cytokine expression, especially IL-2 and IFN-gamma. The decrease in HLA-DR expression may be mediated by the change in IFN-gamma. There were fewer B cells but not fewer plasma cells after CsA and no change in IL-4 expression, suggesting minimal effects on type I hypersensitivity responses. There was no significant reduction in mast cell or eosinophil numbers, but direct effects of topical CsA on their function may play a role in the therapy of ocular allergic disease. These results show that the beneficial effects of topical CsA in AKC are accompanied by important changes in conjunctival immune cell profiles.

Immunoelectron microscopic study of the conjunctiva in cicatricial pemphigoid

BACKGROUND

Immune deposits can be found on the conjunctival basement membrane zone of patients affected by cicatricial pemphigoid using immunofluorescence technique. The purpose of this study was to perform direct immunoelectron microscopy on the conjunctiva of patients with scarring conjunctivitis associated with cicatricial pemphigoid.

METHODS

Conjunctival and skin biopsies were performed in six patients who presented with presumed autoimmune cicatrizing conjunctivitis associated with cicatricial pemphigoid. Specimens were processed for direct immunofluorescence and direct immunoelectron microscopy.

RESULTS

Direct immunofluorescence was positive in all skin samples and in three of six conjunctival samples. Direct immunoelectron microscopy showed immune deposits in the lamina lucida and the lamina densa of all skin and conjunctival samples.

CONCLUSIONS

Direct immunoelectron microscopy can be performed on the conjunctiva. It shows the precise localization of cicatricial pemphigoid target antigens within the conjunctival basement membrane zone.

The role of conjunctival epithelial cells in chronic ocular allergic disease

Recent evidence suggests that mucosal epithelial cells are capable of actively participating in immune reactions via expression of surface antigens, such as adhesion molecules, and synthesis of cytokines. This appears to be important in the pathophysiology of non-ocular allergic disorders. The objectives of the experiments were to compare the expression of HLA-DR, ICAM-I and pro-allergic cytokines in conjunctival epithelial cells in the different chronic ocular allergic disorders with each other and with normal subjects. Conjunctiva from normal patients (n=10) and patients with vernal keratoconjunctivitis (VKC, n=10), atopic keratoconjunctivitis (AKC, n=10) and contact lens-associated giant papillary conjunctivitis (GPC, n=10) were examined by immunohistochemistry. Epithelial cell staining for surface antigens and cytokines was graded by one masked observer using a four point scale based on the percentage of epithelial cells staining positive. There was no expression of ICAM-1 or HLA-DR in the normal conjunctival epithelial cells, but both antigens were induced on conjunctival epithelial cells in the allergic tissue, and there was greater expression in AKC and VKC compared with GPC. Cytokines IL-6, IL-8, RANTES and TNF-alphaall localised to normal conjunctival epithelial cells. RANTES was upregulated in all the allergic disorders and IL-8 was upregulated in GPC. IL-3 and GM-CSF were not expressed in normal conjunctival epithelial cells. GM-CSF was expressed in all disorders and there was greater expression in AKC compared with GPC and VKC. IL-3 was expressed only in AKC and VKC epithelial cells. These results suggest that conjunctival epithelial cells play an important pro-inflammatory role in chronic ocular allergic diseases; ICAM-1 may allow epithelial cells to recruit, retain and locally concentrate leukocytes; the presence of HLA-DR raises the question of conjunctival epithelial cell antigen presentation. The epithelial cytokines which are upregulated are known to promote eosinophilic inflammation and are typical of allergic inflammation. The differences in cytokine patterns may be exploitable for future therapy.

Immunopathogenesis of conjunctival scarring in trachoma

PURPOSE

Trachoma, a chronic follicular conjunctivitis caused by infection with Chlamydia trachomatis, is the leading cause of preventable blindness. The blinding complications are associated with progressive conjunctival scarring that may result from immunologically mediated responses. We studied the processes involved in the regulation of inflammation and fibrosis in trachoma by investigating the expression of fibrogenic cytokines in the conjunctiva.

METHODS

We studied conjunctival biopsy specimens obtained from nine subjects with active trachoma and from four control subjects. We used immunohistochemical techniques and a panel of monoclonal and polyclonal antibodies directed against interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha) and platelet-derived growth factor (PDGF). In addition, we characterised the composition of the inflammatory infiltrate by the use of a panel of monoclonal antibodies. Sirius red and Van Gieson stains were used to characterise the extent of fibrous tissue in the substantia propria.

RESULTS

Trachoma specimens showed greater numbers of inflammatory cells than control specimens. The expression of cytokines was absent in the normal conjunctiva. Cytoplasmic IL-1 alpha and IL-1 beta expression was noted in the conjunctival epithelium in all trachoma specimens. IL-1 alpha, IL-1 beta, TNF-alpha and PDGF were detected in macrophages infiltrating the substantia propria. B lymphocytes predominated over T lymphocytes in six trachoma biopsies with fibrosis confined to the deep substantia propria, whereas T lymphocytes predominated over B lymphocytes in three biopsies with more extensive fibrosis. In all trachoma biopsies helper/inducer T lymphocytes outnumbered suppressor/cytotoxic T lymphocytes.

CONCLUSIONS

The upregulated local production of IL-1 alpha, IL-beta, TNF-alpha and PDGF might contribute to conjunctival damage and scarring in trachoma.

Human mast cells express stem cell factor

Stem cell factor (SCF) is a major cytokine regulator of mast cell growth and function. The present study demonstrates that human mast cells are able to produce SCF. Constitutive synthesis of SCF mRNA was seen in the mast cells isolated from human lung and skin by RT-PCR. This was confirmed by in situ hybridization in conjunctival mast cells of both tryptase-only (MCT) and tryptase/chymase (MCTC) subsets. SCF protein product was found in conjunctival MCT and MCTC mast cells by immunohistochemistry. Soluble SCF protein was detected in the culture supernatant of isolated lung mast cells by ELISA, and cross-linkage of IgE receptor (Fc epsilon-RI) on the lung mast cells in culture did not alter SCF mRNA expression, or the secreted soluble SCF protein. This was consistent with the finding that levels of SCF mRNA expression in conjunctival mast cells were similar between normal subjects and patients with seasonal allergic conjunctivitis (SAC). This study shows that human mast cells themselves are a cellular source of SCF, as well as being target cells for this growth factor. SCF may regulate mast cell growth and function via both paracrine and autocrine mechanisms. The production of SCF by mast cells may be regulated via mechanisms other than IgE receptor-mediated pathways.

The effect of successful contact lens wear on mucosal immunity of the eye

OBJECTIVE

This study aimed to assess the effect of contact lens wear on the mucosal defenses of the outer eye against infection.

DESIGN

A case-controlled study of daily contact lens wearers in their initial 6 months of contact lens wear.

PARTICIPANTS

Contact lens wearers (mean age, 23.1 years; 47 subjects) were compared with age-matched control subjects (mean age, 24.7 years; 44 subjects).

INTERVENTION

Outer eye defenses were studied by assay of tear constituents and quantitative conjunctival microbiology.

MAIN OUTCOME MEASURES

Antimicrobial activity of tears was studied by assay of total immunoglobulin A (IgA), IgA isotype-specific antibodies reactive with Escherichia coli, Haemophilus influenzae, Staphylococcus epidermidis, albumin and lysozyme, and the ocular surface microbial load determined using quantitative microbiology of the conjunctival sac.

RESULTS

The IgA isotype-specific antibodies reactive with E. coli (P = 0.03) and S. epidermidis (P = 0.068) were lower in contact lens wearers, but antibody:albumin ratios were not significantly different in the two groups. Contact lens wear also had no significant effect on tear IgA, albumin, or lysozyme or its ratios with albumin. Bacterial numbers and colonization rates for coagulase-negative staphylococci were greater in contact lens wearers than in age-matched control subjects. Corynebacterium sp. and non-Enterobacteriaceae (P = 0.007) were isolated more frequently and in greater numbers from contact lens wearers. Colonization rates were increased for Corynebacterium sp., but non-Enterobacteriaceae were transient. In both daily contact lens wearers and age-matched control subjects, most conjunctival flora were transient rather than colonizing, and no subject developed an outer eye infection during the study.

CONCLUSION

These results suggest that daily contact lens wear does not significantly alter the mucosal defenses of the outer eye that function to eliminate organisms from the conjunctival sac and prevent outer eye infection.

Immunohistopathologic testing in patients suspected of ocular cicatricial pemphigoid

PURPOSE

Optimizing the sensitivity of immunopathologic methods in detecting target antigens in immune-mediated cicatrizing conjunctivitis.

METHODS

Immunofluorescence was performed on normal and salt-split conjunctival biopsies in fifteen patients with clinical evidence of ocular cicatricial pemphigoid, and results were compared with immunoperoxidase, a technique thought to be more sensitive although more expensive and more difficult technically to perform.

RESULTS

Ten of fifteen biopsies (67%) were positive when conventional and salt-split immunofluorescence results were combined. Four of eight patients with positive conventional immunofluorescence showed more marked immunofluorescence with the salt-split method. All patients were positive with immunoperoxidase (100%).

CONCLUSION

Immunoperoxidase was more sensitive than conventional or salt-split immunofluorescence in detecting immunoreactant deposition along the basement membrane of the conjunctiva. Salt-split immunofluorescence demonstrated more intense staining of conjunctival samples when compared with conventional immunofluorescence, without however increasing the yield of positive biopsies. Finding solutions for the proper handling of conjunctival tissue in salt may improve the diagnostic yield of salt-split immunofluorescence.

Chronic keratoconjunctivitis associated with congenital dyskeratosis and erythrokeratodermia variablis. Two rare genodermatoses

OBJECTIVE

The purpose of the study was to report the ocular manifestations and immunohistopathologic description of two rare forms of genodermatosis: congenital dyskeratosis (CD) and erythrokeratodermia variabilis (EKV).

DESIGN

Case reports.

PARTICIPANTS

Two patients with CD and EKV presenting with chronic keratoconjunctivitis were studied.

INTERVENTION

Clinical photography to show ocular manifestations and dermatologic findings was performed. Conjunctival biopsy was performed to determine the histopathology and immunohistopathology.

RESULTS

In the patient with EKV, the eyelid skin was dry, erythematous, and thickened. The lid margins showed plugging of some of the Meibomian glands, madarosis, and occasional trichiasis. The epibulbar conjunctiva was injected and had a moderate papillary reaction. Both corneas had pronounced vascularization and stromal scarring. Conjunctival biopsy results disclosed a striking number of degranulating mast cells and moderate numbers of plasma cells. Immunohistopathology showed pronounced immunoglobulin G (IgG)-positive cells in the stroma and immunoglobulin A (IgA) positivity in the epithelium. There was scattered immunoglobulin M (IgM) and moderate C3 and C4 positivity in the stroma. In CD, the patient had keratinized lid margins, entropion formation, trichiasis, cicatrizing conjunctivitis, and symblephra formation. The corneal surface was keratinized, with deep and superficial vascularization. Conjunctival biopsy specimens showed pronounced epithelial keratinization and squamous metaplasia. Degranulating mast cells and eosinophils were prominent in the stroma. Immunohistopathology showed C4 and immunoglobulin D positivity on the keratinized epithelial surface with rare foci of immunoglobulin E-positive cells. Basal epithelial cells were positive for IgA and IgG, and a large number of IgA and IgG plasma cells were present in the substantia propria.

CONCLUSION

To the authors' knowledge, these case reports represent the first clinical description of the ocular manifestation of EKV and the first immunohistopathologic description of the affected conjunctiva in EKV and CD, both of which should be considered in the differential diagnosis of genodermatosis associated with chronic keratoconjunctivitis.

Anatomy of mammalian conjunctival lymphoepithelium

Ocular surface immune mechanisms are subservient to the fine function of the eye. A clear cornea with a smooth, well-lubricated facade is prerequisite to lucid vision. Hence, corneal inflammation and post-inflammatory scarring are intolerable, and the cornea contains a minimum of lymphoid elements. Although conjunctival dysfunction and consequent tear film deficiency can malign the corneal surface, conjunctival inflammation is tolerated to a considerable degree. In contrast to the human cornea, human conjunctiva contains an abundance of lymphoid tissue. Certain aspects of human conjunctival immunology elicit little debate. Langerhans cells are abundant in conjunctival epithelium. Isolated CD8+ suppressor/cytotoxic T cells predominate in conjunctival epithelium, while T cells in the substantia propria distribute equally between CD4+ T helper cells and CD8+ cells. Yet the presence of plasma cells in human conjunctiva, the expression of secretory component by human conjunctival epithelium, and the function of human conjunctival lymphoid follicles are in dispute. Confusion may derive in part from the use of inappropriate animal models; rodent conjunctiva does not appear to be a worthy facsimile for human conjunctiva. Discrepancies between different human studies likely result from variance in subject age, biopsy site and extent, histologic or histochemical technique, and perhaps the degree of inflammation present at the time of biopsy. Careful immunohistochemical and in situ molecular assays on well-defined loci within the conjunctiva of comparable human subjects may resolve such questions in the future. Organized mucosa-associated lymphoid tissue is rigorously defined as mucosal lymphoid follicles with an ultrastructurally distinct overlying lymphoepithelium. Based on available evidence, the epithelium overlying mammalian conjunctival lymphoid follicles does not contain distinct M cells. Whether zonal differences in morphology reflect real differences in the capacity to sample tear film antigens for presentation to the mucosal immune system remains to be established.

Alterations of ocular surface gene expression in Sjögren's syndrome

We have demonstrated that conjunctival epithelium of SS patients displays increased numbers of S-phase cells compared with non-dry eye controls. Moreover, in SS patients, these S-phase cells are distributed throughout all strata of the epithelium. The expression of MUC-1, a cell surface marker indicative of terminally differentiated epithelium, is localized to the conjunctival epithelial surface in SS and control patients. However, MUC-1 surface immunoreactivity appears to be reduced in SS epithelium, suggesting disruption of normal epithelial differentiation. A MUC-1 epitope exposed by pretreatment with neuraminidase is expressed in the basal and suprabasal layers of both patient populations. This antigen likely represents nascent, partially processed MUC-1(6) and may serve as a marker of the preterminally differentiated epithelial phenotype. Messenger RNA encoding several different inflammatory cytokines, including TNF-alpha, IL-1 alpha and beta, IL-6, IL-8, IL-10, and TGF-beta 1, is expressed at elevated levels within the conjunctival epithelium of SS patients compared with non-dry eye controls. Based on these observations, we have formulated a model to explain the ocular surface pathology of Sjögren's syndrome. We hypothesize that mechanical abrasion secondary to aqueous tear deficiency creates an inflammatory environment where conjunctival epithelial cells and lymphocytes are stimulated to produce and secrete various cytokines (i.e., IL-1, TNF-alpha, IL-6, IL-8, etc.) into the tear film. Elevated cytokine levels within the tear film, perhaps combined with reduced concentrations of essential lacrimal gland-derived factors (i.e., EGF, retinol), create an environment in which terminal differentiation of the ocular surface epithelium is impaired. As a consequence, the epithelium becomes hyperplastic, displaying increased mitotic activity, and loses the ability to express mature protective surface molecules including the membrane-bound mucin, MUC-1. This would imply that anti-inflammatory medications (i.e., corticosteroids or cyclosporine) that suppress the inflammatory component of this cascade may ameliorate the ocular surface disease and discomfort experienced by SS patients.

Cytological changes and conjunctival hyperemia in relation to sensory eye irritation

In general, irritation is a physiological response to a chemical or physical stimulus involving objective changes (e.g., local redness and edema) and subjective sensations (e.g., pruritus and pain). The perception of an irritating stimulus in the eyes and the upper airways is called sensory irritation. Sensory irritation is a prevalent symptom in relation to complaints about indoor air quality. The intensity of perceived sensory irritation in humans has mainly been evaluated using psychophysical methods. However, perceived sensory irritation is dependent on the subject expressing the symptoms; that is, it is a subjective measure. This is a problem in assessment of irritation effects from air pollution or other factors, since the expression of the irritation symptoms may be biased by, for example, interaction with other people and odors. The subjectivity of the measures is an important complication in several studies dealing with problems regarding indoor air quality. The bias problems make it important to complement the psychophysical measurements of sensory irritation with objective assessments of irritation. In addition, only little is known about the association between sensory irritation and possible physiological/ pathological changes in the mucosal membranes in relation to studies of indoor air. Two studies (study 1 and study 2) were conducted to investigate changes in conjunctival hyperemia and conjunctival fluid cytology for subjects exposed to volatile organic compounds (VOCs) in their eyes only. Eight subjects participated in study 1. Each subject was exposed to three different mixtures of VOCs. A total of 16 subjects participated in study 2. Half of the subjects were exposed to 1-octene and the other half, to n-butanol. In both studies, photographs of bulbar conjunctiva were taken and conjunctival fluid was sampled before and after exposure. Moreover, the perceived irritation intensities were registered continuously during exposure. Overall, perceived irritation intensity and conjunctival hyperemia increased with increasing exposure concentrations, whereas cytological changes in the conjunctival fluid samples did not seen to be related to exposure concentration, perceived irritation, or changes in conjunctival hyperemia.

A novel murine model of allergic conjunctivitis

Allergic conjunctivitis affects over 40 million patients per year in the United States. Here we present the first murine model that incorporates the clinical, cellular, and humoral parameters of allergic conjunctivitis, including a ragweed-induced Th2-type cytokine production by lymphocytes. SWR/J mice were immunized with short ragweed pollen in aluminum hydroxide. Ten days after immunization, allergic conjunctivitis was induced by one topical application of ragweed pollen onto the eye. Immediate response was characterized by chemosis, redness of the conjuctiva, and lid edema. Histopathology and immunohistochemistry showed dense conjunctival infiltration with polymorphonuclear leukocytes, macrophages, and CD4+ T lymphocytes. In addition, ragweed-specific IgG1 and IgE serum levels were significantly higher in immunized animals, and high levels of IL-4 and IL-5 were detected in supernatants from ragweed-activated lymphocytes. This reproducible model is a well-suited instrument for testing the pathophysiology and future therapies of allergic conjunctivitis.

Histopathological effects of topical ophthalmic preservatives on rat corneoconjunctival surface

PURPOSE

Long term use of topical drugs has clearly been shown to induce toxic immunopathological changes in the ocular surface. However, little is known concerning the respective roles of active compounds and preservatives. Benzalkonium chloride (BAC) is the most used preservative and its cytotoxicity is well known, but other preservatives have not yet been clearly evaluated. We thus performed a comparative study to investigate toxic side effects induced in the rat ocular surface by applications of various preservatives, with special attention to inflammatory infiltrates.

METHODS

A total of 35 brown Norway rats were divided into seven groups of five each. They received, for one month, in both eyes, either 0.01% cetrimonium chloride, 0.01% benzalkonium chloride, 0.01% benzododecinium bromide, 0.004% thiomersal, 0.05% methyl parahydroxybenzoate or phosphate-buffered saline (PBS), the last group remaining untreated. Then, animals were sacrificed and eyes were processed for histological and immunological procedures with monoclonal antibodies to rat immunocompetent cells.

RESULTS

When compared to controls, all preservative-treated eyes consistently showed corneal and conjunctival damage, including epithelial alterations, various degrees of keratinization and inflammatory infiltrates at the limbus and within the conjunctival stroma and epithelium. No difference was found between the five tested drugs.

CONCLUSIONS

This study confirms that most preservatives used in ophthalmic eyedrops may similarly induce strong histopathological and inflammatory changes in the ocular surface after short term use. Although obtained in animal model, these results confirm strong toxic side effects in patients with preexisting ocular surface disorders and/or receiving topical drugs for long periods.

Mucosal defense of the outer eye

A combination of mechanical, anatomical, immunological, and microbiological factors prevent infection of the outer eye. Mechanical and anatomical factors include the intact epithelium of the conjunctiva and cornea and the constant blinking action of the eyelids. Tear components that play a role in eye defense include lysozyme, immunoglobulins, lactoferrin, and betalysin. The normal bacterial flora of the conjunctiva may also have an inhibitory effect on the survival of more pathogenic species. The eye is linked to the common mucosal immune system, thus gaining the benefits of a system of microbial defense which is primed in the gastrointestinal tract, where a continuing large antigen load is capable of stimulating ongoing immune protection. The relative roles of the various factors contributing to prevention of eye infection remain to be fully defined.

Immunolocalization of cytokines to mast cells in normal and allergic conjunctiva

BACKGROUND

Recently, the potential role of mast cells in allergic reactions has been extended by the discovery that these cells synthesize, store and secrete multifunctional cytokines. Seasonal allergic conjunctivitis is characterized as an immediate hypersensitivity reaction, in which allergen binds to specific IgE on mast cells, leading to release of pre-formed and newly synthesized inflammatory mediators.

OBJECTIVE

In this study we aimed to localize the cytokines IL-4, IL-5, IL-6, IL-8 and TNF alpha to conjunctival mast cells and to examine the relationship between mast cell-associated cytokines and allergic conjunctivitis.

METHODS

Immunohistochemistry was performed on serial sections of conjunctival biopsies from patients with seasonal allergic conjunctivitis, in and out of the hay fever season, as well as from non-allergic volunteers.

RESULTS

IL-4, IL-5, IL-6 and TNF alpha were localized to mast cells in normal and allergic conjunctiva. IL-8 was localized to mast cells in two patients with seasonal allergic conjunctivitis, one during and the other outside the pollen season. Using the monoclonal antibody 3H4, which identifies the secreted form of IL-4, biopsies from patients with active seasonal allergic conjunctivitis contained a significantly higher proportion of mast cells positive for IL-4, than those from out-of-season patients (P=<0.016). There was no difference between the two groups in the number of mast cells immunostained by the antibody 4D9 which identifies the stored form of IL-4.

CONCLUSIONS

These results suggest that conjunctival mast cells can store a range of multifunctional cytokines and release IL-4 during active disease, which may give them an important role in upregulating allergic inflammation in the conjunctiva.