Diagnostics and new developments in the treatment of ocular allergies.

About 30% of people suffer from allergic symptoms, and 40% to 80% of them have eye symptoms. Atopic conjunctivitis is divided into seasonal allergic conjunctivitis and perennial allergic conjunctivitis. The treatment of seasonal allergic conjunctivitis is simple: antihistamines, anti-inflammatory agents, or cromoglycate. Perennial allergic conjunctivitis needs longer therapy with mast cell stabilizers and sometimes local steroids. Atopic keratoconjunctivitis requires long-term treatment of the lid eczema and keratoconjunctivitis. Vernal keratoconjunctivitis mainly affects children and young people. It commonly calms down after puberty. It demands intensive therapy, often for many years, to avoid serious complicating corneal ulcers. Giant papillary conjunctivitis is a foreign body reaction in contact lens users or patients with sutures following ocular surgery. Nonallergic eosinophilic conjunctivitis affects mostly middle-aged and older women with eosinophilic conjunctivitis and dry eye. Contact allergic blepharoconjunctivitis is often caused by cosmetics and eye medication. Work-related ocular allergies should be considered as a cause of resistant ocular symptoms in workplaces.

Clinical and immunological responses in ocular demodecosis.

The purpose of this study was to investigate clinical and immunological responses to Demodex on the ocular surface. Thirteen eyes in 10 patients with Demodex blepharitis and chronic ocular surface disorders were included in this study and treated by lid scrubbing with tea tree oil for the eradication of Demodex. We evaluated ocular surface manifestations and Demodex counts, and analyzed IL-1ß, IL-5, IL-7, IL-12, IL-13, IL-17, granulocyte colony-stimulating factor, and macrophage inflammatory protein-1ß in tear samples before and after the treatment. All patients exhibited ocular surface manifestations including corneal nodular opacity, peripheral corneal vascularization, refractory corneal erosion and infiltration, or chronic conjunctival inflammatory signs before treatment. After treatment, Demodex was nearly eradicated, tear concentrations of IL-1ß and IL-17 were significantly reduced and substantial clinical improvement was observed in all patients. In conclusion, we believe that Demodex plays an aggravating role in inflammatory ocular surface disorders.

Genetic background determines susceptibility to experimental immune-mediated blepharoconjunctivitis: comparison of Balb/c and C57BL/6 mice.

Balb/c and C57BL/6 mice have been reported to be biased towards Th2 and Th1 immune responses, respectively. We investigated which strain is more susceptible to the development of experimental immune-mediated blepharoconjunctivitis (EC), which is predominantly mediated by Th2 immune responses. EC was induced by three different methods in Balb/c and C57BL/6 mice using ragweed (RW) as the antigen. The mice were thus either actively immunized with RW, passively immunized by transfer of RW-primed T cells, or passively immunized by transfer of RW-specific IgE, followed by RW challenge in eye drops. Twenty-four hours after the challenge, conjunctivas, sera and spleens were harvested for histological analysis, measurement of serum IgE and assessment of cellular immune responses, respectively. The responses of the Balb/c and C57BL/6 mice were compared. In addition, to assess the involvement of IFN-gamma in the development of EC in the two strains, IFN-gamma knockout (GKO) mice of the two strains were actively immunized and evaluated as above. Regardless of the method of induction, EC, as determined by the degree of eosinophil infiltration into the conjunctiva, was more severe in Balb/c mice than in C57BL/6 mice. Moreover, more IgE was produced by actively immunized Balb/c mice than C57BL/6 mice and RW-primed splenocytes from Balb/c mice produced more IL-4 but less IFN-gamma than those from C57BL/6 mice. EC could be induced in the GKO mice of both strains. However, when their EC was compared to that in WT mice, significantly less infiltration of eosinophils was noted in the Balb/c GKO mice. Taken together, Balb/c mice are more susceptible to EC than C57BL/6 mice and this higher susceptibility might be related to the Th2 immune response bias of Balb/c mice. Furthermore, the involvement of endogenous IFN-gamma in the development of EC in these two strains differs.

Suppression of experimental immune-mediated blepharoconjunctivitis in Brown Norway rats by topical application of FK506.

BACKGROUND: Experimental immune-mediated blepharoconjunctivitis (EC) in Brown Norway (BN) rats, which is inducible by transfer of antigen-specific T cells, is a model for human allergic conjunctivitis. We investigated the possible inhibition of EC in BN rats by topical application of FK506, which is an immunosuppressive agent that mainly targets T cells. METHODS: To induce EC by active immunization, ovalbumin (OVA) adsorbed to alum was injected into the hind footpads of BN rats. Three weeks after the initial immunization, rats were challenged with OVA by eye drops. Twenty-four hours later, lids including conjunctivas, lymph nodes (LNs), and sera were harvested for histology or reverse transcriptase PCR, proliferation assays, and measurement of IgE titer, respectively. For passive immunization, rats were intravenously injected with 10 million of in vitro-stimulated OVA-primed LN cells. Four days after the transfer, rats were challenged with OVA and evaluated as above. The rats were divided into two groups. One group received topical FK506 treatment three times per day from 15 to 21 days after active immunization or from 1 to 4 days after transfer. The other group was treated with vehicle as above. RESULTS: FK506 treatment suppressed infiltration of both lymphocytes and eosinophils in the conjunctiva either by active or passive immunization (P<0.002). No differences were noted in antigen-specific cellular and humoral immune responses. Concerning cytokine expression in the conjunctiva, a prominent difference was noted only with IL-4, which was more abundantly detected in the vehicle-treated group. CONCLUSION: Topical FK506 treatment suppressed EC in BN rats, possibly by inhibition of IL-4 in the conjunctiva.

Effects of IL-4 and IL-12 on experimental immune-mediated blepharoconjunctivitis in Brown Norway rats.

IL-12 and IL-4 are critical cytokines for Th1 and Th2 differentiation, respectively. To assess the roles of these cytokines in the development of experimental immune-mediated blepharoconjunctivitis (EC) in Brown Norway (BN) rats, their effects were tested either in vitro or in vivo. Draining lymph node cells from rats immunized with ragweed pollen (RW) in Al(OH)3 were collected and cultured for 3 days with RW in the presence of IL-4, IL-12, or PBS as a control. After harvesting the culture supernatants for cytokine ELISA and the cells for cytokine reverse transcriptase-polymerase chain reaction, 10 million cells were injected intravenously into syngeneic recipient rats (n = 12 per group). The rats were challenged with RW by eye drops 4 days after transfer. Eyes were harvested for histology 24 h later. Furthermore, IL-12 (500 ng per injection) or PBS was injected intraperitoneally every other day seven times from the day of active immunization (n = 6 per group). One day after the last injection, rats were challenged and EC was evaluated as above. Transfer of cells with IL-4 in vitro augmented eosinophilic infiltration in the conjunctiva compared with the other two groups, whereas IL-12 in vitro suppressed eosinophilic infiltration and increased lymphocytic infiltration. Interferon-gamma production was augmented by IL-12. IL-4 RNA expression was augmented by IL-4. IL-12 administration in vivo augmented lymphocytic infiltration in the conjunctiva without affecting infiltration of eosinophils. In conclusion, IL-4 and IL-12 either in vitro or in vivo augmented Th2 and Th1 immunity, respectively, thus leading to distinct histological features of EC.

Experimental immune-mediated blepharoconjunctivitis in rats induced by immunization with ragweed pollen.

BACKGROUND: A study was performed to compare the effects of immunization with ragweed pollen (RW) in two different adjuvants on the characteristics of a previously described model of experimental immune-mediated blepharoconjunctivitis (EC) in rats. METHODS: Lewis or Brown Norway (BN) rats were immunized with 100 microg of RW in emulsion with aluminum hydroxide [Al(OH)3] or complete Freund's adjuvant (CFA). Three weeks later, the animals were challenged with eye drops containing RW in PBS. Twenty-four hours after topical challenge, eyes, blood, and lymph nodes were obtained for histology, measurement of antigen-specific antibodies, and proliferation or cytokine assays, respectively. In addition to active immunization, recipients of RW-primed lymph node cells were challenged and evaluated as above. RESULTS: RW in both adjuvants induced infiltration with predominantly mononuclear cells in Lewis rats and eosinophils in BN rats. As well as active immunization, eosinophils were detected only in BN rats by adoptive transfer of cells. Lymphocyte proliferative responses to RW were high in immunized Lewis rats when CFA was used as an adjuvant. In contrast, proliferative responses in BN rats were higher when Al(OH)3 was used. RW-specific IgE was detected only in BN rats. There were no significant differences in RW-specific IgG1/IgG2a ratio among the four groups. Lewis rats had higher level of RW-specific interferon-gamma in the culture supernatant. CONCLUSIONS: The characteristics of EC are different in Lewis and BN rats, dependent on the genetic background of the rat strains. The response to RW was similar to other previously used antigens, such as ovalbumin.