A flow cytometric study about the immunopathology of vernal keratoconjunctivitis

Potential Biomarkers for Allergic Conjunctival Diseases

Allergic conjunctival diseases (ACDs) are a group of ocular allergies that include allergic conjunctivitis, atopic keratoconjunctivitis, vernal keratoconjunctivitis, and giant papillary conjunctivitis. Although a large body of information exists on the pathophysiology of ACDs, this has not yet lead to the development of clear recommendations and guidelines for the diagnosis of ACDs or development of conclusive and objective diagnostic tools. Identification of objectively measurable biomarkers that represent the molecular and cellular mechanisms associated with ACDs will be an important step toward achieving these aims. This is a comprehensive review of biological markers that have the potential to become "biomarker(s)" for ACDs and aid in the classification, diagnosis, and development of new therapeutic strategies for these group of allergic conditions.

Topical 2% cyclosporine A in preservative-free artificial tears for the treatment of vernal keratoconjunctivitis

BACKGROUND

A double-masked, placebo-controlled trial to evaluate the short-term efficacy and safety of topical 2% cyclosporine A in preservative-free artificial tears for patients with vernal keratoconjunctivitis.

METHODS

Twenty patients with severe vernal keratoconjunctivitis were included in the study. All were treated with topical 2% cyclosporine A eye drops. One eye of each patient was administered 2% cyclosporine A in preservative-free artificial tears; the fellow eye received the placebo (vehicle) for the first 2 weeks, in a double-masked, placebo-controlled trial. Thereafter, the placebo eye received cyclosporine A (open trial). Symptoms and signs were scored on the day of enrollment and at the end of week 2, 4, and 14.

RESULTS

At the end of week 2, no statistically significant decrease was noted from baseline in mean scores of either signs (p = 0.18) or symptoms (p = 0.50) in the eyes that received placebo. On the other hand, a statistically significant decrease was observed in both sign and symptom scores (p < 0.001, for both) of eyes that received cyclosporine A. Significant differences were also noted at 2 weeks in mean scores of both signs and symptoms (p < 0.001, for both) between the eyes that received cyclosporine A and those that received placebo. At week 4 and 14, statistically significant decreases in both sign scores and symptom scores were noted compared with baseline in the eyes that received cyclosporine A and in the eyes that had initially received placebo (p < 0.001, for all).

INTERPRETATION

Topical 2% cyclosporine A in preservative-free artificial tears is effective in alleviating signs and symptoms of patients with severe vernal keratoconjunctivitis and had no observed side effects over the course of the study.

Comparison of the effects of ketotifen fumarate 0.025% and olopatadine HCl 0.1% ophthalmic solutions in seasonal allergic conjunctivities: a 30-day, randomized, double-masked, artificial tear substitute-controlled trial

BACKGROUND

Topical antiallergic agents, such as antihistamines and mast-cell stabilizers, are the main therapeutic options for seasonal allergic conjunctivitis (SAC). Ketotifen fumarate and olopatadine HCl have dual action that offers a combination of these 2 mechanisms. Although clinical studies comparing the efficacy of these 2 drugs have shown that both were effective in the treatment of SAC, the results were contradictory and did not include the effects of these drugs on inflammatory markers.

OBJECTIVES

The aims of this study were to compare the clinical efficacy of topical ketotifen and olopatadine eye drops and to determine the effects of these 2 drugs on the expression of cell adhesion molecules (CAMs) and inflammatory markers in conjunctival surface cells in patients with SAC.

METHODS

This 30-day, randomized, double-masked, artificial tear substitute (ATS)-controlled clinical trial was conducted at the Department of Ophthalmology, Karadeniz Technical University, School of Medicine, Trabzon, Turkey. Patients with SAC were included in the study and randomly assigned to 1 of 3 groups: topical ketotifen fumarate 0.025% ophthalmic solution, topical olopatadine HCl 0.1% ophthalmic solution, or ATS (control group). All drugs were administered 2 drops per eye BID for 30 days. At the beginning of the study (day 0; baseline), on day 15, and on day 30, clinical scores (itching, tearing, redness, eyelid, swelling, and chemosis) and conjunctival impression cytology specimens were obtained. The percentages of cells expressing intercellular adhesion molecule 1, vascular CAM-1, human leukocyte antigen-DR, and beta1-integrin (CD29) from conjunctival impression cytology specimens were determined using flow cytometry. Patients were questioned about adverse events (AEs) at each visit. Ocular discomfort on installation of the drugs was recorded as an AE.

RESULTS

Thirty-nine patients (20 men, 19 women; age range, 18-61 years) with SAC were included. Twelve patients received ketotifen; 13, olopatadine; and 14, ATS. In both active-treatment groups, the improvements of clinical scores (tearing and itching) were more pronounced compared with those in the ATS group, although the day-30 difference in tearing score between the olopatadine and ATS groups was not statistically significant. No significant within-group or between-group differences in mean scores for redness, chemosis, or eyelid swelling were found. The expression rates of CAMs and inflammatory markers in conjunctival surface cells were significantly more reduced with ketotifen and olopatadine compared with ATS. However, clinical and flow cytometric parameters were improved with ATS at 15 and 30 days compared with baseline. No AEs were observed during the study period.

CONCLUSIONS

In this short-term study in a selected, small study population with SAC, ketotifen and olopatadine diminished the expression of CAMs and inflammatory markers on the conjunctival surface cells effectively. Both active treatments were more efficacious compared with ATS and were well tolerated.

Involvement of programmed death-ligand 2 (PD-L2) in the development of experimental allergic conjunctivitis in mice

BACKGROUND/AIM

Involvement of programmed death-1 (PD-1) and its ligands has been demonstrated in experimental allergic airway disease. Here, the authors aimed to examine whether PD-1 and its ligands are involved in the development of experimental allergic conjunctivitis (EC) in mice.

METHODS

EC was induced in Balb/c mice by active immunisation with short ragweed pollen (RW) in alum. 10 days later (day 10), the mice were challenged with eye drops containing RW. 24 hours after the challenge, conjunctivas, spleens, and sera were harvested for histological analysis, cytokine assays, and measurement of RW specific Ig levels. The actively immunised mice were treated with anti-PD-1, anti-PD-L1, anti-PD-L2 antibodies (Abs), or normal rat immunoglobulin G (nrIgG) during either the induction (day 0, 2, 4, 6, and 8) or the effector (2 hours before RW challenge on day 10) phase.

RESULTS

Ab treatment during the induction phase did not affect eosinophil infiltration although immune responses were modulated. In contrast, treatment with anti-PD-L2 Ab, but not anti-PD-1 or anti-PD-L1 Ab, during the effector phase significantly increased eosinophil infiltration into the conjunctiva without affecting systemic immune responses.

CONCLUSIONS

Similar to allergic airway inflammation, PD-L2 is involved in the development of EC during the effector phase but not the induction phase.

The interaction between ICOS and B7RP-1 is not required for the development of experimental murine allergic conjunctivitis

It is still unclear whether the interaction between inducible costimulator (ICOS) and its ligand, B7 related protein (B7RP)-1, is important for the development of allergic diseases. We investigated whether blocking the ICOS/B7RP-1 interaction affects the development of murine experimental allergic conjunctivitis (EC). EC was induced in Balb/c mice either by active immunization of ragweed (RW) or by transferring RW-primed splenocytes, followed by challenge with RW-containing eye drops. The mice were treated with anti-B7RP-1 antibody (Ab) or normal rat immunoglobulin G (IgG) during either the induction or effector phase. Regardless of the induction method or when the animals were treated, eosinophil infiltration into the conjunctiva was not affected by the anti-B7RP-1 Ab treatment. Splenocyte responses were not largely affected by this treatment. However, serum Ig levels were significantly reduced. These data suggest that blocking the ICOS/B7RP-1 in allergic diseases may not always be therapeutic.

Animal models of allergic and inflammatory conjunctivitis

Allergic eye diseases are complex inflammatory conditions of the conjunctiva with an increasing prevalence and incidence. The diseases are often concomitant with other allergic diseases such as allergic rhinitis, atopic dermatitis and allergic asthma. Despite the disabling and prominent symptoms of ocular allergies, they are less well studied and further insights into the molecular basics are still required. To establish new therapeutic approaches and assess immunological mechanisms, animal models of ocular allergies have been developed in the past years. The major forms of allergic ocular diseases, seasonal and perennial allergic conjunctivitis, vernal and atopic keratoconjunctivitis and giant papillary conjunctivitis, each have different pathophysiological and immunological components. In contrast to these distinct entities, the current animal models are based on the sensitization against a small number of allergens such as ovalbumin, ragweed pollen or major cat allergens and consecutive challenge. Different animal species have been used so far. Starting with guinea-pig models of allergic conjunctivitis to assess pharmacological aspects, new models including rats and mice have been developed which mimic major features of ocular allergy. The presently preferred species for the investigation of the immunological basis of the disease is represented by murine models of allergic conjunctivitis. In the future, combined ocular, nasal and aerosolic challenges with allergens may provide a model of allergy that encompasses simultaneously the target organs eye, nose and airways with conjunctivitis, rhinitis and asthma.