Systemic Atopy and Immunoglobulin Deficiency in Turkish Patients with Vernal Keratoconjunctivitis

Allergen Testing: A Review of the Indications, Procedures, and Limitations in Ocular Allergy

Allergen-based diagnostics are essential in the management algorithm of allergic diseases. Unlike systemic allergy, where the indications and interpretation of these diagnostic modalities are well established, their utility in ocular allergy is not well-defined. With the rising prevalence of ocular allergies and the need for personalized treatment strategies, there is a growing demand for precision allergen diagnostics. This review describes the commonly used tests with their indications, procedures, and limitations. A review of the literature was carried out on articles on allergen diagnostics in ocular allergy, and after excluding articles that were not relevant, 82 papers were included in the current review. IgE-mediated pathways contribute significantly to seasonal and perennial ocular allergy and partly to vernal keratoconjunctivitis. Most diagnostic techniques aim to detect IgE sensitization. In vivo tests include skin prick (SPT), intradermal, and patch tests. SPT is considered the gold standard and directly evaluates the presence of allergen-specific IgE in the skin. In vitro tests measure total and specific IgE from either tears or sera. Tear IgE measurement is relatively specific for allergic conjunctivitis and can provide insight into the potential allergens responsible for local sensitization. The conjunctival provocation test can help establish true allergy, especially in patients with polysensitization. This review also provides an overview of evidence in literature segregated based on the test employed. This includes 17 studies on only SPT; 42 studies on IgE measured in serum, tears, or both; and 20 studies which have evaluated both SPT and IgE. The pattern of allergen sensitization can guide recommendations for avoidance measures and immunotherapy. Thus, this could create a corticosteroid-sparing therapy avenue in these patients, reducing disease severity and resulting visual morbidity.

Clarifying the effect of gut microbiota on allergic conjunctivitis risk is instrumental for predictive, preventive, and personalized medicine: a Mendelian randomization analysis

Background

Allergic conjunctivitis is an ocular immune disease which affects the conjunctiva, eyelids, and cornea. Growing evidence implicates the gut microbiota in balancing and modulating immunity response, and in the pathogenesis of allergic disease. As a result, gut microbial imbalance could be a useful indicator for allergic conjunctivitis. From the perspective of predictive, preventive, and personalized medicine (PPPM), clarifying the role of gut microbial imbalance in the development of allergic conjunctivitis could provide a window of opportunity for primary prediction, targeted prevention, and personalized treatment of the disease.

Working hypothesis and methodology

In our study, we hypothesized that individuals with microbial dysbiosis may be more susceptible to allergic conjunctivitis due to an increased inflammatory response. To verify the working hypothesis, our analysis selected genetic variants linked with gut microbiota features (N = 18,340) and allergic conjunctivitis (4513 cases, 649,376 controls) from genome-wide association studies. The inverse-variance weighted (IVW) estimate, Mendelian randomization (MR)-Egger, weighted median estimator, maximum likelihood estimator (MLE), and MR robust adjusted profile score (MR.RAPS) were employed to analyze the impact of gut microbiota on the risk of allergic conjunctivitis and identify allergic conjunctivitis-related gut microbes. Ultimately, these findings may enable the identification of individuals at risk of allergic conjunctivitis through screening of gut microbial imbalances, and allow for new targeted prevention and personalized treatment strategies.

Results

Genetic liability to Ruminococcaceae_UCG_002 (OR, 0.83; 95% CI, 0.70-0.99; P = 4.04×10^-2), Holdemanella (OR, 0.78; 95% CI, 0.64-0.96; P = 2.04×10^-2), Catenibacterium (OR, 0.69; 95% CI, 0.56-0.86; P = 1.09×10^-3), Senegalimassilia (OR, 0.71; 95% CI, 0.55-0.93; P = 1.23×10^-2) genus were associated with a low risk of allergic conjunctivitis with IVW. Besides, we found suggestive associations of a genetic-driven increase in the Oscillospira (OR, 1.41; 95% CI, 1.00-2.00; P = 4.63×10^-2) genus with a higher risk of allergic conjunctivitis. Moreover, MLE and MR.RAPS show consistent results with IVW after further validation and strengthened confidence in the true causal associations. No heterogeneity and pleiotropy was detected.

Conclusions

Our study suggests that gut microbiota may play a causal role in the development of allergic conjunctivitis and provides new insights into the microbiota-mediated mechanism of the disease. Gut microbiota may serve as a target for future predictive diagnostics, targeted prevention, and individualized therapy in allergic conjunctivitis, facilitating the transition from reactive medical services to PPPM in the management of the disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-023-00321-9.

Prevalence of allergic sensitization with vernal keratoconjunctivitis: A systematic review with meta-analyses

To determine the prevalence of allergic sensitization in patients with vernal keratoconjunctivitis (VKC) and to provide an overview of published studies on this topic. We systematically searched 11 literature databases on 24 May 2021, for studies with cross-sectional data on the prevalence of positive allergy tests in patients with VKC. Our main outcome of interest was the prevalence of allergic sensitization and the allergens involved. Prevalence meta-analyses were made to provide summary estimates. We identified 33 eligible studies for qualitative review with 2122 patients with VKC. Studies were predominantly based on patients seen in ophthalmology clinics. Overall, studies reported that the most prevalent positive allergen tests were the inhaled allergens house dust mites and pollen. Twenty-nine studies were eligible for the quantitative analysis. Here, we calculated the prevalence of allergen-positive patients to 57.7% (95% confidence interval: 52.5%-62.8%). Subgroup analyses of pooled estimates on sensitization based on specific testing methods found prevalence estimates of 51.4% for conjunctival provocation test, 68.7% for total tear IgE, 58.9% for specific tear IgE, and 58.2% for skin prick test. The prevalence of allergic sensitization in patients with VKC is 57.7%, and mostly towards inhaled allergens. The most frequent positive allergens are house dust mites and pollen. Identifying possible clinically relevant allergens provide information that may aid in managing VKC, such as environmental allergy-avoidance or allergy-specific treatment.

The role of human immunodeficiency virus in the pathogenesis of vernal keratoconjunctivitis-like disease in adults: A demographic and epidemiological study

Purpose:

The purpose was to identify and describe patients with new-onset vernal keratoconjunctivitis-like (VKC-like) disease after puberty.

Methods:

The study consisted of two parts: a prospective observational descriptive study of patients with new-onset VKC-like disease, and a case-control study to determine the relationship of a CD4 count with VKC-like disease in adults, in the setting of human immunodeficiency virus (HIV). Patients were recruited between January 2016 and November 2017 from a Provincial Eye hospital, one of two large referral hospitals in KwaZulu-Natal, South Africa. Patients presenting to the eye clinic were screened and diagnosed at the Primary Eye Care Unit. Inclusion criteria: age 15 years and older with signs and symptoms of new-onset VKC-like disease. Exclusion criteria: a history of childhood atopic diseases, atopic keratoconjunctivitis and patients who declined HIV testing. Data collected included HIV status, CD4 count, antinuclear antibodies and total serum immunoglobulin E.

Results:

Thirty-three patients were included; females n = 16 and males n = 17. The mean age at presentation was 32.45 ± 9.93 years, 95% CI = 28.94–35.97. Twenty-six patients (78.8%) were HIV positive, 95% CI (62–89). The proportion of HIV positive patients was statistically different from the HIV negative group, Chi-squared = 21.866, P value <0.0001. In the group of HIV positive patients, 72% were classified as immunodeficient according to their CD4 counts. An association was proven between severely immunodeficient patients and the risk of VKC-like disease (Chi-squared = 4.992, P value = 0.0255).

Conclusion:

In this cohort, a statistically significant association was found between VKC-like disease in adults and an HIV positive status. This association calls for more research on the subject.

Current Knowledge in Allergic Conjunctivitis

Allergic conjunctivitis is a disease of increasing prevalence that affects both children and adults and causes significant deterioration of their quality of life and sometimes irreversible visual damage. There are various forms of the disease, some are allergen-induced such as seasonal and perennial allergic conjunctivitis, giant papillary conjunctivitis, and contact allergic blepharoconjunctivitis, whereas others are not always explained by allergen exposure, such as vernal keratoconjunctivitis and atopic keratoconjunctivitis. We review their clinical course, characteristics, and differential diagnosis, and highlight recent advances in their pathophysiology and treatment.

Evaluation of Olfactory Function in Children With Vernal Keratoconjunctivitis

BACKGROUND

Vernal keratoconjunctivitis (VKC) is a chronic, severe allergic disease of the conjunctiva, which mostly affects young males in early to mid-childhood. There is a high incidence of asthma, allergic rhinitis (AR) and eczema among patients with VKC. It is unknown if VKC patients have abnormal olfactory dysfunction, and if so, whether this is related to AR.

OBJECTIVE

Our aim was to evaluate olfactory function in children with VKC, with and without comorbid AR, in comparison to healthy children without VKC.

MATERIALS AND METHODS

Thirty-nine VKC patients and 32 healthy children were included in the study. After eye and ear, nose and throat (ENT) examination, acoustic rhinometry and modified Connecticut Chemosensory Clinical Research Center (CCCRC) tests were performed and the test results were compared between VKC and control groups and between VKC children with or without AR. A p value <0.05 was regarded as statistically significant.

RESULTS

The VKC group included 25 males (64.1%) with a mean age of 11.13 ± 3.22 years, while the control group included 26 males (81.3%) with a mean age of 12.50 ± 2.13 years (p > 0.05 for both age and gender). Fourteen VKC patients (35.9%) had either positive prick test or elevated serum specific IgE levels against house dust mites and pollens. Mean odor thresholds did not differ between the two groups (p = 0.084), while mean odor identification and CCCRC score were statistically significantly lower in VKC group (6.00 ± 1.02 and 6.81 ± 0.75, respectively) compared to control group (7.06 ± 0.77 and 7.5 ± 0.41, respectively) (p < 0.05, both). Thirteen VKC patients had co-associated AR (33.3%). In VKC patients with AR, mean odor threshold and identification scores were even lower (5.31 ± 0.95 and 6.23 ± 0.78, respectively) (p < 0.05, both).

CONCLUSION

Olfactory function was found to be mildly impaired in children with VKC, especially when co-associated with AR. Therefore, loss of smell should be asked as an extraocular symptom.

Eye drop emulsion containing 0.1% cyclosporin (1 mg/mL) for the treatment of severe vernal keratoconjunctivitis: an evidence-based review and place in therapy

Vernal keratoconjunctivitis (VKC) is a rare, recurrent and multifactorial ocular disease, which typically flares up during spring and affects especially male children and adolescents. This condition does not usually respond to common treatments with antihistamines or mast cells stabilizers, whereas corticosteroids have effective results. Corticosteroids need to be carefully administered, to avoid adverse effects, mainly the secondary development of glaucoma, cataracts, or infections. Immunosuppressive agents, such as cyclosporin (CyA) or tacrolimus are, therefore, frequently employed in VKC patients. Only the 0.1% CyA (1 mg/mL) concentration has an approved and specific clinical indication for the treatment of VKC and this drug was given the denomination of orphan drug by the European Commission (EU/3/06/360) in 2006. So far, few studies have been conducted to evaluate the efficacy and the side effects of topical 0.1% CyA. Different topical CyA concentrations, ranging from 0.05% to 2%, and various types of formulation are available at the moment. In the future, 0.1% CyA will presumably take an important part in the management of VKC. The present review focuses on eye drops containing 0.1% CyA; however, more studies will be needed to define its long-term efficacy in the natural course of this severe ocular disease.