Validity of Specific Immunoglobulin E Assay in Tear Film for Detection of Allergens Inducing Different Types of Allergic Conjunctivitis.

ABSTRACT

This is a prospective interventional comparative study which aimed to investigate correlation between tear film allergen specific IgE levels and the skin prick test in diagnosing different types of allergic conjunctivitis. One hundred twenty patients with allergic conjunctivitis were included in this study and were classified into 4 groups based on the type of allergic conjunctivitis. Patients were subjected to skin prick test (SPT). Micro capillary method was used to collect tear samples for the quantitative assessment of specific IgE by Immune blot assay. The most common allergens were mixed mould, mixed pollen, and mixed mite. The results of tear film specific IgE in detection of allergens were evaluated against the SPT. The Receiving Operating Characteristic Curve (ROCs) revealed that tear film allergen-specific IgE specificity was 100% and sensitivity was 75%-100% to the three common allergens in the 4 studied groups. The correlation between tear's specific IgE and skin prick test was statistically significant for pollen, mite, and mould allergens in patient with SAK (r = 0.821, P ˂ 0.001 for pollen, r = 0.964, P ˂ 0.001 for mite, and r= 0.811, P ˂ 0.02 for mould ), PAC (r = 0.851, P ˂ 0.001 for pollen, r = 0.826, P ˂ 0.001 for mite, and r= 0.861, P ˂ 0.001 for mould) and VKC (r = 0.802, P ˂ 0.001 for pollen, r = 0.894, P ˂ 0.001 for mite, and r= 0.861, P ˂ 0.061 for mould). In patient with AKC, the correlation was statistically significant for only mite allergen (r = 1, P ˂ 0.001). We concluded that Tear film specific IgE test can be considered as a good alternative to skin prick test in diagnosis of the causative allergens in allergic conjunctivitis.