Purpose: A new commercial immunochromatographic test (Allerwatch) has recently been developed for determining total immunoglobulin E (IgE). We previously reported on the use of this kit for analyzing tear fluid samples collected during the spring. In this study, we examined the relationship between the total IgE level in tears and the specific serum IgE levels in patients with autumnal allergic conjunctivitis.
Methods: A prospective, nonrandomized cross-sectional study was conducted in 36 patients with autumnal allergic conjunctivitis (autumnal allergic group), in 32 age-matched and sex-matched healthy control subjects (control group), and in 10 patients with epidemic keratoconjunctivitis. Total tear IgE score was determined in all subjects using the Allerwatch test (0, 1, and 2), whereas the serum levels of total IgE and specific IgE for 12 inhaled allergens were measured using the Phadezym PRIST and CAP-RAST systems, respectively.
Results: Positivity rates for total tear IgE were significantly higher in the autumnal allergic group as compared with the control and epidemic keratoconjunctivitis groups (88.9% vs. 0.0% vs. 0.0%, P < 0.00001). In the autumnal allergic group, there was a significant correlation between the total tear IgE score and the log-transformed total serum IgE level (r = 0.84). Significant correlations were also seen with the IgE serum levels for Dermatophagoides pteronyssinus (r = 0.53), house dust (r = 0.51), acarus (r = 0.49), cedar pollen (r = 0.33), and mugwort (r = 0.33). Multivariate logistic regression analysis showed that the only significant predictor of the total tear IgE score was the log-transformed total serum IgE level (odds ratio = 2.76, P < 0.00001).
Conclusions: The correlation between the Allerwatch total tear IgE score and the specific IgE serum levels against house dust mites suggests that house dust mite allergens might be the primary cause of allergic conjunctivitis during autumn in Japan. The Allerwatch methodology can provide rapid measurements of total IgE in the tear fluid, which makes it possible to easily diagnose allergic conjunctivitis in an outpatient setting.