[An ELISA assay for humulus scandens specific IgE antibodies].

OBJECTIVE

Humulus scandens pollen (HSP) has been proved to be the one of the most important causative factors of autumnal hay fever in China. We established an enzyme immunoassay for specific IgE against HSP by using monoclonal anti-IgE antibody to detect sIgE in 143 patients with autumnal hay fever and 30 healthy volunteers.

METHODS

An indirect method of ELISA was developed. The optimal conditions for the test were: coating the allergen at 4 degrees C overnight with a concentration of 12 micrograms/ml; the test serum was diluted 1:16 and incubated with allergen overnight at 37 degrees C; the most suitable dilution and incubative time of the peroxidase-conjugated mouse anti-human IgE antibody were 1:3,000 and 2 hours respectively.

RESULTS

The patients' serum level of sIgE was significantly higher than controls (P < 0.001) and correlated significantly with the degree of skin test reaction (P < 0.01). The concordance between the results of skin test and ELISA was 74%-83%. The specificity of the assay was confirmed by heat inactivation and multiple absorption experiments. The coefficients of variation for the intraassay and interassay reproducibility ranged from 1.20%-8.30% and 8.63%-9.22% respectively.

CONCLUSIONS

Determination of specific HSP IgE with ELISA assay shows good specificity, sensitivity and reproducibility. It favours clinical practice due to its lower cost.