Ragweed IgE and IgG4 antibody in nasal secretions during immunotherapy

Abstract

We have developed sensitive amplified immunoassays for measurement of IgE and IgG4 ragweed (RW) antibodies in unconcentrated nasal washes. IgE to Amb a I (formerly antigen E) can be assayed to less than 0.1 ng/ml using IgE capture by anti-IgE on microtitre plates and an alkaline phosphatase-conjugated Amb a I with an amplification substrate technique. IgG4 to whole RW extract was assayed to less than 0.01 ng/ml by amplification ELISA using monoclonal anti-IgG4. Nasal washes (NW) (10 ml) and serum were obtained in December from 22 RW-sensitive patients before and after 1 and 2 yr of RW immunotherapy (IT), and assayed for Amb a I IgE or RW IgE and RW IgG4 antibodies Amb a I IgE could be measured in the NW of 15/22 pre IT, 19/22 at 1 yr IT, but only 3/10 at 2 yr IT (compared with pre-IT, P less than 0.05). Mean Amb a I IgE in NW was 0.66, 0.36 and 0.21 ng/ml at pre, 1 yr and 2 yr IT (P-values greater than 0.05). Mean serum RW IgE, was 76, 55 and 27 ng/ml at pre, 1 yr and 2 yr IT (P-values greater than 0.05). Amb a I IgE in nasal washes was correlated with RW IgE in serum (r = 0.56, P less than 0.001, n = 44). RW IgG4 was detectable in NW of 15/22 pre-IT, 18/22 at 1 yr IT and 9/10 at 2 yr IT (P-values greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)