The allergens of 24, 19, 16, and 9 kDa are strong candidates to be major allergens, and the 19-kDa allergen was relatively specific for BW-allergic patients. Moreover, measurement of BW-specific IgE and the features of immunoblotting should be very useful tools in the diagnosis of BW allergy.

We conclude that isoallergens of Der p 2 may have different IgE immune responses. Quantification of Der p 2 with 2-site ELISA kits that adopted mAbs, might be affected by the prevalent form of the isoallergens in reservoir dust.

Objectives-Some patients with occupational asthma resulting from exposure to reactive dyes have skin reactivity to the causative dyes and specific IgE to reactive dyes have been found in these patients. However, the usefulness of skin prick tests (SPTs) and serological measurement of specific IgE in screening, diagnosis, and monitoring the occupational asthma resulting from exposure to reactive dyes have not yet been assessed. In this study, the clinical validation of SPTs and measurement of specific IgE to vinyl sulphone reactive dyes by enzyme linked immunosorbent assay (ELISA) was evaluated. Methods-42 Patients with occupational asthma from reactive dyes (true positive group) were enrolled. In these the causative reactive dye was confirmed by bronchial challenge test. 93 Asymptomatic factory workers with negative challenge to the reactive dye (true negative group) and 16 unexposed controls with negative challenge to the reactive dye were also enrolled. Skin prick tests were done with 10 mg/ml reactive dye in 0.4% phenol/0.9% saline. IgE specific to reactive dye conjugated to human serum albumin (HSA) was measured with enzyme linked immunosorbent assays (ELISAs). Results-None of the unexposed controls had a positive response to SPTs. The sensitivity (76.2% v 53.7%), specificity (91.4% v 86.0%), positive predictive value (80.0% v 62.9%), and negative predictive value (89.5% v 80.8%) of SPTs were higher than those of ELISAs. The mean weal size of reaction to reactive dye was weakly correlated with the ELISA optical density of IgE to reactive dye conjugate in patients with occupational asthma from reactive dyes (n=41, r=0.337, p<0.05). In four patients with occupational asthma from reactive dyes and eight control subjects exposed to reactive dye, IgE specific to reactive dye conjugated to HSA was detected with ELISA even though they showed negative skin reactivity. Six patients completely avoided the reactive dye for a mean (SD) 27.8 (10.3) months, IgE specific to reactive dyes decreased in all six patients (p<0.05) during this time.Conclusions-Both SPTs and detection of IgE specific to reactive dye in serum samples could be valuable for screening, diagnosis, and monitoring occupational asthma resulting from exposure to reactive dyes. These two tests would complement each other. (Occup Environ Med 2001;58:411-416)

Denaturation of vRD-HSA by heat affected its allergenicity markedly in five of six sera of RD-OA. When vRD was conjugated to the pre-heated HSA, its allergenicity also disappeared or was markedly attenuated compared with the vRD-HSA in five of six sera. Mercaptoethanol treatment markedly affected the allergenicity of the RD-HSA in all six RD-OA sera. Immunoblotting from non-denatured PAGE showed strong IgE affinity to vRD-HSA but immunoblotting from denatured SDS PAGE did not show IgE affinity. Among six RD-OA patients, five and four patients had pRD-HSA-specific and VS-HSA-specific IgE, respectively. However, the vRD-HSA-specific IgE was neither inhibited by pRD-HSA nor VS-HSA CONCLUSION: We considered that the conformational structure of HSA would be critical for the IgE epitopes during the haptenation process and both of the chromogen and reactive groups of the vRD would contribute to the formation of IgE epitope. Our results also confirmed the heterogeneity of IgE epitopes in the RD-HSA complex.

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