Abstract

BACKGROUND:
Recombinant Hevea brasiliensis (rHev b) natural rubber latex (NRL) allergen components have been developed to assess the patients' allergen sensitization profile and to improve the diagnosis of NRL allergy.

OBJECTIVE:
To examine whether the determination of specific IgE (sIgE) reactivity to a panel of recombinant allergen components would be helpful for diagnosing NRL-induced occupational asthma (OA) in predicting the outcome of a specific inhalation test.

METHOD
S: sIgE levels to NRL extract and 12 recombinant NRL allergen components were assessed in 82 subjects with OA ascertained by a positive specific inhalation challenge (SIC) with NRL gloves and in 25 symptomatic subjects with a negative challenge.

RES
ULTS: The sensitivity, specificity, positive predictive value and negative predictive value of a NRL-sIgE level =0.35 kUA /L as compared to the result of SICs were 94%, 48%, 86%, and 71%, respectively. The positive predictive value increased above 95% when increasing the cut-off value to 5.41 kUA /L. Subjects with a positive SIC showed a significantly higher rate of sIgE reactivity to rHev b 5, 6.01, 6.02 and 11 than those with a negative SIC. A sIgE sum score against rHev b 5 plus 6.01/6.02 =1.46 kUA /L provided a positive predictive value >95% with a higher sensitivity (79%) and diagnostic efficiency (Youden index: 0.67) as compared with a NRL-sIgE =5.41 kUA /L (49% and 0.41, respectively).

CONCLUSION:
In suspected OA, high levels of sIgE against rHev b 5 combined with rHev b 6.01 or 6.02 are the most efficient predictors of a bronchial response to NRL.

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