Alpha amylase is a major allergenic component in occupational asthma patients caused by porcine pancreatic extract

Performance of specific immunoglobulin E tests for diagnosing occupational asthma: a systematic review and meta-analysis

OBJECTIVES

To determine the test performance parameters for the retrievable range of high-molecular-weight (HMW) and low-molecular-weight (LMW) occupational allergens and to evaluate the impact of allergenic components and the implementation of measures for test validation.

METHODS

A protocol with predefined objectives and inclusion criteria was the basis of an electronic literature search of MEDLINE and EMBASE (time period 1967-2016). The specific inhalation challenge and serial peak flow measurements were the reference standards for the specific IgE (sIgE) test parameters. All of the review procedures were reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

Seventy-one studies were selected, and 62 entered meta-analysis. Pooled pairs analysis indicated a sensitivity of 0.74(95% CI 0.66 to 0.80) and specificity of 0.71(95% CI 0.63 to 0.77) for HMW allergens and a sensitivity of 0.28(95% CI 0.18 to 0.40) and specificity of 0.89(95% CI 0.77 to 0.95) for LMW allergens. Component-specific analysis improved the test parameters for some allergens. Test validation was handled heterogeneously among studies.

CONCLUSION

sIgE test performance is rather satisfactory for a wide range of HMW allergens with the potential for component-specific approaches, whereas sensitivity for LMW allergens is considerably lower, indicating methodological complications and/or divergent pathomechanisms. A common standard for test validation is needed.

A case of occupational rhinitis caused by porcine pancreatic extract developing into occupational asthma

Porcine pancreatic extracts (PPE), which are widely used as a digestive drug in Korea, are composed of alpha-amylase and lipase. Such enzymes are commonly described as occupational allergens. This is the first report of occupational rhinitis caused by PPE developing into occupational asthma in a hospital nurse. She showed strong positive response in the skin prick test (SPT) (5+, wheal ratio of allergen to histamine) and had a high serum-specific IgE level to PPE, but showed a negative response in the methacholine bronchial challenge test (MBT). She had been exposed to PPE intermittently with intermittent medications for rhinitis. Two years later, she presented with rhinitis and additional asthmatic symptoms. In contrast to her first visit, she showed a positive response in the MBT, and developed bronchoconstriction in the PPE-bronchial provocation test (BPT). These findings suggest that inhalation of PPE powder can induce IgE-mediated occupational rhinitis in a hospital setting, which will develop into occupational asthma if avoidance is not complete.

Sensitization to Empynase(pronase B) in exposed hospital personnel and identification of the Empynase allergen

BACKGROUND

Empynase is a proteolytic enzyme that is widely used as an anti-inflammatory drug in Korea. We evaluated the prevalence of sensitization to Empynase in association with respiratory allergy symptoms in exposed hospital personnel, and identified the IgE-binding components in the Empynase extract, using sera with high levels of specific IgE antibodies.

METHODS

A total of 154 hospital personnel (135 nurses and 19 pharmacists) who worked in a university hospital and 123 unexposed healthy control subjects were enrolled. A questionnaire was administered that addressed demographics, job category, history of atopic diseases, diverse symptoms including nasal and lower respiratory symptoms, and the association of symptoms with work. Skin prick tests (SPTs) to common aeroallergens and Empynase extract were performed. Empynase-specific IgE antibody was detected by ELISA, and ELISA inhibition tests were conducted. IgE-binding components were identified by SDS-PAGE and IgE immunoblotting.

RESULTS

Forty-two subjects (27.3%) complained of work-related respiratory symptoms (WRRS). Five nurses (3.7%) and one pharmacist (5.3%) had work-related asthma symptoms, and 34 nurses (25.2%) and six pharmacists (31.6%) had work-related rhinitis symptoms. The prevalence of sensitization to Empynase on SPTs was 20.1%, and tended to be higher in pharmacists (31.6%) than in nurses (18.5%). It was estimated that 3.9-8.4% of hospital personnel had WRRS attributable to Empynase. The duration of exposure was longer in positive SPT responders than in negative responders (51.9+/-27.5 vs. 39.2+/-27.3 months, respectively; P<0.05), and the prevalence of Empynase-positive SPTs was significantly higher in subjects with asthma than in those without asthma (57.1% vs. 18.4%, respectively; P<0.05). The levels of Empynase-specific IgE antibodies were significantly higher in pharmacists (76.1+/-83.4 OD units) and nurses (56.3+/-103.0 OD units) than in normal controls (39.8+/-12.7 OD units; P<0.05). Seven subjects (two pharmacists and five nurses) had high serum levels of Empynase-specific IgE antibodies; six of these subjects had WRRS. ELISA inhibition tests were performed with the sera of these six subjects, revealing significant inhibition only with the addition of Empynase. Four strongly staining protein bands (sizes: 36, 33, 16, and 10 kDa) from Empynase extract were observed to bind to the IgE antibodies of sensitized subjects. Conclusion Exposure to Empynase powder may cause rhinitis and asthma in hospital personnel, and the pathogenic mechanism appears to be IgE mediated.

Recent developments in airway and nose occupational sensitizers

PURPOSE OF REVIEW

To describe the latest developments in the field of occupational asthma and occupational rhinitis in 2001 and 2002.

RECENT FINDINGS

Several surveillance programs of occupational diseases, such as Observatoire National des Asthmes Professionnels in France, Surveillance of work-related and Occupational Respiratory Diseases in South Africa (SORDSA), Surveillance of Work-related and Occupational Respiratory Diseases (SWORD) in UK, have reported on the frequency of occupational asthma. The causative agents were mainly flour, isocyanates and latex. The common methods of diagnosis - questionnaires, cutaneous tests, Peak Expiratory Flow Rate (PEFR), bronchial hyperresponsiveness - still create controversy. In addition, the specific bronchial challenge, the classical gold standard of diagnosis, has its limitations since it cannot be performed in every case. Other methods have been assessed as inflammatory markers in induced sputum. Occupational rhinitis appears to be a poorly diagnosed condition.

SUMMARY

Further studies are expected to explore the effect of environmental control and medical surveillance. The key to successful management of occupational asthma and occupational rhinitis may be prospective surveillance of the occurrence of specific IgE antibodies before the onset of allergic symptoms.