Papain Induced Occupational Asthma with Kiwi and Fig Allergy

Abstract

Papain is a proteolytic enzyme which is widely used in food industry, pharmaceuticals, and cosmetics. Occupational and non-occupational papain allergies have previously been documented; however, there are limited publications about papain allergy with its relative fruit allergy. Here, we present a case of occupational, IgE-mediated papain allergy with kiwi fruit and fig fruit allergy. A 53-year-old man suffered from rhinitis for several years, with the onset of his symptoms coinciding with the time he started to work at a sausage processing plant where papain is often used as a meat tenderizer. He began to experience symptoms of chest tightness, shortness of breath and wheezing shortly after starting work 5 years ago. Furthermore, he experienced several episodes of oral itching, and tongue and oropharyngeal angioedema after injestion of kiwi fruit and fig fruit. The patient had a lifelong history of allergic conjunctivitis, allergic rhinitis, and childhood asthma. Specific IgE was positive to kiwi fruit, papain and chymopapain (2.95 kUA/L, >100 kUA/L, and 95.0 kUA/L, respectively). Similar bands at 10-15 kDa in blotting with papain and kiwi fruit extracts were found. This patient showed a potential association between papain allergy and sensitization to kiwi fruit. We also reviewed 13 patients with papain allergy published in the literature, with 85% (11/13) of the patients sensitized through the respiratory tract, and 40% (4/11) having atopy. Further studies should focus on the determination of cross-reactive allergens between papain and its fruit relatives, and the prevalence of food allergy in patients with papain allergy should be investigated in a relatively large cohort.

Keywords: Occupational asthma; cross reactivity; kiwifruit allergy; papain.

Figure. SDS-PAGE analysis and IgE immunoblotting in the patient and a healthy control.SDS-PAGE (A): lane M, molecular mass markers; Lane A1: kiwi fruit protein extract (KPE) 30 µg ; LaneA2: kiwi fruit protein extract 20 µg; lane A3: papain 30 µg; lane A4: papain 20 µg; laneA5: papain10 µg. Western blotting (B): lane M, molecular mass markers; lane B1-B5, immunblotting patterns of protein extracts incubated with the patient's serum, from B1 to B5, the proteins are KPE 30 µg, KPE 20 µg, papain 30 µg, papain 20 µg, and papain 10 µg, respectively. Western blotting (C): lane C1-C5, immunoblotting patterns of protein extracts incubated with the healthy control's serum, from C1 to C5, the loading proteins are KPE 30 µg, KPE 20 µg, papain 30 µg, papain 20 µg, and papain 10 µg, respectively.