Author(s): Z. Sonday, S. Adams, T. Singh, E. Ratshikhopha, MF Jeebhay

Source: Current Allergy & Clinical Immunology Ӏ March 2022 Ӏ Vol 35, No 1

Abstract:

Background: A machine operator at a factory that packages raw forms of legumes and grains developed work-related ocular-nasal and asthma symptoms associated with exposure to legume dust at work. Despite earlier sensitisation, he developed ingestion-related symptoms to lentils much later, after tolerating exposure for years.

Methods: Work-related symptoms were evaluated clinically and by means of a walk-through inspection to ascertain the extent of exposure to legume dust. Respiratory function assessment entailed spirometry accompanied by a bronchodilator challenge and serial peak flow monitoring. Immunological evaluation included investigation for atopy using Phadiatop and skin-prick tests to common aeroallergens, specific IgE reactivity to potential workplace legume and grain food allergens as well as other potentially cross-reacting food agents. SDS-PAGE and immunoblot testing were used to determine the molecular weights of the putative allergen using food samples obtained from the factory and the serum of the index case.

Results: Occupational asthma was confirmed based on the finding of airway reversibility and a positive work effect index score of 3.73 in the presence of sensitisation to different lentils and split peas. The molecular weights of potential allergens were identified as being a ~50 kDa protein (possibly Len C 1 and Pis s 1 respectively), one between 75–100 kDa and another of 25 kDa. There also appeared to be cross-sensitisation to other legumes, notably chickpea.

Conclusion: This rare case of occupational legume (lentil and split pea) allergy resulting in occupational rhinitis and asthma highlights the role of inhalant workplace food allergens and the need for improved workplace dust control measures and exposure standards in the food industry.

Keywords: work-related asthma, occupational food-induced allergy, lentil allergy, split pea allergy, inhalational legume allergy