Author(s): Muvhali, M., Graham, A., Ratshikhopha, E., Singh, T.
Source: Current Allergy & Clinical Immunology, on volume 37 (issue 4)
Abstract: Hypersensitivity pneumonitis (HP) caused by avian antigens is one of the most prevalent forms of HP, with pigeon antigens being the most common culprits. While the health effects on pigeon breeders are well documented, there is limited information on the impact that pigeon breeding has on the health of family members and individuals living near breeding pigeons. This case study describes the condition of a 56-year-old housewife who was referred to an academic hospital’s respiratory outpatient department with a principal complaint of six years of progressively worsening dyspnoea and intermittent dry cough. Comprehensive evaluations included a physical examination, chest X-rays (CXR), high-resolution computed tomography (HRCT) and lung-function testing. Her blood was analysed for specific immunoglobulin G (sIgG) to avian antigens due to the patient’s husband breeding birds at their residence for racing. The clinical work-up suggested an HP diagnosis supported by the laboratory analysis of elevated sIgG antibodies to pigeon mix Ge 91 (pigeon serum proteins, feathers and droppings) and Ge 93 (pigeon serum proteins). These results enabled a confirmatory diagnosis of HP to secondary pigeon exposure. The findings underscore the importance of incorporating sIgG testing to support an HP diagnosis, which is critical to effective disease and exposure management. This case emphasises the necessity of establishing national reference ranges for IgG against common antigens to improve the utility of sIgG antigen testing in the HP diagnostic framework. In addition, it highlights the importance of monitoring exposures in rapidly growing cottage industries in South Africa to reduce the risk of exposure to people, animals and the environment.
Keywords: hypersensitivity pneumonitis, bird antigen sensitisation, bird fanciers disease, avian antigen