SummaryBackgroundHorses are an important source of allergens, but the distribution of horse allergens is poorly understood. Five horse allergens have been identified, Equ c 1‐4 and 6. Equ c 4 seems to be an important allergen, with an IgE‐binding frequency of 77% in horse‐sensitized individuals.ObjectivesThe aim of this study was to investigate levels of horse allergen Equ c 4 in dander, saliva and urine from ten horse breeds.MethodThe study population included 170 horses (87 mares, 27 stallions, 56 geldings) from ten breeds. Horse dander, saliva and urine samples were collected. Levels of horse allergen Equ c 4 were quantified using a two‐site sandwich ELISA (mAb 103 and 14G4) and were expressed as Equ c 4 U/μg protein.ResultsThe horse allergen Equ c 4 was present in all dander and saliva samples from ten horse breeds, with high within‐breed and inter‐breed variations; GM values were 639 Equ c 4 U/μg protein (range 5‐15 264) for dander and 39.5 (4‐263) for saliva. Equ c 4 was found in 19/21 urine samples. Adjusted for age, sex and changes over time, no differences between breeds could be seen in dander, while in saliva the North Swedish horse showed lower levels of Equ c 4 than any other breed. The levels of Equ c 4 protein in dander and saliva were significantly higher in samples from stallions compared to mares and geldings, independent of breed.Conclusions and Clinical RelevanceThe results show a high variability in allergen levels of Equ c 4 in dander and saliva both within and between breeds. Significantly higher levels were found in stallions compared to mares and geldings, independent of breed. Results suggest that none of the horse breeds studied can be recommended for individuals allergic to Equ c 4.

<b><i>Introduction:</i></b> Horse allergens are less studied than allergens from other furry animals and these allergens must be evaluated to understand the complexity of allergy to horses. The aims of this study were to develop assays for the horse allergens Equ c 1 and Equ c 2 in dander and saliva and to determine their levels in ten horse breeds. The study also included a comparison of these findings with previous results on the levels of Equ c 4 performed on the same study population. <b><i>Method:</i></b> The study population included 170 horses from 10 horse breeds including American Curly and Russian Bashkir horse, which have been suggested to be hypoallergenic. Competitive ELISA assays were developed, with polyclonal antibodies as capture antibodies, for the detection of Equ c 1 and Equ c 2 in dander and saliva samples. <b><i>Results:</i></b> The horse allergens Equ c 1 and Equ c 2 were found in all dander and saliva samples from the ten horse breeds. The GM level (ng/µg protein) of Equ c 1 in dander was 470 (range 129–2,569) and in saliva samples, 40 (range 6–160). The GM level of Equ c 2 in dander was 138 (range 18–1,650) and in saliva samples, 0.8 (range 0.03–17). In dander, there were no significant differences in Equ c 1 and Equ c 2 GM levels between stallions, mares, and geldings. <b><i>Conclusion:</i></b> Our results show high intra- and inter-breed variability. Neither the American Curly horse nor the Russian Bashkir horse, earlier categorized as hypoallergenic breeds, was associated with lower allergen levels of Equ c 1, Equ c 2, or Equ c 4 than the other horse breeds investigated.

Occupational exposure accounts for a substantial proportion (16%) of adult asthma [1, 2] and asthma may also be aggravated by triggers at the workplace. Serial measurements of lung function with a peak expiratory flow (PEF) meter may confirm work-related asthma and is recommended in US, European and Swedish national guidelines [3-7]. PEF should ideally be measured at least six times a day at the workplace and at home over a period of several weeks [8], noted down and subsequently analysed. The time-consuming and cumbersome nature of serial PEF thus limits its clinical usefulness [9]. However, this could potentially be alleviated by digital health point-of-care tools [10]. AsthmaTuner (Medituner AB, Stockholm, Sweden) is a cloud-based system for collection and analysis of lung function and symptoms using a wireless spirometer and a smartphone application [11]. We conducted a prospective nonrandomised clinical trial comparing the standard method of serial PEF to AsthmaTuner in patients with suspected asthma referred to the occupational medicine clinics at Lund,