Occupational Asthma Acrylates vs Other Low-Molecular-Weight Agents

Acrylate-induced occupational asthma resulted in more frequent work-related rhinitis compared with occupational asthma induced by isocyanates, and there was a significantly larger increase in postchallenge fractional exhaled nitric oxide (FeNO) levels in acrylate-induced occupational asthma vs occupational asthma induced by either isocyanates or other low molecular weight (LMW) agents, according to a study published in The Journal of Allergy and Clinical Immunology: In Practice.

Despite specific inhalation challenge-confirmed case reports of occupational asthma induced by acrylates, which are known skin sensitizers, the condition is not well characterized, and acrylates are not currently classified as respiratory sensitizers. Investigators aimed to describe a distinct occupational asthma phenotype by comparing that induced by acrylates with occupational asthma induced by other known (isocyanates) and similar (LMW compounds) induction agents.

An international, multicenter, retrospective study enrolled 55 patients with occupational asthma (mean age, 40.0 years; 32.7% men) with a positive specific inhalation challenge to acrylates along with 418 (mean age, 44.0 years; 55.7% men) who had positive specific inhalation challenges to other LMW agents; the latter group included a subgroup of 125 participants (mean age, 43.0 years; 78.4% men) with a positive isocyanate specific inhalation challenge. Confirmation of occupational asthma by specific inhalation challenge was ascertained between January 2006 and December 2015.

Data was collected on individuals’ jobs and chemical exposures, pulmonary function testing results, clinical characteristics, and airway inflammatory marker levels. A pre-post specific inhalation challenge increase in FeNO ≥17.5 parts per billion (ppb) was considered significant, and multivariable logistic regression analysis was used to verify that such increases were independently associated with acrylate exposure, with the odds ratio (OR) and 95% CI reported.

Occupations such as beauty work, dental care and industrial manufacturing typified those impacting occupational asthma, with the most prevalent acrylate-containing products used being glues. Compared with occupational asthma induced by isocyanate, acrylate-induced occupational asthma resulted in more work-related rhinitis (P <.001), as well as greater levels of work-related conjunctivitis (P =.002) and urticaria (P <.001); acrylate-induced occupational asthma was also correlated with more urticaria vs other LMW agents (P =.010).

There was a significantly greater post-challenge increase in FeNO in acrylate-induced occupational asthma (26.0 ppb; range 8.2-38.0) compared with isocyanate-induced occupational asthma (5.0 ppb; range 2.0-16.0; P =.010) or occupational asthma caused by other LMW agents (3.0 ppb; range -1.0 to 10.0; P <.001). And the proportion of individuals with a significant pre-post change in FeNO (≥17.5 ppb) was significantly higher in acrylate-induced occupational asthma (55.6%) vs occupational asthma induced by isocyanate (24.2%; P =.030) or other LMW agents (20.0%; P =.002).

Multivariate analysis revealed that acrylate-induced occupational asthma was independently and significantly associated with a significant post-challenge FeNO increase (OR 5.59; 95% CI, 1.87-17.58; P =.002).

Study strengths included an international multicenter design, minimized selection bias and enhanced generalizability of findings. Study limitations included a lack of airway inflammatory marker information for many patients, which restricted between-group comparisons.

“Our study shows that acrylate-induced occupational asthma has phenotypic characteristics suggesting that acrylates may induce occupational asthma through different immunological mechanisms than other LMW agents,” noted the authors. “Our findings reinforce the need for a re-evaluation of the hazard classification of acrylates, and further investigation of the pathophysiological mechanisms underlying their respiratory sensitizing potential.”

Reference

Suojalehto H, Suuronen K, Cullinan P, et al; European network for the PHenotyping of OCcupational ASthma (E-PHOCAS) investigators. Phenotyping occupational asthma caused by acrylates in a multicentre cohort study [published online October 30, 2019]. J Allergy Clin Immunol Pract. doi:10.1016/j.jaip.2019.10.017