Novel occupational causes of hypersensitivity pneumonitis

Abstract

Purpose of reviewHypersensitivity pneumonitis (HP) remains a challenging diagnosis, and a cause is not established in up to 50% of cases. This paper aims to update clinicians on traditional and novel occupational causes of HP, and clinical tools for identifying of causative exposures and antigens.Recent findingsMetalworking fluid has become the most frequently cited occupational cause of HP, though geographical variations in exposures exist. Occupational HP is usually associated with work-related symptoms. Systematically derived questionnaires and compendia for HP have been developed for use in cryptogenic disease, though have previously lacked validation; these may help identify inciting antigens or relevant occupational exposures.SummaryClinicians should enquire about job roles and work-relatedness of symptoms when considering a diagnosis of HP. Outbreaks of metalworking fluid associated HP from around the world are well described, so clinicians should remain vigilant. The usual classification for causative antigen includes animal and plant proteins, fungi, bacteria, low-molecular weight chemicals and metals; however novel occupational exposures and work processes are frequently reported.

Microbial Community Establishment, Succession, and Temporal Dynamics in an Industrial Semi-Synthetic Metalworking Fluid Operation: A 50-Week Real-Time Tracking

“…Over the years, it has been recognized that significant health and safety risks exist for machine workers exposed to microbially contaminated MWFs [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 67 , 68 , 69 , 70 , 71 ]. In terms of the etiology of health effects, while the infectivity of MWF microbes may be dependent on viability, the immunogenicity is independent of their viability status as non-viable cells may carry the causal antigens repertoire; hence, there is a need to determine the load of both viable as well as non-viable populations of the microbial community in the metalworking fluid.…”

“…Occupational exposure to microbially contaminated MWFs has been associated with various cutaneous and respiratory illnesses such as asthma, hypersensitivity pneumonitis, bacterial pneumonia, among others [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Studies have implied cross-pollination of microbial agents between MWF and human cases of respiratory disease [ 19 , 23 ].…”