Hypersensitivity pneumonitis due to metal working fluids: Detection of specific IgG antibodies to microbial antigens

Occupational exposure to microbially contaminated metal working fluids (MWF) can cause hypersensitivity pneumonitis (HP). An important step in the diagnosis of HP is to identify the triggering antigen by detection of corresponding specific IgG antibodies (sIgG). As commercial sIgG tests are currently not available, protein antigens were prepared from MWF-workplace samples and from MWF-typical bacterial isolates. In 57 % of suspected HP-cases (n = 30) elevated sIgG concentrations were measured to at least one MWF-relevant antigen, of which Mycobacterium immunogenum was most prominent (88 %), followed by Pseudomonas oleovorans and Pseudomonas spec (82 % each), MWF-antigen mix and Pseudomonas alcaliphila (65 % each). Elevated sIgG concentrations to other microorganisms were measured to Micropolyspora faeni (82 %) and Aureobasidium pullulans (77 %). Correlation of sIgG values of all tested microbial antigens showed a significant relationship of MWF-antigen mixture to Pseudomonas antigens, but a low correlation to moulds. These newly prepared MWF-antigens are useful tools for the diagnosis of patients with suspected MWF-HP and are available for further investigations. •Linking microbial exposure in the workplace and occupational HP is an important aspect of the diagnostic workflow.•The newly established and validated serological sIgG test tools described here contribute to this process.•The most prominent MWF-antigens among serologically positive serum samples were M. immunogenum and Pseudomonas .•Most IgG reactive mould and actinomyces antigens were A. pullulans and M. faeni.•Significant correlations occurred among sIgG to pseudomonas species or to mould species, but not between bacteria and mould.