Evaluation of Hypersensitivity Pneumonitis Among Workers Exposed to Metal Removal Fluids

Abstract

Hypersensitivity pneumonitis (HP) was identified among employees in an automobile parts manufacturing facility. Mycobacteria immunogenum (MI) was identified as a metal removal fluid (MRF) contaminant at this facility and had been identified as a contaminant in other facilities where HP had occurred. We therefore questioned whether measurement of MI-specific cell-mediated immunity would be associated with HP in this facility. We also questioned whether measures of cell-mediated immunity would be more informative about the presence of HP than evaluation of serum anti-MI antibody levels. Workers were categorized for exposure and disease status by questionnaire and review of medical records. Cell-mediated immunity to MI was assessed by measuring in vitro secretion of cytokines (interleukin 8, tumor necrosis factor alpha, and interferon-gamma) from peripheral blood mononuclear cells or anticoagulated whole blood induced by culture with MI antigen. Serum antibodies against MI were also measured. Six study participants met our survey definition for HP and 48 did not. As has been reported for various agents causing HP, serum antibody levels against MI were increased in both exposed workers and workers with HP. Serum antibodies did not distinguish between the two. When expressed as a percentage of secretion induced by lipopolysaccharide, MI induced a significant increase in interleukin-8 secretion in exposed participants' whole blood cultures. There were trends for increased MI-induced secretion of interferon-gamma by peripheral blood mononuclear cells from both exposed workers and workers with HP. However, these trends did not attain statistical significance. Thus, several measures of immunity to MI distinguished between exposed and unexposed workers but not between workers with and without HP. These evaluations of cell-mediated immunity were not more informative than measurement of serum antibodies. As was done at this facility, institution of a comprehensive safety and health plan for MRF is necessary to eliminate (or minimize) health effects related to occupational exposures in the machining environment.

Factors Influencing the Microbial Composition of Metalworking Fluids and Potential Implications for Machine Operator's Lung

“…Since the first reports (5,27), most described cases of MWFrelated HP have been in the U.S. automotive industry (4,18,20,24,28,32,37,42,56). The first European case clusters were recently reported in automotive plants in Great Britain (8) and in France (41).…”

“…Although asthma and dermatitis seem to be caused by the chemical toxicity of MWFs due to additional components (e.g., biocides, defoamers, corrosion inhibitors, or dyes) (22,33,38), MOL has been related to microorganisms that frequently contaminate MWFs, especially Mycobacterium immunogenum, a recently described, fast-growing mycobacterium included in the Mycobacterium chelonae-Mycobacterium abscessus complex (18,24,37,48,52,54). Arguments in favor of this etiology are the presence of specific precipitins in MWF-related HP cases (5,14,32) and/or the presence of M. immunogenum in their environment (4,18,42,52). The ability to induce HP in mice exposed intranasally to M. immunogenum (16,40) is evidence of the role of this microorganism.…”

Biocidal Activity of Formaldehyde and Nonformaldehyde Biocides toward Mycobacterium immunogenum and Pseudomonas fluorescens in Pure and Mixed Suspensions in Synthetic Metalworking Fluid and Saline

“…The occurrence of mycobacteria in MWF and their potential occupational health significance has been highlighted (8,10,18). Mycobacterium immunogenum, a nontuberculous Mycobacterium species, has been reported in MWF and implicated as possible causative agent of hypersensitivity pneumonitis in machine workers who have been exposed to it (21,23,24). Among other MWF microbial communities, pseudomonads often constitute the major fraction of gram-negative organisms responsible for endotoxin release and accumulation in the fluids, resulting in occupational health hazards in metalworkers (2).…”

Hypersensitivity pneumonitis and metalworking fluids contaminated by mycobacteria

“…Although referenced by TILLIE-LEBLOND et al [1], the detailed immunological investigation performed on workers from a MWF-HP outbreak in the USA, where mycobacterial contamination was identified [11], is not discussed in any detail. In this key study [11], in vitro secretion of interleukin-8, tumour necrosis factor-a and interferon-c were measured in whole blood and from peripheral blood mononuclear cells in response to incubation with M. immunogenum antigen.…”