Overview of occupational diseases induced by trichloroethylene and associated basic research

Objective: To provide an overview of the pathogenesis of pneumatosis cystoides intestinalis (PCI) and hypersensitivity syndrome (HS) caused by trichloroethylene (TCE) and the basic research into their toxicity. Subjects and Methods: We reviewed previously published research articles. Results: PCI clustered in Japan in the 1980s is a rare disease characterized by cyst-like distention of gas in the intestinal wall, which can be secondary or primary. No TCE users were found in the former group, whereas approximately 71% of the latter group were TCE users, suggesting the involvement of TCE exposure in primary PCI. However, the pathogenesis was unclear. TCE is metabolized by the drug-metabolizing enzyme CYP2E1, and intermediate immunocomplexes with CYP2E1 may be involved in hepatotoxicity. HS clustered in the southern part of China since early 2000 is a systemic skin-liver disorder involving anti-CYP2E1 autoantibodies and HLA-B*13:01 polymorphisms, with elevated cytokines and reactivation of Human Herpesvirus 6. Discussion and Conclusion: PCI and HS, occupational diseases caused by TCE, were clustered in Japan and southern China, respectively. HS was mediated by immune system disorders and genetic polymorphisms, whereas their relevance to PCI occurrence remained unknown.