Identification of antigenic proteins associated with trichloroethylene-induced autoimmune disease by serological proteome analysis

Although many studies indicated that trichloroethylene (TCE) could induce autoimmune diseases and some protein adducts were detected, the proteins were not identified and mechanisms remain unknown. To screen and identify autoantigens which might be involved in TCE-induced autoimmune diseases, three groups of sera were collected from healthy donors (I), patients suffering from TCE-induced exfoliative dermatitis (ED) (II), and the healed ones (III). Serological proteome analysis (SERPA) was performed with total proteins of TCE-treated L-02 liver cells as antigen sources and immunoglobins of the above sera as probes. Highly immunogenic spots (2-fold or above increase compared with group I) in group II and III were submitted to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and tandem mass spectrometry sequencing. Western blot analysis was followed using commercial antibodies and individual serum. Six proteins were identified. Among them, Enoyl Coenzyme A hydratase peroxisoma 1 and lactate dehydrogenase B only showed stronger immunogenicity for group II sera, while Purine nucleoside phosphorylase, ribosomal protein P0 and proteasome activator subunit1 isoform1 also showed stronger immunogenicity for group III sera. Noteworthy, NM23 reacted only with group II sera. Western blot analysis of NM23 expression indicated that all of the individual serum of group II showed immune activity, which confirmed the validity of SERPA result. These findings revealed that there exist autoantibodies in group II and III sera. Besides, autoantibodies of the two stages of disease course were different. These autoantigens might serve as biomarkers to elucidate mechanisms underlying TCE toxicity and are helpful for diagnosis, therapy and prognosis of TCE-induced autoimmune diseases.