AIM: To analyze the role of complement system(CS)and its classical pathway in the pathogenesis of lacrimal gland benign lymphoepithelial lesions(LGBLEL).

METHODS: The tissues of patients with LGBLEL or orbital cavernous hemangioma(CH)were collected. Proteomics analysis was used for the identification of different proteins. Reverse transcription-polymerase chain reaction(RT-PCR), immunohistochemical staining(IHC)and Western Blotting were employed to verify the changes of the differential proteins in CS signal pathway, in order to identify its role in the pathogenesis of LGBLEL.

RESULTS: The results of proteomic analysis showed that the expression levels of proteins C3, C5, C9 and C1q in CS signal pathway in the lacrimal gland tissues of LGBLEL patients were all changed compared with those of orbital CH patients.The results of RT-PCR showed that the mRNA expression levels of C1qA, C5 and C9 in patients with LGBLEL were significantly higher than those patients with orbital CH. The results of IHC showed that the expression levels of C1qA, C3, C5 and C9 were significantly increased in patients with LGBLEL compared with those patients with orbital CH. The results of Western Blotting showed that the protein expression levels of C1qA, C3, and C9 were significantly increased in patients with LGBLEL compared with those patients with orbital CH.

CONCLUSION: The CS has been shown to participate in the pathogenesis of LGBLEL and its classical pathway may be one of the pathways which plays a role.