Objective:To investigate CD1a and CD83 expression in tumor infiltrating dendritic cell (TIDC) of esophageal squamous cell carcinoma (ESCC) and tumorinfiltrating lymph node tissues, and to discuss its relationship with the clinical pathological characteristics of esophageal carcinoma. Methods:Seventyeight paraffin samples were obtained from pathologically diagnosed esophageal carcinoma patients in the fourth hospital of Hebei medical university during 2002 to 2003. Flow cytometry was used to examine the expression of CD1a and CD83 on TIDC in 78 esophageal carcinoma tissues, 24 normal esophageal mucosal samples, 35 normal lymph nodes and 32 tumorinfiltrating lymph nodes.Results: (1) The expression of CD1a and CD83 in ESCC tissues was significantly lower than those in the normal esophageal mucosa (P<005). (2) CD1a expression was not correlated with the tumor infiltration, clinical stage and lymph node metastasis of esophageal carcinoma (all P>0.05), while CD83 expression was correlated with the clinical stage and lymph node metastasis (all P<0.05). (3) There was no significant difference in CD1a expression between normal lymph node and tumorinfiltrating lymph node (P>0.05), but CD83 expression in tumorinfiltrating lymph node was less than that in the normal lymph node (P<005). Conclusion:The expression of CD83 in TIDC can reflect the local immune status of esophageal carcinoma, and also plays an important role in the development and progression of esophageal carcinoma. CD83 expression may serve as a biomarker for evaluating biological characteristics of esophageal carcinoma.