B cell subsets have been found to exhibit a negative regulatory function, like Tregs. The present study investigates the effects of CD5+CD19+ interleukin (IL)-10 (B10) on the occurrence and development of oesophageal carcinoma by analysing B10 levels in the peripheral blood of patients with oesophageal carcinoma. Peripheral blood of 120 oesophageal cancer patients and 120 healthy controls were collected, and regulatory B cell counts were determined by flow cytometry. The level of B10 cells in the peripheral blood of patients with oesophageal carcinoma was significantly higher than that in healthy controls (p < 0.05). In addition, B10 levels in stage III-IV patients (3.5 ±0.7%) were higher than those in stage I-II patients (2.5 ±0.6%), which were in turn higher than those in the healthy controls (1.3 ±0.3%). The level of B10 increased with clinical progression of oesophageal cancer, suggesting that B10 cells may influence the development or progression of oesophageal cancer.