Expression of Interleukin-21 and Interleukin-21 receptor in lymphocytes derived from tumor-draining lymph nodes of breast cancer.

BACKGROUND: Interleukin-21 (IL-21) is produced by various cell types inducing positive and negative effects in immunity against tumors. OBJECTIVE: To investigate the expression of IL-21 by CD4⁺T and IL-21 receptor (IL-21R) by B lymphocytes isolated from breast-tumor draining lymph nodes (TDLNs). METHODS: Fresh lymph node samples were obtained from 45 patients with breast cancer. To assess IL-21 expression, mononuclear cells were briefly stimulated whereas IL-21R expression was assessed in unstimulated B cells. Cells were stained with antibodies for CD4, IL-21, CD19 and IL-21R and acquired by flow cytometry. RESULTS: The frequency of IL-21⁺CD4⁺T cells did not show significant association with disease parameters. However, the geometric mean fluorescence intensity (gMFI) of IL-21 in CD4⁺T cells was significantly lower in patients with grade III tumor than grade I + II (P = 0.042). In non-involved LNs, the intensity of IL-21 was significantly higher in patients with stage II compared with stage III (P = 0.038) and correlated negatively with the number of involved LNs. The frequency of IL-21R⁺CD19⁺B cells was significantly higher in grade III than grade I + II (P = 0.037). CONCLUSION: The higher intensity of IL-21 in CD4⁺T cells showed association with good prognosticators in breast cancer and warrants further investigation of the role played by IL-21 in immunity against breast cancer. [ABSTRACT FROM AUTHOR]