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.