Objective: In the present study we compared the lymphocyte composition of tumor draining lymph nodes (TDLN) in 13 cervical (CC) and 26 endometrial cancer (EC) patients with special emphasis on the suppressive CD4(+) T cell subset constitutively expressing CD25 (T regulatory, Treg, cells).
Methods: Microscopically uninvolved TDLNs (n = 122) collected at different distances from the primary tumor site were used. Proximal TDLN included obturator, and internal and external iliac nodes. Distal TDLN included common iliac, presacral, and aortic nodes. Sixteen relevant lymphocyte subsets were assessed. The proliferative response to PHA and TCR crosslinking, the suppressive activity of Treg cells, and IFN-gamma and IL-4 production were also assessed.
Results: Compared to EC patients, TDLN from CC patients contained a higher proportion of naive CD4(+) and CD8(+) cells (P < 0.01), a lower proportion of CD4(+) pre-effector cells (P < 0.05), and a higher proportion of the most potent Treg cell subset identified by coexpression of a high level of CD25 and CD152 (P < 0.05). Functionally, Treg cells were anergic and efficiently inhibited other T cell proliferation, thereby fulfilling the requirements of genuine Treg cells. The proliferative response of TDLN to both PHA and TCR crosslinking tended to be lower in CC than EC patients and was inversely related to the Treg cell content in both type of tumors. No differences were noticed between CC and EC patients in terms of IFN-gamma and IL-4 production. Using pairs of TDLN from individual patients, we showed that proximal TDLN in CC and EC patients displayed a higher CD4/CD8 ratio (P < 0.05 and 0.001, respectively) compared to distal TDLN of the same individual. By contrast, only in EC patients did proximal TDLN contained a proportion of Treg cells higher than distal TDLN (P < 0.02).
Conclusions: The present data highlight differences in immune competency of TDLN in CC and EC patients, suggesting that the former is in a relative immunosuppressive status, and also underlines the importance of the proximity to the primary tumor site.