Radiotherapy-induced changes of peripheral blood lymphocyte subpopulations in cervical cancer patients: relationship to clinical response.

Purpose: To determine the absolute number and percentage of peripheral blood lymphocyte subpopulations positive (+) cells CD8(+), CD8(+)NKG2D(+), CD8(+), Granzyme B(+) (GrB), CD16(+), CD16(+)NKG2D(+), CD56(+) and CD56(+)NKG2D(+) in cervical cancer patients before and after radiotherapy (RT), and to analyze whether their changes are related to the clinical response.

Materials And Methods: Stage IIB - IVA cervical cancer patients received external irradiation and concomitant intracavitary brachytherapy. Blood samples for immunophenotypic analysis by flow cytometry were collected from each patient one day before starting RT and one day after completing RT. Fifteen healthy volunteers served as controls. Surface marker expression and granzyme B positivity were quantified on FACSCalibur flow cytometer.

Results: Unlike their absolute numbers, the percentages of all analyzed lymphocyte subsets of all patients, including those with complete response (CR), were significantly increased (p <0.05) after RT. Only in patients with progressive disease (PD), CD8(+), CD8(+)NKG2D(+), CD16(+) and CD56(+)NKG2D(+) lymphocytes were not significantly increased. In healthy volunteers, the percentage of CD8(+)GrB(+) lymphocytes was lower than in patients after RT, while the percentages of CD56(+) and CD56(+)NKG2D(+) cells were higher than in patients before RT (p <0.05).

Conclusion: Our data indicate that RT, besides its direct cytoreductive effect on tumor cells, may contribute to better immunological control of cervical cancer.