Ex Vivo Apoptosis in CD8+ Lymphocytes Predicts Rectal Cancer Patient Outcome

Abstract EN

Background.

Apoptotic rates in peripheral blood lymphocytes can predict radiation induced normal tissue toxicity.

We studied whether apoptosis in lymphocytes has a prognostic value for therapy outcome.

Methods.

Lymphocytes of 87 rectal cancer patients were ex vivo irradiated with 2 Gy, 8 Gy, or a combination of 2 Gy ionizing radiation and Oxaliplatin.

Cells were stained with Annexin V and 7-Aminoactinomycin D and apoptotic and necrotic rates were analyzed by multicolor flow cytometry.

Results.

After treatment, apoptotic and necrotic rates in CD8+ cells are consistently higher than in CD4+ cells, with lower corresponding necrotic rates.

Apoptotic and necrotic rates of CD4+ cells and CD8+ cells correlated well within the 2 Gy, 8 Gy, and 2 Gy and Oxaliplatin arrangements ( p ≤ 0.009 ).

High apoptotic CD8+ rates after 2 Gy, 8 Gy, and 2 Gy + Oxaliplatin treatment were prognostically favorable for metastasis-free survival ( p = 0.009 , p = 0.038 , and p = 0.009 ) and disease-free survival ( p = 0.013 , p = 0.098 , and p = 0.013 ).

Conclusions.

Ex vivo CD8+ apoptotic rates are able to predict the patient outcome in regard to metastasis-free or disease-free survival.

Patients with higher CD8+ apoptotic rates in the peripheral blood have a more favorable prognosis.

In addition to the prediction of late-toxicity by utilization of CD4+ apoptotic rates, the therapy outcome can be predicted by CD8+ apoptotic rates.