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T-cell abnormalities after mediastinal irradiation for lung cancer. The in vitro influence of synthetic thymosin alpha-1

Journal Article · · Cancer (Philadelphia); (United States)

The effects of mediastinal irradiation (RT) on the numbers and functions of purified peripheral blood T-lymphocytes from patients with locally advanced non-small cell lung cancer were evaluated. The patients were candidates for a randomized trial to evaluate the immunorestorative properties of synthetic thymosin alpha-1. Twenty-one patients studied before RT did not exhibit any significant difference in T-cell numbers or function compared to age-matched healthy subjects. However, 41 patients studied within 1 week after completing RT exhibited significant depressions of E-rosette-forming cells at 4 degrees C (E4 degrees-RFC)/mm3, E-rosette-forming cells at 29 degrees C (E29 degrees-RFC)/mm3, OKT3/mm3, OKT4/mm3, and OKT8/mm3 (P . 0.0001); total T-cell percentages (%OKT3, P . 0.01); and T-cell proliferative responses in mixed lymphocyte cultures (MLR) (P . 0.01) and to the mitogen phytohemagglutinin under suboptimal conditions (P less than or equal to 0.03). Nine patients studied before and after RT showed a significant increase in OKT4/OKT8 (P . 0.01) following RT. A short-term in vitro incubation with thymosin alpha-1 could enhance MLR of T-cells in 12 of 27 patients with post-RT abnormalities. In 13 patients who were treated with placebo, the RT-induced depression of T-cell numbers and function persisted for at least 3 to 4 months. In addition, in 12 patients progressive decreases developed in %E4 degrees-RFC, %OKT3, %OKT4, and OKT4/OKT8, which always preceded clinical relapse.

Research Organization:
George Washington Univ. Medical Center, Washington, DC
OSTI ID:
5832156
Journal Information:
Cancer (Philadelphia); (United States), Journal Name: Cancer (Philadelphia); (United States) Vol. 55:5; ISSN CANCA
Country of Publication:
United States
Language:
English