Dynamic changes in T-cell subsets and C-reactive protein after radiation therapy in lung cancer patients and correlation with symptomatic radiation pneumonitis treated with steroid therapy.

OBJECTIVES

To investigate relationships among serum T-cell subsets, CRP, levels and radiation pneumonitis (RP) in lung cancer patients receiving radiotherapy.

METHODS

A case-control study with frequency matching was carried out. The case group comprised 36 lung cancer patients who had developed grade ≥2 RP after thoracic radiotherapy. The control group was 36 patients with lung cancer without RP. Patients in the case group received steroid therapy for 1 month after diagnosis of RP and were followed up for 3 months. T-cell subsets, CRP, and pulmonary function were detected at three time points (onset of RP and 1 and 3 months after diagnosis). Data for the control group were collected 3 months after radiotherapy. Treatment effectiveness was evaluated at 1 and 3 months after diagnosis of RP.

RESULTS

Of the 36 patients in the case group, three with grade5 RP died from respiratory failure. The other 33 cases had all improved with steroid therapy at 3 months after RP diagnosis. In these 33, CD3T-cell quantity, CD4T-cell quantity, and of CD4:CD8 ratio in T-cell subsets decreased significantly and CRP increased (<0.05) at the onset of RP compared with the control group. After steroid therapy, CD4T-cell quantity increased significantly compared to before treatment. The same change was seen in CD4:CD8 ratio, whereas CRP levels decreased obviously, with treatment effectiveness improved. In addition, with the damage level of RP increased, CD4 T -cell quantity decreased obviously and CRP levels increased accordingly at the onset of RP (<0.05).

CONCLUSION

T-cell subsets and CRP may become effective immunological biomarkers for predicting damage from RP and evaluating treatment effectivesness of steroid therapy.