Circulating Humoral Factors and Lymphocyte Subsets as Markers for Radiation Pulmonary Injury
Presenter: Yuhchyau Chen, M.D.
Affiliation: University of Rochester
Radiation induced pulmonary changes can cause serious, even life-threatening problems in patients whose lung function my already be compromised by tumor burden and/or smoking. Humoral factors and immune cells have been previously associated with the presence of radiation-induced pulmonary injury.
The authors prospectively monitored multiple factors, including IL-1a, IL-6, TNF-a, TGF-b1, bFGF, vascular endothelial growth factor (VEGF), and multiple adhesion molecules, prior to, during, and post-treatment. Treatment consisted of thoracic radiation therapy with or without chemotherapy. Radiation pneumonitis was scored using clinical symptoms and radiographic changes on chest X-ray and computerized tomography scans.
- Of 38 evaluable patients, 27 were found to have some degree of pneumonitis at 3 to 4 months post-treatment,
- 14 of 38 patients experienced symptomatic pneumonitis requiring steroids.
- IL-1a and IL-6 were found to be significantly higher before, during, and after treatment in patients with pneumonitis (p < 0.05). In particular, patients with elevated serum IL-6 prior to treatment were more likely to develop symptomatic radiation pneumonitis.
- TGF-b1, bFGF, the selectins, MCP1, VEGF followed regular patterns during and after treatment, but were not correlated with radiation pneumonitis.
- CD4+, CD8+, and CD19+ lymphocytes were monitored during treatment in 16 patients. CD4+ count declined in all patients receiving thoracic RT, but recovery was lower for patients with symptomatic radiation pneumonitis than without (p < 0.05).
- These data contribute to the pre-existing information suggesting the association of humoral factors and immune cells with radiation lung injury. As such, they may be a valuable adjunct in selecting and monitoring patients at risk for symptomatic pneumonitis.
- The exact role played by each of these factors in radiation lung injury, whether reactive or causal, requires further investigation.
- The contribution of chemotherapy to toxicity deserves attention, as does the relatively high rate of symptomatic pneumonitis in this study group.
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