Dynamic Changes Of Circulating CD4~+T Cell Subsets Following Severe Thoracic Trauma

Background and AimsTrauma ativates immune system in a controlable manner to eradicate necrotic tissue and repair the injuried part, whereas severe trauma leads to the imbalance of pro/anti-inflammatory immune response, which subsequently results in sepsis and multiple organ dysfunction syndromes (MODS) and enventually increases mortality. CD4+T cells are key component of adaptive immunity and are of paramount important in the post-traumatic immune response. Previous studies have shown a decline of Thl percentage in peripheral T cell compartment as well as Th1 cytokine levels, and an increase of Th2 percentage and Th2 cytokine levels. Recently,a Th17/Treg imbalance was observed after trauma. In the study, we dynamically measured the constitution of CD4+T cell subsets to evalute the alteration of post-traumatic immune response during the clinical course of disease. The study would help to precisely evaluate immune status of traumatic patients.MethodsSeven male patients with thoracic traumahospitalized in the Intensive Care Units (ICU) in our hospital were enrolled in the study. Peripheral blood was collected from all the patients on the 1st,7th,14th and 21st day of admission, respectively. Flow cytometry was carried out to determine the percentage of CD3+ T cells, CD4+ T cells, CD8+T cells and CD4+ T cells differentiated into Th1, Th2, Th17 and Treg subsets, based on which the ratios of Th1/Th2 and Th17/Treg were also calculated. Twenty-five healthy male individuals in the hospital in the same period of time served as controls.ResultsThe frequencies of all the four subsets (Th1, Th2, Th17 and Treg) in the traumatic patients showed significant dynamic changes compared with those of the controls at the defined time points. A transient increase of Thl frequency was found within 1st week after admission, followed by subsequent decline, while Th2 frequency gradually increased from 1st week after admission. The ratio of Thl/Th2 increased after admission and was reversed on the 14th day. Th17 frequency displayed a transient increase at admission, whereas a sustained high level of Treg frequency was observed. The ratios of Th17/Treg showed significant decrease at the study interval. No significant change of CD3, CD4 and CD8 T cell percentages were observed during the clinical course of disease.ConclusionA dynamic change of T cell subset compartment was observed in patients with severe thoracic trauma. The imbalance of Th1/Th2 and Th17/Treg at the present study all reflected the immune dysfunction of CD4+ T cells followed by the severe thoracic trauma.