Objective: To evaluate changes in lymphocyte subsets after major abdominal and thoracic operations, and to correlate changes with the development of clinically relevant infections postoperatively.
Design: Open study.
Setting: University hospital, Italy.
Subjects: 33 patients who were to undergo major abdominal or thoracic operations.
Interventions: Lymphocyte subsets were measured by cytofluorimetry before operation and 1, 3, 5, and 7 days postoperatively.
Main outcome measures: Correlation between changes in the number of lymphocyte subsets and development of infection.
Results: Lymphocyte subsets were within the reference range in all patients before operation. 10/33 Patients developed infections (pneumonia, bacteraemia, or wound or urinary tract infections) between the second and the ninth days postoperatively (30%). On day 1 the numbers of all lymphocyte subsets had decreased significantly compared with the preoperative measurements in all patients (CD3 p < 0.01, CD4 p < 0.001, and CD8 p < 0.05). The reduction in CD3 was significantly greater in the group that developed infections (p < 0.001). Among patients who did not develop infections the numbers of lymphocyte subsets had returned to the reference range within a week of operation whereas among patients who developed infections they remained depressed (p < 0.05).
Conclusion: The synchronous reduction in numbers of all lymphocyte subsets on the first day postoperatively to below 50% of the reference range (CD3 to < 600/microliters, CD4 to < 400/microliters, and CD8 to < 250/microliters) predicted the development of infection postoperatively with an accuracy of 89%, a sensitivity of 80%, and a specificity of 96%.