Correlation and significance of changes of T lymphocyte subsets and FEV1 in asthmatic patients

Objective: To investigate the relationship between the changes of T lymphocyte subsets and ventilatory function (FEV1) in asthmatic patients and its clinical significance. Methods: Flowcytometry was used to compare and analyze the T lymphocyte subsets (CD4+, CD8+) in the peripheral blood from 22 acute attack asthmatic patients, 22 asthmatic patients with cough variant asthma and 25 healthy subjects. Indexes of ventilatory function (FEV1) were recorded. Results: There was no significant difference between acute attack patients and cough variant asthma in the percentage of CD4+ (P 0.05), as well as the normal control group (P 0.05), but the percentage of CD4+ was significantly lower in patients with cough variant asthma than that in the normal control group (P 0.01). The percentage of CD8+ was significantly lower in acute attack patients than that in the normal control group as well as that in the patients with cough variant asthma (P 0.01); the percentage of CD8+ was significantly lower in cough variant asthma than in the normal control group (P 0.01). The ratio of CD4+/CD8+ in acute attack asthmatic patients was significantly higher than that in the patients with cough variant asthma and the normal control group (P 0.01). And the ratio of CD4+/CD8+ in the patients with cough variant asthma was higher than that in the normal control group (P 0.01). The correlation analysis showed that the value of FEV1 (forced expiratory volume in 1 second) had significantly positive relation with CD8+ (r=0.57, P 0.01), but had a significantly negative correlation with the ratio of CD4+/CD8+ (r=-0.62, P 0.01). Conclusions: The decrease of CD8+ cells, the imbalance in the ratio of CD4+/CD8+ and the disturbance of the immune system in asthmatic patients may result in the recurrence of asthma and further deterioration of ventilatory functions. Therefore, to improve their ventilatory functions, immunity-regulating drugs must be used in addition to routine therapy.