Objectives: A predominance of type 2 helper T cells (Th2) in the bronchoalveolar space and peripheral blood is a well-accepted feature of bronchial asthma. However, the relationship between peripheral blood Th2 cells and asthma severity has not been thoroughly investigated.
Methods: As Th1 cells predominantly express the chemokine receptor CXCR3 and Th2 cells express CCR4, we assessed the distribution of peripheral blood CXCR3+ and CCR4+ lymphocytes using flow cytometry in 186 patients with asthma and 75 normal subjects.
Results: The proportion of CXCR3+/CD45RO+ cells in CD4+ T cells increased as the severity of asthma increased. The percentage of CCR4+/CD45RO+ cells in CD4+ T cells were elevated in mild to severe asthma patients compared with controls. However, there was no significant difference in CCR4+/CD45RO+ cells between the mild to severe asthma patients. There was no relationship between the patient's age and the numbers of CXCR3+ or CCR4+ T cells. The percentage of CCR4+ cells in CD45RO+/CD4+ T cells correlated with the levels of total serum IgE (r = 0.630, P < 0.0001).
Conclusions: The proportion of CCR4+ cells in blood memory helper T cells may be increased in patients with asthma and is associated with the level of serum IgE, but severity of asthma is also associated with the increase of blood CXCR3+ cells in memory helper T cells.