Decrease of memory T helper cells (CD4+ CD45R0+) in hairy cell leukemia

Patients with hairy cell leukemia (HCL) are prone to opportunistic infections, which suggests an impaired T-cell functioning. To investigate a possible mechanism of such an impairment, we determined the numbers of naive and memory T cells by measuring the expression of CD45R0 on CD4 + and CD8 - T cells in 23 HCL patients. As control, 13 healthy subjects and 13 patients with other chronic B-cell leukemias were studied. In HCL patients with active disease, the percentage of CD4 + CD45R0 + T cells was significantly lower compared to healthy subjects (41% versus 57%, p=0.01)