Regulatory T-cell modulation by green tea in chronic lymphocytic leukemia.

Regulatory T cells (Tregs) are considered to be key immunomodulatory cells of the immune system and are increased in chronic lymphocytic leukemia (CLL). Rai stage 0 identifies patients with early stage CLL for which there is no effective intervention at the present time and a "wait and see" policy is usually adopted. Some biological and clinical studies have reported that green tea constituents, such as epigallocatechin-gallate (EGCG), have antitumor effects on hematologic malignancies including CLL. We report data on a clinical trial in which green tea extracts were given orally to 12 patients with stage 0 CLL and 12 healthy subjects. Ten patients and 10 controls completed the 6-month scheduled therapy. Two patients and 2 controls stopped therapy within 1 month because of tachycardia and epigastralgia. Eight out 10 evaluable patients (80 percent) showed a reduction of lymphocytosis and absolute number of circulating Tregs, as well. One patient (10 percent) had a stabilization of lymphocytosis and a reduction of Tregs, and 1 patient (10 percent) showed an increase of both lymphocytosis and Tregs. Only the non-responding patient progressed after 5 months from the end of green tea administration and chemotherapy was given. Interestingly, both IL-10 and TGF-beta serum levels declined throughout the green tea intake period, in both patients and controls. These data seem to indicate that green tea is able to modulate circulating Tregs in CLL patients with early stage of the disease. This can result in the control of lymphocytosis as well as in the prevention of disease progression.

Circulating regulatory T cells in "clinical" monoclonal B-cell lymphocytosis.

Regulatory T-cells (Tregs) constitute a small subset of cells involved in antitumour immunity and are generally increased in patients with chronic lymphocytic leukemia (CLL). No data is available on Tregs in monoclonal B-cell lymphocytosis (MBL), a disease entity characterized by less than 5000/microL circulating clonal B-cells in absence of other features of lymphoproliferative disorders. We used multicolour flow cytometry to evaluate the number of circulating Tregs in 56 patients with "clinical" MBL, 74 patients with previously untreated CLL and 40 healthy subjects. MBL patients showed a lower absolute number of Tregs, compared to CLL patients, but slightly higher than controls. Moreover, the absolute cell number of Tregs directly correlated both with more advanced Rai/Binet clinical stages and peripheral blood B-cell lymphocytosis. Of note, the absolute number of Tregs was found lower in MBL patients than in CLL patients staged as 0/A Rai/Binet. The study showed that Treg increase gradually from normal subjects to "clinical" MBL patients and are significantly higher in CLL patients as compared to MBL patients. Moreover, a significant direct relationship was found between higher Treg values and a higher tumor burden expressed by B-lymphocytosis or more advanced clinical stages. In light of this data, MBL seems to be a preliminary phase preceding CLL. The progressive increase of Treg numbers might contribute both to the clinical evolution of MBL to overt CLL and to CLL progression.