CD4 and B-cell chronic lymphocytic leukemia: However, recent studies in patients with chronic lymphatic leukemia have demonstrated that elevated numbers of circulating Vγ9Vδ2 T cells with dominant TEM and TEMRA phenotypes are a negative prognosticator [43], which is reminiscent of data previously reported in conventional CD4+ and CD8+ cells [44,45]; in these patients, TEMRA CD8+ cells displayed the phenotypic hallmarks of functional exhaustion, further supporting the concept that long-lasting tumor-induced chronic activation may lead to the undesired accumulation of cells unable to exert effective antitumor activity.