The unfavorable clinical evolution in indolent non-Hodgkin lymphomas suggests defective control of neoplastic growth by the immune system. To address this issue, we evaluated phenotype, function, and maturation profile of CD4 ؉ and CD8 ؉ T cells from peripheral-blood, lymph nodes, or bone marrow of patients with B-cell non-Hodgkin lymphoma (NHL) at diagnosis. T cells from these patients frequently showed an activated but apoptosis-prone phenotype with low frequency of tumor-reactive T cells show-
IntroductionIndolent non-Hodgkin lymphomas (NHLs) arise from transformation of relatively well-differentiated, antigen-responsive Blymphocytes present in germinal centers. 1 Although neoplastic transformation at early stages of B-cell development usually results in aggressive diseases, malignant clonal proliferation of mature B cells generally leads to indolent B-cell lymphomas, 1 although clinical courses can show a considerable heterogeneity even within the same histologic subtype. This reflects the emerging complexity in the biologic and molecular basis of these diseases. 2,3 Although the available therapeutic strategies for indolent B-cell lymphoma, such as standard chemotherapy, high-dose chemotherapy, and bone marrow transplantation, have improved the outcome of these diseases, the majority of patients are not cured. 1 For these reasons, other approaches, including immunotherapy, 4 are being currently investigated, based on the evidence indicating that these tumors may be responsive to T-cell-mediated immunity in vivo. This has been suggested by the evidence for a prognostic significance of CD4 ϩ T cells at tumor site 5,6 and, more recently, by the identification of a molecular signature of tumor-infiltrating lymphocytes that predicts improved survival in patients with follicular lymphoma (FL). 7 Moreover, several B-cell NHLs (BNHLs) have been shown to express an array of T-cell-defined epitopes, such as those encoded by the tumor-specific B-cell receptor, 8,9 by CD19 and CD20 differentiation antigens, 10 or by overexpressed genes as BCL2 11 and fibromodulin. 12 These determinants represent attractive candidates for vaccination approaches, and initial results of studies targeting the B-cell idiotype have documented clinical responses in some patients. 4 In addition, these studies have shown that it is possible to boost/promote T-cellmediated responses to autologous B-cell tumor in the majority of vaccinated patients. 12 These findings point to the existence of a significant pool of tumor-specific T cells even in untreated patients. However, the often unfavorable clinical evolution of these diseases suggests that activation of effective antitumor immunity may be frequently impaired in vivo. To investigate this possibility we evaluated phenotype, function, antitumor activity, and maturation profile of CD4 ϩ and CD8 ϩ T cells from a large panel of patients with B-NHL. The results indicated that T cells from tumor site of these patients frequently show an activated phenotype but a low frequency of tumor-reactive effe...