Comparison of long-term outcome between white and Vietnamese children treated for acute lymphoblastic leukemia according to the FRALLE 2000 protocol.

AIM OF THIS STUDY: To compare the relapse-free survival (RFS) in Vietnamese (n=141) and white (n=94) children living in Vietnam and Belgium, respectively, and treated in their own country for acute lymphoblastic leukemia according to the same FRALLE 2000 protocol. RESULTS: RFS was significantly worse in Vietnamese children (hazards ratio=4.48; 95% confidence interval [CI], 2.16-9.3; P<0.01). The 5-year RFS was 83.8% (95% CI, 76.3%-92.0%) and 47.8% (95% CI, 35.6%-64.2%) for white and Vietnamese children, respectively. In the latter group, relapses occurred in bone marrow and cerebrospinal fluid at a much earlier stage. The outcome was compared at first relapse only because of different treatments afterward, according to the country. Both series were similar for sex, age at diagnosis, initial white blood cell count, cytogenetic abnormalities, and corticosensitivity at day 8. Higher frequency of L2-acute lymphoblastic leukemia (P<0.001) but lower frequency of T-acute lymphoblastic leukemia (P=0.004) were observed in Vietnamese children. CONCLUSIONS: Several factors may contribute to the poor RFS in Vietnamese children, which include the time interval before the first intrathecal therapy and differences in the management of drug-related toxicity. However, additional contribution of socioeconomic factors and/or variations in pharmacogenetic polymorphisms in Vietnamese patients cannot currently be ruled out.

CXCL13-producing TFH cells link immune suppression and adaptive memory in human breast cancer.

T follicular helper cells (TFH cells) are important regulators of antigen-specific B cell responses. The B cell chemoattractant CXCL13 has recently been linked with TFH cell infiltration and improved survival in human cancer. Although human TFH cells can produce CXCL13, their immune functions are currently unknown. This study presents data from human breast cancer, advocating a role for tumor-infiltrating CXCL13-producing (CXCR5-) TFH cells, here named TFHX13 cells, in promoting local memory B cell differentiation. TFHX13 cells potentially trigger tertiary lymphoid structure formation and thereby generate germinal center B cell responses at the tumor site. Follicular DCs are not potent CXCL13 producers in breast tumor tissues. We used the TFH cell markers PD-1 and ICOS to identify distinct effector and regulatory CD4+ T cell subpopulations in breast tumors. TFHX13 cells are an important component of the PD-1hiICOSint effector subpopulation and coexpanded with PD-1intICOShiFOXP3hi Tregs. IL2 deprivation induces CXCL13 expression in vitro with a synergistic effect from TGFß1, providing insight into TFHX13 cell differentiation in response to Treg accumulation, similar to conventional TFH cell responses. Our data suggest that human TFHX13 cell differentiation may be a key factor in converting Treg-mediated immune suppression to de novo activation of adaptive antitumor humoral responses in the chronic inflammatory breast cancer microenvironment.