Schéma : B-acute lymphoblastic leukaemia (ALL) is the most common childhood malignancy. Despite enhancement of childhood B-ALL outcome, relapses remain difficult to treat. Several studies in adult acute myeloid leukaemia have shown that proliferation of immunosuppressive cells -particularly T regulatory (Treg) cells and deficient natural killer (NK) cells- was associated with poor response to chemotherapy. However, few studies have been done on childhood ALL and none on relapse of B-ALL. Moreover, a newly described immunosuppressive B cells subset (Breg cells) seems to have a role in oncogenesis in mice model, but its significance has never been evaluated in human cancers. The purpose of this study is to prospectively evaluate the immune status of children newly diagnosed with first relapse of B-cell ALL, and to compare results with those of children treated for B-ALL in complete remission. Classic lymphocytic phenotype, proportions of immunosuppressive cells (Treg cells, deficient NK cells, Cytotoxic T-lymphocyte-associated protein 4 and/or Programmed T cell death 1) and thymopoiesis will be evaluated. The investigators assume that increase of immunosuppressive cells proportions could be associated with B-ALL relapse.
- Relapse Group
Collection of blood samples will be done in newly diagnosed relapse of B-ALL children at the time of relapse diagnosis.
Children aged from 1 to 18 years at the time of first B-ALL relapse diagnosis.
- Control Group
Collection of blood samples will be done at the same stage of treatment as the relapse group has been collected.
Children aged from 1 to 18 years enrolled into FRALLE (protocol of treatment) or EORTC (European Organisation for Research and Treatment of Cancer) treatment protocols, treated for B-ALL and who are in complete molecular remission.
These control patients will be recruited at the same time from the beginning of B-ALL treatment as paired-relapsed control patients.
Current primary outcome:
Measure of Treg (CD4+,CD25+, Foxp3+) and deficient natural killer (NK) cells (CD3-,CD56+,NKp30-) proportions by FACS in children newly diagnosed with their first relapse of B-ALL. [ Time Frame: At the time of the inclusion. ]
Comparison of the immune status of patients at the diagnosis of their first relapse diagnosis with those of children treated for B-ALL who are in complete remission and at the same stage of treatment.
Current secondary oucomes:
- Measure of the number of T CD4+ lymphocytes (Cluster of Differentiation 4), T CD8+ lymphocytes (Cluster of Differentiation 8), NK cells and Natural killer T (NKT) cells by FACS. [ Time Frame: At the time of the inclusion. ]
- Measure of percentage of TCD4+ naive and memory cells and TCD8+ naive and memory cells by FACS. [ Time Frame: At the time of the inclusion. ]
- Measure of percentage of gamma delta and alpha-bêta TCR CD3+ T cells by FACS. [ Time Frame: At the time of the inclusion. ]
- Measure of TRECs (T cell receptor excision circle) by QPCR and naïve CD4+CD45RA+CD31+ T cells by FACS. [ Time Frame: At the time of the inclusion. ]
Phase : IV
Stade : NA