The novel TERF2::PDGFRB fusion gene enhances tumorigenesis via PDGFRB/STAT5 signalling pathways and sensitivity to TKI in ph-like ALL.

Patients with Philadelphia chromosome-like acute lymphoblastic leukaemia (Ph-like ALL) often face a grim prognosis, with PDGFRB gene fusions being commonly detected in this subgroup. Our study has unveiled a newfound fusion gene, TERF2::PDGFRB, and we have found that patients carrying this fusion gene exhibit sensitivity to dasatinib. Ba/F3 cells harbouring the TERF2::PDGFRB fusion display IL-3-independent cell proliferation through activation of the p-PDGFRB and p-STAT5 signalling pathways. These cells exhibit reduced apoptosis and demonstrate sensitivity to imatinib in vitro. When transfused into mice, Ba/F3 cells with the TERF2::PDGFRB fusion gene induce tumorigenesis and a shortened lifespan in cell-derived graft models, but this outcome can be improved with imatinib treatment. In summary, we have identified the novel TERF2::PDGFRB fusion gene, which exhibits oncogenic potential both in vitro and in vivo, making it a potential therapeutic target for tyrosine kinase inhibitors (TKIs).

Treatments of Ph-like acute lymphoblastic leukemia: a real-world retrospective analysis from a single large center in China.

Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is a high-risk subtype of ALL. We retrospectively studied 70 cases with Ph-like ALL and here present the largest study of CAR-T cell treatment and haplo-HSCT for this leukemia. Median age was 26 years and median leukocyte count was 31.44 × 109/L. The proportion of patients receiving chemotherapy, KIs, CAR-T cells, and allo-HSCT was 19%, 30%, 46%, and 61%, respectively. The overall response rate was 62%, 73%, and 100% after one month of KI treatment combined with chemotherapy, CAR-T cell therapy, and allo-HSCT, respectively. Five-year DFS and OS were 35% and 51%, respectively. The five-year cumulative incidence of relapse and non-relapse mortality was 63% and 11%, respectively. Allo-HSCT was associated with a better DFS (p = 0.010) and OS (p = 0.000) by univariate analysis. In conclusion, allo-HSCT after KIs together with chemotherapy or CAR-T cell therapy is a safe and feasible treatment modality for Ph-like ALL.

[The immune effects of rituximab on dendritic cells derived from patients with primary immune thrombocytopenia].

OBJECTIVE: To explore the changes of surface antigen and function of rituximab on dendritic cells derived from patients with Primary immune thrombocytopenia (ITP) to further understand the effective mechanism of immunotherapy. METHODS: The peripheral blood mononuclear cells (PBMCs) were isolated from remission patients with ITP before and after low-dose rituximab infusion, and the PMNCs were stimulated for 5 days by rhGM-CSF and rhlL-4 in 5% CO2 air at 37°C incubator. Then all of DCs were cultured with TNF-α for 48 hours. The morphology of DCs was monitored under inverted microscope daily, and the surface antigens of the DCs were analysed by flow cytometry, meanwhile the levels of IL-12p70 and TGF-ß1 in supernatants were detected by ELISA, mix lymphocyte reaction was performed by MTT assay. RESULTS: (1) Rituximab-treated-DCs showed no obvious tree-like protruding compared with untreated-DCs. The former cells were small and most of nucleus were centric. (2) The expressions of HLA-DR, CD80, CD83 and CD86 on rituximab-treated-DCs \[56.37 ± 3.95)%, (36.41 ± 2.82)%, (30.45 ± 4.61)% and (41.98 ± 4.17)%, respectively\] were significantly lower than those untreated-DCs \[(73.71 ± 7.61)%, (55.14 ± 7.30)%, (80.91 ± 7.09)% and (59.03 ± 3.43)%, respectively\](all P < 0.05), the concentration of IL-12p70 was significantly lower, \[(66.87 ± 4.29)% vs (50.17 ± 14.52)%\], while that of TGF-ß1 \[(9.70 ± 0.31)%\] higher than the untreated-DCs \[(2.70 ± 0.36)%\] (P < 0.05). (3) The abilities to activate T cells proliferation of rituximab-treated-DCs reduced compared with untreated-DCs. CONCLUSION: The surface antigen of ITP-DCs and the concentration of IL-12p70 reduced after the low-dose rituximab infusion. The abilities to activate T cells proliferation reduced while the concentration of TGF-ß1 increased. Rituximab may achieve its therapeutic effect on ITP by downregulating the immunoreactivity of DCs.