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Background The major challenge for cord blood transplantation (CBT) is higher rates of delayed and failed engraftment. In an attempt to broaden the application of CBT to more candidates, ex vivo expansion of hematopoietic stem/progenitor cells in CB is a major area of investigation. The purpose of this study was to employ human BM mesenchymal stromal cells (hBM-MSC) as the feeding-layer to expand CB cells ex vivo. Methods In this study, hBM-MSC were isolated and characterized by morphologic, mmunophenotypic and RT-PCR analysis. The hBM-MSC at passage 3 were employed as the feeding-layer to expand CB CD34+ cells in vivo in the presence of thrombopoietin, flt3/flk2 ligand, stem cell factor and G-CSF. The repopulating capacity of the ex vivo-expanded CB cells was also evaluated in a NOD/SCID mice transplant experiment. Results After 1 or 2 weeks of in vitro expansion, hBM-MSC supported more increasing folds of CB in total nucleated cells, CD34+ cells and colony-forming units (CFU) compared with CB without hBM-MSC. Furthermore, although NOD/SCID mice transplanted with CB cells expanded only in the presence of cytokines showed a higher percentage of human cell engraftment in BM than those with unexpanded CB CD34+ cells, expanded CB cells co-cultured with hBM-MSC were revealed to enhance short-term engraftment further in recipient mice. Discussion Our study suggests that hBM-MSC enhance in vitro expansion of CB CD34+ cells and short-term engraftment of expanded CB cells in NOD/SCID mice, which may be valuable in a clinical setting. [ABSTRACT FROM AUTHOR]

Objective: To assess the efficacy of induction chemotherapy followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of FLT3-ITD(+) acute myeloid leukemia (AML) with normal karyotype. Methods: The clinical data of FLT3-ITD(+) AML patients with normal karyotype in the First Affiliated Hospital of Nanjing Medical University from Jan 2018 to March 2021 were retrospectively analyzed. Results: The study included 49 patients with FLT3-ITD(+)AML, 31 males, and 18 females, with a median age of 46 (16-59) years old. All patients received induction chemotherapy, and 24 patients received sequential allo-HSCT (transplantation group) . The median follow-up time was 465 days, the one-year overall survival (OS) from diagnosis was (70.0 ± 7.4) %, and one-year disease-free survival (DFS) was (70.3±7.4) %. The one-year OS was significantly different between the transplantation group and the non-transplantation group [ (85.2 ± 7.9) % vs (52.6 ± 12.3) %, P =0.049]. but one-year DFS [ (84.7 ± 8.1) % vs (55.2 ± 11.9) %, P =0.061] was not. No significance was found in one-year OS between patients with low-frequency and high-frequency FLT3-ITD(+) ( P >0.05) . There were 12 patients with high-frequency FLT3-ITD(+) in the transplantation and the non-transplantation groups, respectively. The one-year OS [ (68.8 ± 15.7) % in the transplantation group vs (26.2 ± 15.3) % in the non-transplantation group, P =0.027] and one-year DFS [ (45.5 ± 21.3) % in the transplantation group vs (27.8±15.8) % in the non-transplantation group, P =0.032] were significantly different between the two groups. Conclusion: Induction chemotherapy followed by allo-HSCT can enhance the prognosis of FLT3-ITD(+) patients, particularly those with FLT3-ITD high-frequency mutation.

Objective: The clinical characteristics and prognosis of 20 patients with small B-lymphocyte proliferative disease with t (14;19) (q32; q13) were analyzed to improve the understanding of such rare cases. Methods: The clinical data of 20 patients with t (14; 19) (q32; q13) small B lymphocyte proliferative disease treated in the First Affiliated Hospital of Nanjing Medical University from April 2013 to December 2020 were retrospectively collected and analyzed. Among them, 10 cases were chronic lymphocytic leukemia (CLL) and 10 cases were other small B-cell malignancies. Results: Among the 20 cases, 10 were male and 10 were female, and the median age at diagnosis was 53.5 (35-88) years old. All patients had absolute lymphocytosis, 19 patients had lymphadenopathy, and 10 patients had splenomegaly. With a median follow-up of 36 (4-163) months, three patients died, and 11 patients had a time to treatment (TTT) ≤12 months. Ten patients (50%) were accompanied by +12, two patients (2/17, 12%) were accompanied by 13q-. Moreover, we found that t (14;19) was associated with unmutated immunoglobulin heavy-chain variable (IGHV) somatic mutation (17/19, 89%) and a biased use of IGHV4-39 (7/17, 41%) was observed. Next-generation sequencing detected one or more gene mutations in 14 (14/17, 82%) cases and a total of 25 gene mutations had been revealed, of which the most frequent were NOTCH1 (35%) , followed by SF3B1 (24%) and KMT2D (18%) . For 10 CLL patients, five (50%) were defined as Rai Ⅲ/Binet C. It is noteworthy that among the 20 cases, two cases actually involved Richter transformation. Conclusions: Small B-cell malignant tumors with abnormal t (14; 19) show unique clinical biological characteristics, often accompanied by a variety of adverse prognostic factors, and tend to have an aggressive clinical course.