[Clinical study of induction chemotherapy followed by allogeneic hematopoietic stem cell transplantation in the treatment of FLT3-ITD(+) acute myeloid leukemia with normal karyotype].

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.

[Clinical analysis of 20 cases of small B lymphocyte proliferative disease with t (14;19) (q32;q13)].

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.

Unusual amplification pattern by SSP HLA-B typing led to discovery of a novel HLA-C allele.

We report here the unique sequence of a novel human leucocyte antigen (HLA)-C allele resulted in amplification of a product with a primer pair used in sequence-specific primer (SSP) HLA-B typing, which led subsequently to identification of a new allele of Cw*0339 by sequence-based typing method. This new allele is closely related to Cw*031101 with only two nucleotide changes from T to G at position 97, and T to C at position 105 in the exon 2 region of HLA-C locus. The first nucleotide substitution causes an amino acid alteration from tyrosine to aspartic acid at amino acid residue 9 (Y to D), while the second one keeps alanine at residue 11 unchanged. Most interestingly, the nucleotide change from T to G at position 97 makes it identical to the 3' end sequence of one SSP of the commercial HLA-B SSP typing kit we were using. In this specific case, it resulted in amplification of a product of HLA-C gene instead of B gene.

The polymorphism and haplotype analysis of HLA-A, -B and -DRB1 genes of population in Jiangsu province of China.

The polymorphism of human leucocyte antigen (HLA)-A, -B and -DRB1 genes and their computed haplotype analysis results from a population of Jiangsu province of China are presented here. The data consist of 20 248 unrelated peripheral blood stem cell donors in Jiangsu Branch of Chinese National Marrow Donor Program registry. In total, 18 different HLA-A alleles, 34 different HLA-B alleles and 13 different HLA-DRB1 alleles were found in Jiangsu Han population. The most frequent alleles in HLA-A, -B and -DRB1 loci were A*02 (29.55%), B*15 (14.40%), and DRB1*09 (16.15%), respectively. The most common haplotype in A-B-DRB1 loci was A*30-B*13- DRB1*07 (6.92%), in A-B loci was A*30-B*13 (8.05%), in B-DRB1 loci was B*13-DRB1*07 (8.17%), and in A-DRB1 loci was A*02-DRB1*09 (8.30%). The dendrogram study indicated that the distribution of HLA genes in Jiangsu Han population, as expected, represented a mixture of Northern and Southern Han population in China. These findings could shade new lights in population genetics and anthropology studies of Han-Chinese.

Human leukocyte antigens in 295 Chinese patients with chronic myeloid leukemia.

Experimental studies using synthetic peptides identical to the bcr-abl fusion region in chronic myeloid leukemia (CML) patients have revealed that some specific peptides could bind to human leukocyte antigen (HLA) class I and class II molecules. Previous clinical observations have also reported some significant HLA associations with the development of CML in their populations. Due to high diversity of HLA alleles, the present study assessed the possibility of an association of HLA molecules in CML patients living in Jiangsu province, the eastern part of China. HLA-A, B and DRB1 allele distributions in 295 CML patients (aged 4-65 years) were analysed and compared with unrelated healthy hematopoietic stem cell donors from the same ethnic and geographic background. By comparison of the HLA gene distribution characteristics between CML and healthy donor populations, differences with statistical significance were found in HLA-A*30 (5.42% versus 9.13%) with odds ratio (OR) 0.57, DRB1*07 (8.14% versus 12.51%; OR = 0.62), and B*81 (0.51% versus 0.09%, OR = 5.44). These results suggest that expression of HLA-A*30, DRB1*07 might imply a protective effect on CML acquisition, while B*81 might be associated with CML susceptive factors in our population.

Co-culture of cord blood CD34(+) cells with human BM mesenchymal stromal cells enhances short-term engraftment of cord blood cells in NOD/SCID mice.

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.

Characterization of a novel DRB1*14 allele (DRB1*1449) in the Han-Chinese population.

We report here a novel human leukocyte antigen (HLA) allele, DRB1*1449, in the Han-Chinese population. The nature of the new allele was confirmed by the sequencing-based typing (SBT) method. Genomic DNA and six subclones containing DNA fragment of DRB1 exon 2 were sequenced in both forward and reverse directions. The exon 2 nucleotide sequence of DRB1*1449 is closely related to DRB1*1432 allele based on sequence homology. It has four nucleotide (nt) substitutions at positions 71, 196, 244 and 245 in exon 2, which lead to changes of amino acid sequences. The serological assignment of DRB1*1449 is DR14 based on the serological HLA typing result. This novel allele might be a result of recombination between DRB1*1402 and DRB1*140101 like alleles, which are very common among Chinese population.

A novel HLA allele, DRB1*1609, identified in the Chinese Han population*.

A novel human leucocyte antigen-DRB1*16 (HLA-DRB1*16) allele (DRB1*1609) has been identified by sequencing-based typing (SBT) in Chinese Han population. This new allele has identical nucleotide sequence to DRB1*160101 in exon 2, except for a single-nucleotide substitution from A to T at position 127. This change leads to an amino acid change from tyrosine to phenylalanin at residue 47 (Y47F). SBT was performed for cloned DRB1*16-specific polymerase chain reaction fragment. The serological phenotype of DRB1*1609 is equivalent to DR16 antigen.

Identification of an HLA-B*07 allele variant (B*0740) in the Chinese Han population.

A novel HLA-B*07 allele, B*0740, has been identified by sequence-based typing (SBT) in the Chinese Han population. This new allele is identical to B*0705 and B*0706 for exons 2, 3, and 4, except for a single nucleotide at position 605 of codon 202 in exon 3 (AAG-->ATG) leading to an amino acid change from lysine to methionine. SBT was performed following allele separation using the Haploprep method. The serological equivalence of B*0740 to the B7 antigen did not change.