Kinetics of MDSC in Patients Treated Steroids-Ruxolitinib as the First Line Therapy for aGVHD / 中国实验血液学杂志

OBJECTIVE@#To analyze the kinetic characteristics of lymphocyte subsets and myeloid-derived suppressor cell (MDSC) in patients who newly diagnosed intermediate- to high-risk aGVHD and treated with steroids-ruxolitinib as the first line therapy from a single-arm, open clinical trial (NCT04061876).@*METHODS@#We prospectively observed the efficacy of 23 patients having intermediate- to high-risk aGVHD and treated with steroids-ruxolitinib as the first line therapy. The kinetic characteristics of lymphocyte subsets and MDSC were monitored, and then we compared them in steroids-ruxolitinib group (n=23), free-aGVHD group (n=20) and steroids group (n=23).@*RESULTS@#Of the 23 patients, the CR rate was 78.26% (18/23) on day 28 after first-line treatment with steroids-ruxolitinib. On day 28 after treatment, patients had lower level of CD4+CD29+ T cells (P=0.08) than that of pre-treatment, whereas levels of other lymphocyte subsets in this study were higher than that of pre-treatment; CD4+CD29+ T cells in CR patients decreased, compared with refractory aGVHD patients. On day 28 of treatment, CD8+CD28- T cells (P=0.03) significantly increased in patients with aGVHD than that in patients without aGVHD, so did CD8+CD28- T / CD8+CD28+ T cell ratio (P=0.03). Compared with patients without aGVHD, patients with aGVHD had lower level of G-MDSC, especially on day 14 after allo-HSCT (P=0.04). Compared with pre-treatment, M-MDSC was higher in CR patients on day 3 and 7 post-treatment (P3=0.01, P7=0.03), e-MDSC was higher on day 28 post-treatment (P=0.01). Moreover, compared with CR patients, M-MDSC was lower in refractory aGVHD patients on day 3 post-treatment (P=0.01) and e-MDSC was lower on day 28 post-treatment (P=0.01). Compared with steroids group, MDSC in steroids-ruxolitinib group was higher, with the most significant difference in M-MDSC (P3=0.0351; P7=0.0142; P14=0.0369).@*CONCLUSION@#We found that patients newly diagnosed intermediate- to high-risk aGVHD receiving first-line therapy with steroids-ruxolitinib achieved high response rate. Moreover, the novel first-line therapy has a small impact on the immune reconstitution of patients after allo-HSCT. Elevated MDSC might predict a better response in aGVHD patients receiving this novel first-line therapy. M-MDSC responded earlier to steroids-ruxolitinib than e-MDSC, G-MDSC.

Characteristics of N6-methyladenosine modification patterns in t(8;21) acute myeloid leukemia / 南方医科大学学报

OBJECTIVE@#To investigate the relationship between AML1-ETO (AE) fusion gene and intracellular N6-methyladenosine (m6A) modification pattern in t(8;21) acute myeloid leukemia (AML).@*METHODS@#RNA m6A sequencing was performed in SKNO-1 and AE knockdown SKNO-1 (SKNO-1 siAE) cells using RNA-protein co-immunoprecipitation and high-throughput sequencing (methylated RNA immunoprecipitation sequencing, MeRIP-Seq) to analyze the changes in m6A modification of the entire transcriptome. Transcriptome sequencing (RNA-seq) was performed using high-throughput sequencing. The differentially modified mRNAs were further functionally annotated by Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The changes in m6A-related enzyme expressions were detected using real-time PCR.@*RESULTS@#A total of 26 441 genes were identified in AE knockdown AML cells and AE-expressing cells, containing 72 036 m6A peaks. AE knockdown caused a reduction of the number of intracellular m6A peaks from 37 042 to 34 994, among which 1278 m6A peaks were significantly elevated and 1225 were significantly decreased; 1316 genes with newly emerged m6A modification were detected and 1830 genes lost m6A modification after AE knockdown. The differential peaks were mainly enriched in pathways involving cancer and human T-lymphocytic leukemia virus I. RNA-seq results showed that 2483 genes were up-regulated and 3913 genes were down-regulated after AE knockdown. The combined analysis of MeRIP-Seq and RNA-Seq results revealed relatively high expression levels of m6A-modified genes as compared with the genes without m6A modification (SKNO-1: 0.6116±1.263 vs 2.010±1.655, P < 0.0001; SKNO-1 siAE: 0.5528±1.257 vs 2.067±1.686, P < 0.0001). The m6A modified genes located in the 3'UTR or 5 'UTR had significantly higher expression levels than those located in exonic regions (SKNO-1: 2.177± 1.633 vs 1.333 ± 1.470 vs 2.449 ± 1.651, P < 0.0001; SKNO-1 siAE: 2.304 ± 1.671 vs 1.336 ± 1.522 vs 2.394 ± 1.649, P < 0.05). Analysis of RNA-seq data identified 3 m6A-related enzymes that showed significantly elevated mRNA expression after AE knockdown, namely WTAP, METTL14, and ALKBH5 (P < 0.05), but the results of real-time PCR showed that the expressions of WTAP and ALKBH5 were significantly increased while the expression of METTL14 was lowered after AE knockdown (P < 0.05).@*CONCLUSION@#AE knockdown results in differential expressions of m6A-associated enzymes, suggesting that the AE fusion gene regulates the expression of one or more m6A-associated enzymes to control cellular methylation levels.