Contributions
Abstract: EP922
Type: E-Poster Presentation
Session title: Myelodysplastic syndromes - Clinical
Background
Myelodysplastic syndromes (MDSs) are hematopoietic stem cell disorders with features of dysplasia in hematopoietic cells, ineffective hematopoiesis, and an increased risk of leukemia transformation. The revised international prognostic scoring system (IPSS-R) has been widely used to risk-stratify MDS patients and guide treatment strategies. Nevertheless, the prognosis of patients may vary greatly, even in the same risk group. Recent evidences dictate the central role of the bone marrow (BM) microenvironment, infiltrating immune cells, and relevant inflammatory pathways in the pathogenesis of MDS. However, the prognostic significance of immune cells in the BM of MDS patients remains unclear.
Aims
This study was aimed to investigate the clinical significance of BM-infiltrating immune cells in MDS patients and to construct an immune cell scoring system for better risk-stratification of these patients.
Methods
We recruited 316 primary MDS patients diagnosed at the National Taiwan University Hospital (1997-2019) who had adequate cryopreserved BM samples for RNA sequencing. We adopted TruSight myeloid sequencing panel and HiSeq platform to analyze the gene alterations of 54 myeloid-neoplasm relevant genes. The purified RNA was used to construct gene expression libraries with the Illumina Stranded mRNA Library Prep Kit and then sequenced on the Illumina NextSeq 500 platform. CIBERSORTx, a Next-generation of CIBERSORT (Cell type Identification By Estimating Relative Subsets Of known RNA Transcripts), which can quantify the relative expression of cell type-specific signatures in bulk tumors without doing cell sorting, was employed to estimate the relative cell fractions of 22 subtypes of immune cells that are intensely involved in innate and adaptive immunity.
Results
We applied univariate Cox regression analysis to examine the prognostic impact of 22 immune cell subtypes on the overall survival (OS) of MDS patients. A higher percentage of macrophages M0 was significantly correlated with better survival, whereas higher fractions of macrophages M2 and eosinophils, two cell types whose infiltration in tumors were correlated with prognosis, were associated with inferior survival. An immune-cell scoring system (ICSS) was constructed based on the fractions of M0, M2, and eosinophils, which could well divide MDS patients into three risk groups with distinct clinical outcomes. ICSS high-risk group, defined as having lower M0, higher M2, and higher eosinophils, had the worst leukemia-free survival (LFS) and OS among the three risk groups in the total cohort as well as in subgroups of patients with higher- or lower-risk IPSS-R (Figure 1, 2a). The prognostic significance was then confirmed in an independent validation cohort. Furthermore, ICSS high-risk group more frequently harbored mutations in NPM1, TP53, and WT1, but less commonly, SF3B1 mutation. Time-dependent ROC curves revealed that ICSS could be complementary to IPSS-R in prognostication (Figure 2b). More importantly, multivariable analysis proved that the immune-cell score was an independent predictor of clinical outcomes in MDS patients. Bioinformatic analysis revealed that high-risk ICSS was significantly correlated with the oxidative stress and leukemic stem cell signatures (Figure 3).
Conclusion
In conclusion, we show that besides clinical features and genetic alterations, immune cells in the BM microenvironment also significantly impact LFS and OS in MDS patients. The ICSS is a concise yet powerful risk-stratification system that can be incorporated into IPSS-R to refine the risk-stratification of MDS patients.
Keyword(s): Immune response, Microenvironment, Myelodysplasia, Risk factor
Abstract: EP922
Type: E-Poster Presentation
Session title: Myelodysplastic syndromes - Clinical
Background
Myelodysplastic syndromes (MDSs) are hematopoietic stem cell disorders with features of dysplasia in hematopoietic cells, ineffective hematopoiesis, and an increased risk of leukemia transformation. The revised international prognostic scoring system (IPSS-R) has been widely used to risk-stratify MDS patients and guide treatment strategies. Nevertheless, the prognosis of patients may vary greatly, even in the same risk group. Recent evidences dictate the central role of the bone marrow (BM) microenvironment, infiltrating immune cells, and relevant inflammatory pathways in the pathogenesis of MDS. However, the prognostic significance of immune cells in the BM of MDS patients remains unclear.
Aims
This study was aimed to investigate the clinical significance of BM-infiltrating immune cells in MDS patients and to construct an immune cell scoring system for better risk-stratification of these patients.
Methods
We recruited 316 primary MDS patients diagnosed at the National Taiwan University Hospital (1997-2019) who had adequate cryopreserved BM samples for RNA sequencing. We adopted TruSight myeloid sequencing panel and HiSeq platform to analyze the gene alterations of 54 myeloid-neoplasm relevant genes. The purified RNA was used to construct gene expression libraries with the Illumina Stranded mRNA Library Prep Kit and then sequenced on the Illumina NextSeq 500 platform. CIBERSORTx, a Next-generation of CIBERSORT (Cell type Identification By Estimating Relative Subsets Of known RNA Transcripts), which can quantify the relative expression of cell type-specific signatures in bulk tumors without doing cell sorting, was employed to estimate the relative cell fractions of 22 subtypes of immune cells that are intensely involved in innate and adaptive immunity.
Results
We applied univariate Cox regression analysis to examine the prognostic impact of 22 immune cell subtypes on the overall survival (OS) of MDS patients. A higher percentage of macrophages M0 was significantly correlated with better survival, whereas higher fractions of macrophages M2 and eosinophils, two cell types whose infiltration in tumors were correlated with prognosis, were associated with inferior survival. An immune-cell scoring system (ICSS) was constructed based on the fractions of M0, M2, and eosinophils, which could well divide MDS patients into three risk groups with distinct clinical outcomes. ICSS high-risk group, defined as having lower M0, higher M2, and higher eosinophils, had the worst leukemia-free survival (LFS) and OS among the three risk groups in the total cohort as well as in subgroups of patients with higher- or lower-risk IPSS-R (Figure 1, 2a). The prognostic significance was then confirmed in an independent validation cohort. Furthermore, ICSS high-risk group more frequently harbored mutations in NPM1, TP53, and WT1, but less commonly, SF3B1 mutation. Time-dependent ROC curves revealed that ICSS could be complementary to IPSS-R in prognostication (Figure 2b). More importantly, multivariable analysis proved that the immune-cell score was an independent predictor of clinical outcomes in MDS patients. Bioinformatic analysis revealed that high-risk ICSS was significantly correlated with the oxidative stress and leukemic stem cell signatures (Figure 3).
Conclusion
In conclusion, we show that besides clinical features and genetic alterations, immune cells in the BM microenvironment also significantly impact LFS and OS in MDS patients. The ICSS is a concise yet powerful risk-stratification system that can be incorporated into IPSS-R to refine the risk-stratification of MDS patients.
Keyword(s): Immune response, Microenvironment, Myelodysplasia, Risk factor