PB2136: THE VALUE OF PERIPHERAL BLOOD LYMPHOCYTE SUBSETS IN PREDICTING THE PROGNOSIS OF NEWLY DIAGNOSED MULTIPLE MYELOMA

Topic: 14. Myeloma and other monoclonal gammopathies - Clinical Background: Multiple myeloma(MM), which is characterized by the proliferation of malignant plasma cells producing monoclonal immunoglobulins, is the second most common hematological malignancy. With deep understanding in MM, it is stressed that the role of immune dysregulation in the pathogenesis of MM. The certain immune profiling has value in predicting the prognosis of MM patients. Aims: To explore the value of peripheral blood lymphocyte subsets in predicting prognosis in newly diagnosed multiple myeloma (NDMM) patients. Methods: 110 patients in Tianjin Medical University General Hospital were included. The percentage and absolute numbers of CD3+ T cells, CD3+CD4+ T cells, CD3+CD8+ T cells, CD3-CD56+ NK cells and CD3-CD19+ B cells were detected. The least absolute shrinkage and selection operator (LASSO) regression was conducted to investigate the independent risk factors. Best cut-off values were calculated by ROC analysis. Univariate and Multivariate COX analysis was used to evaluate the independent prognostic factors of overall survival. Kaplan-Meier curves and log rank test were used for analyzing overall survival. Results: We selected the predicting factors by using LASSO regression. The risk scores was calculated by the corresponding lambda values(the percentage of CD3+ T cells: -0.02670097, CD3+CD4+ T cells: 0.03081192, CD3-CD56+ NK cells: -0.02376163 and the absolute numbers of CD3+CD4+ T cells: -0.001719961, CD3-CD56+ NK cells: -0.00006968683. The best cut-off value is -2.022(AUC=0.750). We divided the patients into two groups(high risk: 37 vs low risk 73). The serum calcium(P<0.001) and the creatinine(P=0.001) were different in the patients’ characteristics between two groups). The univariate and multivariate analysis revealed that the values≤-2.022 was an independent prognostic factor for predicting OS(P<0.001).The 3-year OS rate of patients was higher in low risk group than high risk group(91.8% vs 56.8%, P<0.001). We further analyzed the significance in predicting prognosis of values in different staging system for MM. The 3-year OS rate is different in both low-medium and high risk in different staging system (ISS I-II:92.5% vs 61.5%,P=0.002; ISS III: 90.9% vs 54.2%, P=0.001; R-ISS I-II: 93.2% vs 58.3%, P<0.001; R-ISS III: 85.7% vs 46.2%, P=0.02; R2-ISS I-II: 100% vs 66.7%, P=0.001; R2-ISS III-IV: 87.2% vs 54.8%, P<0.001). Summary/Conclusion: The findings suggested that lymphoid subsets have prognostic value in NDMM patients and mightbe a potential factor in distinguishing patients at different risk.Keywords: Multiple myeloma, Immunity