Abstract Number: PB0816
Meeting: ISTH 2021 Congress
Background: Immune thrombocytopenia (ITP) is an autoimmune disease caused by immune intolerance. Rituximab is a monoclonal antibody for therapeutic B-cell depletion, which has been used as second-line therapy in chronic ITP with up to 60% response rates. However, considering its high cost and complications, it is necessary to find biomarkers to predict clinical efficacy to help clinicians make better choices.
Aims: To explore the immune-related biomarkers for predicting response to rituximab in patients with chronic ITP.
Methods: We prospectively included 30 patients with chronic ITP in our center from May 2019 to Nov 2020. We examined the phenotypes of peripheral blood lymphocytes, monocytes, and T helper (Th) cells in 4 hours cultured peripheral blood mononuclear cells in vitro stimulated by PMA/ ionomycin. Efficacy was evaluated 3 months after rituximab treatment. Optimal cutoff values were established using ROC analysis.
Results: Among 30 patients, there were 9 males and 21 females, with a median age of 30 (11-57) years. Eighteen patients showed response (PLT≥30×109/L after treatment). Comparing immune status before rituximab therapy, naïve B cells /CD19+B lymphocyte(Bn/B) in the effective group was significantly higher than that in the ineffective group [(68.9±9.8)% vs (57.6±11.6)%, P=0.024]. Memory B cells/CD19+B lymphocyte(Bm/B) had a lower level in the effective group compared with the ineffective group [(29.5±9.9)% vs (41.7±11.5)%, P=0.014]. Significantly difference was observed in the ratio of Th1/Th2 between the effective and the ineffective group [(8.0±4.1)% vs (13.3±5.2)%, P=0.012]. Patients were divided further using an optimal cut-off Bn/B of 62.7%, Bm/B of 37.0% and Th1/Th2 of 9.8. The model had an AUC of 0.910 (95% CI 0.778-1.000).
Conclusions: ITP patients with Bn/B>62.7%,Bm/B<37.0% and Th1/Th2<9.8 tend to achieve response by rituximab treatment. Our study proposed a model for predicting the efficacy of rituximab, which is helpful to assist clinicians in making treatment decisions.
To cite this abstract in AMA style:Wang X, Li H, Liu X, Xue F, Liu W, Chen Y, Fu R, Zhang L, Yang R. Exploring the Immune-related Biomarkers for Predicting the Efficacy of Rituximab Treatment in Patients with Chronic Immune Thrombocytopenia [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/exploring-the-immune-related-biomarkers-for-predicting-the-efficacy-of-rituximab-treatment-in-patients-with-chronic-immune-thrombocytopenia/. Accessed November 30, 2023.
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