PB0665 - Th1 cells is the predictive factor of early response to rituximab in children with immune thrombocytopenia

Monday, June 24, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

Juntao Ouyang

Master Degree Candidate
Beijing Children's Hospital
Beijing, Beijing, China (People's Republic)

Co-Author(s)

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zheyan lin

Master degree candidate
Beijing Children's Hospital
Beijing, Beijing, China (People's Republic)
Zhifa Wang, PhD

Resident physician
Department II of Hematology Center, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, 100045, China
Beijing, Beijing, China (People's Republic)
Jingyao Ma, MD

attending physician
Hematology Department, National Center for Children’s Health, Beijing Children’s Hospital, Capital Medical University, Beijing 101300, China.
Beijing, Beijing, China (People's Republic)
Runhui Wu, PhD, MD

Professor
Department of Hematology, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, 100045, China
Beijing, Beijing, China (People's Republic)
Zhenping Chen

Associate professor
Hematologic Diseases Laboratory, Hematology Center, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children’s Health, Beijing, 100045, ChinaChildren’s Health, Beijing, 100045, China
Beijing, Beijing, China (People's Republic)

Background: Primary immune thrombocytopenia (ITP) is an acquired immune-mediated disease characterized by excessive platelet destruction and inadequate platelet production. Rituximab (RTX) has been widely used as the second-line treatment of ITP patients. However, it has not been clearly demonstrated whether peripheral blood T lymphocytes subsets before RTX administration is associated with the early response of RTX in children with ITP.

Aims: Investigating whether T lymphocyte subsets before RTX administration could predict the response of RTX in pediatric patients with ITP.

Methods: Pediatric ITP patients treated with RTX from September 2018 to July 2023 were enrolled in this study. RTX was administrated intravenously at a single dose of 375 mg/m2. The proportions of T cell subsets (CD4+ T, CD8+ T, CD8- T, Th1, Th2, Th17 and Tregs) were assessed by flow cytometry. Patients were divided into two groups by the platelet counts at 3 months after RTX. Response (R) was defined as platelet count≥30×109/L and at least 2-fold increase the baseline count and absence of bleeding. No Response (NR) was defined as platelet count＜30×109/L or less than 2-fold increase of baseline platelet count or bleeding.

Results: Totally, 108 patients were enrolled in this study. Of these patients, 43 experienced R and 65 had NR. The median (IQR) age in 108 patients was 4.46 (2.78-8.81) years with 47.2% male. The median (IQR) percentage of Th1 in CD4+ T cells were 12.53 (8.78-20.60) % for R patients and 19.03 (10.97-25.33) % for NR patients. Th1 cells were significantly higher in the NR patients compared to the R patients (P = 0.045). However, there was no statistical significance in CD4+ T, CD8+ T, CD8- T, Th2, Th17 and Treg cells between R patients and NR patients.

Conclusion(s): Th1 cells may be the predictive factors of early response to rituximab in pediatric ITP patients.