PB0267 - High-dose dexamethasone corrects the elevated TCRαβ+ double-negative T cells in pediatric patients with primary immune thrombocytopenia

Sunday, June 25, 2023

18:30 – 19:30 ET

Room: Exhibition

Co-Author(s)

XX

Xingjuan Xie

Doctor
Beijing Children's Hospital, Capital Medical University
Beijing, Beijing, China (People's Republic)
Hui Chen, PhD

Doctor
Beijing Children's Hospital, Capital Medical University
Beijing, Beijing, China (People's Republic)
Hao Gu, MD

Doctor
Beijing Children's Hospital, Capital Medical University
Beijing, Beijing, China (People's Republic)
JM

Jinyao Ma

Doctor
Beijing Children's Hospital, Capital Medical University
Beijing, Beijing, China (People's Republic)
LF

Lingling Fu

Doctor
Beijing Children's Hospital, Capital Medical University
Beijing, Beijing, China (People's Republic)
RW

Runhui Wu

Doctor
Beijing Children's Hospital, Capital Medical University
Beijing, Beijing, China (People's Republic)

Presenting Author(s)

Zhenping CHEN, MD

Beijing Children’s Hospital, Capital Medical University
Beijing, Beijing, China (People's Republic)

Background: TCRαβ+ CD4-CD8- (double-negative, DN) T cells play vital roles in diverse autoimmune disorders, but little is known in pediatric primary immune thrombocytopenia (ITP). High-dose dexamethasone (HD-DXM) is recognized as one of the first-line therapies in ITP. However, the effect of dexamethasone on DNT cells in ITP patients is still not been defined.

Aims: This study aims to investigate the clinical importance of DNT cells in children with ITP and uncover the effect of HD-DXM on DNT cells in pediatric ITP patients.

Methods: All patients were treated with HD-DXM and followed up for 6 months at least. Identification and enumeration of DNT cells were measured by flow cytometry using specific antibodies.

Results: In this prospective study, we enrolled 130 children with ITP and 50 age- and sex-paired healthy controls. Significantly increased frequency of DNT cells was found in patients with ITP than that in healthy controls (percentage of T cells: 1.3% vs 1.0%, P< 0.0001; percentage of lymphocytes: 0.76%vs 0.68%, P=0.010). HD-DXM resistant patients had a higher percentage of DNT cells than HD-DXM sensitive patients before treatment (DNT/T: 1.45% vs 1.30%, P=0.018; DNT/Lym: 0.84%vs 0.72%, P=0.006). Interestingly, the elevated DNT cells can be effectively reduced in HD-DXM sensitive group but not in resistant group (DNT/T: P=0.030; DNT/Lym: P=0.001; DNT counts: P=0.006).

Conclusion(s): DNT cells seems to play a role in the pathogenesis of pediatric ITP. The correction of elevated DNT cells in patients who responded to HD-DXM may provide a novel insight for immune therapy in ITP.