Excessive expressions of T cell activation markers in pediatric immune thrombocytopenia

Immune thrombocytopenia (ITP) is an immune-mediated bleeding disorder in children. Activated T cells have been shown to play important roles in ITP. The aims of this study were to evaluate whether these T cell activation markers could be used as indicators to differentiate ITP patients from controls, and to assess whether they could be used as predictors of IVIG response in ITP patients.

A cohort of 92 hospitalized ITP patients, 49 unrelated healthy children, and 48 thrombocytosis patients were enrolled in this retrospective study between February 2013 and September 2018. Expression of CD25, HLA-DR, and CD69 on the surfaces of CD4+ and CD8+ T cells were detected by flow cytometry. All statistical analyses were performed using SPSS 20.0 software.

Compared to the healthy controls, ITP patients had higher percentages of CD4 + CD25+ T cells, CD4 + HLA-DR+ T cells, CD8 + HLA-DR+ T cells, and CD8 + CD69+ T cells. Compared to the thrombocytosis patients, ITP patients had higher percentages of CD4 + HLA-DR+ T cells and CD8 + HLA-DR+ T cells, and lower CD4 + CD69+ T cells and CD8 + CD69+ T cells. Platelet count at admission had a negative correlation with CD4 + CD25+ T cells in ITP. CD4 + CD69+ T cells were decreased in chronic compared to the newly diagnosed and persistent ITP patients. Activated T cell markers had no predictive value for IVIG response in ITP patients.

T cell activation markers were excessively expressed in pediatric ITP, and those markers had no predictive value for IVIG response in ITP patients.