Excessive expressions of T cell activation markers in pediatric immune thrombocytopenia

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