Evaluation of the effect of eltrombopag therapy on the platelet collagen receptor glycoprotein VI (GPVI) expression and soluble GPVI levels in young patients with immune thrombocytopenia.

BACKGROUND: Platelet glycoprotein VI (GPVI) receptor is essential for platelet adhesion and aggregation. Eltrombopag is as an effective treatment for chronic immune thrombocytopenia (ITP); yet, its effect on platelet function is not fully characterized. AIM: This prospective study investigated the effect of eltrombopag therapy on platelet function through assessment of GPVI receptor expression and soluble GPVI levels among pediatric patients with persistent or chronic ITP. METHODS: Thirty-six children and adolescents with persistent or chronic ITP were divided equally into two groups either to receive eltrombopag therapy or the standard of care. All patients were followed-up for 12 months with assessment of bleeding score and complete blood count (CBC). Evaluation of GPVI expression using flow cytometry and measurement of its soluble form by ELISA was done at baseline and at 6 months. RESULTS: ITP patients on eltrombopag had significantly lower bleeding score after 6 months of therapy while the quality of life has significantly improved. Platelet count was significantly increased throughout the study. GPVI expression by flow cytometry and soluble GPVI levels were significantly increased after eltrombopag therapy. After 12 months, ITP patients on eltrombopag were able to maintain a good quality of life and low bleeding score. CONCLUSION: Our data suggest that eltrombopag, through its effect on the GPVI receptor expression and its soluble form, might reduce bleeding manifestations and improve the quality of life of chronic and persistent ITP children independent of its effect on the platelet count.

Silent bleeding in children and adolescents with immune thrombocytopenia: relation to laboratory parameters and health related quality of life.

Occult hemorrhage can occur in any internal organ in ITP patients. Four sites of occult hemorrhage require attention including microscopic hematuria, fecal occult blood loss, retinal hemorrhage, and silent intracranial hemorrhage. The aim of this study was to investigate the frequency of subclinical bleeding in children with ITP and its relation to clinical and laboratory disease parameters including bleeding score and health related quality of life. This cross-sectional study included 40 ITP patients recruited from the Pediatric Hematology/Oncology unit, Children's Hospital, Ain Shams University, Cairo, Egypt. Inclusion criteria were patients with ITP (acute, persistent or chronic) having platelet count of 20,000/cmm or less at diagnosis/relapse, patients with overt bleeding and patients with secondary ITP were excluded. Occult blood in stools and urine analysis, fundus examination, and non-contrast brain MRI for microbleeds were done. Out of the forty included patients, 24 had chronic, 11 had acute and 5 had persistent ITP. Eleven patients had occult bleeds. Two patients had occult blood in stools, five had microscopic hematuria, one had retinal bleeds and three patients had brain microbleeds. Their mean age was 10.23 ± 4.18 years and their mean initial bleeding score was 2.55 ± 0.82. Nine patients with occult bleeding were chronic, one persistent and one acute ITP patients. There were no significant differences between patients with occult bleeding and those without as regards the initial bleeding score, platelet counts and hemoglobin level, as well as the mean platelet counts and mean hemoglobin level over the disease duration (p > 0.5). The scoring of the parent's life, Child and parents' quality of life was low in 3 out of 11 patients with occult bleeding. There was no significant difference between patients with occult bleeding and those without as regards the ITP child and parents' quality of life items (p = 0.850 and 0.511 respectively). Our results suggest that subclinical bleeding is a potential risk in children with ITP, more commonly chronic ITP patients. We could not demonstrate a significant relation of occult bleeding to the laboratory findings, bleeding score, and the ITP health quality of life; nevertheless, the significance of the routine assessment of occult bleeding in ITP and the identification of high-risk patients require additional studies.