Immune Markers in Pediatric ITP on Second Line Therapy

Study Overview
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Brief Summary
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Immune thrombocytopenia (ITP) is a common autoimmune disease characterized by low platelet count and increased risk of bleeding. It affects approximately 50 to 100 cases per million people per year, with children accounting for half of the cases.

Detailed Description
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Antiplatelet factors in the plasma of ITP patients, specifically IgG, have been attributed to platelet destruction through phagocytosis or complement-mediated lysis. However, these antibodies are only present in 60-70% of ITP patients, suggesting that other mechanisms may be involved in platelet destruction. B lymphocytes play a critical role in immune responses through antibody production, antigen presentation to T cells, and cytokine secretion. CD4+ T helper cells play a crucial role in supporting B cell development into antibody-secreting plasma cells. Furthermore, evidence of auto reactive CD4+ T cells targeting platelet epitopes has been reported. It was found that there is clonal expansion of a particular subset of CD8+ T cells, known as terminally differentiated effector memory T cells (TEMRA cells), in refractory ITP. Furthermore, CD8+ T cells induce platelet activation and apoptosis in an antibody-independent mechanism for refractory thrombocytopenia that may be amenable to therapeutic targeting. IFN-γ is an important cytokine involved in host defence and immune regulation. It is primarily produced by T helper, cytotoxic T, and natural killer cells. Dysregulated secretion of IFN-γ has been implicated in the development of autoimmune disorders. Initial studies on ITP focused on the role of autoantibodies. Therefore, drug discovery efforts have focused on suppressing aberrant humoral immunity through B cell depletion, disruption of immunoreceptor, and inhibition of autoantibody activity. By comparing the marker expression in different treatment response groups, the investigator can potentially identify markers that may serve as predictive or prognostic indicators of treatment response. This information could be valuable for guiding treatment decisions and optimizing patient outcomes in pediatric ITP.

Official Title
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Marker Expression in Pediatric Patients With Immune Thrombocytopenic Purpura Receiving Second Line Therapy

Conditions
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ITP - Immune Thrombocytopenia

Intervention / Treatment
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* Diagnostic Test: complete blood count, CD3+ , CD4+ , CD8+, CD16+, CD56+, IFN-γ.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pediatric patients diagnosed with immune thrombocytopenia who are undergoing second line therapy with either eltrombopag or romiplostim. Exclusion Criteria: Include acute immune thrombocytopenic children receiving first line therapy and those with secondary immune thrombocytopenia.

Ages Eligible for Study
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Maximum Age: 17 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Respondents to second-line therapy<br>Immune markers in ITPpatients Respondant to second line therapy | Diagnostic Test: complete blood count, CD3+ , CD4+ , CD8+, CD16+, CD56+, IFN-γ.<br>* Full history Thorough clinical examinations Laboratory investigations will include: complete blood count with focus on platelet count, platelet distribution width and mean platelet volume. Platelet count will be confirmed by direct blood film and blood smear. Measurements of CD3+, CD4+, CD8+ and natural killer cells (CD16+, CD56+) will be conducted using flow cytometry. Serum IFN-γ levels will be determined using an ELISA kit. Response to the treatment will be assessed according to The International Working Group criteria which defines Response as platelet count ≥ 30 x 10⁹/L and >2-fold increase in platelet count from baseline and absence of bleeding, measured on 2 occasions greater than 7 days apart. No response is characterized by a platelet count <30 x 10⁹/L or a less than 2-fold increase in platelet count from baseline, or the presence of bleeding.<br>|
| Non-Respondents to second-line therapy<br>Immune markers in ITPpatients nonrespondant to second line therapy | Diagnostic Test: complete blood count, CD3+ , CD4+ , CD8+, CD16+, CD56+, IFN-γ.<br>* Full history Thorough clinical examinations Laboratory investigations will include: complete blood count with focus on platelet count, platelet distribution width and mean platelet volume. Platelet count will be confirmed by direct blood film and blood smear. Measurements of CD3+, CD4+, CD8+ and natural killer cells (CD16+, CD56+) will be conducted using flow cytometry. Serum IFN-γ levels will be determined using an ELISA kit. Response to the treatment will be assessed according to The International Working Group criteria which defines Response as platelet count ≥ 30 x 10⁹/L and >2-fold increase in platelet count from baseline and absence of bleeding, measured on 2 occasions greater than 7 days apart. No response is characterized by a platelet count <30 x 10⁹/L or a less than 2-fold increase in platelet count from baseline, or the presence of bleeding.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation analysis | Analysis of the correlation between specific markers expression ( CD3,CD4,CD8,Interferon gamma and natural killer cells) and treatment response in pediatric patients with immune thrombocytopenia who are receiving second line therapy. | One year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of treatment response | Assessment of response to second line therapy (eltrombopag, romiplostim) in pediatric patients with immune thrombocytopenic purpura using clinical and laboratory findings. | One year |