NATURAL KILLER CELLS IN IMMUNOLOGIC THROMBOCYTOPENIC PURpura of Adults

Study Overview
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Brief Summary
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Immunologic thrombcytopenic purpura (ITP) affects both children and adults. The incidence is estimated in adults about 1,6/100 000/per year. Chronic and relapsing forms of the disease that represent 70% of adult cases are associated with impairment of quality of life related to treatments side effects and bleeding. ITP is secondary to the destruction of circulating platelets through an auto-immune process and to a decrease of platelet production in bone marrow. Auto antibodies are usually directed against epitopes of the GPIIb/IIIa, expressed by platelets. The destruction of the platelets seems to occur mainly in the spleen through antibody dependent cytotoxicity. Both macrophages and cytotoxic T lymphocytes subsets participate to the platelet destruction through the CD16, the low affinity receptor for the Fc of IgG. Thus the CD16 pathway is a target for treatments in ITP as for example intravenous immunoglobulins and more recently inhibitors of the syk kinase.

Detailed Description
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Natural Killer cells (NK) cells, who are now implicated in the pathophysiology of several autoimmune diseases, express CD16 and display antibody dependent cytotoxicty. Moreover NK cells are present in human spleen. However their role in ITP has not been studied so far. NK could represent a new target for treatments in ITP. We propose thus to conduct a study to characterizes NK cells changes in patients with ITP.

Official Title
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NK-ITP STUDY : NATURAL KILLER CELLS IN IMMUNOLOGIC THROMBOCYTOPENIC PURPURA OF ADULTS.

Conditions
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Immunologic Thrombcytopenic Purpura (ITP) Adults

Intervention / Treatment
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* Other: blood samples


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ITP patients,platelets less than 50000 G/L Exclusion Criteria: Secondary ITP (VIH, VHC...) treatment with Immunosuppressive agents except corticoids (10 mg/day) treatment with Ig IV less than 3 weeks treatment with Rifuximab less than 6 months

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: PTI patients<br>Study NK cells functions, phenotypic changes and transcripts from ITP patients | Other: blood samples<br> <br> |
| Other: healthy volunteers<br>Study NK cells functions, phenotypic changes and transcripts from healthy volunteers | Other: blood samples<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Compare NK cells functions, phenotypic changes and transcripts from ITP patients and controls in a case control, multicentric study | Flow cytometry,transcripts. | 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Influence of the Ig (IV) treatment on ITP patients' NK cells |  | 24 months |