Evaluation of Immune Status Before and After Splenectomy in Immune Thrombocytopenia Patients

A total of 30 ITP patients will be enrolled in the study. These patients should fail to have sustained response to multiple first- and second-line treatments of ITP and agree to have splenectomy. Before splenectomy, these patients will be reassessed and still diagnosed with ITP.Their platelet level will be raised to a safe state before surgery, and the laparoscopic splenectomy will be performed in Tianjin People's Hospital. The investigators plan to take 20ml of peripheral blood (PB) of these patients at 6 time points, including 1 day before surgery, 1 week, 1 month, 3 months, 6 months, and 12 months after surgery, and take a small amount of spleen tissue during surgery.

18 age- and gender- matched healthy donor will also be enrolled as controls and taken 20ml of peripheral blood. The investigators also plan to take splenic tissue from 10 patients who have splenectomy due to Hereditary spherocytosis or trauma.

And then the investigators will do the experiments step by step. 1, Isolation of peripheral blood and splenic mononuclear cells;2, Detection of the percentage of cell population;3, Activation and proliferation of B lymphocyte; 4, Activation and proliferation of T lymphocyte;5,Apoptosis of platelets by cytotoxic T cells;6,Phagocytosis of platelets by macrophages in spleen;7,Enzyme-linked immunosorbent assay (ELISA) for cytokines.

• splenectomy (Procedure): These patients should fail to have sustained response to multiple first- and second-line treatments of ITP and agree to have splenectomy.Before splenectomy, these patients will be reassessed and still diagnosed with ITP.Their platelet level will be raised to a safe state before surgery, and the laparoscopic splenectomy will be performed in Tianjin People's Hospital.

Primary outcomes

• Changes of the percentage of cell population [1 year]: To assess the changes of the percentage of B cell subsets，regulatory B cells（Breg），regulatory T cells (Treg)，supressor T cells（Ts），monocyte Fc receptor（FCR）I/II, FCRIII and FCRIIb, helper T cells（Th）subsets and the functionally-polarized CD4+ T cell subsets in peripheral blood mononuclear cells（PBMCs）at 6 time points, including 1 day before surgery, 1 week, 1 month, 3 months, 6 months, and 12 months after surgery, and to compare with the healthy controls.
• Changes of activation and proliferation of B and T lymphocyte, apoptosis of platelets by cytotoxic T cells(CTLs) [1 year]: To assess the changes of activation and proliferation of B and T lymphocyte, apoptosis of platelets by cytotoxic T cells(CTLs) in peripheral blood mononuclear cells（PBMCs）at 6 time points, including 1 day before surgery, 1 week, 1 month, 3 months, 6 months, and 12 months after surgery, and to compare with the healthy controls.
• Changes of cytokines in the cell culture supernatants and plasma [1 year]: To assess the changes of cytokines in the cell culture supernatants and plasma at 6 time points, including 1 day before surgery, 1 week, 1 month, 3 months, 6 months, and 12 months after surgery, and to compare with the healthy controls.

Secondary outcomes

• Changes of phagocytosis of platelets by macrophages in itp patients spleen and the normal spleen controls. [The day of the splenectomy]: To assess the changes of phagocytosis of platelets by macrophages in itp patients spleen and the normal spleen controls.
• Changes of the percentage of cell population, activation and proliferation of B and T lymphocyte, apoptosis of platelets by cytotoxic T cells(CTLs) in itp patients spleen and the normal spleen controls. [The day of the splenectomy]: To assess the changes of the percentage of B cell subsets，regulatory B cells（Breg），regulatory T cells (Treg)，supressor T cells（Ts），monocyte Fc receptor（FCR）I/II, FCRIII and FCRIIb, helper T cells（Th）subsets ,the functionally-polarized CD4+ T cell subsets, activation and proliferation of B and T lymphocyte, apoptosis of platelets by cytotoxic T cells(CTLs) in itp patients spleen and the normal spleen controls.

Sex: All, ages: 18 Years to 60 Years, accepts healthy volunteers

Inclusion Criteria:

* Aged 18 to 60 years old, male or female;
* Conform to the diagnostic criteria of immune Thrombocytopenia (ITP)
* Needed splenectomy;
* People who are willing to sign the informed consent voluntarily and follow the research program.

Exclusion Criteria:

* Secondary thrombocytopenic purpura;
* Patients with poor compliance;
* Researchers believe that patients should not participate in the test of any other condition.

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• Lei Zhang, MD, Principal investigator, Chinese Academy of Medical Science and Blood Disease Hospital