The Analysis of Memory Cells, T-Cell Receptor Excision Circles, T-Cell Receptor Repertoires in Patients with Wiskott-Aldrich Syndrome Protein (WASP) Mutation

The Wiskott-Aldrich syndrome (WAS), is an X- linked recessive disorder characterized by immunodeficiency, eczema, micro-thrombocytopenia and increased risk of autoimmune disorders and malignancies. X-linked thrombocytopenia (XLT), typified by thrombocytopenia and small platelets but without the other findings associated with WAS, is caused by mutations of the same gene, the Wiskott-Aldrich syndrome protein (WASP). More than 500 patient mutations have been identified, most of which are based on research on Caucasian and Japanese people. The phenotype ratio of XLT patients to classic WAS patients ranges from 23/27, 88/79 and 110/148. A correlation between the genotype and the phenotype has been controversially described. However, Taiwanese patients with XLT phenotype are not yet identified. The relationship between genotype and phenotype is rarely investigated in Chinese descent people, nor is there systemic and comprehensive report on Taiwanese with WASP mutations. In this study, one component of long-term researches for Taiwanese patients with primary immunodeficiency diseases (PIDs), we will investigate the clinical features of WAS/XLT, discuss the abnormal laboratory findings, and explore the function of WASP, on emphasis of the effect of WASP mutations on memory cells, T-cell (or B cell) receptor repertoires, and T cell receptor excision circles (TRECs) that will elucidate, in part, the phenotype severity of recurrent infections and autoimmune disorders. The specific aims of this project are summarized as below: The First Year To recognize patients with mutation of WASP protein from male patients (age below 18) in childhood period treated as idiopathic thrombocytopenia purpura (ITP) in our hospital, including primary thrombocytopenia (ICD10 code 2873; n=350); secondary thrombocytopenia (2874; n=9); thrombocytopenia unspecified (2875; n=637); and transient neonatal thrombocytopenia (7761; n=171). The first important thing we will do is to measure the volume of platelet. If micro-thrombocytopenia found, we will perform WASP genetic sequencing and basic immunologic functions including innate (phagocytosis, free radical production, NK cytotoxicity, CH50) and adaptive (lymphocyte subsets and proliferation) immunity. The Second Year To analyze quantity and function of two types of memory B cells: IgM+ memory B cells (CD27+IgM+IgD−) and isotype switched memory B cells (CD27+IgM−IgD−) and two memory T cells: the localization of effector memory T (TEM; CD45RO+CCR7-) cells and central memory T (TCM; CD45RO+CCR7+) cells. Intracellular staining of cytokines (IL-2; IFN-γ), granzyme B and perforin will be executed to patients’ lymphocytes co-cultured with antigens. The Third Year To assess the effect of mutant WASP on thymic output and the longevity of naïve T cells by detecting TRECs and TCR (or BCR) receptor repertoires. To compare TRECs and receptor repertoires between classic WAS and XLT phenotypes, even the same mutations but extreme presentations, will release contribution factors to explain the clinical spectrum.

Project ID:PC9907-2533
External Project ID:NSC99-2314-B182A-096-MY3