http://repub.eur.nl/res/aut/2594/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/26561/ 2011-07-01T00:00:00Z Background Sézary syndrome (SS) is a cutaneous T-cell lymphoma characterized by erythroderma, lymphadenopathy and malignant clonal T cells in the skin, lymph nodes and peripheral blood. A role for superantigens in the pathogenesis of SS has been postulated before. Objectives To investigate a putative involvement of chronic (super-)antigenic stimulation in driving T-cell expansion in SS. Methods Antigenic specificity of the T-cell receptor (TCR) was assayed by molecular analysis of the TCRA (n = 11) and TCRB (n = 28) genes, followed by detailed in silico analysis. Results Sequence analysis of clonally rearranged TCRB genes showed over-representation of Vβ8, Vβ13, Vβ17, Vβ21 and Vβ22, and under-representation of Vβ2 and Jβ1.1 when compared with healthy controls. No similarity was detected in amino acid motifs of the complementarity determining region 3 (CDR3). Analysis of TCRA rearrangements showed that there was no common Vα or Jα gene usage, and that TCRA CDR3 amino acid motifs were not highly similar. Conclusions The lack of clear stereotypic TCRA and TCRB CDR3 amino acid motifs would argue against involvement of a single common antigen in the pathogenesis of SS. Nevertheless, the skewing of Vβ and Jβ gene usage does seem to point to a restricted TCR repertoire, possibly as a result of superantigenic selection prior to neoplastic transformation. © 2011 The Authors. BJD http://repub.eur.nl/res/pub/29014/ 2008-12-01T00:00:00Z Recent studies suggest the potential involvement of common antigenic stimuli on the ontogeny of monoclonal T-cell receptor (TCR)- αβ+/CD4+/NKa+/CD8-/+dimT-large granular lymphocyte (LGL) lymphocytosis. Because healthy persons show (oligo)clonal expansions of human cytomegalovirus (hCMV)-specific TCRVβ+/ CD4+/cytotoxic/memory T cells, we investigate the potential involvement of hCMV in the origin and/or expansion of monoclonal CD4+T-LGL. Peripheral blood samples from patients with monoclonal TCR-αβ+/ CD4+T-LGL lymphocytosis and other T-chronic lymphoproliferative disorders were evaluated for the specific functional response against hCMV and hEBV whole lysates as well as the "MQLIPDDYSNTHSTRYVTVK" hCMV peptide, which is specifically loaded in HLADRB1*0701 molecules. A detailed characterization of those genes that underwent changes in T-LGL cells responding to hCMV was performed by microarray gene expression profile analysis. Patients with TCR-αβ+/ CD4+T-LGL displayed a strong and characteristic hCMV-specific functional response, reproduced by the hCMV peptide in a subset of HLA-DRB1*0701+patients bearing TCRVβ13.1+clonal T cells. Gene expression profile showed that the hCMV-induced response affects genes involved in inflammatory and immune responses, cell cycle progression, resistance to apoptosis, and genetic instability. This is the first study providing evidence for the involvement of hCMV in the ontogeny of CD4+T-LGL, emerging as a model disorder to determine the potential implications of quite a focused CD4+/ cytotoxic immune response. http://repub.eur.nl/res/pub/29361/ 2008-02-01T00:00:00Z TCRαβ+/CD4+T-large granular lymphocyte (LGL) lymphocytosis is a subgroup of monoclonal T-LGL lymphoproliferative disorders that are different from the CD8+TCRαβT-LGL. An increasing evidence supports the involvement of a common antigen-driven mechanism in the etiology of TCRαβ+/CD4+T-LGL. In this study, we tested several polymorphic markers associated with chronic viral infections and autoimmune diseases, including cytotoxic T-lymphocyte antigen-4 (CTLA-4), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), interferon-γ (IFN-γ), RANTES, IL-1α, FAS, FAS-ligand (FASL), and NKG2D, to investigate the potential association of these immunogenetic factors with the development of T-LGL. Overall, 38 patients with CD4+T-LGL were analyzed and compared with a group of both CD8+/TCRαβ+T-LGL patients (n = 43) and a group of control subjects (n = 176). Our results did not show any clear association between the different single nucleotide polymorphisms (SNPs) analyzed and the development of CD4+/TCRαβ T-LGL. An increase in the frequency of -380 (AA/GA) TNF-α genotype associated with a greater production of this cytokine was found among CD8+T LGL patients in comparison to the CD4+LGL patients and the control group. Our results suggest that the frequency of SNP of the genes coding for the studied immunoregulatory molecules are not associated with the development of CD4+/TCRαβ+T-LGL. http://repub.eur.nl/res/pub/10209/ 2007-06-13T00:00:00Z During T-cell development, thymocytes undergo a sequence of immunophenotypic and immunogenotypic changes resulting in the formation of mature T cells with receptors that recognize antigens with high specificity: the T-cell receptor (TCR). Recombination processes underlie the generation of the antigen-specificity of TCR molecules. The central theme of this thesis constitutes the basic aspects of V(D)J recombination of TCR genes and the diagnostic applications of the TCR in mature T-cell malignancies. The BIOMED-2 multiplex polymerase chain reaction (PCR) primers and protocols have been developed for the detection of immunoglobulin (Ig) and TCR gene rearrangements in human lymphoid cells. Using these assays we studied TCR diversity (repertoire) formation during T-cell development in human T lymphocytes. In addition, TCR gene rearrangement analysis was performed in malignant lymphoproliferations to determine its clinical diagnostic relevance, as well as to gain insight into the pathogenesis of mature T-cell malignancies. http://repub.eur.nl/res/pub/10397/ 2005-01-01T00:00:00Z To establish the most sensitive and efficient strategy of clonality diagnostics via immunoglobulin and T-cell receptor gene rearrangement studies in suspected lymphoproliferative disorders, we evaluated 300 samples (from 218 patients) submitted consecutively for routine diagnostics. All samples were studied using the BIOMED-2 multiplex polymerase chain reaction (PCR) protocol. In 176 samples, Southern blot (SB) data were also available, and the two types of molecular results were compared. Results of PCR and SB analysis of both T-cell receptor and immunoglobulin loci were concordant in 85% of samples. For discordant results, PCR results were more consistent with the final diagnosis in 73% of samples. No false-negative results were obtained by PCR analysis. In contrast, SB analysis failed to detect clonality in a relatively high number of samples, mainly in cases of low tumor burden. We conclude that the novel BIOMED-2 multiplex PCR strategy is of great value in diagnosing patients with suspected B- and T-cell proliferations. Because of its higher speed, efficiency, and sensitivity, it can reliably replace SB analysis in clonality diagnostics in a routine laboratory setting. Just as with SB results, PCR results should always be interpreted in the context of clinical, immunophenotypical, and histopathological data.