RESUMO
Gammadelta T cells localize at mammalian epithelial surfaces to exert both protective and regulatory roles in response to infections. We have previously characterized the Mexican axolotl (Ambystoma mexicanum) T cell receptor delta (TRD) chain. In this study, TRD repertoires in spleen, liver, intestine and skin from larvae, pre-adult and adult axolotls were examined and compared to the thymic TRD repertoire. A TRDV transcript without N/D diversity, TRDV1S1-TRDJ1, dominates the TRD repertoires until sexual maturation. In adult tissues, this canonical transcript is replaced by another dominant TRDV1S1-TRDJ1 transcript. In the thymus, these two transcripts are detected early in development. Our results suggest that gammadelta T cells that express the canonical TRDV1S1-TRDJ1 transcript emerge from the thymus and colonize the peripheral tissues, where they are selectively expanded by recurrent ligands. This particular situation is probably related to the neotenic state and the slow development of the axolotl. In thymectomized axolotls, TRD repertoires appear different from those of normal axolotls, suggesting that extrathymic gammadelta T cell differentiation could occur. Gene expression analysis showed the importance of the gut in T cell development.
Assuntos
Rearranjo Gênico da Cadeia delta dos Receptores de Antígenos dos Linfócitos T , Sistema Imunitário/crescimento & desenvolvimento , Receptores de Antígenos de Linfócitos T gama-delta/genética , Ambystoma mexicanum , Sequência de Aminoácidos , Animais , Sequência de Bases , Diferenciação Celular , DNA Nucleotidilexotransferase/genética , Fator de Transcrição GATA3/genética , Expressão Gênica , Proteínas de Homeodomínio/genética , Fator de Transcrição Ikaros/genética , Sistema Imunitário/imunologia , Sistema Imunitário/metabolismo , Hibridização In Situ , Mucosa Intestinal/metabolismo , Intestinos/crescimento & desenvolvimento , Intestinos/imunologia , Larva/crescimento & desenvolvimento , Larva/imunologia , Larva/metabolismo , Fígado/crescimento & desenvolvimento , Fígado/imunologia , Fígado/metabolismo , Dados de Sequência Molecular , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T gama-delta/análise , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Alinhamento de Sequência , Pele/crescimento & desenvolvimento , Pele/imunologia , Pele/metabolismo , Baço/crescimento & desenvolvimento , Baço/imunologia , Baço/metabolismo , Linfócitos T/citologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Timo/crescimento & desenvolvimento , Timo/imunologia , Timo/metabolismoRESUMO
Hepatosplenic gammadelta T-cell lymphoma (HSTL) is a clinicopathological entity associated with an immunocompromised status in approximately 25% of patients. Herein is described a case of HSTL in a 53-year-old Brazilian man with seven previous malaria infections, initially misdiagnosed as a hyperreactive splenomegaly due to chronic malaria. A characteristic lymphoid infiltrate was observed in spleen, liver and bone marrow sinusoids/sinuses. Neoplastic cells had a CD45RO+, CD2+, CD7+, CD3+, CD5-, CD8+, CD56+, perforin+, FasL-negative, T-cell receptor (TCR)alphabeta-negative, TCRgammadelta+ profile. Analyses of gamma and delta TCR rearrangements confirmed diagnosis of gammadelta T-cell lymphoma by detecting VgammaI/Vdelta1-Jdelta1 clonal rearrangements. Sensitive polymerase chain reaction (PCR) for Plasmodium falciparum, Epstein-Barr virus and herpesvirus-8 failed to demonstrate infection. The disease progressed to a fatal outcome following cutaneous infiltration and leukemic proliferation. The authors also comment on the association of lymphoma and infection, focusing on PCR diagnosis of TCRgamma and delta clonal rearrangements and the presumed pathogenic events leading to HSTL in the context of chronic malaria infection. Initial lymphomagenic stages might not be direct consequences of antigenic stimulation of Vdelta1 T-cells, but might depend on interactions between gammadelta T and B cells during cooperative or regulatory responses to Plasmodium sp.
Assuntos
Neoplasias Hepáticas/patologia , Linfoma de Células T/patologia , Malária/patologia , Receptores de Antígenos de Linfócitos T gama-delta/biossíntese , Neoplasias Esplênicas/patologia , DNA de Neoplasias/análise , Evolução Fatal , Rearranjo Gênico da Cadeia delta dos Receptores de Antígenos dos Linfócitos T , Rearranjo Gênico da Cadeia gama dos Receptores de Antígenos dos Linfócitos T , Humanos , Hospedeiro Imunocomprometido , Imunofenotipagem , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/imunologia , Linfoma de Células T/genética , Linfoma de Células T/imunologia , Malária/imunologia , Masculino , Pessoa de Meia-Idade , Receptores de Antígenos de Linfócitos T gama-delta/genética , Neoplasias Esplênicas/genética , Neoplasias Esplênicas/imunologiaRESUMO
The leptomeningeal involvement of central nervous system is defined in the most centers by the presence of blast cells in the CSF or the presence of cranial-nerve palsies. Sometimes, cytology does not allow clear distinction between lymphoblasts and normal cells, and auxiliary methods to the precise identification of leukemic cells in cerebrospinal fluid is necessary. We analyzed CSF from 11 consecutive patients, in whom a differential diagnosis of leptomeningeal involvement was made, including 4 patients at diagnosis and 7 patients during the treatment by cytomorphological analysis and PCR and automatic sequencing. Six patients were considered with leptomeningeal involvement by conventional analysis: unequivocal cytomorphological involvement was considered in 5 patients, and in one it was assumed to be due to cranial-nerve palsy, with no blast cells detected in cerebrospinal fluid. In 2 it was considered suspicious and in 3 negative. PCR and sequencing analysis showed involvement in 6 patients; 5 of the 6 patients were considered to have leptomeningeal involvement based on clinical and cytomorphological criteria, and, in one of the patients, it was suspicious. Our data suggest that the use of PCR and sequencing can be useful in confirming CNS leukemia and eliminating other conditions when used together with the cytomorphological analysis.
Assuntos
Líquido Cefalorraquidiano/citologia , Citodiagnóstico/métodos , Neoplasias Meníngeas/líquido cefalorraquidiano , Meninges/patologia , Reação em Cadeia da Polimerase/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras/líquido cefalorraquidiano , Células da Medula Óssea/química , Células da Medula Óssea/patologia , Criança , Células Clonais/patologia , DNA de Neoplasias/líquido cefalorraquidiano , Rearranjo Gênico da Cadeia delta dos Receptores de Antígenos dos Linfócitos T/genética , Rearranjo Gênico da Cadeia gama dos Receptores de Antígenos dos Linfócitos T/genética , Genes Codificadores da Cadeia delta de Receptores de Linfócitos T/genética , Genes Codificadores da Cadeia gama de Receptores de Linfócitos T/genética , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Neoplasias Meníngeas/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Reprodutibilidade dos TestesRESUMO
BACKGROUND: The initial response to induction therapy is currently considered one of the most important prognostic factors in acute lymphoblastic leukemias (ALL). A series of methods for the detection of submicroscopic levels of residual disease in patients with ALL mainly based on PCR and immunophenotyping has been developed, demonstrating that the presence of high levels of residual disease at the end of induction therapy is an important, independent prognostic factor. We determined the usefulness of PCR detection of minimal residual disease using consensus primers as a non-remission criterion. PROCEDURE: Bone marrow samples obtained from 49 children with ALL were analyzed at diagnosis and at the end of induction therapy for the detection of clonal IgH, TCRdelta, and TCRgamma rearrangements by PCR. The results were compared with those obtained by standard morphologic analysis and risk group classification. RESULTS: Patients who had clonality detected at the end of induction showed a significantly higher recurrence rate and lower event-free survival than those without detected clonality (24.9% vs. 89.7%) (P < 0.0001). Multivariate analysis revealed that detection of clonality at the end of induction was the most important, independent prognostic factor when associated with age, number of white blood cells, and immunophenotyping. CONCLUSIONS: PCR detection of clonality using consensus primers is a relatively simple technique that is able to identify patients with a high chance of recurrence, and shows a higher sensitivity and a better prognostic value than standard morphologic analysis and risk group classification, defining a new remission criterion. However, further multicentric prospective studies using this technique employing a larger number of cases are necessary to confirm these findings.
Assuntos
DNA de Neoplasias/análise , Rearranjo Gênico da Cadeia delta dos Receptores de Antígenos dos Linfócitos T/genética , Rearranjo Gênico da Cadeia gama dos Receptores de Antígenos dos Linfócitos T/genética , Reação em Cadeia da Polimerase/normas , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Adolescente , Medula Óssea/patologia , Criança , Pré-Escolar , Células Clonais/patologia , Primers do DNA , Intervalo Livre de Doença , Feminino , Genes Codificadores da Cadeia delta de Receptores de Linfócitos T/genética , Genes Codificadores da Cadeia gama de Receptores de Linfócitos T/genética , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Imunofenotipagem , Lactente , Masculino , Neoplasia Residual/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais , Indução de Remissão , Sensibilidade e EspecificidadeRESUMO
Mammals and birds have two major populations of T cells, based on the molecular composition and biological properties of their antigen receptors (TCR). alpha beta T cells recognize antigenic peptides linked to major histocompatibility complex (MHC) molecules, and gamma delta T cells recognize native peptide or non-peptide antigens independently of MHC. Very little is known about gamma delta T cells in ectothermic vertebrates. We have cloned and characterized the TCRdelta chains of an urodele amphibian, the Mexican axolotl (Ambystoma mexicanum). The Cdelta domain is structurally similar to its mammalian homologues and the transmembrane domain is very well conserved. Four of the six Valpha regions that can associate with Calpha (Valpha2, Valpha3, Valpha5 and Valpha6) can also associate with Cdelta, but no specific Vdelta regions were found. This suggests that the axolotl TRD locus is nested within the TRA locus, as in mammals, and that this organization has been present in all tetrapod vertebrates and in the common ancestor of Lissamphibians and mammals, for over 400 million years. Two Jdelta regions were identified, but no Ddelta segments were clearly recognized at the Vdelta-Jdelta junctions. This results in shorter and less variable CDR3 loops than in other vertebrates and the size range of the Vdelta-Jdelta junctions is similar to that of mammalian immunoglobulin light chains. Equivalent quantities of TRD mRNA were found in the lymphoid organs, and in the skin and the intestines of normal and thymectomized axolotls. The analysis of several Valpha/delta6-Cdelta and Vbeta7-Cbeta junctions showed that both the TCRdelta and the TCRbeta chains were limited in diversity in thymectomized axolotls.
Assuntos
Ambystoma mexicanum/genética , Ambystoma mexicanum/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , DNA Complementar/genética , Expressão Gênica , Rearranjo Gênico da Cadeia delta dos Receptores de Antígenos dos Linfócitos T , Variação Genética , Humanos , Dados de Sequência Molecular , Filogenia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Antígenos de Linfócitos T alfa-beta/química , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T gama-delta/química , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Timectomia , Distribuição TecidualRESUMO
El diagnóstico de los linfomas cutáneos tiene importantes implicancias para los pacientes. Tradicionalmente el diagnóstico de cualquier lesión cutánea está basado en criterios clínicos e histopatológicos. Ninguno de estos criterios es absoluto y en los últimos años se ha destacado la trascendencia de la inmunohistoquímica y la biología molecular en relación con el diagnóstico y pronóstico. La inmunohistoquímica permite definir subpoblaciones de linfocitos, estableciendo el fenotipo, categorizando algunos cuadros y destacando en algunos casos el pronóstico a partir del CD30 (+) o (-). La biología molecular define el genotipo, aportando el concepto de monoclonalidad que sugiere malignidad. Por otra parte, proponemos una clasificación de los linfomas cutáneos primarios que ha sido recientemente introducida
Assuntos
Humanos , Imuno-Histoquímica/normas , Linfoma de Células B/diagnóstico , Linfoma Cutâneo de Células T/diagnóstico , Diagnóstico Diferencial , Rearranjo Gênico da Cadeia delta dos Receptores de Antígenos dos Linfócitos T/imunologia , Linfoma de Células B/classificação , Linfoma de Células B/genética , Linfoma Cutâneo de Células T/classificação , Linfoma Cutâneo de Células T/genética , Biologia Molecular/tendências , Reação em Cadeia da Polimerase/tendênciasRESUMO
El diagnóstico de los linfomas cutáneos tiene importantes implicancias para los pacientes. Tradicionalmente el diagnóstico de cualquier lesión cutánea está basado en criterios clínicos e histopatológicos. Ninguno de estos criterios es absoluto y en los últimos años se ha destacado la trascendencia de la inmunohistoquímica y la biología molecular en relación con el diagnóstico y pronóstico. La inmunohistoquímica permite definir subpoblaciones de linfocitos, estableciendo el fenotipo, categorizando algunos cuadros y destacando en algunos casos el pronóstico a partir del CD30 (+) o (-). La biología molecular define el genotipo, aportando el concepto de monoclonalidad que sugiere malignidad. Por otra parte, proponemos una clasificación de los linfomas cutáneos primarios que ha sido recientemente introducida (AU)
Assuntos
Humanos , Linfoma Cutâneo de Células T/diagnóstico , Linfoma de Células B/diagnóstico , Imuno-Histoquímica/normas , Linfoma de Células B/classificação , Linfoma de Células B/genética , Linfoma Cutâneo de Células T/classificação , Linfoma Cutâneo de Células T/genética , Biologia Molecular/tendências , Rearranjo Gênico da Cadeia delta dos Receptores de Antígenos dos Linfócitos T/imunologia , Reação em Cadeia da Polimerase/tendências , Antígeno Ki-1/diagnóstico , Diagnóstico DiferencialRESUMO
PURPOSE: B cell precursors acute lymphoblastic leukemia (ALL) present rearrangements in the heavy chain immunoglobulin and T cell receptor genes, especially in the complementarity determining region 3 (CDR-3) and T cell receptor delta (TCR delta) (V delta 2 D delta 3) regions. These rearrangements may be amplified by the polymerase chain reaction (PCR) and used as clonal markers of B lineage ALL. Our purpose was to study clonality at the DNA level by PCR in B lineage ALL. PATIENTS AND METHODS: Fifty-three pediatric patients (36 with B lineage ALL, 7 with ALL-T, and 10 with nonlymphocytic disease) were investigated using consensus primers for the CDR-3 regions of IgH and TCR delta. RESULTS: Clonality was detected in 86.1% of the patients with B lineage ALL when the primers for the CDR-3 regions were used, in 41.6% when the primers for TCR delta were used, and in 91.6% when the two primers were used together. Biclonality was found in 22.5% and 6.6% of patients that have shown clonality for CDR-3 and TCR delta, respectively. Clonality was not detected in any other samples using these primers. CONCLUSIONS: PCR using CDR-3 and TCR delta primers can be used as an aid for B lineage ALL diagnosis and clonal evolution of theses disease.