Delta Chain Gene Research Articles

Deficiency of CD3gamma, delta, epsilon, and zeta expression in T cells from AML patients

In order to elucidate the feature of T‐cell receptor (TCR) signal transduction in T‐cells from acute myeloid leukemia (AML), the expression levels of CD3gamma, delta, epsilon and zeta chain genes in CD3+ T cells were analyzed using real‐time PCR. CD3+ T cells sorted from peripheral blood of 10 AML patients and 10 healthy donors were used in the study. Significantly lower expression levels of all four CD3gamma, delta, epsilon, and zeta chain genes were found in the AML samples. The expression pattern of the four CD3 chains was epsilon>gamma>delta>zeta in CD3+ T cells from AML samples, which was different from the healthy control group. In conclusion, the results provide a global gene expression profile of CD3gamma, delta, epsilon, and zeta chains in AML patients. Deficiency of all four CD3 gene expression levels might represent the feature related to T‐cell immunodeficiency.

Hemophagocytic lymphohistiocytosis associated with myelodysplastic syndromes

Hemophagocytic lymphohistiocytosis/hemophagocytic syndrome (HLH/HPS) is a reactive disorder of the mononuclear phagocytic system, characterized by generalized histiocytic proliferation with marked hemophagocytosis in the bone marrow [1]. It comprises two different categories: a primary (genetic) and a secondary (acquired) form. Malignant neoplasm-associated HPS (MAHS) is categorized as a secondary HLH. MAHS is mainly associated with lymphoma and rarely with other carcinomas [2]. To our knowledge, HLH associated with myelodysplastic syndromes (MDS) has not been described, although MDS with hemophagocytosis has been observed. Here, we describe a case of HLH associated with MDS, which presented with abundant CD8 T cells in the bone marrow and elevated plasma-soluble interleukin 2 receptor (sIL-2R). A 60-year-old Japanese man was admitted with pancytopenia, epitaxis, fever and general fatigue. A hematological examination showed a hemoglobin concentration of 6.5 g/dL, a platelet count of 14,000/lL and a leukocyte count of 3,200/lL with 42.8% atypical lymphocytes (Fig. 1a). Blood biochemistry showed increased levels of lactate dehydrogenase (LDH) (331 IU/L), ferritin (649 ng/mL) and sIL-2R (4,054 U/mL). NK cytolytic activity was measured by the standard 51-chromium (Cr) release assay. NK cytolytic activity was not reduced at both the E/T ratios of 10:1 (13.1%, normal range 8.9–29.5%) and 20:1 (22.5%, normal range 17.1–48.7%). Serological studies for hepatitis B, hepatitis C and HTLV-1 were negative. IgM antibodies to parvovirus were negative. Serological test for EBV revealed that anti-viral capsid antigen IgM was negative in the presence of anti-viral capsid antigen IgG (1609) and anti-EBV nuclear antigen antibody (409). The number of EBV DNA copies in serum was under 2.0 9 10 copies/mL (normal \200 copies/mL). Computed tomography (CT) revealed hepato-splenomegaly, ascites and bilateral pleural effusion. Bone marrow aspirate showed dyserythropoietic changes (abnormally lobulated nuclei) (Fig. 1c) and dysplastic megakaryocytes (micromegakaryocytes) (Fig. 1d). Erythrocytic precursors were 10.4% and bone marrow myeloblasts were 2.0% (Fig. 1e). Chromosome analysis showed severe complex karyotype: 54–57XY, ?1[2],?3[2],?4[4],?6[4],?8[4],add(9)(p22)[2],?11[3],add (15)(p11.2)[4],add(16)(q24)[4],add(19)(p13.1)[4],add(20) (p13)[4],?21[2],2–5mar[cp4]/46,XY[8]. A diagnosis of refractory anemia with excess blasts-1 (WHO classification) was made. In addition, bone marrow examination revealed increased numbers of atypical lymphocytes (Fig. 1b) and multiple sites of active hemophagocytosis (Fig. 2a–c). Atypical lymphocytes in bone marrow were positive for CD2, CD3 (surface, cytoplasmic), CD5, CD7, CD8, HLA-DR, TCR-ab, and negative for CD4. No monoclonal rearrangement of TCR beta, gamma and delta chain genes was detected by Southern blotting. These findings suggested that the atypical lymphocytes were reactive CD8 T cells. Combining fever, hemophagocytosis, splenomegaly, increased levels of ferritin and sIL-2R, a diagnosis of HLH was established. Although steroid therapy was administered for HLH, pancytopenia was not improved. Two months after the initial diagnosis, the levels of LDH and ferritin were further elevated (LDH 1,474 U/mL, ferritin 4,347 ng/mL). Bone marrow examination T. Tsuji (&) H. Yamasaki H. Tsuda Division of Hematology and Oncology, Kumamoto City Hospital, Kotoh 1-1-60, Kumamoto 862-8505, Japan e-mail: tsuji.takahiro@city.kumamoto.lg.jp

Chromosomal excision of TCRδ chain genes is dispensable for αβ T cell lineage commitment

TCRbeta, delta and gamma chain genes are assembled and expressed in double-negative thymocytes prior to alphabeta or gammadelta T cell lineage commitment. Thus, cells committed to the alphabeta T cell lineage can possess completely assembled TCRdelta and/or TCRgamma chain genes. However, these genes are not expressed. TCRgamma chain gene expression may be silenced through the activity of a cis-acting silencer element. In the TCRalpha/delta locus, the TCRdelta genes lie between the Valpha and Jalpha gene segments, which rearrange by deletion. Moreover, Valpha to Jalpha rearrangements occur on both alleles in essentially all developing alphabeta T cells. Consequently, both TCRdelta chain genes are excised from the chromosome and placed on extrachromosomal circles in mature alphabeta T cells. It has been proposed that this excision process is important for silencing TCRdelta gene expression and permitting alphabeta T cell lineage commitment. A gene-targeting Cre-loxP strategy was used to invert a 75-kb region of the TCRalpha/delta locus encompassing all the Jalpha gene segments, generating the TCRalpha/delta(I) allele. Initial Valpha to Jalpha rearrangements on the TCRalpha/delta(I) allele occur by inversion, resulting in chromosomal retention of TCRdelta chain genes. These TCRdelta chain genes can be productively rearranged and are expressed at levels similar to TCRdelta chain genes in gammadelta T cells. However, alphabeta T cell development appears unperturbed in TCRalpha/delta(I/I) mice. Thus, excision of TCRdelta genes from the chromosome per se is not required for commitment of developing lymphocytes to the alphabeta T cell lineage.

Hepatosplenic γδ T-cell lymphoma

To investigate the clinicopathologic characteristics, immunophenotype and TCR gene rearrangements of hepatosplenic T-cell lymphoma in eight Chinese patients. Eight Chinese patients with hepatosplenic gammadelta T-cell lymphomas were studied. Hematoxylin-eosin-stained slides and clinical histories were reviewed. We also carried out immunohistochemical staining for CD3, CD4, CD8, CD20, CD43, CD56, CD79a, UCHL-1, and TCR gammadelta. Rearrangements of TCR gamma and delta chain genes were also studied. The spleens were enlarged and the cut surfaces were homogeneous and red-purple in color without identifiable gross lesions or enlarged hilar lymph nodes. Histologically, lymphoma cells infiltrated the cords of Billroth and often packed the sinuses. Liver biopsy showed lymphoma cell infiltrations in the sinusoids, and three cases showed involvements of the portal tracts. Immunohistochemically lymphoma cells were positive for CD3, CD43, and CD56 in all cases. Four of eight cases were positive for CD8, and all cases were negative for CD4 (6/6). Monoclonal rearrangements of TCR gamma gene were demonstrated by PCR analysis in five out of the eight cases. TCR delta gene rearrangements were detected in six out of the eight cases, which demonstrated single bands on PAGE gel, and the amplification products in two cases were confirmed by sequencing. The clinicopathology of hepatosplenic gammadelta T-cell lymphoma in Chinese patients is similar to what was previously reported except that the splenomegaly is not so massive, and CD8 is positive.

Prevalence of mycosis fungoides and its association with EBV and HTLV-1 in Pakistanian patients.

Mycosis fungoides (MF) is an indolent T cell lymphoma that is distinguished from other lymphomas by its initial appearance on the skin. The histologic diagnosis of MF may be difficult because there is significant overlap in the histologic features of neoplastic T-cell infiltrates and inflammatory dermatoses. This T-cell neoplasm commonly occurs in a mixed, reactive background and can show only a subtle degree of cytologic atypia, rendering histologic diagnosis difficult. In this study MF constituted 0.86% of all non-Hodgkin s lymphoma (NHL) both T and B, as compared to the Western studies which have reported 0.5% prevalence for MF of all NHL. Polymerase chain reaction (PCR) technique was used to assess T-cell clonality in paraffin-embedded skin biopsies clinically and pathologically suspicious for early MF. Out of the 14 cases diagnosed as MF, amplifiable DNA was isolated from 6 cases, which were further studied for T-cell receptor (TcR) beta, gamma, and delta chain gene rearrangements. Clonal product was seen in 4 out of 6 cases for beta, gamma, and delta TcR chain genes. Association for Epstein Barr virus (EBV) was observed in 3 out of 6 cases (50%) of MF. Although these 3 cases were positive for EBV by PCR, but were negative by in-situ hybridization (ISH). No heterogeneity was noted in these 3 cases of MF for BamHI E, K, N, and Z regions of EBV. All six cases were negative for HTLV-1 (tax region) by PCR. It was concluded that the prevalence of MF in Pakistani population is comparable to the Western data, and that EBV association to MF cases was higher than in Western studies.

Assignment of T cell receptor (TCR) alpha-chain gene (A), beta-chain gene (B), gamma-chain gene (G), and delta-chain gene (D) loci on swine chromosomes by in situ hybridization and radiation hybrid mapping

Using the cDNA sequence of porcine T-cell receptor (TCR) α-, β-, γ-, and δ-chain genes, we screened a porcine BAC library to isolate clones containing these genes. The isolated BAC clones were confirmed to carry these TCR genes by partial nucleotide sequencing. Among the clones obtained in the present screening, two clones carried both the TCR α-chain gene (TRA) and the TCR δ-chain gene (TRD) while one clone each carried only the sequence of either TRA or TRD. This observation demonstrated that TRA and TRD are localized in close proximity on a swine chromosome. Also two clones contained the sequence of the TCR β-chain gene (TRB), and two clones contained the sequence of TCR γ-chain gene (TRG). Fluorescence in situ hybridization using the above BAC clones as probes revealed that TRA and TRD, TRB, and TRG loci reside on swine chromosomes 7q15.3→q21, 18q11.3→q12, and 9q21→q22, respectively. The chromosome positions of TRA and TRB are consistent with those determined by somatic cell hybrid analysis (Rettenberger et al., 1996). In addition, RH mapping of these genes was performed using the INRA-University of Minnesota RH panel DNA. The result confirmed the position of TRA and TRB reported earlier (http://imprh.toulouse.inra.fr/), and further demonstrated that TRG was located 11 cR away from genetic marker SW989 toward the marker S0019.

Lymphocyctes Tgammadelta in clinically normal skin and peripheral blood of patients with systemic lupus erythematosus and their correlation with disease activity.

Human Tgammadelta lymphocytes constitute from 1 to 15% of all peripheral blood lymphocytes. Recent work has demonstrated that this population plays a major role in the pathogenesis of infectious and immune diseases. Increased numbers of gammadelta T cells have been found in affected skin from systemic sclerosis and chronic cutaneous lupus erythematosus patients. In our study, we have determined the numbers of Tgammadelta lymphocytes and their subpopulations in peripheral blood from 29 patients with systemic lupus erythematosus (SLE) and in 19 healthy volunteers using flow cytometry and specific monoclonal antibodies. The same cells in uninvolved skin from SLE patients and human controls using immunohistochemical analysis were estimated. T-Cell receptor (TCR) delta chain gene rearrangement was identified with primers for Vdelta1, Vdelta2 and Vdelta3 by the polymerase chain reaction. Statistical analysis showed a significantly decreased number of gammadelta T cells in SLE patients (26.4+/-16.9/microl) compared with the control group (55.3+/-20.6/microl (p < 0.001). The number of Vdelta2 TCR+ and Vgamma9 TCR+ subpopulations was also lower in SLE patients than in healthy persons. No statistical correlation between disease activity and the number of gammadelta T cells was demonstrated. The percentage of Tgammadelta lymphocytes in clinically normal skin from SLE patients was twice (22.0+/-9.4%) that found in the skin from healthy persons (11.1+/-5.5%) (p < 0.002). Higher percentages of the Vdelta2 TCR+ and Vgamma9 TCR+ subpopulation of lymphocytes were found in the skin from SLE patients. We have also found positive correlation between the percentage of Tgammadelta lymphocytes in skin and the activity of SLE (r=0.594, p < 0.001), and between subpopulation Vdelta3 TCR+ and disease activity (r=0.659, p< 0.001). In conclusion, the results of our studies demonstrate that, in patients with SLE, accumulation of Tgammadelta lymphocytes can be seen in clinically normal skin, and the percentage of these cells correlates with the activity of the disease.

Decreased severity of myelin oligodendrocyte glycoprotein peptide 33 - 35-induced experimental autoimmune encephalomyelitis in mice with a disrupted TCR delta chain gene.

Immunization of C57BL / 6 mice with myelin oligodendrocyte glycoprotein (MOG) peptide (p) 35 - 55 induces chronic experimental autoimmune encephalomyelitis (EAE). The role of gamma delta T cells in the regulation of EAE is unclear. We investigated gamma delta T cells in C57BL / 6 wild-type mice and C57BL / mice with a disrupted TCRdelta chain gene (delta(- / -) mice) using MOG p35 - 55. We found significantly less disease in delta(- / -) mice immunized with MOG / complete Freund's adjuvant (mean maximal EAE score 4.3 +/- 0.8 in wild-type vs. 2.3 +/- 0.5 in delta(- / -) mice). Transfer of wild-type spleen cells restored the ability of delta(- / -) mice to develop equally severe EAE as wild-type mice. In addition to IFN-gamma, IL-2, IL-5 and IL-10 was decreased in delta(- / -) mice. Decreased immune responses were also seen in delta(- / -) animals immunized with OVA peptide or protein and in concanavalin A-stimulated splenocytes from delta(- / -) mice. Enriched dendritic cells from delta(- / -) mice secreted significantly less TNF-alpha in response to lipopolysaccharide stimulation. Furthermore, when EAE was induced by adoptive transfer of an anti-MOG p35 - 55 alpha beta T cell line, there was a striking reduction of disease incidence (0 %) and severity in delta(- / -) as compared to wild-type mice (83 % incidence). delta(- / -) mice showed no cellular infiltration in the spinal cord whereas wild-type animals had infiltration of macrophages, B cells, alpha beta- and gamma delta T cells. In adoptive transfer EAE, there was reduced IL-2 and IFN-gamma secretion in delta(- / -) mice. These results demonstrate an impaired immune response in the delta(- / -) mouse that is associated with a defect in developing both actively induced and adoptively transferred EAE.

TCR-delta gene rearrangement and selection during fetal thymocyte development.

TCR delta-chain gene rearrangements were analyzed at different stages of thymic ontogeny. The VDJ delta junctional sequences of the dominantly expressed TCR delta-chain V7 subfamily are highly conserved in fetal and neonatal thymocytes. They are equally conserved in C delta-targeted mice lacking cell surface expression of gamma delta receptors, indicating evolutionary selection acting at the level of DNA rearrangement. Yet, in C delta-mutant mice, the frequency of in-frame transcripts is reduced to 61%, from 88% in wild-type mice, suggesting cellular selection of this DV7-overexpressing gamma delta thymocyte subset. In contrast, in genomic DNA rearrangements, no difference was found in the frequency of productive rearrangements between mutant (26%) and wild-type mice (31%). This in-frame rate, characteristic of random rearrangements, indicates that positive selection is not required for thymic maturation of gamma delta T cells. The results are discussed with regard to models of alpha beta/gamma delta lineage commitment.

T-cell receptor alpha, beta, gamma, and delta chain gene microsatellites show no association with multiple sclerosis.

Genetic predisposition to multiple sclerosis (MS) is determined, in part, by certain HLA genotypes, but the contribution of T-cell receptor (TCR) germline polymorphisms to MS susceptibility is less clear. Reports of disease associations with restriction fragment length polymorphisms of TCR alpha and beta chain genes have been difficult to confirm, and little data is available on the influence of the TCR gamma delta germline in MS. We investigated the TCR alpha, beta, gamma, and delta chain genes of Northern Irish patients with MS using four microsatellite markers of high heterozygosity. There were similar allele frequencies in patients and controls for all microsatellites studied. We conclude there is no convincing evidence for an association of MS with TCR alpha, beta, gamma, and delta chain gene polymorphisms.

Restricted T cell receptor delta chain genes repertoire in peripheral blood of multiple sclerosis patients

Multiple sclerosis (MS) is a chronic inflammatory disease characterized by focal demyelination of central nervous system (CNS). Susceptibility to MS is thought to be affected by multiple genes including HLA and T cell receptor (TCR) genes. In view of the recent evidence, that in addition to α/β T lymphocytes also γ/δ T cells may have autoreactive potential, TCR delta repertoire in peripheral blood of MS patients has been studied. TCR delta repertoire, as assessed by Vδ‐Jδ rearrangements, has been analysed in 13 MS cases and in 30 healthy individuals by seminested PCR technique. Oligonucleotide primers specific for six Vδ regions and for Jδ1 gene were used for amplification of Vδ‐Jδ junctional region responsible for the diversity of γ/δ TCR. In the majority of MS patients PAGE analysis of Vδ1‐Jδ1, Vδ3‐Jδ1 and Vδ5‐Jδ1 rearrangements showed single‐band or two‐band pattern. The most striking result has been observed in Vδ5‐Jδ1 rearrangement, where in nine cases studied single band and in four patients two bands have been found. In all but one MS cases multi‐band pattern of Vδ2‐Jδ1 rearrangement was obtained. None of the 13 MS patients showed single‐band rearrangement pattern of Vδ4‐Jδ1 and Vδ6‐Jδl. Contrary to the MS group almost all healthy individuals produced smear‐like or multi‐band pattern of Vδ1‐Vδ5 to Jδ1 rearrangements. On the basis of the banding pattern produced by Vδ‐Jδ rearrangement in MS, it can be suggested that T lymphocytes had undergone clonal expansion in vivo, most likely due to stimulation by antigen related to CNS. In particular a very consistent single‐band pattern of Vδ5‐Jδ1 rearrangement observed in almost all MS patients studied, argues very strongly for a significant role of γ/δ T cells with Vδ5 rearrangement in the pathogenesis of MS. However, it cannot be excluded that the observed patterns of TCR δ gene rearrangement in MS patients may represent secondary changes to CNS damage.

A δ T-Cell Receptor Deleting Element Transgenic Reporter Construct Is Rearranged in αβ but not γδ T-Cell Lineages

T cells can be divided into two groups on the basis of the expression of either alpha beta or gamma delta T-cell receptors (TCRs). Because the TCR delta chain locus lies within the larger TCR alpha chain locus, control of the utilization of these two receptors is important in T-cell development, specifically for determination of T-cell type: rearrangement of the alpha locus results in deletion of the delta coding segments and commitment to the alpha beta lineage. In the developing thymus, a relative site-specific recombination occurs by which the TCR delta chain gene segments are deleted. This deletion removes all D delta, J delta, and C delta genes and occurs on both alleles. This delta deletional mechanism is evolutionarily conserved between mice and humans. Transgenic mice which contain the human delta deleting elements and as much internal TCR delta chain coding sequence as possible without allowing the formation of a complete delta chain gene were developed. Several transgenic lines showing recombinations between deleting elements within the transgene were developed. These lines demonstrate that utilization of the delta deleting elements occurs in alpha beta T cells of the spleen and thymus. These recombinations are rare in the gamma delta population, indicating that the machinery for utilization of delta deleting elements is functional in alpha beta T cells but absent in gamma delta T cells. Furthermore, a discrete population of early thymocytes containing delta deleting element recombinations but not V alpha-to-J alpha rearrangements has been identified. These data are consistent with a model in which delta deletion contributes to the implementation of a signal by which the TCR alpha chain locus is rearranged and expressed and thus becomes an alpha beta T cell.

Horse (Equus caballus) T-cell receptor alpha, gamma, and delta chain genes: nucleotide sequences and tissue-specific gene expression.

Horse (Equus caballus) T-cell receptor alpha (TCRA), gamma (TCRG), and delta (TCRD) chain genes were isolated from a cDNA library and characterized. Five unique TCRAV families, including four full-length sequences, five distinct TCRAJ genes, and a single TCRAC gene were identified. TCRAV genes had closest homology with human sequences and least similarity to rat genes. Among eight horse TCRG genes, two distinct constant region genes with considerable variation in the connecting region were identified, but no variable or joining genes were present. Southern blot hybridization confirmed the presence of at least two TCRGC genes and indicated that the vast majority of horse alpha beta T cells rearrange either one or both TCRG alleles. Analysis of horse TCRD genes revealed the presence of eight unique TCRDV genes representing seven families, each having closest nucleotide homology with sheep sequences. Six unique TCRDJ genes were isolated; however, four of these sequences differed by only one base pair and thus likely represented alleles of a single gene. One horse TCRDC gene was present among fifteen clones analyzed and, based on Southern blot hybridizations, was deleted in polyclonal alpha beta T-cell populations, indicating that the TCRD locus is probably located within the TCRA locus as in other species. Polymerase chain reaction using horse-specific primers for the detection of TCRAC and TCRDC gene expression indicated that gamma delta T cells are located at numerous sites throughout the body, and with the exception of bone marrow where only TCRAC transcripts were detected, are closely associated with alpha beta T cells. This finding indicates that these two T-cell populations may be functionally interactive.

Dysregulation of HOX11 by chromosome translocations in T-cell acute lymphoblastic leukemia: a paradigm for homeobox gene involvement in human cancer.

The translocation t(10;14)(q24;q11) is observed in the course of routine cancer cytogenetic studies in 5-10% of patients with T-cell acute lymphoblastic leukemia (ALL). Recent molecular dissections of t(10;14) translocations support the hypothesis that these relatively gross chromosomal mutations represent key genetic steps in neoplastic transformation. The genes consistently involved are the T-cell receptor (TCR) delta-chain gene in 14q11 and a human homeobox-containing gene in 10q24, HOX11, initially identified through cloning of t(10;14) translocations. Like other homeoproteins, HOX11 binds DNA with sequence specificity and is likely to be a transcription factor, controlling the expression of developmentally important genes. The t(10;14) translocations arise as a result of aberrant physiological recombinational events that occur at early stages of T-cell development, probably during failed attempts at TCR gene rearrangement. The net result of the aberrant genetic recombinations is inappropriate expression of HOX11 in individual T-cells that acquire the mutation. Tlx-1, the murine homolog of HOX11, is expressed embryologically in the developing spleen and in structures derived from cranial neural crest cells and migratory paraxial mesoderm. Mice homozygously deleted for Tlx-1 are asplenic. Thus, HOX11 may be one of the first examples in mammals of a "master gene" acting as a regulatory switch controlling a downstream program of organ-specific cell growth and proliferation. Preliminary tumorigenicity assays suggest that HOX11 expression in hematopoietic cells most likely plays an immortalization role in neoplastic transformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Malignant lymphoma originating from the earliest T‐lineage precursor cell

The earliest T-lineage precursor cells with a CD3-CD4+CD8- phenotype and germline-state T-cell receptor (TCR) genes have recently been identified in the murine thymus. We report a case of malignant lymphoma that was considered to originate from the human counterpart of this newly defined murine T-cell population. The surface phenotype of the lymphoma cells was CD2+CD3-CD4+CD8-CD25-CD34-CD44+HLA-DR+. TCR-beta, -gamma, -delta chain genes and immunoglobulin heavy and light chain genes were all in a germline state. These characteristics were markedly similar to those of the murine earliest T-lineage precursor cells. The present case thus strongly suggests the presence of the human counterpart of this novel murine T-cell population.

Direct sequence analysis of TCR V delta 2-D delta 3 rearrangements in common acute lymphoblastic leukaemia and application to detection of minimal residual disease.

T cell receptor delta chain (TCR delta) gene rearrangements were studied by Southern blot analysis in 36 patients with common acute lymphoblastic leukaemia, including 14 adults and 22 children. The majority of patients (68%) had either a rearrangement or deletion of one or more TCR delta genes. The most frequent rearrangement involved a partial recombination of V delta 2 to D delta 3 (55%). D delta 2-D delta 3 rearrangements were present in five patients (14%). To investigate the TCR delta rearrangement as a tumour marker in minimal residual disease studies, presentation samples from 18 patients were amplified by PCR and directly sequenced. Although the size of the V delta 2-D delta 3 junction varied by only 40 bp, sequence analysis showed extensive diversity. This was derived from four factors: deletion of the 5' end of D delta 3 gene (15/18) and 3' end of V delta 2 gene (16/18); the presence of D delta 2 sequences (6/18); insertion of N nucleotides (15/18); association of P nucleotides with intact V delta 2 and D delta 3 genes (5/18). N nucleotides were the major feature, contributing to 75% of the junction. D delta 1 sequences were not involved. Twenty base oligonucleotide probes, constructed from the junctional sequences, were capable of detecting residual tumour cells at the 10(-4) sensitivity level. Cross hybridization studies confirmed the probes to be clone specific. Longitudinal studies on patients undergoing treatment were capable of detecting tumour in remission samples.

Double-negative (CD4- CD8-) T cells from adult T-cell leukemia patients also have poor expression of the T-cell receptor alpha beta/CD3 complex

We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8- [double-negative, DN], T-cell receptor [TCR] alpha beta+). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN-ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S100 beta in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR beta and gamma chain gene rearrangements, with deletion of TCR delta chain gene and mRNA expression for TCR alpha, beta, and CD3 delta but not for TCR gamma and delta chain genes. Thus, CD4- CD8- TCR alpha beta T cells are also a target for human T-cell lymphotrophic virus type I-induced leukemogenesis. In addition, expression of the TCR alpha beta/CD3 complex on the DN-ATL cells was further diminished by the addition of anti-CD3 or anti-TCR alpha beta monoclonal antibody. These results suggest that the decreased expression of the TCR alpha beta/CD3 complex by ATL cells plays a key role in the development of ATL, irrespective of CD4 expression.

Double-Negative (CD4– CD8–) T Cells From Adult T-Cell Leukemia Patients Also Have Poor Expression of the T-Cell Receptor αβ/CO3 Complex

Abstract We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8- [double-negative, DN], T-cell receptor [TCR] alpha beta+). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN- ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S100 beta in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR beta and gamma chain gene rearrangements, with deletion of TCR delta chain gene and mRNA expression for TCR alpha, beta, and CD3 delta but not for TCR gamma and delta chain genes. Thus, CD4- CD8- TCR alpha beta T cells are also a target for human T-cell lymphotrophic virus type I-induced leukemogenesis. In addition, expression of the TCR alpha beta/CD3 complex on the DN-ATL cells was further diminished by the addition of anti-CD3 or anti-TCR alpha beta monoclonal antibody. These results suggest that the decreased expression of the TCR alpha beta/CD3 complex by ATL cells plays a key role in the development of ATL, irrespective of CD4 expression.

Immunoglobulin heavy-chain and CD3 delta-chain gene enhancers are DNase I-hypersensitive in hemopoietic progenitor cells.

Multipotential interleukin 3-dependent non-immortalized murine hemopoietic progenitor cells have DNase I-hypersensitive sites in the immunoglobulin heavy-chain and CD3 delta enhancers and transcribe germ-line T-cell antigen receptor gamma-chain (TCR gamma), but not IgM or TCR beta, genes. Induction of myeloid differentiation in these cells clones down expression and/or transcriptional accessibility of the immunoglobulin heavy-chain and TCR gamma genes. The CD3 delta enhancer region remains DNase I-hypersensitive but closes down in B cells. In embryonic stem cells and pan-mesodermal cells, these genes or enhancer regions are neither expressed nor DNase I-hypersensitive. These data suggest that lineage potential may be programmed, at least in part, by alterations in the accessibility or conformation of regulatory regions of genes and that some promiscuity of gene expression and/or accessibility can precede lineage commitment and maturation in progenitor cells induced to self-renew by interleukin 3.

Acute undifferentiated leukemia with CD7+ and CD13+ immunophenotype. Lack of molecular lineage commitment and association with poor prognostic features.

The authors studied six adult patients with acute leukemia with these unusual characteristics: unclassifiable morphology and undifferentiated cytochemistry by French-American-British (FAB) criteria; concurrent expression of CD13 (and CD33) myeloid and early T-cell CD7 immune markers; no evidence of T-cell lineage commitment as determined by T-cell receptor beta (beta), gamma (gamma), and delta (delta) chain gene rearrangement study and cytoplasmic CD3 epsilon expression; and no evidence of myeloid cell lineage commitment, as shown by absent myeloid-specific c-fms proto-oncogene expression and negative myeloperoxidase ultrastructural staining (one case). Clinically, these diagnostic features matched with a poor prognosis, being associated with refractoriness to treatment, relapse and progression of disease, antecedent hematologic abnormality, and other malignancy. These cases may represent a distinct stem cell leukemia syndrome deserving immediate recognition and a nonconventional chemotherapeutic approach.