Rearrangement of the gene for the beta chain of the T-cell receptor in T-cell chronic lymphocytic leukemia and related disorders

Molecular Analysis of Genetic Markers for Non-Hodgkin Lymphomas

Molecular analysis complements the clinical and histopathologic tools used to diagnose and subclassify hematologic malignancies. The presence of clonal antigen-receptor gene rearrangements can help to confirm the diagnosis of a B or T cell lymphoma and can serve as a fingerprint of that neoplasm to be used in identifying concurrent disease at disparate sites or recurrence at future time points. Certain lymphoid malignancies harbor a characteristic chromosomal translocation, a finding that may have significant implications for an individual's prognosis or response to therapy. The polymerase chain reaction (PCR) is typically used to detect antigen-receptor gene rearrangements as well as specific translocations that can be supplemented by fluorescence in situ hybridization (FISH) and karyotype analysis. © 2017 by John Wiley & Sons, Inc.

Molecular analysis of genetic markers for non-Hodgkin lymphomas

Molecular analysis complements the clinical and histopathologic tools used to diagnose and subclassify hematologic malignancies. The presence of clonal antigen-receptor gene rearrangements can help to confirm the diagnosis of a B or T cell lymphoma and can serve as a fingerprint of that neoplasm to be used in identifying concurrent disease at disparate sites or recurrence at future time points. Certain lymphoid malignancies harbor a characteristic chromosomal translocation, a finding that may have significant implications for an individual's prognosis or response to therapy. The polymerase chain reaction (PCR) is typically used to detect antigen-receptor gene rearrangements as well as specific translocations that can be supplemented by fluorescence in situ hybridization (FISH) and karyotype analysis.

Molecular analysis of DNA rearrangements in leukemias and non-Hodgkin's lymphomas

Genetic markers for leukemias and lymphomas include chromosomal translocations and antigen-receptor gene rearrangements. Clonal rearrangements of immunoglobulin or T cell receptor (TCR) genes reflect clonal proliferations of lymphocytes, a characteristic feature of lymphoid neoplasia. These rearrangements can be detected as described in this unit by Southern blot hybridization or, in many instances, the polymerase chain reaction (PCR). Specific chromosomal translocations can also serve as markers for clonality, for malignant transformation, and for various defined subtypes of hematopoietic cancers. PCR protocols are described for detection of the two most commonly assayed translocations, t(9;22) of chronic myelogenous leukemia or acute lymphoblastic leukemia, and t(14;18) of follicular lymphomas.

Adult T-cell leukemia/lymphoma presenting with bilateral hearing loss: a case report

A 44-yr-old Jamaican male who presented only with bilateral hearing loss was found to have hypercalcemia, which, upon further investigation, was found to be due to adult T-cell leukemia/lymphoma (ATLL) syndrome. This is the first case of ATLL presenting with bilateral auditory conduction hearing loss, which responded to combination chemotherapy along with alleviation of other manifestations of ATLL.

Structured polychotomous machine diagnosis of multiple cancer types using gene expression

MOTIVATION

The problem of class prediction has received a tremendous amount of attention in the literature recently. In the context of DNA microarrays, where the task is to classify and predict the diagnostic category of a sample on the basis of its gene expression profile, a problem of particular importance is the diagnosis of cancer type based on microarray data. One method of classification which has been very successful in cancer diagnosis is the support vector machine (SVM). The latter has been shown (through simulations) to be superior in comparison with other methods, such as classical discriminant analysis, however, SVM suffers from the drawback that the solution is implicit and therefore is difficult to interpret. In order to remedy this difficulty, an analysis of variance decomposition using structured kernels is proposed and is referred to as the structured polychotomous machine. This technique utilizes Newton-Raphson to find estimates of coefficients followed by the Rao and Wald tests, respectively, for addition and deletion of import vectors.

RESULTS

The proposed method is applied to microarray data and simulation data. The major breakthrough of our method is efficiency in that only a minimal number of genes that accurately predict the classes are selected. It has been verified that the selected genes serve as legitimate markers for cancer classification from a biological point of view.

AVAILABILITY

All source codes used are available on request from the authors.

Distinct bone marrow findings in T-cell granular lymphocytic leukemia revealed by paraffin section immunoperoxidase stains for CD8, TIA-1, and granzyme B

Unlike other leukemia types in which the bone marrow findings are diagnostic, the bone marrow pathology of T-cell granular lymphocytic leukemia (GLL) is subtle and ill-defined. In this study, bone marrow biopsy specimens from 36 patients with T-cell GLL and from 25 control patients with cytopenias and relative or absolute increases in blood large granular lymphocytes were studied by immunohistochemistry using antibodies to the cytolytic lymphocyte antigens CD8, CD56, CD57, TIA-1, and granzyme B. The goals were to clarify the bone marrow pathology of T-cell GLL and to refine the diagnostic criteria for T-cell GLL. Most bone marrow specimens from the T-cell GLL patients contained interstitially distributed clusters of at least 8 CD8(+) (83%) or TIA-1(+) (75%) lymphocytes or clusters of at least 6 granzyme B(+) (50%) lymphocytes. Interstitial clusters of CD8(+), TIA-1(+), or granzyme B(+) cells were present in 36%, 12%, and 0%, respectively, of the control bone marrows (all values significantly different, P <.001). An additional T-cell GLL disease-specific finding was the presence of linear arrays of intravascular CD8(+), TIA-1(+), or granzyme B(+) lymphocytes, found in 67% of cases of T-cell GLL and in none of the 25 control samples (P <.001). Staining for CD56 and CD57 was noncontributory. These findings clarify the bone marrow histopathology of T-cell GLL and provide an additional tool by which the discrete, abnormal lymphocyte population required for a diagnosis of T-cell GLL can be identified.

Lymphoma-type adult T-cell leukaemia-lymphoma with a bulky cutaneous tumour showing multiple human T-lymphotropic virus-1 DNA integration

Human T-lymphotropic virus-1 (HTLV-1) is considered to be the cause of adult T-cell leukaemia-lymphoma (ATL). Monoclonal integration of HTLV-1 proviral DNA, as is analysed by Southern blotting, has been demonstrated in ATL patients. Unusual integration patterns of HTLV-1 proviral DNA have occasionally been described, and it is suggested that the patterns have clinical implications for ATL pathophysiology. Multiple, complete and defective types of integration patterns, in that order, are apparently associated with prognoses from good to poor. We report a 73-year-old Japanese woman with lymphoma-type ATL and a bulky cutaneous tumour on the left thigh. Four bands of slightly differing intensity were seen after EcoRI digestion of skin and lymph node samples on Southern blot analysis of HTLV-1 proviral DNA. Analysis for T-cell receptor-beta gene revealed five novel bands after restriction enzyme digestion with HindIII, indicating that the patient has four separate tumour cell clones, each of which carries one copy of the provirus. She was treated with chemotherapy and radiation and remains under reasonable control despite some relapsing cutaneous nodules. The indolent course in this present case could be related to the multiple integration pattern of HTLV-1 proviral DNA detected.

T-large granular lymphocyte leukaemia with natural killer cell-like cytotoxicity and expression of two different alpha- and beta-T-cell receptor chains

We describe a case of cytotoxic T-large granular lymphocyte leukaemia showing typical morphological features, expressing antigens characteristic for cytotoxic T cells and exhibiting marked natural killer-like cytotoxicity towards different target cells. Moreover, characterization of the T-cell receptors revealed simultaneous expression of two different types of beta-chains as well as alpha-chains by the malignant cell clone. The patient had an 8 year history of indolent disease, before progressing to an aggressive clinical course hardly responsive to chemotherapeutic treatment. This is the first description of a peripheral T-cell neoplasm expressing four distinct types of T-cell receptor molecules.

Large granular lymphocyte leukemia: case report of chronic neutropenia and rheumatoid arthritis-like symptoms in a child

Lymphoproliferative disorders of large granular lymphocytes (LGL) are heterogeneous, with a clinical/pathologic spectrum ranging from a benign polyclonal expansion to an aggressive clonal disease. Often these lymphoproliferative disorders are associated with autoimmune disease. The clonal form of the disorder, LGL leukemia, typically occurs in older adults with a median age of 55 years at diagnosis. Pediatric cases are referred to in review articles; however, no detailed reports of T-cell LGL leukemia in children exist. This report illustrates a case of a child who presented initially at age 2 and 1/2 years with psoriasis, juvenile rheumatoid arthritis-like symptoms, and neutropenia. Bone marrow examinations obtained throughout his course have demonstrated progressive hypercellularity with increased reticulin fibers and replacement of the normal marrow elements by lymphocytes, which were later identified as large granular lymphocytes. Further testing with immunophenotyping by flow cytometry and T-cell receptor gene rearrangement studies revealed a monoclonal proliferation of large granular lymphocytes and confirmed a diagnosis of LGL leukemia. Although rare, large granular lymphocyte leukemia should be included in the differential diagnosis of chronic neutropenia in children.

Clinical utility of molecular probes in lymphoproliferative disorders

The use of molecular probes to diagnose and evaluate human malignancies has been most prominent in the disease category of malignant lymphoma. While this technology is daunting, it has gained rapid entry into the laboratories of both academic and community hospitals. This is because the molecular analysis of genetic changes in human disease, especially the human lymphomas, contributes to many facets of care including aiding the diagnosis, providing prognosis and helping to monitor the disease process. This review aims to highlight both the current routinely available technology and its practical applications in human lymphoma.

Unusual and unrelated polyclonality in a case of myeloid disease

A case of myelofibrosis with myeloid metaplasia was found to have five cytogenetically unrelated clones in the marrow, four of these clones being abnormal. We present the hypothesis that the hematologic disease in this patient was caused by a genetic event not discernible microscopically (cytogenetically) and that the distinctive abnormal clones may have been generated at different anatomic sites.

Monoclonal lymphocyte proliferation and bcl-2 rearrangement in essential mixed cryoglobulinaemia

A patient with essential mixed cryoglobulinaemia (EMC) type II and hepatitis C virus (HCV) infection, in whom immunophenotypic and genotypic studies demonstrated a clonal proliferation of B lymphocytes, is described. Fluorescent in situ hybridization with probes to Ig heavy chain gene and to the oncogene bcl-2 demonstrated a translocation of bcl-2 to the immunoglobulin heavy chain locus on chromosome 14. A sharp rise in the level of the monoclonal IgM was associated with a second genetic aberration [t(8:22) (q24:q11)]. No other clinical evidence of disease progression could be demonstrated. Low grade lymphoproliferative disorder with typical cytogenetic abnormalities developed on the background of EMC and HCV. Clinical progression was associated with a second genetic abnormality involving the myc oncogene. It is possible that HCV chronic infection may indirectly influence oncogenes associated with lymphoma.

Lymphoproliferative disease of granular lymphocytes

We report a case of lymphoproliferative disease of granular lymphocytes that was associated with cutaneous manifestations. Marker studies of skin and blood in this patient revealed that the circulating and infiltrating cells were negative for CD3 and T-cell antigen receptor but were positive for CD16, CD56, and CD57, suggesting natural killer cell origin. The patient had a rapidly progressive course and died within 1 month of presentation.

Chronic lymphoid leukemias: recent advances in biology and therapy

There exists a wide variety of lymphoid leukemias derived from B and T lymphocytes. These diseases have distinct immunologic and biologic features as well as varied responses to therapeutics. The most common lymphoid leukemia is chronic lymphocytic leukemia (CLL) which is a clonal proliferation of a subset of B cells expressing the CD5 antigen. Prolymphocytic leukemia is usually derived from B cells and shares some features with CLL but is clearly a distinct entity. Hairy-cell leukemia is a B cell malignancy that is uniquely responsive to a variety of biologic and chemotherapeutic agents. Waldenström's macroglobulinemia is a B cell malignancy that secretes immunoglobulin M (IgM) and may present with the hyperviscosity syndrome. Other B cell malignancies that less commonly present as leukemias include non-Hodgkin's lymphomas such as follicular lymphoma or mantle zone lymphoma. Multiple myeloma may rarely present or evolve into a plasma cell leukemia, typically in far advanced disease. T cell malignancies that may present as chronic lymphoid leukemias, and in the past have often been referred to as T cell chronic lymphocytic leukemia, are large granular lymphocytic leukemia, adult T cell leukemia/lymphoma, Sézary cell leukemia and rare cases of non-Hodgkin's lymphoma that are T cell derived and may present or evolve into a leukemic phase. There is also a rare T cell counterpart of prolymphocytic leukemia. Distinguishing these diseases is critical for optimal care of these patients.

Multiple karyotypic abnormalities in three cases of small cell variant of T-cell prolymphocytic leukemia

Cytogenetic, clinical, and laboratory findings of three patients with a small cell variant of T-cell prolymphocytic leukemia (T-PLL) are presented. Immunophenotypic studies of the morphologically typical small cell variant prolymphocytes showed a mature helper T-cell phenotype (CD4+CD8-) in one patient and a common thymocyte phenotype (CD4+ CD8+) in two other patients. The cytogenetic analysis revealed complex karyotypes with several structural aberrations in the peripheral blood lymphocytes of all three patients. In all cases chromosome 14 was affected with the breakpoint at 14q11. Inversion (14) and isochromosome 8q, often reported as an additional aberration in T-PLL, were detected in two of the patients. In two patients a translocation of the short arm of chromosome 12 was also seen. The T-cell receptor beta-chain gene showed a clonal rearrangement in all three patients, whereas no rearrangements were detected in the immunoglobulin genes. The survival of the patients ranged from 10 weeks to 48 months. The association between cytogenetic, clinical, and laboratory data is discussed.

Lymphoproliferative disorder of granular lymphocytes associated with severe neutropenia. Response to granulocyte colony-stimulating factor

Lymphoproliferative disorder of granular lymphocytes (LPGL) is an indolent process that is often associated with neutropenia. Although splenectomy, corticosteroids and cytotoxic agents have all been used to treat patients with life-threatening neutropenia, there are few data supporting their effectiveness. We describe a patient with LPGL, severe neutropenia, and a life-threatening infection who had a dramatic response after treatment with granulocyte colony-stimulating factor (G-CSF). The neutrophil count increased from less than 10 cells/microliters to more than 10,000/microliters after seven doses of G-CSF. The infection promptly healed. A review of the literature indicates that 8 of 11 patients with LPGL and severe neutropenia responded to treatment with G-CSF or granulocyte-macrophage colony-stimulating factor (GM-CSF). In view of their relative lack of toxicity and rapid onset of action, the colony-stimulating factors should be considered for initial therapy in patients with LPGL and severe neutropenia. In addition, the high rate of response achieved with colony stimulating factors suggests that in many cases, a defect in myeloid maturation rather than accelerated granulocyte removal is the cause of neutropenia.

Increase in T cells bearing the gamma/delta receptor associated with lymphoproliferative disease of granular lymphocytes in an infant with intractable diarrhea

A two-year-old infant with intractable diarrhea and lymphoproliferative disease of granular lymphocytes attributed to a persistent cytomegalovirus infection showed an increase in cells bearing the gamma/delta T-cell receptor (TCR), which accounted for approximately 20% of total peripheral blood lymphocytes and 40% of CD3+ T cells. Of the gamma/delta TCR+ cells, two-thirds were double negative (CD4-/CD8-) and the other one-third CD8 positive. The majority of gamma/delta+ cells were delta TCS 1 positive. The predominance of delta TCS 1 positive cells was also confirmed on biopsy of lymphoid tissues from the colon. After improvement of watery diarrhea and malnutrition following three-month hyperalimentation, the number of gamma/delta TCR+ cells decreased. The patient subsequently died of pneumonia at the age of 2 years and 11 months. A possible site-specific role for the gamma/delta TCR+ cells, particularly delta TCS 1+ cells, in the human intestine is discussed.

Diagnostic and prognostic significance of clonal T-cell receptor beta gene rearrangements in lymph nodes of patients with mycosis fungoides

In this study, 25 involved and uninvolved lymph nodes from 22 patients with mycosis fungoides (MF) and seven dermatopathic lymph nodes from patients with benign skin disorders were studied for the presence of clonal T-cell receptor beta (TCR beta) gene rearrangements by Southern blot analysis. These results were correlated with the histological classification, follow-up data, and survival. The results of the histological classification and Southern blot analysis were concordant in 26 of 32 cases. Clonal TCR beta gene rearrangements were found in all six MF lymph nodes showing (partial) effacement of the normal lymph node architecture, but in none of the eight uninvolved dermatopathic MF lymph nodes and in none of the seven dermatopathic control lymph nodes. In addition, in 5 of 11 dermatopathic MF lymph nodes that were considered to have early involvement by MF at histological examination, clonal TCR beta gene rearrangements were detected. In the group of MF patients with dermatopathic lymphadenopathy, patients with detectable clonal T-cell populations had a significantly shorter survival than patients without such a population (P < 0.01). The results of this study indicate that within the group of dermatopathic MF lymph nodes, prognostically different groups can be distinguished and that TCR beta gene rearrangement analysis may be an important adjunct in the early diagnosis of lymph node involvement by MF.

Systemic T-cell lymphoma presenting with isolated neurological dysfunction and intraparenchymal brain lesions. Case report

Secondary non-Hodgkin's lymphoma of the central nervous system is typically a late manifestation of systemic T-cell lymphoma, with a 2-month median survival time after the development of neurological disease. Of the reported patients with this late complication, only 1% manifest spread of the disease to the brain parenchyma. The authors report a patient with an unusual initial neurological presentation of systemic T-cell lymphoproliferative disorder and associated space-occupying lesions of the brain parenchyma. The diagnosis was supported by extensive molecular, immunological, and histopathological analysis. Neurological symptoms appeared early in the course of systemic disease and were characterized by spontaneous exacerbations and remissions. The patient has survived for more than 5 years since the onset of his neurological symptoms. Histopathological characterization including immunoperoxidase staining for T-cell markers, DNA content, and cell-cycle analysis of brain tissue obtained at stereotactic biopsy were compared to those of atypical lymphoid cells of peripheral blood, bone marrow, and liver. The neurological manifestations and possible etiologies of T-cell lymphoma are discussed.

T-cell receptor gene rearrangement studies as a diagnostic tool in lymphoproliferative skin diseases

The growth of our knowledge in T-cell biology, in particular the molecular biology of the T-cell receptor (TCR), has provided a means to molecularly characterize lymphoproliferative diseases of the skin based on the presence or absence of a clonal population of T lymphocytes. TCR gene rearrangement studies, by Southern blot analysis, have aided the investigative dermatologist in gaining insights into the pathogenesis and clonal evolution of lymphoproliferative skin diseases. In addition, the application of TCR gene rearrangement studies as a diagnostic aid in the evaluation of lymphoproliferative skin diseases has been introduced into clinical dermatology. Despite its enormous research value, TCR gene rearrangement studies presently have limited applications as an independent diagnostic tool. However, as our knowledge and experience grows and as the application of new techniques provides us with greater detection sensitivity and specificity, the diagnostic utility of TCR gene rearrangement studies will be enhanced.

Pyoderma gangrenosum-like ulcer in a patient with large granular lymphocytic leukemia

Large granular lymphocytic leukemia refers to a clonal expansion of lymphocytes that have abundant cytoplasm and azurophilic granules. The disease is characterized clinically by chronic neutropenia and it may be associated with recurrent pyogenic infections. Except for these infections, cutaneous manifestations of this disease have not been well characterized. We describe a patient with large granular lymphocytic leukemia, which was confirmed by molecular genetics studies, who had a pyoderma gangrenosum-like ulcer on his leg. Results of an evaluation of the histologic characteristics and the leukocytic immunophenotype of a skin biopsy specimen from the ulcer demonstrated large granular lymphocytes within the blood vessels. Cutaneous ulceration may be a manifestation of large granular lymphocytic leukemia, and this disease should be considered when diagnosing patients with otherwise unexplained pyoderma gangrenosum-like ulcers of the skin.

Human NK cells in health and disease: clinical, functional, phenotypic and DNA genotypic characteristics

Natural killer (NK) cells are the subject of great current interest because of their possible (in vivo) role in tumour cell surveillance and killing, and because of the potential application of cytokine-modulated NK cells in cancer immunotherapy. In addition, clonal proliferations of NK-associated (NKa) cell populations represent a high proportion of chronic (non-B) lymphoid malignancies and abnormal (both clonal and non-clonal) NKa components are being increasingly reported in association with diverse clinical pictures such as autoimmune disease. This communication extensively reviews what is presently known regarding normal and leukaemic NKa phenotypic diversity, the mechanisms of NK-mediated cytolysis, the role of NK cells in malignancy, and the diagnostic and cellular aspects of malignant NKa proliferations.

Cytogenetic biclonality in malignant hematologic disorders

Generally, malignant hematologic disorders have been believed to be of monoclonal origin. However, cytogenetically unrelated clones have been reported in some disorders including one case of acute leukemia (AL), one of acute lymphoblastic leukemia (ALL), one of acute myeloblastic leukemia (AMMoL), and five of myelodysplastic syndromes (MDS). The most frequent chromosome abnormality was trisomy 8 (75%), followed by trisomy 21 (37.5%, including tetrasomy 21) and trisomy 11 (25%). Two patients showed both trisomy 8 and 11, one also had trisomy 21 (triclonal). One patient showed two cytogenetically distinctive clones in which one was 47,XY,+8, related to myeloid cells, and the other had a del(6q) and del(9p), suggesting lymphoid cells. One patient we report and 5 from the literature had two unrelated clones with trisomy 8 and deletion of the long arm of chromosome 5 (5q-); all had MDS. Review of our records showed that 11 patients with both trisomy 8 and 5q- in the same abnormal karyotype (not biclonal) had AL, i.e., 10 of acute nonlymphocytic leukemia (ANNL) and one of chronic myelogenous leukemia (CML) in blastic crisis. These findings suggest that cytogenetically unrelated clones may indicate hematopoietic biclonality.

Data sharing and evaluation

Interinstitutional evaluations of molecular markers for the diagnosis and staging of cancer are highly dependent on strict standardization of assays to make clinical comparisons valid. New assays for cancer markers depend on discoveries of biochemical or cellular functions coupled with technologies suitable for making relevant measurements. Transfer of these technologies from the research laboratory to the diagnostic laboratory requires method validation that consists of specific information regarding assay principle, reagents, calibration, sensitivity, assay behavior, specimen requirements, clinical and method correlations, reference range, quality control, proficiency testing, critical steps, and guidelines for interpretation. Fulfillment of all the components of method validation will guarantee the fastest and most accurate implementation of new diagnostic assays in clinical studies and practice.

Immune markers in hematologic malignancies

The precise delineation of biologic traits that distinguish normal hematopoietic cells from their malignant counterparts is of fundamental importance in understanding all aspects of hematologic malignancies. An increasingly sophisticated technologic battery has been utilized to dissect out these differences--primarily utilization of monoclonal antibodies, by immunoperoxidase, immunoalkaline phosphatase and flow cytometric techniques. An even more basic understanding of normal and malignant hematopoietic cells has begun to evolve as molecular biology begins to unravel gene misprogramming by Southern and Northern blot analysis and the polymerase chain reaction. These techniques not only help distinguish a normal cell from a malignant one, but characterize the malignant clone as B-lymphoid, T-lymphoid or myeloid and allow further subcategorization within these broad lineages. These distinctions are vital to the entire spectrum of basic and clinical research involving hematologic malignancies and are assuming an increasingly important role in their diagnosis, prognosis and treatment.

Immunohistochemistry and gene rearrangement studies in the diagnosis of malignant lymphomas: a comparison of 152 cases

One hundred fifty-two cases (155 specimens) of lymphoproliferative disorders were studied by immunohistochemistry and gene rearrangement analysis. Ninety-five of 96 B-cell lymphomas (99%) showed genotypic B-cell monoclonality. Of these, five cases had rearranged T-cell receptor (TCR) beta chain gene in addition to immunoglobulin heavy chain (IgH) and kappa light chain (Ig-K), one case had rearranged IgH and TCR-gamma chain but not Ig-K or TCR-beta, and two cases had only Ig-K rearrangement. One exceptional case in the B-cell lymphoma group had unrearranged, germline genotypes. In contrast, only 10 of 19 (53%) phenotypic T-cell lymphomas had rearranged TCR-beta, eight with concurrent TCR-gamma rearrangement. Of the remaining nine cases, six had germline configuration, two had rearranged Ig-K only, and one had both IgH and Ig-K rearrangement. This last case was reclassified as T-cell predominant, B-cell lymphoma. Thirteen of 16 cases of Hodgkin's disease had germline configuration; three cases had rearranged IgH and Ig-K, of which two were lymphocyte predominant with light chain monoclonality and one was a recurrence. Among 21 reactive lesions, 17 had germline configuration and four had rearranged IgH and Ig-K genes. Of these four cases, two were orbital lesions, one was a partially involved lymph node, and one developed a nodular lymphoma 9 months later. Our results indicate that almost all B-cell lymphomas have IgH and/or Ig-K rearrangement. In contrast, peripheral T-cell lymphomas have greater genotypic heterogeneity, and germline patterns for TCR genes are not uncommon. Reactive lesions and Hodgkin's disease tend to retain germline configuration, and any exception is often associated with an unusual clinical setting and/or histology. Genotypic analysis is thus most indicated in B-cell lymphomas with equivocal immunohistochemistry findings, T-cell lymphomas, and atypical cases of Hodgkin's disease and reactive lesions.

Diagnostic value of T-cell receptor beta gene rearrangement analysis on peripheral blood lymphocytes of patients with erythroderma

Differentiation between Sézary's syndrome (SS) and benign forms of erythroderma may be extremely difficult. In this study T-cell receptor beta (TCR beta) gene rearrangement analysis was performed on peripheral blood lymphocytes (PBL) from 32 patients with erythroderma, including 10 patients with SS, three patients with another type of cutaneous T-cell lymphoma, and 19 patients with a benign form of erythroderma. The aim of this study was to define the sensitivity and specificity of this technique in the diagnosis of SS. Clonal TCR beta gene rearrangements were found in eight of 10 patients with SS, one T-CLL patient, one of two patients with erythrodermic mycosis fungoides, and only one of 19 patients from the benign group. In the two "false-negative" cases of SS clonal TCR beta gene rearrangements were detected in PBL obtained during follow-up. The results indicate that TCR beta gene rearrangement analysis on PBL is a sensitive and highly specific technique, that may contribute significantly to the differential diagnosis of patients with erythroderma. However, because both "false-positive" and "false-negative" results may occur, the results of gene-rearrangement analysis should always be considered in conjunction with clinical, histologic, and immunophenotypical data.

T-cell receptor gene rearrangement analysis: cutaneous T cell lymphoma, peripheral T cell lymphoma, and premalignant and benign cutaneous lymphoproliferative disorders

T-cell receptor gene rearrangement analysis is a useful technique to detect clonality and determine lineage of lymphoid neoplasms. We examined 103 patients with mycosis fungoides, Sézary syndrome, peripheral T cell lymphoma, potentially malignant lymphoproliferative disorders including pre-Sézary syndrome, large plaque parapsoriasis, lymphomatoid papulosis and follicular mucinosis, and various benign inflammatory infiltrates. A clonal rearrangement was detected in skin samples in 20 of 24 patients with mycosis fungoides and in peripheral blood samples in 19 of 21 patients with Sézary syndrome. A clonal population was also detected in seven of eight cases classified as peripheral T cell lymphoma. The potentially malignant dermatoses tended to have clonal rearrangement, with the exception of large plaque parapsoriasis, and further follow-up is needed to correlate clonality with the disease course. These studies demonstrate the value of molecular genetics as an adjunct to morphology in the examination of patients with cutaneous lymphoproliferative disease.

Gene rearrangement analysis in lymphoid neoplasia

Current uses for gene rearrangement analysis in clinical dermatology are listed in Table 3. This technique is useful for determining the existence of clonal populations within a background of polyclonal lymphoid cells; therefore, it is helpful in the diagnosis and staging of patients with CTCL and PTCL. Although dual genotypes do occur, this technique is usually capable of determining lineage in a clonal lymphoid infiltrate and elucidating and characterizing the etiopathogenesis of certain neoplasms. On the basis of this review of the literature and our own experience, we conclude that gene rearrangement analysis shows great promise for monitoring response to therapy and detecting progression or relapse in patients with CTCL and PTCL. With the recent technology of PCR, it is possible to amplify specific sequences of DNA, detect molecular alterations in individual malignant T cells, and even identify exogenous retroviral gene sequences in tissues of patients with CTCL. Although gene rearrangement analysis has supported or established the clonal nature of lymphomatoid papulosis, pre-Sézary syndrome, granulomatous slack skin syndrome, and follicular mucinosis, the clinical significance of these findings is not yet clear. In the case of primary cutaneous B-cell lymphoma and its benign counterpart, B-cell pseudolymphoma, further investigation will be needed to determine the clinical significance of clonal rearrangements.

Rearrangement of T-cell Receptor (Delta, Gamma and Beta) Genes and its Significance in T-cell Chronic Leukaemias

The configuration of the delta, gamma and beta TCR genes and IgH genes was studied using appropriate DNA probes in 12 patients previously diagnosed as having T-cell chronic leukaemia. One or more TCR genes showed rearrangement and/or deletion in 11 patients, whereas rearrangement of IgH genes were seen in 3 patients only. TCR genes showed four distinct patterns: (a) rearrangement and/or deletion of each of the three TCR genes (7 patients), (b) re-arrangement of two TCR genes (3 patients), (c) rearrangement/deletion of one TCR gene only (1 patient), (d) germ-line state of all TCR genes (1 patient). These patterns had no demonstrable relationship with the clinical status either at the time of diagnosis or during the subsequent course of the disease. The findings provided unequivocal evidence of T-cell lineage of the leukaemic cells in 10 out of 12 patients. In one patient the lineage of leukaemic cells remained indeterminate. In the last patient the germ-line state of all TCR genes and rearrangement of both IgH alleles genes indicated that the leukaemia was of B-cell origin, even though the leukaemic cells had other features regarded as characteristic of T-lymphocytes. The different patterns of TCR genes, seen in the context of the hierarchical nature of the rearrangement process, suggest that the leukaemic transformation occurred at different stages of T-cell ontogeny and was followed by arrest of subsequent TCR gene rearrangement.

Genotype and phenotype: a practical approach to the immunogenetic analysis of lymphoproliferative disorders

Determination of cell lineage and clonality in lymphoproliferative disorders (LPD) is greatly enhanced by molecular genetic analysis in conjunction with morphologic and immunologic techniques. We now report on a technique in which we used cryostat-cut, fresh-frozen sections (CCFFS) prepared from tissues in a manner that allows DNA hybridization studies to be coordinated readily with routine morphologic and immunohistologic studies. Thirty-seven cases representing a broad spectrum of reactive and malignant LPD were examined with this method. Samples of DNA were extracted from frozen sections, subjected to Southern blot hybridization, and probed for rearrangements of the immunoglobulin (Ig) heavy-chain and the kappa and lambda light-chain genes, as well as for the T-cell receptor beta-chain gene. We also evaluated the effects of (1) diagnostic category of LPD, (2) volume of the tissue sample, and (3) fibrosis, necrosis, and ice crystal artifacts in the sample on the recovery of DNA. Ice artifact and sample size had the greatest negative impacts on the quantity and condition of DNA recovered. Of 19 samples involved by B-cell LPD, the results of immunogenetic studies were consistent with the immunophenotypes in all but one case. Of the T-cell lymphomas from which sufficient DNA was available (three out of five of the T-cell cases), all showed rearrangements of the T-cell beta-chain gene. In order to reduce sample processing time, we evaluated alternate blot hybridization methods, rapid alkaline transfers, and direct hybridization of synthetic oligonucleotides in dried agarose gels, and found that they decreased the time required for hybridization studies. In summary, the use of CCFFS as the source of DNA allows study of gene rearrangements and, at the same time, preserves frozen-tissue blocks in tumor banks for further immunologic studies. The development of time-effective methods will make the routine use of molecular-genetic analysis more practical in the diagnostic hematopathology laboratory.

Translocation between chromosomes 8q24 and 14q11 in T-cell acute lymphoblastic leukemia

Cytogenetic study was performed on a patient with T-cell acute lymphoblastic leukemia (T-ALL). It revealed a chromosomal translocation between chromosome bands 8q24 and 14q11. 8q24 is known to encode the oncogene c-myc, while 14q11 encodes the genes for T-cell receptor-alpha (TCR-alpha) and T-cell receptor-delta (TCR-delta). Therefore, this chromosomal translocation t(8;14) (q24;q11) seemed to be unique and specific to T-cell malignancy.

Recurrent chromosomal aberrations in peripheral T-cell lymphoma

Histological, immunological, and cytogenetic analysis of the same neoplastic tissues have been performed on seven patients with peripheral T-cell lymphomas (PTCL). Clonal chromosomal abnormalities in five cases are reported. The most common chromosomal aberration, observed in four patients, is a rearrangement of chromosome 14 with a breakpoint in q11.2. Aberrations of chromosome 8 also occurred in four patients, three of whom had an extra 8q. The data indicate that breakpoints of malignant diseases affecting similar cell types might cluster to specific chromosomal regions, which can be helpful in recognition and classification of PTCL.

Biclonality of composite B- and T-cell lymphomas. A case report

Most composite lymphomas which are composed morphologically of two different tumor cell types are considered to represent different morphological expressions of a single clone. However, in recent years, composite B- and T-cell lymphomas and biclonality of B-cell lymphoma have been reported. We experienced a case of composite lymphoma which initially developed as cutaneous lymphoma composed of lymphoplasmacytes associated with large clear cells. It was confirmed that the tumor cells of these two systems were biclonal on the basis of surface markers and DNA rearrangements, i.e. B cells of the IgG kappa type, showing IgH and kappa chain DNA rearrangement, and T-cells with CD4 surface marker, showing rearrangement of the T-cell receptor beta chain gene. This case showed a predominant B-cell pattern at the initial stage, and terminated in T-cell lymphoma, as revealed at autopsy. Therefore we considered this case to be a unique composite lymphoma showing biclonality of both B- and T-cell systems, providing a number of suggestions for future study of malignant lymphoma.

Mycosis fungoides in children and adolescents

The clinical and histologic findings in five young patients with mycosis fungoides are reviewed. The skin specimen from a 16-year-old boy had an infiltrate predominantly Leu-1+, Leu-4+, Leu-3a + 3b+, OKT6+, Leu-2a-, Leu-8-, and Leu-9-, and rearrangements were noted in T cell receptor gene (beta chain [constant region probe] and gamma chain [J region probe]); no rearrangements were found in a histologically normal lymph node or peripheral blood. The skin specimen from an 11-year-old girl contained predominantly Leu-4+ and Leu-9+ lymphoid cells. No T cell receptor gene rearrangements were found in the skin or in an involved lymph node. The variations in clinical, histologic, and immunopathologic features suggest that mycosis fungoides in young patients represents a heterogeneous subgroup of cutaneous T cell lymphoma.

Increased numbers of T lymphocytes with gamma delta-positive antigen receptors in a subgroup of individuals with pulmonary sarcoidosis

Individuals with sarcoidosis were evaluated for preferential usage of T cells with the gamma delta-positive (+) type of T cell antigen receptor. Compared with normal subjects (n = 19), the group with sarcoidosis had increased numbers of CD3+ alpha beta-negative (-) T cells in the blood (normal, 58 +/- 12 cells/microliters; sarcoid, 192 +/- 45 cells/microliters, P less than 0.05) and in the epithelial lining fluid of the lung (normal, 78 14 cells/microliters; sarcoid, 240 +/- 60 cells/microliters, P less than 0.04) and a concomitant elevated number of blood and lung CD3+ gamma delta+ T cells, owing to a striking increase in the number of CD3+ gamma delta+ T cells in a subgroup (7 of 20) of sarcoid individuals. The elevated numbers of sarcoid blood gamma delta+ T lymphocytes were mostly Ti gamma A+ and delta TCS1-, a pattern also seen in normal individuals, consistent with the majority of gamma delta+ T cells expressing one gamma-chain variable region, V gamma 9. The observation of an increase in the total gamma delta+ T cell numbers in a sarcoid subgroup suggests that various specific stimuli may trigger the expansion of different T cell subpopulations within different groups of individuals with sarcoidosis.