Recombination pattern of the TCR gamma locus in human peripheral T-cell lymphomas

STAT3 mutation and its clinical and histopathologic correlation in T-cell large granular lymphocytic leukemia

Although T-cell large granular lymphocytic leukemia (T-LGLL) is a clinically indolent disorder, patients with moderate to severe cytopenia require therapeutic intervention. The recent discovery of STAT3 mutations has shed light on the genetic basis of T-LGLL pathogenesis. However, the association of STAT3 mutational status with patients' clinical, histopathologic, and other laboratory features has not been thoroughly evaluated in T-LGLL. In this study, STAT3 mutations were identified in 18 of 36 patients with T-LGLL (50%), including Y640F (12/18, 66.7%), N647I (3/18, 16.7%), E638Q (1/18, 5.6%), I659L (1/18, 5.6%), and K657R (1/18, 5.6%). Interestingly, pure red cell aplasia was seen exclusively in T-LGLL patients without STAT3 mutations (6/15 in the wild-type STAT3 group versus 0/13 in the mutant STAT3 group; P = .02); these patients also were the only responders to T-LGLL therapy (mainly cyclophosphamide) in wild-type STAT3 group. Patients harboring STAT3 mutations were more prone to rheumatoid arthritis (4/13 versus 0/15 in the wild-type STAT3 group; P = .04), frequently requiring therapy for neutropenia/neutropenia-associated infections, and demonstrated good therapeutic responses to methotrexate. No significant differences were seen in complete blood count, flow cytometric immunophenotypic features, T-cell receptor γ V-J rearrangement repertoire, and bone marrow biopsy morphology among the STAT3-mutation and wild-type groups other than significantly larger tumor burden in patients with STAT3 mutations. The distinct disease association and therapeutic responses observed in patients with mutant and wild-type STAT3 warrant further investigation to elucidate the underlying mechanisms. They also highlight the importance of identifying STAT3 mutational status in patients with T-LGLL, which may aid in clinical therapeutic choice.

γδ T Cells and dendritic cells in refractory Lyme arthritis

Lyme disease is a multisystem infection transmitted by tick vectors with an incidence of up to 300,000 individuals/yr in the United States. The primary treatments are oral or i.v. antibiotics. Despite treatment, some individuals do not recover and have prolonged symptoms affecting multiple organs, including the nervous system and connective tissues. Inflammatory arthritis is a common symptom associated with Lyme pathology. In the past decades, γδ T cells have emerged as candidates that contribute to the transition from innate to adaptive responses. These cells are also differentially regulated within the synovia of patients affected by RLA. Here, we review and discuss potential cellular mechanisms involving γδ T cells and DCs in RLA. TLR signaling and antigen processing and presentation will be the key concepts that we review in aid of understanding the impact of γδ T cells in RLA.

Clonality analysis of lymphoid proliferations using the BIOMED-2 clonality assays: a single institution experience

Background

Clonality determination in patients with lymphoproliferative disorders can improve the final diagnosis. The aim of our study was to evaluate the applicative value of standardized BIOMED-2 gene clonality assay protocols for the analysis of clonality of lymphocytes in a group of different lymphoid proliferations.

Materials and methods.

With this purpose, 121 specimens from 91 patients with suspected lymphoproliferations submitted for routine diagnostics from January to December 2011 were retrospectively analyzed. According to the final diagnosis, our series comprised 32 cases of B-cell lymphomas, 38 cases of non-Hodgkin’s T-cell lymphomas and 51 cases of reactive lymphoid proliferations. Clonality testing was performed using the BIOMED-2 clonality assays.

Results

The determined sensitivity of the TCR assay was 91.9%, while the sensitivity of the IGH assay was 74.2%. The determined specificity of the IGH assay was 73.3% in the group of lymphomas and 87.2% in the group of reactive lesions. The determined specificity of the TCR assay was 62.5% in the group of lymphomas and 54.3% in the group of reactive lesions.

Conclusions

In the present study, we confirmed the utility of standardized BIOMED-2 clonality assays for the detection of clonality in a routine diagnostical setting of non-Hodgkin’s lymphomas. Reactions for the detection of the complete IGH rearrangements and reactions for the detection of the TCR rearrangements are a good choice for clonality testing of a wide range of lymphoid proliferations and specimen types while the reactions for the detection of incomplete IGH rearrangements have not shown any additional diagnostic value.

CD8+ clonality is associated with prolonged acute plasma viremia and altered mRNA cytokine profiles during the course of feline immunodeficiency virus infection

Acute lentiviral infection is characterized by early CD8(+) cytotoxic T cell (CTL) activity and a subsequent decline in plasma viremia. However, CD8(+) lymphocytes fail to eliminate the virus and a progressive T cell immune dysfunction develops during the course of chronic lentiviral infection. To further define this CD8(+) immune dysfunction we utilized PARR (PCR for antigen receptor rearrangements), a technique which measures clonally expanded lymphocyte populations by comparison of highly conserved T cell receptor (TCR) regions to identify the prevalence of clonal CD8(+) T cells following FIV infection. We then compared phenotype, mRNA profiles, CD8(+) proliferation and plasma viremia during acute and chronic infection for PARR positive (PARR(+)) and PARR negative (PARR(-)) Feline Immunodeficiency Virus (FIV) infected cats. We demonstrated that approximately forty percent of the FIV(+) cats examined exhibit CD8(+) clonality compared to none of the FIV(-) control cats. There were no phenotypic differences between PARR(+) and PARR(-) CD8(+) lymphocytes from FIV(+) cats but retrospective analysis of plasma viremia over the course of infection revealed a delayed peak in plasma viremia and a decline in lymphocyte counts were observed in the PARR(+) group during acute infection. CD8(+) lymphocytes isolated from chronically infected PARR(-) cats exhibited significantly higher mRNA expression of IFN-γ and IL-2 following mitogenic stimulation when compared to PARR(+) CD8(+) lymphocytes. These data suggest that clonal CD8(+) expansion may be related to impaired control of acute viremia and less effective CD8(+) anti-viral function. Using PARR to assess changes in CD8(+) clonality during the progression from acute to chronic FIV infection may help to better characterize the factors which contribute to CD8(+) anergy and lentiviral persistence.

Thymic involution, a co-morbidity factor in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating disease, characterized by extremely rapid loss of motor neurons. Our studies over the last decade have established CD4(+) T cells as important players in central nervous system maintenance and repair. Those results, together with recent findings that CD4(+) T cells play a protective role in mouse models of ALS, led us to the current hypothesis that in ALS, a rapid T-cell malfunction may develop in parallel to the motor neuron dysfunction. Here, we tested this hypothesis by assessing thymic function, which serves as a measure of peripheral T-cell availability, in an animal model of ALS (mSOD1 [superoxide dismutase] mice; G93A) and in human patients. We found a significant reduction in thymic progenitor-cell content, and abnormal thymic histology in 3-4-month-old mSOD1 mice. In ALS patients, we found a decline in thymic output, manifested in the reduction in blood levels of T-cell receptor rearrangement excision circles, a non-invasive measure of thymic function, and demonstrated a restricted T-cell repertoire. The morbidity of the peripheral immune cells was also manifested in the increase of pro-apoptotic BAX/BCXL2 expression ratio in peripheral blood mononuclear cells (PBMCs) of these patients. In addition, gene expression screening in the same PBMCs, revealed in the ALS patients a reduction in key genes known to be associated with T-cell activity, including: CD80, CD86, IFNG and IL18. In light of the reported beneficial role of T cells in animal models of ALS, the present observation of thymic dysfunction, both in human patients and in an animal model, might be a co-pathological factor in ALS, regardless of the disease aetiology. These findings may lead to the development of novel therapeutic approaches directed at overcoming the thymic defect and T-cell deficiency.

Comparison of BIOMED-2 versus laboratory-developed polymerase chain reaction assays for detecting T-cell receptor-gamma gene rearrangements

Detecting clonal T-cell receptor (TCR)-gamma gene rearrangements (GRs) is an important adjunct test for diagnosing T-cell lymphoma. We compared a recently described assay (BIOMED-2 protocol), which targets multiple variable (V) gene segments in two polymerase chain reaction (PCR) reactions (multi-V), with a frequently referenced assay that targets a single V gene segment in four separate PCR reactions (mono-V). A total of 144 consecutive clinical DNA samples were prospectively tested for T-cell clonality by PCR using laboratory-developed mono-V and commercial multi-V primer sets for TCR-gamma GR. The combination of TCR-beta, mono-V TCR-gamma and multi-V TCR-gamma detected more clonal cases (68/144, 47%) than any individual PCR assay. We detected clonal TCR-beta GR in 47/68 (69%) cases. Using either mono-V or multi-V TCR-gamma primers, the sensitivities for detecting clonality were 52/68 (76%) or 51/68 (75%). Using both mono-V and multi-V TCR-gamma primers improved the sensitivity for detecting clonality, 60/68 (88%). Combining either mono-V or multi-V TCR-gamma primers with TCR-beta primers also improved the sensitivity, 64/68 (94%). Significantly, TCR-gamma V11 GRs could only be detected using the mono-V-PCR primers. We conclude that using more than one T-cell PCR assay can enhance the overall sensitivity for detecting T-cell clonality.

Improved polymerase chain reaction-based method to detect early-stage epitheliotropic T-cell lymphoma (mycosis fungoides) in formalin-fixed, paraffin-embedded skin biopsy specimens of the dog

In the dog, early-stage epitheliotropic T-cell lymphoma (ETCL) can clinically and histologically mimic a large range of inflammatory dermatoses and often progresses rapidly to a more aggressive tumor stage. Early diagnosis of ETCL is essential to proceed with a specific oncologic therapy that is favorable for the prognosis. In the present study, an improved method for the detection of T-cell receptor gamma (TCRgamma) rearrangement was developed by designing a new set of consensus primers to amplify the different forms of rearranged canine TCRgamma gene sequences by polymerase chain reaction. The amplicons were analyzed by conventional polyacrylamide gel electrophoresis, which requires minimal specific equipment and may be performed in almost every pathology laboratory at low costs. The method proved to be highly specific and sensitive to detect early ETCL in formalin-fixed, paraffin-embedded biopsy specimens, providing an efficient tool for veterinary pathologists to distinguish early neoplastic from reactive cutaneous T-cell infiltrates (tumor-specific marker) or to discriminate T-cell lymphoma from B-cell lymphomas or nonlymphoid neoplasms (T-cell lineage marker). By direct sequencing analysis of amplified TCRgamma gene sequences, ETCL was found to rearrange exclusively the joining (J) 4 region, which suggests specific biology for primary cutaneous T-cell lymphomas. Also, a novel (seventh) functional J region in the TCRgamma gene, localized approximately 2.3 kb upstream of J5, was identified.

Molecular assessment of thymus capabilities in the evaluation of T-cell immunodeficiency

T-cell immunodeficiency may pose a diagnostic challenge to clinicians, especially when the basic T-cell immune workup is not sufficiently informative. An intensive assessment of thymus capabilities that involves either measuring the recent thymic emigrant cells or analyzing the T-cell receptor (TCR) repertoire is often required to estimate the severity and nature of the immune disorder. A comprehensive T-cell immune workup, including TCR excision circles (TRECs) and TCR repertoire analyses, was performed in three patients with various degrees of severity of T-cell immunodeficiency. All three patients had normal peripheral CD3+ T lymphocytes. TCR repertoire analysis revealed oligoclonal (patient 1), restricted (patient 2), and near-normal (patient 3) patterns. TREC quantification was significantly reduced in patients 1 and 2 but normal in patient 3. Based on clinical features at presentation and at follow-up, and supported by the results of immunologic studies, patients 1 and 2 were diagnosed as having significant T-cell immunodeficiency and patient 3 as having T-cell immunocompetence. Assessment of thymus capabilities by TRECs and TCR repertoire analyses is helpful in diagnosing patients with T-cell immunodeficiency and should be part of the evaluation of every patient suspected of having that condition.

TCRgamma-chain gene rearrangement by PCR-based GeneScan: diagnostic accuracy improvement and clonal heterogeneity analysis in multiple cutaneous T-cell lymphoma samples

Cutaneous T-cell lymphomas are a heterogeneous group of lymphomas where the tumor population emerges within a multiple subclone pattern ("clonal heterogeneity"). PCR analysis has been shown to be useful in the diagnosis of mycosis fungoides (MF) and Sézary Syndrome (SS). Focusing the attention on clonal heterogeneity, the efficacy of the multiplex/heteroduplex (HD) PCR and the GeneScan (GS) capillary electrophoresis analysis was compared in the early diagnosis of MF/SS, using a multiple sample approach. Indeed, GS demonstrated TCRgamma gene rearrangement (GR) in all the 57 SS (100%) and in 123/146 (84%) of the MF samples, whereas the multiplex/HD PCR was less sensitive. An increase in clonality was observed in connection with both a worsening of the cutaneous disease (79% T1/T2; 100% T3/T4) and an increase in the histopathological score (HS < 5, 76%; HS > or = 5, 94%). Clonal heterogeneity with adjunctive reproducible skin TCRgamma-GRs was also observed. "Clonal instability," with different GRs, was present in a small percentage of patients. Therefore, it can be concluded that GS analysis in TCRgamma-GR is able to improve diagnosis in MF/SS patients and the multiple sample approach is helpful for a correct interpretation of clonal patterns in skin lesions, especially in early-stage MF and in SS skin/blood samples.

Analysis of T-cell receptor-gamma gene rearrangements using oligonucleotide microchip: a novel approach for the determination of T-cell clonality

T-cell clonality estimation is important for the differential diagnosis between malignant and nonmalignant T-cell proliferation. Routinely used methods include polymerase chain reaction (PCR) analysis of T-cell receptor-gamma (TCR-gamma) gene rearrangements followed by Genescan analysis, polyacrylamide gel electrophoresis, or heteroduplex analysis to visualize amplification products. Here, we present a new method for the analysis after PCR of TCR-gamma rearrangements using hybridization on oligonucleotide microchip. A microchip was designed to contain specific probes for all functional variable (V) and joining (J) gene segments involved in rearrangements of the TCR-gamma locus. Fluorescently labeled fragments of rearranged gamma-chain from patients and donors were obtained in a multiplex nested PCR and hybridized with a microchip. The results were detected using a portable microchip analyzer. Samples from 49 patients with T-cell lymphomas or leukemias and 47 donors were analyzed for T-cell clonality by microchip and single-strand conformation polymorphism analysis, which served as a standard reference method. Comparison of two techniques showed full concordance of the results. The microchip-based approach also allowed the identification of V and J gene segments involved in the particular TCR-gamma rearrangement. The sensitivity of the method is sufficient to determine 10% of clonal cells in the sample.

Powerful strategy for polymerase chain reaction-based clonality assessment in T-cell malignancies Report of the BIOMED-2 Concerted Action BHM4 CT98-3936

Polymerase chain reaction (PCR) assessment of clonal T-cell receptor (TCR) and immunoglobulin (Ig) gene rearrangements is an important diagnostic tool in mature T-cell neoplasms. However, lack of standardized primers and PCR protocols has hampered comparability of data in previous clonality studies. To obtain reference values for Ig/TCR rearrangement patterns, 19 European laboratories investigated 188 T-cell malignancies belonging to five World Health Organization-defined entities. The TCR/Ig spectrum of each sample was analyzed in duplicate in two different laboratories using the standardized BIOMED-2 PCR multiplex tubes accompanied by international pathology panel review. TCR clonality was detected in 99% (143/145) of all definite cases of T-cell prolymphocytic leukemia, T-cell large granular lymphocytic leukemia, peripheral T-cell lymphoma (unspecified) and angioimmunoblastic T-cell lymphoma (AILT), whereas nine of 43 anaplastic large cell lymphomas did not show clonal TCR rearrangements. Combined use of TCRB and TCRG genes revealed two or more clonal signals in 95% of all TCR clonal cases. Ig clonality was mostly restricted to AILT. Our study indicates that the BIOMED-2 multiplex PCR tubes provide a powerful strategy for clonality assessment in T-cell malignancies assisting the firm diagnosis of T-cell neoplasms. The detected TCR gene rearrangements can also be used as PCR targets for monitoring of minimal residual disease.

Genomic organization of the T-cell receptor gamma gene and PCR detection of its clonal rearrangement in canine T-cell lymphoma/leukemia

Because the T-cell receptor gamma (TCRgamma) gene is rearranged at an early stage of T-cell development in both TCRalphabeta and TCRgammadelta lineages, it has been preferentially targeted to detect T-cell clonality in human lymphoma/leukemia. We isolated 22 independent cDNA clones encoding canine TCRgamma and the following analysis of nucleotide sequences using the dog genome database revealed that the canine TCRgamma locus contains at least four repertories of variable genes that can be organized into two distinct subgroups and six repertories of joining genes belonging to two distinct subgroups according to the nucleotide sequence similarity. The findings allowed us to design PCR primers that were directed to the conserved or specific nucleotide sequences for each subgroup of variable and joining genes. By using four different combinations of primers, a PCR-based analysis was performed on cell samples collected from T-cell lymphoma/leukemia and B-cell lymphoma cases and hyperplastic and normal lymph nodes. All cell samples from 11 T-cell malignancy cases exhibited clonal amplification by two out of four primer combinations. This finding was considered to be valuable in PCR-based analysis for detecting T-cell clonality in canine lymphoma/leukemia.

The frequency of B- and T-cell gene rearrangements and epstein-barr virus in T-cell lymphomas: a comparison between angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma, unspecified with and without associated B-cell proliferations

We report on a series of 58 cases of angioimmunoblastic T-cell lymphoma (AILT) and 59 cases of peripheral T-cell lymphoma, unspecified (PTCL-NOS). Subsets of cases from both diagnostic groups were complicated by associated B-cell proliferations, and we performed B- and T-cell clonality studies and in situ hybridization for Epstein-Barr virus (EBV) to investigate the relationship between B-cell proliferation, B-cell clonality, and EBV. Using multiplex polymerase chain reaction assays based on the BIOMED-2 collaborative study, we detected TCRgamma T-cell clones in 78 and 81% of AILT and PTCL-NOS cases, respectively, and IGH B-cell clones in 34 and 35% of AILT and PTCL-NOS cases, respectively. The majority of cases contained EBV-positive cells, including 50% of AILT and 57% of PTCL-NOS cases, and cases with B-cell proliferations were more often EBV-positive. Although a relatively high rate of B-cell clonality has been shown for AILT, our findings for PTCL-NOS differ from previous reports in that B-cell clonality was relatively frequent. Overall, a positive B-cell clone correlated, in part, with the presence of a B-cell proliferation but not with EBV. Our findings demonstrate that B-cell clonality is a common finding in AILT and PTCL-NOS, and its presence should not negate the diagnosis established by morphologic, immunophenotypic, and clinical findings.

T-cell non-Hodgkin lymphoma

T-cell non-Hodgkin lymphomas (NHLs) are uncommon malignancies. The current WHO/EORTC classification recognizes 9 distinct clinicopathologic peripheral T-cell NHLs. These disorders have unique characteristics and require individualized diagnostic and therapeutic strategies. Tremendous progress has been made in recent years in the understanding of the pathogenesis of these disorders. Specific chromosomal translocations and viral infections are now known to be associated with certain lymphomas. In this review, we describe their clinical and pathologic features. We also discuss the use of molecular studies in the diagnostic work-up of T-cell lymphomas. Because of the rarity of these disorders and the lack of well-designed clinical trials, the treatment of peripheral T-cell NHLs is often challenging. Additional studies are required to learn more about the biology of these diseases, which may lead to more optimal and possibly targeted therapies.

Characterization of feline T cell receptor gamma (TCRG) variable region genes for the molecular diagnosis of feline intestinal T cell lymphoma

A diagnosis of intestinal lymphoma is currently made on the basis of clinical and morphologic criteria. This can prove problematic for many reasons that include inadequate sample size, the coexistence of lymphoma and inflammation, and the inability to assess architectural integrity of all tissue compartments in biopsy specimens obtained endoscopically. The detection of a clonal population of cells in a lymphoproliferative lesion represents an important criterion for the diagnosis of neoplasia, but this has not been assessed in feline intestinal lymphoma. T cell receptor gamma (TCRG) gene rearrangement analysis using polymerase chain reaction (PCR) is a methodology that can be used to detect clonality in T cell populations. The basis of this assay depends on the assessment of the junctional diversity that results from rearrangement of TCRG V (variable) and J (joining) gene segments. Feline TCRG transcripts from normal small intestine and spleen were obtained using a rapid amplification of cDNA ends (5'RACE) method. Limited diversity of TCRG V and J gene segments was observed. The high degree of sequence homology in the TCRG V and J gene segments was exploited to develop a PCR test for the assessment of TCRG V--J junctional diversity and hence clonality determination of T cell populations in cats. Molecular clonality determination was applied to feline intestinal lymphoplasmacytic inflammatory bowel disease (IBD) (9 cats), and transmural and mucosal T cell lymphoma (28 cats). Clonal rearrangement of the TCRG V--J junction was detected in 22 of 28 intestinal T cell lymphomas, and oligoclonality was detected in 3 intestinal T cell lymphomas. This contrasted with the detection of polyclonal rearrangement in normal intestinal tissues (3 cats) and in lymphoplasmacytic IBD (9 cats). It is proposed that assessment of TCRG V--J junctional diversity for the detection of clonality represents an important adjunctive tool for the diagnosis of T cell lymphoma in the cat.

Design and standardization of PCR primers and protocols for detection of clonal immunoglobulin and T-cell receptor gene recombinations in suspect lymphoproliferations: report of the BIOMED-2 Concerted Action BMH4-CT98-3936

In a European BIOMED-2 collaborative study, multiplex PCR assays have successfully been developed and standardized for the detection of clonally rearranged immunoglobulin (Ig) and T-cell receptor (TCR) genes and the chromosome aberrations t(11;14) and t(14;18). This has resulted in 107 different primers in only 18 multiplex PCR tubes: three VH-JH, two DH-JH, two Ig kappa (IGK), one Ig lambda (IGL), three TCR beta (TCRB), two TCR gamma (TCRG), one TCR delta (TCRD), three BCL1-Ig heavy chain (IGH), and one BCL2-IGH. The PCR products of Ig/TCR genes can be analyzed for clonality assessment by heteroduplex analysis or GeneScanning. The detection rate of clonal rearrangements using the BIOMED-2 primer sets is unprecedentedly high. This is mainly based on the complementarity of the various BIOMED-2 tubes. In particular, combined application of IGH (VH-JH and DH-JH) and IGK tubes can detect virtually all clonal B-cell proliferations, even in B-cell malignancies with high levels of somatic mutations. The contribution of IGL gene rearrangements seems limited. Combined usage of the TCRB and TCRG tubes detects virtually all clonal T-cell populations, whereas the TCRD tube has added value in case of TCRgammadelta(+) T-cell proliferations. The BIOMED-2 multiplex tubes can now be used for diagnostic clonality studies as well as for the identification of PCR targets suitable for the detection of minimal residual disease.

The distribution of gene segments in T-cell receptor gamma gene rearrangements demonstrates the need for multiple primer sets

Limited data exist regarding the distribution of gene segments used in T-cell receptor gamma gene rearrangements (TCR gamma GR) in T-cell lymphoproliferative disorders. The reported efficacy of TCR gamma GR protocols ranges from 60% to greater than 90%. Laboratories reporting a lower detection rate tend to use a limited set of primers. The goal of our study was to provide TCR gamma GR data to demonstrate the molecular biological basis for needing multiple primer sets targeting all gene segments. Sixty cases with a confirmed histological diagnosis of a T-cell lymphoproliferative disorder and TCR gamma GR were identified in our lymphoma registry from 1995 to 2001. DNA was obtained from fresh/frozen tissue, cell lysates, or paraffin-embedded tissue. Variable (V gamma) region gene segments were identified using denaturing gradient gel electrophoresis, which was used to select the cases in the study. Capillary electrophoresis using fluorescent-labeled joining (J gamma) region primers was performed to identify J gamma segments. Sixty cases contained a total of 98 TCR gamma GR, as some cases have more than one rearrangement. The most frequent gene segment combination involved the V gamma 1-8 and J gamma 1/2 segments. If a single primer set directed at these two segments were used for clinical diagnosis, that pair of primers would only diagnose 67% of cases as positive for TCR gamma GR. Our gene segment distribution data emphasize the importance of using a comprehensive set of V gamma and J gamma primers for an optimal detection rate of TCR gamma GR. Protocols with limited numbers of primers should be reconsidered.

T-cell receptor Vbeta repertoire in nodal non-anaplastic peripheral T-cell lymphomas

The aim of this study was to evaluate the T-cell receptor (TCR) Vbeta repertoire in the two main histological subtypes of nodal non-anaplastic peripheral T-cell lymphoma: Not Otherwise Specified (NOS) and angioimmunoblastic lymphoma (AIL). Frozen lymph node tissues of eight NOS and six AIL were analyzed. A reverse transcriptase polymerase chain reaction (RT-PCR) was carried out to assess the expression of the 24 Vbeta gene families. Our study showed a broad TCR Vbeta repertoire in AIL and NOS, with a slight increase in the number of Vbeta families in AIL (16 vs 10 on agarose gels). Nevertheless, there was a clear difference in four cases. A predominant Vbeta family was observed in two NOS, whereas no predominant Vbeta family was observed in the AIL. Two AIL showed the whole Vbeta repertoire, whereas it was never observed in NOS. This pattern may help to categorize these histopathological entities and further suggests a differential T-cell response. These results show that numerous reactive T-cells are present both in AIL and NOS. Possibly, they play a role in the growth of these lymphomas.

Diagnosis of canine lymphoid neoplasia using clonal rearrangements of antigen receptor genes

Although the diagnosis of canine leukemia and lymphoma in advanced stages is usually uncomplicated, some presentations of the disease can be a diagnostic challenge. In certain situations, lymphoma and leukemia can be difficult to distinguish from a benign reactive proliferation of lymphocytes. Because clonality is the hallmark of malignancy, we have developed an assay that uses the polymerase chain reaction to amplify the variable regions of immunoglobulin genes and T-cell receptor genes to detect the presence of a clonal lymphocyte population. The assay detected clonally rearranged antigen receptor genes in 91% of the 77 dogs with lymphoid malignancy. Of the 24 dogs tested, that were either healthy or had clearly defined conditions not related to lymphoid malignancy, a clonally rearranged antigen receptor gene was found in one (a dog with Ehrlichia canis infection). Gene rearrangement was appropriate for the immunophenotype (immunoglobulin gene rearrangement in B-cell leukemias and T-cell receptor gene rearrangement in T-cell leukemias). Dilution analysis showed that the clonal rearrangement could be detected when 0.1-10% of the DNA was derived from neoplastic cells, depending on the source tissue. Potential applications of this assay include the diagnosis of lymphoma or leukemia in biopsy samples, cavity fluids, fine needle aspirates, bone marrow and peripheral blood; the determination of lineage (B or T cell); staging of lymphoma; and detection of residual disease after chemotherapy.

Comparative evaluation of PCR-based methods for the assessment of T cell clonality in the diagnosis of T cell lymphoma

AIMS

The accurate diagnosis of T cell lymphoma often depends on the demonstration of a monoclonal T cell population in a lymphoproliferative disorder (LPD). The aim of this study was to evaluate four polymerase chain reaction (PCR)-based methods used to analyse T cell receptor (TCR) gene rearrangements in the assessment of T cell clonality.

METHODS

DNA was tested from 23 T cell neoplasms, seven B cell non-Hodgkin's lymphomas (B-NHL), three Hodgkin's lymphomas (HL), 14 benign LPD and peripheral blood from a healthy donor. TCRgamma rearrangements were assessed by McCarthy's et al. two primer set method, Benhattar's et al. linear pre-amplification method, and Chhanabhai's et aL heteroduplex method. TCRbeta D-J rearrangements were analysed by Slack's et al. method.

RESULTS

Monoclonal TCRgamma rearrangements were found in 91% (21 of 23) of T cell neoplasms using McCarthy's et al. method; in 83% (19 of 23) using Benhattar's et al. or Chhanabhai's et al. methods and monoclonal TCRbeta rearrangements were found in 43% (10 of 23) using Slack's et al. method. Monoclonality was established in all T cell neoplasms using one or more PCR methods. One follicular B-NHL had inappropriate monoclonal TCRbeta rearrangement, while the remaining B-NHL and all HL samples had no monoclonal TCRgamma or TCRbeta rearrangements. In addition to polyclonal products, one reactive lymph node had oligoclonal TCRgamma rearrangements and two others generated monoclonal products of uncertain significance. McCarthy's et al. TCRgamma method was the most sensitive in establishing T cell monoclonality, and in combination with Slack's et al. TCRbeta method, monoclonality was demonstrated in 100% of T cell neoplasms (23 of 23).

CONCLUSIONS

These data indicate that multiple primer set PCR methods should obviate a need for the more expensive and time-consuming Southern blot (SB) technique and are the preferred diagnostic molecular test for assessing T cell clonality.

Effectiveness of capillary electrophoresis using fluorescent-labeled primers in detecting T-cell receptor gamma gene rearrangements

We describe the use of fluorescent-labeled primers to analyze T-cell receptor gamma gene rearrangements (TCR gamma GR) using capillary electrophoresis in the ABI Prism 310 Genetic Analyzer. We also compare the performance with denaturing gradient gel electrophoresis (DGGE). In a single multiplex polymerase chain reaction (PCR) we amplified TCR gamma GR with primers for all known groups of variable region genes, and joining region genes described in lymphoid neoplasms. Ten reactive samples, followed by five cell lines and 25 tumor samples with 41 individual TCR gamma GR (due to many biallelic rearrangements) previously identified by DGGE, were analyzed to validate the technique. The capillary electrophoresis protocol has 92% concordance for both TCR clonal status (23 of 25) and 95% concordance in the number of individual TCR gamma GR (38 of 41) identified by DGGE. The reproducible sensitivity for detecting TCR gamma GR diluted in reactive lymphoid DNA is 2% in clinical applications. Discrimination of predominant rearrangements requires a minimum ratio of two times the height of the normal distribution of polyclonal peaks. Capillary electrophoresis can provide results within 60 minutes for each specimen after PCR is complete. Capillary electrophoresis provides a faster result than sequence-based separation methods and gives an archival electronic record. Fluorescent labeling allows the identification of both the variable and joining gene segments used in a TCR gamma GR. The effectiveness of capillary electrophoresis is similar to DGGE.

Oligoclonal T cell expansions in pulmonary lymphoproliferative disorders: demonstration of the frequent occurrence of oligoclonal T cells in human immunodeficiency virus-related lymphoid interstitial pneumonia

We used a denaturing gradient gel electrophoresis (DGGE) procedure with 40-nucleotide guanine- and cytosine-rich sequences in the polymerase chain reaction (PCR) and sequencing analysis to analyze the T cell antigen receptor (TCR)-Vgamma gene repertoire of infiltrating T lymphocytes in pulmonary lymphoproliferative disorders. Six of 15 low-grade mucosa-associated lymphoid tissue (MALT) lymphomas and 8 of 15 cases of lymphocytic interstitial pneumonia (LIP) showed some oligoclonal bands for TCR-Vgamma genes on DGGE. Sequencing analysis demonstrated plural oligoclonal TCR-Vgamma clones among the oligoclonal PCR products on DGGE, leading to the conclusion that conventional antigen-specific oligoclonal expansions may play some role in the pathogenesis of pulmonary lymphoproliferative disorders. The frequency of oligoclonal infiltrating T cell expansions in human immunodeficiency virus (HIV)-related LIP (100%) was significantly higher than in low-grade pulmonary MALT lymphomas (40%) or in HIV-negative LIP (30%). Because recent evidence demonstrates that the V3 loop in the proviral amino acid sequences of mononuclear cells from bronchoalveolar lavage is more homogeneous than those from peripheral blood, this homogeneity might result in oligoclonal expansions of infiltrating T lymphocytes as a consequence of ongoing reactions against lung-specific viral strains.

Diagnostic and prognostic importance of T-cell receptor gene analysis in patients with Sézary syndrome

BACKGROUND

Sézary syndrome (SS) is characterized by erythroderma, peripheral lymphadenopathy, and circulating Sézary cells and is clinically heterogeneous.

METHODS

T-cell receptor (TCR) gene analysis was performed using DNA extracted from peripheral blood mononuclear cells from 74 patients, and the results were correlated with a variety of other diagnostic parameters and patient outcomes.

RESULTS

Two groups were identified: 66 patients with clonal TCR gene rearrangement (clonal patients) detected with Southern blot analysis and/or polymerase chain reaction/single-strand conformational polymorphism analysis and 8 patients with no clonal rearrangement detected (nonclonal patients) using either technique. Clonal patients were compared with nonclonal patients. The following median blood parameters were significantly greater in the clonal group: total white cell count (13.7 10(9)/L vs. 9.6 10(9)/L), lymphocyte count (4.9 10(9)/L vs. 2.2 10(9)/L), absolute Sézary count (3.22 10(9)/L vs. 0.99 10(9)/L), CD4 count (3.17 10(9)/L vs. 1.36 10(9)/L), and CD4:CD8 ratio (15.86 vs. 3.21). An expanded population of T-cells of a specific TCR variable beta subset was detected in 7 of 36 clonal patients and in 1 of 4 nonclonal patients. Cytogenetic analysis of peripheral blood from 1 nonclonal patient and 6 clonal patients was normal. The median survival from the time of diagnosis was 45 months in the clonal group, and 40 of 49 deaths were cutaneous T-cell lymphoma (CTCL)-related, whereas 3 deaths in the nonclonal group were unrelated to CTCL (P < 0.01; log-rank test). Multivariate proportional hazards analysis showed that the absolute Sézary count and lymph node status were independent prognostic variables (P = 0.016 and P = 0.036, respectively).

CONCLUSIONS

TCR gene analysis defines a distinct clinicopathologic group of patients with SS. Clonal patients have a poor prognosis and are likely to die from leukemia/lymphoma, whereas nonclonal patients may have a reactive, inflammatory T-cell disorder. The authors suggest that the definitive diagnostic criteria for patients with SS should include the presence of a clonal TCR gene rearrangement.

New insights into the applicability of T-cell receptor gamma gene rearrangement analysis in cutaneous T-cell lymphoma

BACKGROUND

Detection of clonal T-cell receptor (TCR) gamma gene rearrangement by polymerase chain reaction (PCR) based method is a marker for cutaneous T-cell lymphoma (CTCL) although it can be seen in some benign dermatoses. To determine the accuracy of histologic criteria alone as well as the adjuvant diagnostic role of TCR gene rearrangement for the diagnosis of CTCL, we studied 100 patients with cutaneous T-cell infiltrates by both histology and TCR gene rearrangement.

METHODS

The histologic features of the 100 patients were first reviewed by two independent dermatopathologists and their confidence in the diagnosis of CTCL was assigned one of four levels. Then the specimens were analyzed for TCR gene rearrangement either on paraffin-embedded or fresh-frozen tissue by PCR/denaturing gradient gel electrophoresis (DGGE).

RESULTS

The clonality was detected in 100% (15/15) diagnostic of, 84.6% (11/13) consistent with, 57.6% (19/33) suggestive of CTCL. In 9 cases TCR gene rearrangement was compared between formalin-fixed and fresh specimens of the same individual, but with different degrees of histologic confidence (no lower than suggestive). In all cases fresh specimens were positive. In 5 of the cases (2-diagnostic, 2-consistent, 1-suggestive) formalin-fixed specimens were positive as well, and in 4 cases (1-consistent, 3-suggestive) formalin-fixed specimens were negative. When TCR gene rearrangement was studied in eight cases on sequential biopsies from the same patient, the clonality was detected in only one or two biopsies in four cases in which the histologic confidence was low (suggestive or nondiagnostic). The TCR gene rearrangement study showed identical banding patterns in lesions from different clinical stages in most patients. However, we observed that in one case, oligoclonal-banding pattern was seen in initial biopsy with histopathologic consistent with CTCL, while monoclonal banding pattern in more advanced lesion.

CONCLUSIONS

Our data have demonstrated that TCR gene rearrangement studies by PCR/DGGE are consistently positive regardless of tissue fixation (formalin-fixed, paraffin-embedded vs. fresh-frozen tissue) and biopsy site when the histologic degree of confidence is very high (diagnostic). So, it may be of less importance as an adjuvant to histopathologic diagnosis for the cases with diagnostic CTCL histology. However, TCR gene rearrangement studies are particularly important in earlier cases with less conclusive histology, which provides strong confirmatory evidence of an evolving CTCL. In these cases, multiple biopsies may be required to establish the diagnosis and analysis of fresh tissue is suggested to increases the sensitivity. Moreover, our observation also suggested that some CTCL might not be monoclonal de novo, but oligoclonal instead.

Molecular analysis of T-cell clonality with concomitant specific T-cell proliferation in vitro in nickel-allergic individuals

BACKGROUND

The peripheral blood mononuclear cells (PBMC) of individuals with nickel contact allergy are reported to proliferate to a varying degree upon nickel stimulation in vitro. Different phenotypes of the T cells involved are described. With regard to preferential use of the T-cell receptor (TCR), analysis of the several families of the TCR-gamma gene allows rearrangement evaluation of all T cells regardless of predominant surface expression of TCR alpha/beta.

METHODS

The PBMC of 10 nickel-allergic and five nonallergic individuals were cultured for 4 days in the presence of either medium, PHA, NiSO4, or tetanus toxoid (TT). Proliferation was measured by radioactive thymidine uptake and expressed as stimulation index (SI). T-cell clonality was assessed by analysis of the TCR-gamma chain gene, including the use of PCR with a primer combination covering the four main groups (Vgamma1-8, Vgamma9, Vgamma10, and Vgamma11) of the variable region of the TCR-beta chain gene.

RESULTS

In the allergic individuals, proliferation to NiSO4 was significantly (P<0.05) higher than in nonallergics (mean SI: 18.05/17.87 vs 0.67/2.27). In unstimulated and PHA-stimulated cultures, there was a random TCR spectrum in both groups. In contrast, in nickel-allergic individuals or individuals with recent TT-booster, oligoclonality could be observed in the correspondingly stimulated cultures.

CONCLUSION

In addition to proliferation assay, analysis of T-cell clonality may be a further means to characterize clinical hypersensitivity reactions on the basis of antigen-dependent oligoclonal T-cell expansion, as in the case of tissue-infiltrating lymphocytes.

A novel four-color PCR assay to assess T-cell receptor gamma gene rearrangements in lymphoproliferative lesions

We describe a novel 4-color polymerase chain reaction (PCR) assay combined with GeneScan analysis to assess for T-cell receptor gamma chain gene (TCRgamma) rearrangements and evaluate its usefulness in 86 lymphoproliferative lesions. In this assay, each variable region (Vgamma) family primer is 5' end-labeled with a different fluorescent dye, allowing determination of the Vgamma family involved in each TCRgamma rearrangement. PCR products were analyzed by capillary electrophoresis. We detected clonal TCRgamma rearrangements in 60 (98%) of 61 T-cell lymphomas, 2 (15%) of 13 B-cell lymphomas, and 3 (25%) of 12 reactive lesions. These results compared favorably with conventional PCR methods using denaturing gradient gel electrophoresis, which revealed clonal TCRgamma rearrangements in 37 (90%) of 41 T-cell lymphomas, 1 (25%) of 4 B-cell lymphomas, and 2 (25%) of 8 reactive lesions. This 4-color PCR assay is at least equivalent to conventional PCR methods and is convenient, allows accurate size determination of TCRgamma rearrangements, and identifies the specific Vgamma family involved, providing more specific information about TCRgamma rearrangement.

PCR-heteroduplex analysis of T-cell receptor gamma gene rearrangement in paraffin-embedded skin biopsies

We developed a rapid, simple, and sensitive method for the detection of T-cell receptor-gamma (TCRgamma) gene rearrangements in paraffin-embedded skin biopsies. Available techniques often require either fresh tissue, several primer pairs, nested amplifications, or specialized electrophoresis steps such as denaturing gradient gel electrophoresis. Our method is based on heteroduplex analysis of polymerase chain reaction (PCR) products of the TCRgamma in a nondenaturing modified polyacrylamide gel using a single pair of primers and is adapted for paraffin-embedded tissue. When tested against Southern blot analysis, the PCR results correlated in 8 of 9 cases. Six mature cutaneous B-cell lymphomas and 29 inflammatory skin disorders all resulted in a polyclonal amplification pattern. When analyzing 3-mm or 4-mm punch biopsies of 51 cases of cutaneous T-cell lymphoma, 37 (72.5%) showed a clonal rearrangement with this technique. For 7 cases of patch stage mycosis fungoides, frozen tissue and formalin-fixed and paraffin-embedded tissue was available, and in 5 of 7 cases (71%), the results in frozen and paraffin-embedded tissue were concordant. One case showed a clonal pattern in frozen tissue but not in paraffin-embedded tissue, and one case was polyclonal in frozen tissue but monoclonal in paraffin-embedded tissue. Using serial dilutions of DNA from a T-cell ALL in a polyclonal background (tonsil), we established a sensitivity of 0.5%. Heteroduplex PCR of the TCRgamma is a rapid, sensitive, and inexpensive screening procedure as well as a useful adjunct to histologic analysis and immunophenotyping of cutaneous T-cell proliferations.

Hepatosplenic alphabeta T-cell lymphoma: an unusual case with clinical, histologic, and cytogenetic features of gammadelta hepatosplenic T-cell lymphoma

Hepatosplenic gammadelta T-cell lymphoma is a recently identified entity in which lymphoma cells bearing the gammadelta T-cell receptor (TCR) infiltrate the sinusoids of the liver and the sinuses of the splenic red pulp and bone marrow, without lymph node involvement. It is also characterized by a recurrent cytogenetic finding, isochromosome 7q (i7q10). The authors report a case of hepatosplenic lymphoma of alphabeta T-cell phenotype that shares the same clinical, histologic, and cytogenetic characteristics of the previously described hepatosplenic gammadelta T-cell lymphoma. Fluorescent in situ hybridization performed with chromosome 7 probes showed the typical pattern of isochromosome 7q. Genomic analysis of the TCR gamma locus failed to detect a clonal rearrangement. This unique case of hepatosplenic lymphoma of alphabeta T-cell phenotype supports the possibility that lymphoid populations of different alphabeta or gammadelta phenotype that share similar homing and presumably functional properties could give rise to lymphomas displaying similar clinical and pathologic findings.

T-cell clonality determination using polymerase chain reaction (PCR) amplification of the T-cell receptor gamma-chain gene and capillary electrophoresis of fluorescently labeled PCR products

We compared the effectiveness of polymerase chain reaction (PCR) and DNA blot analysis (DBA) for detecting clonal T-cell populations and investigated whether a nonradioactive PCR method could be used in routine clinical diagnosis. We analyzed DNA from 117 cases for T-cell clonality by PCR amplification. DBA was performed on 77 of these cases. Denaturing polyacrylamide gel electrophoresis (PCR-PAGE) of radiolabeled PCR products and capillary electrophoresis (PCR-CE) of fluorescently labeled PCR products were used for PCR product separation and quantitation. Complete agreement was obtained between PCR-PAGE and DBA in 67 of 77 cases. One case was positive by DBA and negative by PCR-PAGE, and 3 cases were positive by PAGE and negative by DBA. Five cases indeterminate by DBA were positive by PCR-PAGE, and 1 indeterminate case was negative by PCR-PAGE. In the comparison of PCR-PAGE and PCR-CE, of 63 cases with height ratios less than 2.0, all were negative by PCR-PAGE. Of 52 cases with height ratios of 2.0 or more, 50 were positive by PCR-PAGE. We conclude that PCR-CE is analytically equivalent to DBA and PCR-PAGE for detecting clonal T-cell populations. The PCR-CE method is semiquantitative and, therefore, may be more objective than gel-based methods.

gammadelta T-cell lymphomas: a homogeneous entity?

gammadelta T-cells comprise an immunologically distinct lymphoid population, characterized by specific morphological, phenotypical and functional properties. Therefore it seems reasonable to speculate that neoplasms derived from this particular T-cell subset display distinct features. Indeed, the prototype gammadelta T-cell lymphoma, hepatosplenic T-cell lymphoma constitutes a unique clinicopathological entitity which is intimately associated with a gammadelta T-cell phenotype. However, gammadelta T-cell lymphomas have also been described in other extranodal sites where, unlike reactive gammadelta T-cells and hepatosplenic gammadelta T-cell lymphomas, they display an important morphological heterogeneity. Moreover, these nonhepatosplenic gammadelta T-cell lymphomas are essentially not that different from their alphabeta T-cell receptor for antigen (TCR)-expressing counterparts and thus may be incorporated in the established T-cell lymphoma subclasses. However, subtle differences regarding their histopathological appearance as well as their biological behaviour indicate that further studies to determine the exact significance of TCR expression are required. Such inquiries may contribute to the general understanding of T-cell lymphomagenesis in general, which is still obscure.

Frequent T and B cell oligoclones in histologically and immunophenotypically characterized angioimmunoblastic lymphadenopathy

The identification of clonal rearrangements of T cell receptor (TCR) genes is central to the diagnosis of T cell lymphomas. However, in angioimmunoblastic lymphadenopathy (AILD), first described as a nonneoplastic proliferation associated with immunodeficiency, the heterogeneity of TCR and IgH gene rearrangements suggest that some cases may harbor multiple lymphoid clones. In this study we have isolated DNA from archival paraffin biopsy material from 22 cases of AILD identified on the basis of classical histological and immunohistochemical features with the aim of establishing the occurrence of clones and oligoclones, the frequency of TCR and immunoglobulin heavy chain (IgH) variable (v) gene use, and the relationship of these findings to the presence of Epstein-Barr virus. DNA extracted from the biopsies was amplified using the polymerase chain reaction (PCR) and sequenced to detect functional and nonfunctional gene rearrangements. Epstein-Barr virus-encoded short RNA species (EBERs) were detected using in situ hybridization combined with immunochemistry to identify the phenotype of the Epstein-Barr virus-infected cells. Fifty-seven clonal products were found in 20/22 patients: TCRgamma clonal products were identified in 16/22, TCRbeta clonal products in 16/22 and IgH clonal products in 6/22 cases. Oligoclonal PCR products were seen for TCR in 3/22 and for IgH in 3/22 cases. In one biopsy PCR products from all reactions were polyclonal. Sequence analysis revealed functional TCRgamma, TCRbeta, and IgH sequences in 6/12, 9/11, and 8/8 cases, respectively. Functional TCR and/or IgH oligoclones were detected in 6/20 (30%) cases. In addition, nonfunctional TCR and IgH sequences were found in 11 cases. EBERs were identified in 18/20 cases varying from occasional to 25 to 30% nuclei staining and were associated with both T and B cells, although the majority were of indeterminate phenotype. The presence of EBERs was not associated with all clonal IgH gene rearrangements but was associated with B cell oligoclones. Patterns of gene recombinations indicated that the majority of TCRgamma recombinations used GV1 and GJ1S3/2S3 genes. Six out of eleven cases used TCR BV4S1 or BV2S1 genes associated with various BJ and BD1/2 genes. No common IgH gene usage was identified, but 8 clones had varying degrees of replacement and silent mutations (0.6-10.1%), consistent with B cell clones having undergone somatic mutation in the germinal center, and 3 clones harbored unmutated V genes, consistent with naive B cells. Our data do not support the concept of AILD as a clearly defined peripheral T cell lymphoma (PTCL). Rather, they suggest that AILD as defined by histology and immunohistochemistry is either a heterogeneous entity or represents a lymphoproliferation associated with immunodeficiency in which clonal T cell or B cell proliferation may occur.

Detection of a peripheral blood T cell clone is an independent prognostic marker in mycosis fungoides

T cell receptor gene analysis is a sensitive method for assessment of peripheral blood involvement in mycosis fungoides. This study uses polymerase chain reaction/single-strand conformational polymorphism (PCR/SSCP) analysis of the T cell receptor gamma gene and relates the results to skin stage and outcome in mycosis fungoides. Seventy-five peripheral blood samples from 66 patients were obtained from 1990 onwards and subjected to PCR/SSCP. Both Southern blot analysis and PCR/SSCP analysis were performed on 63 samples from 56 patients. Fourteen patients had T1 disease (12 IA, two IIA), 20 T2 (14 IB, five IIA, one IVA), 29 T3 (24 IIB, two IVA, three IVB, two patients tested at both T2 and T3), and five T4 (all III). The percentage of positive samples was higher with PCR/SSCP than with Southern blot analysis (29 of 63 vs eight of 63 samples, p < 0.001), and the percentage of positive samples increased with each stage (21% at T1, 35% at T2, 58% at T3, and 71% at T4). Proportional hazards analysis corrected for age, skin, and lymph node stage showed that the presence of a peripheral blood clone is associated with a worse outcome (p = 0.03, CI 1.1-6.03). These results indicate that the presence of a peripheral blood clone is an independent prognostic variable in patients with mycosis fungoides after correcting for age, skin, and lymph node stage, and that peripheral blood involvement is present in a large proportion of patients with early stage mycosis fungoides.

KEYWORDS

polymerase chain reaction/single-strand conformational polymorphism/T cell receptor gene rearrangement. J Invest Dermatol 114:117-121, 2000

CD4 + /CD7- T cell frequency and polymerase chain reaction-based clonality assay correlate with stage in cutaneous T cell lymphomas

In cutaneous T cell lymphomas, tumor cells can be found in skin and in other compartments. A precise definition of extracutaneous spread including blood involvement is necessary for staging and treatment design. We investigated peripheral blood in 51 patients with various types of cutaneous T cell lymphomas by the analysis of blood smears for Sézary cells, the CD4 + /CD7- T helper cell frequency in the peripheral blood by fluorescence activated cell sorter analysis and by polymerase chain reaction for the T cell receptor gamma-chain followed by denaturing gradient gel electrophoresis. Eleven polymerase chain reaction products were sequenced. Thirty-five per cent of patients with stage Ia-IIb cutaneous T cell lymphomas presented a peripheral blood T cell clone. In patients with stage III-IVb cutaneous T cell lymphomas 75% were positive for clonality in the peripheral blood by polymerase chain reaction. Interestingly, three of 13 Sézary patients showed a TCR-gamma joining region pseudogene (JgammaP1/JgammaP2) usage. CD4 + /CD7- cell counts were significantly higher in patients with advanced cutaneous T cell lymphomas than in patients with early cutaneous T cell lymphomas. There was a correlation between increased percentage of circulating CD4 + /CD7- cells and detection of clonality by polymerase chain reaction (p = 0.001). There was no significant correlation between the polymerase chain reaction data and the percentage of Sézary cells on blood smears. A significant correlation between CD4 + /CD7- cells and Sézary cells was found, however. Stepwise logistic regression analysis showed that the CD4 + /CD7- cell count and clonal T cell detection in peripheral blood are independently correlated with stage. The combination of both parameters gives more information than each one separately. In conclusion, our data indicate that fluorescence activated cell sorter analysis of peripheral blood and polymerase chain reaction-based clonality assays can improve the accuracy of staging investigations in cutaneous T cell lymphomas patients.

Successful treatment of immunoblastic lymphadenopathy-like T-cell lymphoma with cyclosporin A

Immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma is considered to belong to peripheral T-cell lymphoma. Its prognosis is grave and effective treatments have not been established. Recently, we gave oral cyclosporin A (CsA) to a patient with IBL-like T-cell lymphoma, and succeeded in achieving dramatic remission. In this case, serum levels of interleukin-12 (IL-12) and tumor necrosis factor-alpha (TNF alpha) were elevated and decreased or returned to normal after achieving remission. Since CsA is a potent suppressor of the immune system and most notably T-cells, the immunosuppression of T-cell function might have played an important role in achieving remission in this case, although the precise mechanism still remains to be elucidated. The present case indicates that administration of CsA may be a very effective and safe selection of therapy for IBL-like T-cell lymphoma, as well as analogous disorders such as IBL and angioimmunoblastic lymphadenopathy with dysproteinemia (AILD), thereby will contribute to improving the prognosis of patients with these diseases.

An immunophenotypic study of canine leukemias and preliminary assessment of clonality by polymerase chain reaction

There is a relative lack of information in the veterinary literature regarding the immunophenotypes present in canine leukemias. Utilizing a panel of thirty monoclonal antibodies, canine leukemias were assessed by flow cytometry alone or by flow cytometry in combination with immunocytochemical staining of smears. Canine chronic lymphocytic leukemia (CLL) occurred in older dogs (mean age 9.75 years; range 1.5-15 years; n = 73 cases). Blood lymphocyte counts ranged from 15,000 to 1,600,000/microl. Surprisingly, 73% of CLL cases involved proliferation of T lymphocytes (CD3+), and 54% of CLL cases had large granular lymphocyte (LGL) morphology. LGL CLL's were almost exclusively proliferation's of T cells that expressed CD8 and the leukointegrin alphaDbeta2 and more frequently expressed T cell receptor (TCR) alphabeta (69%) than TCRgammadelta (31%). The non-LGL T cell CLL cases (19% of CLL) involved proliferation of TCRalphabeta T cells in which no consistent pattern of CD4 or CD8 expression was found. B cell CLL, based on expression of CD2 or CD79a, comprised 26% of canine CLL cases. These results are in marked contrast to people where greater than 95% of CLL cases involve proliferation of B lymphocytes. Thirty eight (38) acute leukemias were also immunophenotyped. The majority (55%) of these leukemias had a phenotype most consistent with a myeloid origin. Acute LGL leukemias were also observed (7/38), although less commonly than the CLL counterpart. CD34 expression was common in acute, non-LGL leukemias of dogs, both myeloid and lymphoid. In some circumstances, it can be difficult to differentiate a reactive (polyclonal) lymphoid proliferation from a neoplastic (monoclonal) one. Therefore, as an adjunct to phenotypic studies, we have developed a polymerase chain reaction (PCR) based test for assessment of clonality in T cell proliferations. The test amplifies the junction of the variable gamma (Vgamma) and joining gamma (Jgamma) gene segments region of the TCR gamma genes. Preliminary data indicates that our test is effective and is capable of differentiating a neoplastic from a reactive lymphoproliferative process.

T-cell receptor gene analysis in the diagnosis of Sézary syndrome

Diagnosing Sézary syndrome (SS) on clinicopathological grounds alone is far from straightforward, particularly in the early stages of the disease. Atypical lymphocytes may be seen in the peripheral blood of patients with reactive forms of erythroderma, so additional criteria are needed to establish the diagnosis of a T-cell leukemia/lymphoma. A wide variety of confirmatory tests have been proposed in the literature, but there has been no systematic attempt to compare the specificity and sensitivity of these different methods. Recent data indicate that T-cell receptor (TCR) gene analysis is the most useful test currently available and that methods based on polymerase chain reaction are more sensitive than Southern blot analysis. We propose that the diagnostic criteria for SS should include erythroderma, atypical circulating mononuclear cells, and evidence of a clonal T-cell population in the peripheral blood. Clonality can be established with certainty by cytogenetic or TCR gene analysis, but only the latter is sufficiently sensitive to be of value in routine diagnosis. Immunophenotypic data showing an expanded CD4(+)/CD7(-) population, an elevated CD4/CD8 ratio, or restricted V beta expression are not specific to T-cell malignancy and should not be used as a sole diagnostic criteria in SS. Entry criteria for future clinical studies will need to be more rigorous if meaningful comparisons are to be made between different treatment options.

Detection of clonal T-cell receptor gamma gene rearrangements in paraffin-embedded tissue by polymerase chain reaction and nonradioactive single-strand conformational polymorphism analysis

The diagnosis of T-cell lymphoproliferative disorders, which frequently involve the skin and other extranodal sites, is often problematic because of the difficulty in establishing clonality in paraffin-embedded tissue. To this end, we developed a simple, nonradioactive method to detect T-cell receptor gamma (TCR-gamma) gene rearrangements by polymerase chain reaction single-strand conformational polymorphism (PCR-SSCP) in paraffin-embedded tissue. Jurkat and HSB-2 cell lines and peripheral blood samples from normal individuals were used as monoclonal and polyclonal controls, respectively. DNA was extracted from 24 biopsies of T-cell lymphomas, 12 biopsies of reactive lymphoid infiltrates, and 2 biopsies of primary cutaneous large B-cell lymphomas. Vgamma1-8, Vgamma9, Vgamma10, Vgamma11, and Jgamma1/Jgamma2 consensus primers were used for TCR-gamma gene rearrangement amplification and PCR products were analyzed by nonradioactive SSCP. Monoclonal controls yielded a well-defined banded pattern, whereas all polyclonal T-cell controls showed a reproducible pattern of smears. We detected monoclonality in 20/21 (95%) T-cell lymphoma cases, whereas no dominant T-cell clones were found in any of the reactive lymphoid infiltrates or B-cell lymphomas. Sensitivity of 1-5% was demonstrated by serially diluting Jurkat cells in mononuclear blood cells from normal individuals. We conclude that nonradioactive PCR-SSCP for TCR-gamma gene rearrangement analysis is a useful adjunct to routine histological and immunophenotypic methods in the diagnosis of T-cell lymphoproliferative disorders in paraffin-embedded tissue.

Primary cardiac lymphoma in an immunocompetent woman

We report a fatal primary cardiac non-Hodgkin's lymphoma in a 62 years old immunocompetent woman presenting with tamponade and complete atrioventricular block. CT-scan, echocardiography and autopsy examination showed a tumor largely infiltrating the heart without extracardiac involvement. A surgical biopsy revealed high grade B-cell non-Hodgkin's lymphoma with a misleading myelomonocytic CD68 (KPI) expression. Polymerase Chain Reaction analysis revealed a clonal rearrangement of the immunoglobulin heavy chain gene and confirmed the B-cell origin of the lymphoma. Our report also emphasizes the role of immunohistochemical and molecular techniques in the diagnosis.

Molecular evidence of bone marrow involvement in advanced case ot Tgammadelta lymphoma with secondary myelofibrosis

We describe the case of a middle-aged man with long indolent course of generalized Tgammadelta lymphoma. The onset of secondary myelofibrosis made cytological monitoring of the bone marrow infiltrates impossible. As during progression of the disease splenectomy revealed typical histological features of a high-grade hepatosplenic Tgammadelta lymphoma, the low-grade bone infiltrate was considered a secondary lymphoma. The use of the polymerase chain reaction helped to detect a constant and identical monoclonal rearrangement pattern of the T-cell receptor gamma-chain gene in both bone marrow and splenic T-cell infiltrates. The notion of a secondary spread of malignant T-cells to the bone marrow was thereby confirmed despite striking cytological differences between bone marrow and splenic infiltrates. This is the first report of a diagnostic DNA-based molecular approach using fixed decalcified bone marrow. This method may provide a major tool when dealing with myelofibrosis, which normally hampers sampling of cytological specimens.

Simple, reliable detection of T cell clones by PCR-LIS-SSCP analysis of TCRgamma rearrangement

Clonal populations of T cells can be identified by polymerase chain reaction (PCR) amplification of the rearranged T cell receptor gamma (TCRG) chain gene. However, because of the limited combinatorial diversity of this locus it is necessary to separate the PCR product on the basis of sequence as well as size to distinguish clonal and polyclonal T cell populations. A simple method is described which achieves this by analysing the PCR product on a single-stranded conformation polymorphism (SSCP) gel. Sensitivity has been improved by denaturing the DNA using a low ionic strength (LIS) method rather than the more conventional alkali or formamide. Results from the PCR-LIS-SSCP method on a wide range of disorders and types of tissue samples show that clonality could be demonstrated in 40/44 cases.

Nasal T/natural killer (NK)-cell lymphomas are derived from Epstein-Barr virus-infected cytotoxic lymphocytes of both NK- and T-cell lineage

The cellular nature of nasal T/natural killer (NK)-cell lymphomas (NLs) remains controversial. It is still debatable whether these represent T-cell lymphomas with extensive loss of surface antigens or are, in fact, true NK-cell lymphomas. They are associated closely with Epstein-Barr virus (EBV), to the extent that EBV-encoded small non-polyadenylated RNAs (EBER) expression can be used as a marker for the neoplastic cells. The cell lineage of this group of lymphomas was examined further by correlating immunophenotype, genotype and EBV status with the expression of cytotoxic granule-associated proteins, perforin and T-cell intracellular antigen-1 (TIA-1) in 13 cases of NL. Combined immunophenotypic and gene rearrangement analyses demonstrated that NLs can be identified clearly as either NK-cell or T-cell tumours. Nasal NK-cell lymphomas lacked clonal rearrangement of both T-cell receptor (TCR) gamma and immunogloulin heavy chain (IgH) genes and were either CD3(Leu4)-CD56+ (8 cases) or CD3(Leu4)+CD56+ (2 cases), whereas nasal T-cell lymphomas had rearranged TCRgamma and germ-line IgH genes and were either CD3(Leu4)+CD56+ (2 cases) or CD3(Leu4)+CD56- (1 case). Immunohistochemical (IH) studies showed that both perforin and TIA-1 were expressed universally in NL, irrespective of NK- or T-cell lineage. Dual labelling of TIA-1 by IH and EBER by in situ hybridisation demonstrated that the granule proteins were expressed predominantly by the EBER+ tumour cells. Our results indicate that NLs are derived from EBV-infected cytotoxic lymphocytes of both NK- and T-cell lineage. We postulate that cytotoxic lymphocytes generated during the cellular immune response to EBV infection or re-activation at the nasal region themselves may become targets for EBV infection and subsequent transformation.

Nasopharyngeal lymphomas: further evidence for a natural killer cell origin

The authors report four cases of sinonasal lymphomas with immunophenotypic (four cases) and genotypic (three cases) studies. These lymphomas are frequent in Oriental countries, but unusual in Western populations, particularly in France. Although they have been originally considered as T-cell lymphomas, their origin remains unclear, and several authors have recently suggested that they are a natural killer (NK)-cell proliferation. The tumor cells of the four cases reported here showed characteristics of NK cells. On cryostat sections, they were CD3 negative, but CD2 and CD56 positive. The cytoplasm of the tumor cells exhibited azurophilic granulations. Using polymerase chain reaction (PCR), no clonal rearrangement of the T-cell receptor gamma gene was present. Furthermore, clinically, two presented a pharyngeal involvement, and two were also characterized by hepatosplenic involvement at the time of the diagnosis. Thus, the present cases provide additional evidence toward the NK-cell origin of these rare lymphomas. Many sinonasal lymphomas, including the present cases, are positive for Epstein-Barr virus (EBV) (LMP-1 antibody and EBER-messenger RNA probes). This may suggest an important role of EBV as a local factor in their pathogenesis.

VJ rearrangements of the TCR gamma locus in peripheral T-cell lymphomas: analysis by polymerase chain reaction and denaturing gradient gel electrophoresis

Using Southern blotting for the diagnosis of clonality in peripheral T-cell lymphomas (PTCLs), analysis of the T-cell receptor (TCR) gamma gene rearrangement was shown to be more informative than that of the TCR beta gene rearrangement. In order to amplify every VJ gamma rearrangement, a polymerase chain reaction (PCR) procedure using newly designed GC-clamp primers has been developed. All primers can be mixed in a single multiplex PCR. PCR products are analysed by denaturing gradient gel electrophoresis (DGGE), providing tumour-specific imprints inasmuch as the procedure characterizes N sequence polymorphism at the VJ junctions. In a series of 30 PTCL cases, the PCR procedure demonstrated 27 cases to be clonally rearranged and failed in three cases. PCR was more accurate than Southern blotting, showing 47 rearranged gamma alleles, four of which were undetectable on the Southern blot. When lymphomas were studied at different sites and at relapse, the DGGE pattern remained unchanged. In PTCL, the proposed PCR is helpful for the diagnosis and staging of the disease and should improve the follow-up monitoring. The undetectability of clonal rearrangements in a few cases is discussed in the light of concepts of lymphomagenesis and T-cell differentiation.

The polymerase chain reaction in the demonstration of monoclonality in T cell lymphomas

AIMS

To evaluate polymerase chain reaction (PCR) amplification of T cell receptor (TCR) beta and gamma chain genes as a means of demonstrating monoclonality in T cell lymphomas using histological samples; to compare the performance of PCR with Southern blot analysis.

METHODS

TCR-beta, TCR-gamma and immunoglobulin heavy chain (IGH) genes were analysed using PCR in 55 cases of T cell lymphoma (28 frozen tissue and 27 paraffin wax embedded samples), diagnosed using morphological and immunohistochemical criteria. The 28 frozen samples were subjected to Southern blot analysis using TCR-beta, TCR-gamma and IGH gene probes. Twenty five B cell lymphomas and 21 non-neoplastic lymphoid tissue samples were used as controls.

RESULTS

Using TCR-beta PCR, monoclonality was detected in 24 (44%) of 55 T cell lymphomas compared with 43 (78%) of 55 using TCR-gamma PCR and in 82% with both techniques. Five (9%) of 55 T cell lymphomas were IGH PCR positive. None of the non-neoplastic lymphoid control samples were PCR positive. All B cell lymphomas showed a polyclonal pattern with TCR-beta PCR while a single B cell lymphoma was positive using TCR-gamma primers. With TCR-beta PCR, a monoclonal result was seen in 12 (43%) of 28 frozen samples of T cell lymphoma, compared with 23 (82%) of 28 using Southern blot analysis. With TCR-gamma PCR, 19 (68%) of 28 frozen tissue samples were positive, compared with 26 (93%) of 28 using Southern blot analysis. A single case showed IGH rearrangement by Southern blot analysis.

CONCLUSION

TCR-gamma PCR should be the method of choice for analysis of clonality in paraffin wax embedded sections of lymphoproliferative lesions, as TCR-beta PCR has a high false negative rate. Southern blot analysis remains the most successful technique when sufficient fresh tissue samples and resources are available.