Clonal T-cell Receptor Gene Rearrangements Research Articles

T-Cell Receptor Gene Rearrangement and CD30 Immunoreactivity in Traumatic Ulcerative Granuloma With Stromal Eosinophilia of the Oral Cavity

Traumatic ulcerative granuloma with stromal eosinophilia (TUGSE) is an ulcerative lesion of the oral mucosa with unknown pathogenesis. A few recent case reports have demonstrated molecular evidence of T-cell clonality in TUGSE and CD30 immunoreactivity in the large atypical mononuclear cells, raising the possibility that a TUGSE subset may represent the oral counterpart of primary cutaneous CD30+ T-cell lymphoproliferative disorders. We examined the immunoreactivity for CD30 and T-cell receptor (TCR) gamma gene rearrangement in 37 TUGSE cases. Clonal TCR gene rearrangements were demonstrated in 7 (24%) of 29 cases with amplifiable DNA, and the morphologic features and CD30 immunoreactivity of these cases did not differ from those with polyclonal TCR gene rearrangements. Clinical follow-up was available for 5 of 7 TUGSE cases with clonal TCR gene rearrangement for an average period of 1.75 years after the initial biopsy or excision, and there was no evidence of local recurrence or development of systemic T-cell lymphoproliferative disorder. Without morphologic and/or clinical evidence of lymphoma, T-cell clonality and/or CD30 positivity in these lesions is not indicative of malignancy and should be interpreted with caution.

Primary T-cell Lymphoma of the Retina and Cerebellum: Immunophenotypic and Gene Rearrangement Confirmation

To document fully the first credible primary T-cell lymphoma of the retina and central nervous system in a 71-year-old man. Interventional, retrospective report. Critical analysis of clinical history and findings, which included bilateral vitreitis with anterior chamber reaction, creamy intraretinal infiltrates, and retinal detachment; complete blood counts and other blood studies (anti-neutrophil cytoplasmic antibody [ANCA], angiotensin-converting enzyme levels, and Lyme and fluorescent treponemal antibody absorption titers); magnetic resonance imaging (MRI) scanning of the brain with total body computed tomographic and positron emission tomographic scanning; interleukin (IL) level determinations (IL-10 and IL-6); cytologic and electron microscopic evaluations; immunophenotyping of cells; and polymerase chain reaction studies for viral deoxyribonucleic acid and ribonucleic acid, and immunoglobulin heavy-chain, and T-cell receptor (TCR) gene rearrangements. The first vitreous specimen was diagnosed mistakenly as cytologically reactive and contained elevated levels of IL-10 and IL-6 in a ratio of 7 to 1. T cells predominated on immunophenotypic analysis. Computed tomographic and positron emission tomographic whole body scanning showed negative results for lymphoma. An MRI scan of the brain eventually revealed a cerebellar lesion. A retinal biopsy harbored cytologically atypical pleomorphic cells that were almost all immunophenotypically T cells; polymerase chain reaction studies demonstrated a clonal TCR gene rearrangement. T-cell lymphocytes in the biopsy specimen of the cerebellum had an identical clonal TCR gene rearrangement. This case unequivocally establishes that primary retinal T-cell lymphoma accompanied by central nervous system involvement can occur. Elevation in the IL-10 to IL-6 ratio in the face of inconclusive or confusing vitreous cytologic and immunophenotypic findings (a predominance of "reactive T cells with some atypicality") should lead to gene rearrangement studies on biopsies of involved tissues for the detection of T-cell clonality.

Application of BIOMED-2 primers in analysis of T-cell receptor gamma gene rearrangements in paraffin-embedded tissue specimens of T-cell lymphoma

To evaluate the practical values of PCR detectable T-cell receptor (TCR) gene rearrangement in paraffin embedded tissue samples in the diagnosis of T-cell malignancies using BIOMED-2 PCR multiplex tubes TCRgamma(A+B). Traditional phenol-chloroform method was used to extract DNA from 55 cases of archival paraffin embedded tissues samples of T-cell malignancies and the DNA quality was evaluated by PCR-based amplification of housekeeping gene beta-globin. The selected BIOMED-2 PCR multiplex tubes TCRgamma(A+B) were used to detect TCR gene rearrangement and comparison with the results of universal TCR primers (T(VG)/T(JX)) was performed. Positive detection rates by the BIOMED-2 multiplex tubes TCRgamma(A+B) and the universal primers (T(VG)/T(JX)) were 76.4% and 60.0%, respectively. There were not statistical difference between the methods (P > 0.05). BIOMED-2 multiplex tubes TCRgamma(A+B) is suitable for detection of clonal rearrangements of TCR genes in current archival paraffin embedded tissue samples of T-cell malignancies.

Quantification of fusion transcript reveals a subgroup with distinct biological properties and predicts relapse in BCR/ABL-positive ALL: implications for residual disease monitoring

Minimal residual disease (MRD) monitoring is an essential tool for risk group stratification in current treatment protocols for childhood acute lymphoblastic leukaemia (ALL). Although quantitative detection of clonal immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements is currently considered to be the standard method, leukaemia fusion genes provide other possible targets for MRD follow-up, as already demonstrated in TEL/AML1-positive ALLs. We analysed and compared MRD levels quantified by BCR/ABL transcript detection and by the standard Ig/TCR-based method in 218 bone marrow specimens from 17 children with BCR/ABL-positive ALL. We found only a limited overall correlation of MRD levels as assessed by the two methods (correlation coefficient R(2)=0.64). The correlation varied among patients from excellent (R(2)=0.99) to very poor (R(2)=0.17). Despite identical sensitivity of the approaches, 20% of the samples were negative by the Ig/TCR approach whereas positive by the BCR/ABL method. We show that multilineage involvement is at least partly responsible for the discrepancy. Moreover, our data demonstrate that BCR/ABL monitoring enables better and earlier prediction of relapse compared to the standard Ig/TCR methodology. We conclude that BCR/ABL-based MRD monitoring of childhood ALL is a clinically relevant tool and should be performed in parallel with the standard Ig/TCR follow-up.

Angioimmunoblastic T Cell Lymphomas: Frequent Cutaneous Skin Lesions and Absence of Human Herpes Viruses

Angioimmunoblastic T-cell lymphoma (AITL) is a complex lymphoproliferative disorder and often mimics a viral infection with frequent skin involvement. Epstein-Barr virus (EBV) and human herpes virus (HHV)-6 are reported to be associated with AITL, but there are conflicting results. We evaluated the association of EBV and HHV-6 with AITL. We reviewed the clinical, histological and immunophenotypical features of 19 cases of AITL. Among them, 11 lymph node biopsies of AITL were examined for HHV-6, -7, and -8 by polymerase chain reaction (PCR) using virus-specific primers. In situ hybridization of EBV early region RNA (EBER) was performed and T cell receptor (TCR) gene rearrangement was also investigated in some cases. Among these 19 cases, maculopapular, plaque or nodular skin lesions accompanied AITL in 12 cases. Clonal TCR gene rearrangement was seen in 8/9 cases tested. EBER in situ hybridization was positive in 8 cases (57.1%). Among 7 cases with skin biopsies, five cases were consistent with cutaneous involvement of AITL, 1 case was a drug eruption, and the other case was Kaposi's sarcoma. Except a HHV-8 (+) case who also had Kaposi's sarcoma, all of these cases were negative for HHV-6, -7 and -8. Skin manifestation seems to be a cardinal component of AITL, be it in the context of presentation, progression or recurrent disease. Recognition of clinicopathological features of skin lesions in AITL as diagnostic clues should be stressed among dermatologists. The lack of HHV-6, -7 and -8 in lymph node biopsy of AITL argues against a pathogenic role for HHVs in AITL.

Novel CD19 expression in a peripheral T cell lymphoma: A flow cytometry case report with morphologic correlation

Peripheral T-cell lymphomas are uncommon lymphomas that show T-cell antigenic loss and clonal T-cell receptor (TCR) gene rearrangement. Rare cases of T-cell lymphomas with aberrant expression of CD20 have been described. However, CD19 coexpression in a mature T-cell neoplasm has not been reported. Histology, immunohistochemistry (IHC), and PCR for TCR gene rearrangement were performed on an excised lymph node specimen and a subsequent fine needle aspiration (FNA) of an additional lymph node. Flow cytometry (FC) was performed on FNA and peripheral blood specimen. The lymph node's architecture was effaced by a diffuse atypical lymphoid proliferation that, by IHC, was positive for CD3, CD2, and CD43 and negative for CD4, CD5, CD8, TdT, CD1a, and B-cell-associated antigens PAX-5, CD20, and CD79a. A clonal TCR gene rearrangement was detected. FC was performed on a subsequent FNA, and peripheral blood specimen demonstrated an aberrant T-cell population with expression of CD2, CD3, CD27, TCR alpha/beta, CD52, CD38, CD45, and CD26 (partial expression) and negative for CD4, CD5, CD7, CD8, CD10, CD30, and CD56. The aberrant T-cell population also expressed bright CD19. Using FC, we describe the first case of peripheral T-cell lymphoma with aberrant coexpression of CD19.

Primary cutaneous CD4-positive small/medium-sized pleomorphic T-cell lymphoma: a clonal T-cell lymphoproliferative disorder with indolent behavior

Primary cutaneous CD4-positive small/medium-sized pleomorphic T-cell lymphoma, a provisional entity in the 2005 WHO-EORTC classification for cutaneous lymphomas, is not well characterized. Fifteen cases meeting the definition of this entity were identified. Fourteen represented solitary lesions on the head/neck (n=9), upper extremity (n=4), or trunk (n=1). One patient presented with multiple lesions on the trunk and extremities. Histologically, the infiltrate showed a nodular pattern in the dermis and subcutis without epidermotropism, and had a polymorphous composition with a predominance of small to medium-sized CD4-positive T cells. Most cases showed normal T-cell antigen expression; diminished/absent expression of CD7 was seen in three cases and CD2 expression was absent in one case. All cases showed a notable reactive infiltrate including frequent B cells, plasma cells, and histiocytes. Clonal TCR gene rearrangements were detected in each case. No clonal Ig gene rearrangements were detected. Out of the 11 patients with follow-up, none showed systemic disease. The majority resolved without relapse, one without treatment, four with excision, and four with radiation therapy. One patient developed local recurrence. The patient with multiple lesions had disease progression despite chemotherapy and stem cell transplant. These cases highlight the polymorphous histology and prominent reactive B-cell component of this entity. Diagnosis requires molecular genetic analysis, as prominent cytologic atypia and immunophenotypic aberrancy are rare. The differential diagnosis includes reactive lymphoid hyperplasia, mycosis fungoides and cutaneous B-cell lymphomas. In patients with isolated cutaneous lesions, the indolent behavior of this rare T-cell neoplasm should be recognized to avoid unnecessary treatment.

Diagnostic significance of immunophenotyping and detection of gene rearrangement in subcutaneous panniculitis-like T-cell lymphoma

To explore the diagnostic implication of immunophenotyping and gene rearrangement in subcutaneous panniculitis-like T-cell lymphoma (SPTL). According to the selection criteria of 2005 WHO-EORTC classification for cutaneous lymphomas, 20 SPTL patients were enrolled in this study. A 10-antibody panel was used for immunophenotyping and in addition, polymerase chain reaction for TCR gamma and IgH gene rearrangement and in situ hybridization for EBER1/2 were also employed. There were 9 males and 11 female with a mean age of 29.5 years. Immunophenotypic study showed that all the patients expressed one to three T-cell associated antigens (CD2, CD3 or CD45RO), 18 patients were positive for beta F1, 18 for CD8, 20 for TIA-1 and 16 for granzyme B. None of the patients expressed CD4, CD20 and CD56. TCR gamma gene rearrangement was found in 16 of 20 cases (80.0%) and none for IgH gene rearrangement. The positive rate of EBER1/2 was 25.0% (5/20). Since the majority of SPTL patients show clonal TCR gene rearrangements, correlations among clinical presentation, histological features, immunophenotype and gene rearrangement data are considered important in confirming a diagnosis of SPTL.

CD4+/CD56+ hematodermic neoplasm: report of a rare variant with a T‐cell receptor gene rearrangement

CD4+/CD56+ hematodermic neoplasm (HN), formerly known as a blastic natural killer (NK) cell lymphoma, is a rare subtype of a cutaneous dendritic cell neoplasm notable for highly aggressive behavior. The characteristic features are: expression of the T-helper/inducer cell marker CD4 and the NK-cell marker CD56 in the absence of other T cell or NK-cell specific markers. In particular, CD3 (surface or cytoplasmic) and CD2 are not expressed. Although T-cell receptor (TCR) genes are generally reported to be in a germline configuration, we present an unusual variant of a CD4+/CD56+ HN with a clonal rearrangement of TCR genes. This feature of a CD4+/CD56+ HN has been only rarely reported. Recognition of the presence of clonal TCR gene rearrangements in a small subset of CD4+/CD56+ HN is important to avoid misdiagnosis of this entity as an unusual variant of a cutaneous T-cell lymphoma.

The pattern of clonal immunoglobulin and T-cell receptor (Ig/TCR) gene rearrangements in Chinese adult acute lymphoblastic leukemia patients

We have studied forty Chinese adult ALL patients at newly diagnosis, using standard primers and protocols of BIOMED-2 multiplex PCR, to determine the feasibility of Ig and TCR gene rearrangements as diagnostic and patient-specific MRD-RQ-PCR targets for molecular monitoring. Clonal IGH, IGK, IGL, TCRB, TCRG and TCRD rearrangements were found in 86%, 22%, 9%, 19%, 77%, 55% of adult patients with B-lineage ALL, respectively. While in T-ALL, clonal IGH, TCRB, TCRG and TCRD rearrangements were detected in 6%, 83%, 78%, 33% of patients. Several specialties in the pattern of Ig/TCR gene rearrangements in Chinese adult ALL patients in comparison with those reported for children and adult patients in other countries have been noted. These results are useful for further MRD-RQ-PCR detection and quantification for all patients.

Primary Cutaneous Follicle Center Lymphoma Associated with Alopecia Areata

We report a patient who presented simultaneously with primary cutaneous follicle center lymphoma (PCFCL) of the face and scalp and alopecia areata of the scalp and beard bearing a clonal T-cell receptor gene rearrangement. To our knowledge, alopecia areata has not been previously reported in association with PCFCL. Both lesions regressed with topical imiquimod and systemic steroids, which suggests an inter-relationship in this case between the clonal B-cell and T-cell populations in driving outgrowth of these lesions.

Primary T-cell lymphoma of the thyroid: case report and review of the literature

Here we report a rare case of primary T-cell lymphoma of the thyroid gland. A 32-year-old Chinese man was admitted to our hospital because of marked goiter and subcutaneous nodules. Computed tomography (CT) scan of the neck disclosed diffuse enlargement of the thyroid gland. A diagnosis of peripheral T-cell lymphoma was made according to cytopathological findings of fine-needle aspiration (FNA) of the thyroid gland and skin biopsy. Immunohistochemistry stain showed that the tumor was positive for CD3 and negative for CD20. Clonal T-cell receptor (TCR-gamma) gene rearrangements were demonstrated by polymerase chain reaction. After six cycles of combination chemotherapy (bleomycin, cyclophosphamide, doxorubicin, vincristine, and prednisone), the thyroid retracted to normal size gradually.

TCR Gene Rearrangement in B-Cell Chronic Lymphocytic Leukaemia.

Background: Chronic lymphocytic leukaemia (B-CLL) is a heterogenous B cell disorder. However, clonal/oligoclonal T cell expansion has also been detected at a low frequency in B-CLL using a range of methodologies including Southern blotting and flow cytometric analysis. The underlying cause of this phenomenon is unclear and it has even been suggested that this clonal T cell receptor (TCR) gene rearrangement occurred in the leukaemic cells, leading to the concept of lineage infidelity. Other suggestions include that the observed T cell clonality may simply be related to the normal aging process or that it may result from the immune response to malignant cells or viral infection. During normal T cell maturation in the thymus, the TCR genes undergo a complex process of V(D)J segment rearrangement to produce a wide repertoire of antigen specificity. As it is an early event in T cell development, TCRγ gene rearrangement is commonly used as a marker of clonality. The TCRβ gene is also routinely investigated due to its greater combinatorial diversity. Lack of sufficiently sensitive detection methodology is often a limiting factor in the discrimination between clonal and polyclonal T-cell populations.Aims: The aim of this study was to use high resolution heteroduplex gel and fluorescence GeneScan analysis to screen for TCRγ and TCRβ gene rearrangements respectively in a cohort of B-CLL patients and to ascertain if the clonal rearrangement occurred in B cells or T cells.Methods: B and T cells were purified from peripheral blood from 34 B-CLL patients using a CD19+ or CD3+ magnetic bead system (autoMACS). DNA was extracted from purified B or T cells and the TCRγ and TCRβ genes were amplified by BIOMED-2 multiplex PCR assays (InVivoScribe Technologies). Heteroduplex and GeneScan analysis were then performed to detect clonal TCR gene rearrangments.Results: Clonal TCR gene rearrangements were detected in11/34 (32%) of cases in purified T cell fractions. No clonal TCR gene rearrangements were found in purified B cell fractions. Clonal TCRβ rearrangements were found in 10/34 (29%) and clonal TCRγ in 8/34 (23%). In most instances a weak clonal pattern was observed. Clonal TCR rearrangements were detected in 7 males and 4 females. Five patients had mutated IGHV genes, while the remaining 6 possessed unmutated IGHV genes. Seven patients presented with more advanced clinical stage (Binet B or C), and 8 patients received treatment.Summary/conclusions: These results are in agreement with previous work demonstrating that T-cell clonal/oligoclonal expansions occur frequently in B-CLL patients. However this is the first report to demonstrate that the clonal expansions occur in T cells and not in B cells. In most instances a weak clonal pattern was observed which was probably due to minor clonal T-cell populations. It is possible that T-cell clonality may be associated with a poorer prognosis in this disease category. Of interest, we found that 8/11(73%) patients in our B-CLL sub-group with T-cell expansion also had advanced stage disease and/or unfavourable molecular (IGHV gene usage/mutational status) markers. We are currently investigating the possibility of a specific antigenic stimulus resulting in this clonal T-cell expansion.

Clinical Molecular Diagnosis of T-Cell Receptor Gene Rearrangement in Thai Patients.

Thirteen Thai patients, seven with pathologic diagnosis of T-cell lymphoma, four with clinical and/or pathological suspicion of T-cell lymphoma, one with lymphadenitis and one with chronic hypertrophic tonsillitis, were investigated for T-cell receptor gene rearrangement (TCR-GR) by polymerase chain reaction (PCR). Clonal TCR-GR was demonstrated in each T-cell lymphoma whereas polyclonal TCR-GR was found in the rest of the patients, including the four cases that were suspected of T-cell lymphoma.Aim: To identify T-cell receptor gene rearrangement in malignant lymphoma in Thai patients.Material and method: Thirteen specimens of formalin-fixed, paraffin-embedded tissue were collected from Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University. After conventional morphological evaluation and immunohistochemical studies, DNA in each specimen was extracted from 10μm thick paraffin sections using QIAamp DNA mini kit (QIAGEN) for TCR-GR analysis by multiplex PCR. Two pairs of primers were selected for Vγ11 (VγI), Vγ101(VγIII/IV), Jγ12(Jγ1/2) and Jp12(JPγ1/2). DNA of the four cases suspected of malignant lymphoma were repeated by using IdentiClone™ TCRG Gene Clonality Assay kit (InVivoScribe Technologies).Results: According to the WHO classification (2001), the seven cases of T-cell lymphoma were angioimmunoblastic type (3 cases) and unspecified type (4 cases). All cases showed monoclonal TCR-GR. Only one of the four cases suspected of T-cell lymphoma was doubtful for nasal NK/T-cell lymphoma while the others were suspected clinically. All of these four cases and the two reactive conditions revealed polyclonal TCR-GR. After using IdentiClone™ kit twice, the four cases suspected of T-cell lymphoma still showed polyclonal TCR-GR.Conclusion: The molecular analysis of TCR-GR performed in thirteen cases demonstrated the monoclonal TCR-GR in all seven cases of T-cell lymphoma and polyclonal TCR-GR in the four cases suspected of T-cell lymphoma and the two cases of reactive condition. Therefore, this technique is very useful to confirm the diagnosis of T-cell lymphoma and to provide information for further management in patients suspected of malignant lymphoma.

Primäres zerebelläres T-Zell-Lymphom

Primary central nervous system T-cell lymphomas are rare and have to be differentiated from reactive lesions. It is therefore essential to use all possible tools to establish the diagnosis, including immunohistochemistry, molecular genetic analysis, and/or cytogenetic methods. In this paper we present the case of a primary cerebellar T-cell lymphoma in a 50-year-old man; a clonal T-cell receptor gene rearrangement was documented. After two cycles of methotrexate therapy the patient developed Pneumocystis carinii-induced pneumonia, dying 10 weeks after his diagnosis. The autopsy did not reveal any residual tumour.

Why and how to quantify minimal residual disease in acute lymphoblastic leukemia?

Several studies have demonstrated that monitoring of minimal residual disease (MRD) in childhood and adult acute lymphoblastic leukemia (ALL) significantly correlates with clinical outcome. MRD detection is particularly useful for evaluation of early treatment response and consequently for improved front-line therapy stratification. MRD information is also significant for children undergoing allogeneic hematopoietic stem cell transplantation and those with relapsed ALL. Currently, three highly specific and sensitive methodologies for MRD detection are available, namely multiparameter flow cytometric immunophenotyping, real-time quantitative polymerase chain reaction (RQ-PCR)-based detection of fusion gene transcripts or breakpoints, and RQ-PCR-based detection of clonal immunoglobulin and T-cell receptor gene rearrangements. In this review, characteristics, pitfalls, advantages and disadvantages of each MRD technique are critically discussed. The special emphasis is put on interlaboratory standardization, especially in view of the results obtained within the European collaborative BIOMED-1, BIOMED-2, and Europe Against Cancer projects and recent developments by European Study Group on MRD detection in ALL and EuroFlow Consortium. Standardized MRD techniques form the basis for stratification of patients into the risk groups in new treatment protocols mainly in childhood ALL. Only the results of these studies can answer the question whether MRD-based treatment intervention is associated with improved outcome.

Significantly improved PCR-based clonality testing in B-cell malignancies by use of multiple immunoglobulin gene targets. Report of the BIOMED-2 Concerted Action BHM4-CT98-3936

Polymerase chain reaction (PCR) assessment of clonal immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements is an important diagnostic tool in mature B-cell neoplasms. However, lack of standardized PCR protocols resulting in a high level of false negativity has hampered comparability of data in previous clonality studies. In order to address these problems, 22 European laboratories investigated the Ig/TCR rearrangement patterns as well as t(14;18) and t(11;14) translocations of 369 B-cell malignancies belonging to five WHO-defined entities using the standardized BIOMED-2 multiplex PCR tubes accompanied by international pathology panel review. B-cell clonality was detected by combined use of the IGH and IGK multiplex PCR assays in all 260 definitive cases of B-cell chronic lymphocytic leukemia (n=56), mantle cell lymphoma (n=54), marginal zone lymphoma (n=41) and follicular lymphoma (n=109). Two of 109 cases of diffuse large B-cell lymphoma showed no detectable clonal marker. The use of these techniques to assign cell lineage should be treated with caution as additional clonal TCR gene rearrangements were frequently detected in all disease categories. Our study indicates that the BIOMED-2 multiplex PCR assays provide a powerful strategy for clonality assessment in B-cell malignancies resulting in high Ig clonality detection rates particularly when IGH and IGK strategies are combined.

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.

Human T-cell lines with well-defined T-cell receptor gene rearrangements as controls for the BIOMED-2 multiplex polymerase chain reaction tubes

The BIOMED-2 multiplex polymerase chain reaction (PCR) tubes for analysis of immunoglobulin and T-cell receptor (TCR) gene rearrangements have recently been introduced as a reliable and easy tool for clonality diagnostics in suspected lymphoproliferations. Quality and performance assessment of PCR-based clonality diagnostics is generally performed using human leukemia/lymphoma cell lines as controls. We evaluated the utility of 30 well-defined human T-cell lines for quality performance testing of the BIOMED-2 PCR primers and protocols. The PCR analyses of the TCR loci were backed up by Southern blot analysis. The clonal TCRB, TCRG and TCRD gene rearrangements were analyzed for gene segment usage and for the size and composition of their junctional regions. In 29 out of 30 cell lines, unique clonal TCR gene rearrangements could be easily detected. Besides their usefulness in molecular clonality diagnostics, these cell lines can now be authenticated based on their TCR gene rearrangement profile. This enables their correct use in molecular clonality diagnostics and in other cancer research studies.

Peripheral T-Cell Lymphoma With Extensive Dendritic Cell Network Mimicking Follicular Dendritic Cell Tumor

Peripheral T-cell lymphoma (PTCL) with a nodular pattern of growth is uncommon and may be misdiagnosed initially as a B-cell lymphoma or reactive process. We report a case of a rapidly growing PTCL with a distinctly nodular pattern in an axillary lymph node from an 89-year-old man. Immunohistochemical stains for CD21, CD23, and CD35 highlighted an extensive dendritic cell network that imparted the nodular appearance and, in addition, was associated intimately with the neoplastic cells. The neoplastic cells otherwise had an immunophenotype similar to previously reported cases of PTCL with a nodular pattern and germinal center origin (CD3+, CD4+, CD5+, bcl-6+, CD31+, subset CD10+, subset CXCL13+, and subset CD79a+). Molecular studies confirm a clonal T-cell receptor gene rearrangement. This case emphasizes unusual morphologic features in a PTCL that may be mistaken for follicular lymphoma or a tumor of follicular dendritic cell origin.