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

Peripheral T-cell lymphomas expressing CD30 and CD15 expand the spectrum of anaplastic large cell lymphoma, ALK-negative

Peripheral T-cell lymphomas (PTCL) are morphologically and biologically heterogeneous and a subset expresses CD30, including anaplastic large cell lymphomas (ALCL) and a minority of PTCL, not otherwise specified (PTCL, NOS). ALCL with ALK translocations (ALCL, ALK+) are readily identified by routine diagnostic methods, but differentiating ALCL without ALK translocation (ALCL, ALK-) and PTCL, NOS expressing CD30 (PTCL CD30+) can be challenging. Furthermore, rare PTCL co-express CD30 and CD15 (PTCL CD30+CD15+); some resemble ALCL, ALK- while others resemble classic Hodgkin lymphoma. To explore the relationship between PTCL CD30+CD15+ and ALCL, ALK-, we analysed 19 cases of PTCL with CD30 expression, previously diagnosed as ALCL, ALK- (nine cases) and PTCL CD30+CD15+ (10 cases) for DUSP22/IRF4 rearrangements, coding RNA expression and selected transcriptome analysis using the NanoString nCounter gene expression analysis platform. Unsupervised clustering showed no clear segregation between ALCL, ALK- and PTCL CD30+CD15+. Three cases previously classified as PTCL CD30+CD15+ showed DUSP22/IRF4 rearrangements, favouring a diagnosis of ALCL, ALK-. Our results suggest that cases previously designated PTCL CD30+CD15+, likely fall within the spectrum of ALCL, ALK-; additionally, a subset of ALCL, ALK- with DUSP22/IRF4 rearrangement expresses CD15, consistent with previous reports and expands the immunophenotypic spectrum of this lymphoma subgroup.

Tissue Eosinophilia in B-cell Lymphoma: An Underrecognized Phenomenon

Tissue eosinophilia is seldom reported in B-cell lymphoma. It poses diagnostic challenges and frequently leads to the consideration of other diagnoses, particularly T-cell lymphomas. The scarce literature underscores the need for in-depth studies to enhance awareness and understanding of this phenomenon. We investigated 54 cases of B-cell lymphoma with notable tissue eosinophils, analyzing clinical information, hematoxylin and eosin staining, immunohistochemistry, and PCR-based clonality analysis. Nodal marginal zone lymphoma (NMZL) emerged as the most prevalent type (n=26), followed by B-cell lymphoma, not otherwise specified (n=13), diffuse large B-cell lymphoma (n=10), follicular lymphoma (n=2), chronic lymphocytic leukemia/small lymphocytic lymphoma (n=1), extranodal marginal zone lymphoma (n=1), and primary cutaneous marginal zone lymphoma (n=1). Shared features across different lymphoma types, best exemplified by NMZL, included plasmacytic differentiation (57.7%), increased vascularity (84.6%) with a tendency for perivascular distribution of neoplastic cells, and a tumor microenvironment abundant in T cells and histiocytes; some cases showed increased PD-1-positive cells. These features often raise consideration of angioimmunoblastic T-cell lymphoma. Along with clonality analysis, features supporting the diagnosis of B-cell lymphoma included cytological atypia in B cells rather than T cells, and the lack of follicular dendritic cell meshwork expansion. In addition, diffuse large B-cell lymphoma frequently exhibited interfollicular distribution and monocytoid appearance, indicating the possibility of transformed NMZL. Collectively, tissue eosinophilia can occur in diverse B-cell lymphomas but is most prevalent in tumors with a postgerminal stage of differentiation.

Autophagy-associated immune dysregulation and hyperplasia in a patient with compound heterozygous mutations in ATG9A

ABBREVIATIONS

BCL2: BCL2 apoptosis regulator; BCL10: BCL10 immune signaling adaptor; CARD11: caspase recruitment domain family member 11; CBM: CARD11-BCL10-MALT1; CR2: complement C3d receptor 2; EBNA: Epstein Barr nuclear antigen; EBV: Epstein-Barr virus; FCGR3A; Fc gamma receptor IIIa; GLILD: granulomatous-lymphocytic interstitial lung disease; HV: healthy volunteer; IKBKB/IKB kinase: inhibitor of nuclear factor kappa B kinase subunit beta; IL2RA: interleukin 2 receptor subunit alpha; MALT1: MALT1 paracaspase; MS4A1: membrane spanning 4-domain A1; MTOR: mechanistic target of rapamycin kinase; MYC: MYC proto-oncogene, bHLH: transcription factor; NCAM1: neural cell adhesion molecule 1; NFKB: nuclear factor kappa B; NIAID: National Institute of Allergy and Infectious Diseases; NK: natural killer; PTPRC: protein tyrosine phosphatase receptor type C; SELL: selectin L; PBMCs: peripheral blood mononuclear cells; TR: T cell receptor; Tregs: regulatory T cells; WT: wild-type.

Transitioning From T-Cell Clonality Testing to High-Throughput Sequencing

This commentary highlights the article by Grumaz et al that describes the use of molecular sequencing for fast detection of pathogens directly from blood samples from septic patients.

The utility and limitations of B- and T-cell gene rearrangement studies in evaluating lymphoproliferative disorders

A hallmark of lymphoid malignancies is the presence of a monoclonal lymphocyte population. Monoclonality of B- and T-cell populations can be established through immunoglobulin (IG) or T-cell receptor (TCR) gene rearrangement analysis, respectively. The biological rationale of IG and TCR gene rearrangement analysis is that due to the extensive combinatorial repertoire made possible by V(D)J recombination in lymphocytes, it is unlikely that any substantive lymphocyte population would share the same IG or TCR gene rearrangement pattern unless there is an underlying neoplastic or reactive origin. Modern IG and TCR gene rearrangement analysis is typically performed by polymerase chain reaction (PCR) using commercially available primer sets followed by gel capillary electrophoresis. This process is highly sensitive in the detection of nearly all lymphoid malignancies. Several pitfalls and limitations, both biological and technical, apply to IG/TCR gene rearrangement analysis, but these can be minimised with high quality controls, performance of assays in duplicate, and adherence to strict criteria for interpreting and reporting results. Next generation sequencing (NGS) will likely replace PCR based methods of IG/TCR gene rearrangement analysis but is not yet widespread due to the absence of standardised protocols and multicentre validation.

Expansion of PD1-positive T Cells in Nodal Marginal Zone Lymphoma: A Potential Diagnostic Pitfall

The diagnosis of nodal marginal zone lymphoma (NMZL) can be challenging, with the differential diagnosis including other low-grade B-cell lymphomas, reactive hyperplasia, and even some cases of peripheral T-cell lymphoma (PTCL). PTCL may have a perifollicular growth pattern mimicking NMZL. We and others have noted an atypical distribution of T-follicular helper (TFH) cells in some cases of NMZL. This study was prompted by the diagnosis of NMZL in several cases in which a marked increase of TFH cells, as determined by staining for programmed death-1 (PD1), had prompted suspicion for a diagnosis of PTCL. We analyzed PD1 staining in 48 cases of NMZL to characterize the extent and pattern of the PD1-positive infiltrate. Three main patterns of PD1 staining were identified: follicular pattern (peripheral, n=16; central, n=9; mixed, n=3), diffuse pattern (n=4), and a reduced or normal staining pattern in residual follicles (n=16). A comprehensive analysis of other TFH markers was undertaken in 14 cases with a high content of PD1-positive cells that were confirmed as B-cell lymphoma by clonality analysis. We describe in detail 5 of these cases in which PTCL was an initial consideration. This study illuminates the diverse immunohistochemical patterns encountered in NMZL and highlights a diagnostic pitfall important for diagnostic accuracy.

Human Herpes Virus 6 (HHV-6)-associated Lymphadenitis: Pitfalls in Diagnosis in Benign and Malignant Settings

Human herpes virus 6 (HHV-6) is a member of the β-herpesvirinae subfamily. Most people acquire HHV-6 primary infection early in life and reactivation may occur, most often in immunocompromised individuals, leading to various clinical manifestations. HHV-6 infected cells may be identified in lymph nodes in both reactive and neoplastic conditions. Cases were retrieved from the hematopathology consultation service archives at National Institutes of Health from 2003 to 2017 in which infection by HHV-6 had been documented by immunohistochemical stains to HHV-6 gp60/110 envelope glycoprotein. Five cases of reactive lymphadenitis and 3 cases of lymphoma; 2 angioimmunoblastic T-cell lymphoma and 1 classic Hodgkin lymphoma, positive for HHV-6 were identified. The reactive lymph nodes showed marked paracortical hyperplasia and admixed large atypical lymphoid cells exhibiting pleomorphic nuclei, vesicular chromatin, and prominent eosinophilic intranuclear inclusions. Vascular proliferation and necrosis were also present, raising suspicion of peripheral T-cell lymphoma. The 3 cases of lymphoma showed similar viral inclusions, in addition to the characteristic features diagnostic of the lymphoma. Staining for HHV-6 was positive with a membranous and Golgi pattern and was restricted to cells with evident inclusions on hematoxylin and eosin. HHV-6 infected cells were positive for CD3 and CD4. HHV-6 lymphadenitis can present with morphologic atypia creating a diagnostic pitfall for lymphoma. In such cases, careful attention to the characteristic viral inclusions can lead to immunohistochemical analysis highlighting the replicating virus. In cases of lymphoma, identification of the inclusions is key in detecting the associated infection as well as in avoiding misinterpretation of the lymphoma subtype.

A New and Simple TRG Multiplex PCR Assay for Assessment of T-cell Clonality: A Comparative Study from the EuroClonality Consortium

Supplemental Digital Content is available in the text

T-cell Receptor Gamma (TRG) rearrangements are commonly used to detect clonal lymphoproliferations in hematopathology, since they are rearranged in virtually all T lymphocytes and have a relatively limited recombinatorial repertoire, which reduces the risk of false negative results, at the cost of potential false positivity. We developed an initial one-tube, 2-fluorochrome EuroClonality TRG PCR multiplex (TRG-1T-2F) which was compared to the original 2-tube, 2-fluorochrome EuroClonality/BIOMED-2 TRG PCR (TRG-2T-2F) and a commercial Invivoscribe one-tube, one-fluorochrome kit (IVS-1T-1F) on a series of 239 samples, including both T-cell malignancies and reactive cases. This initial assay yielded discrepant results between the 10 participating EuroClonality laboratories when using 2 fluorochromes, leading to adoption of a final single color EuroClonality strategy (TRG-1T-1F). Compared to TRG-2T-2F, both TRG-1T-1F and IVS-1T-1F demonstrated easier interpretation and a lower risk of false positive from minor peaks in dispersed repertoires. Both generate smaller fragments and as such are likely to be better adapted to analysis of formalin-fixed paraffin-embedded (FFPE) tissue samples. Their differential performance was mainly explained by (i) superposition of biallelic rearrangements with IVS-1T-1F, due to more extensive overlapping of the repertoires and (ii) intentional omission of the TRGJP primer in TRG-1T-1F, in order to avoid the potential risk of confusion of consensus TRG V9-JP normal rearrangements with a pathological clone.

Specific TCR gene rearrangements in mycosis fungoides: does advanced clinical stage show a preference?

AIMS

The relationship between the presence of specific T-cell receptor (TCR) gene rearrangements and clinical stage in mycosis fungoides (MF) has not been studied. We analysed a cohort of patients with a diagnosis of MF to determine the different types of specific TCR gene rearrangements present and their relationship to disease stage.

METHODS

A retrospective chart review was used to select patients with a diagnosis of MF who had a skin biopsy and a positive TCR gene rearrangement study in either blood or tissue and at least 2 years of clinical follow-up.

RESULTS

43 patients were identified and divided into two groups. The first group consisted of 23 patients with early stage disease (IA-IIA) that was either stable or went into partial or complete remission with minimal intervention. None of these patients advanced to late stage disease. The second group consisted of 20 patients who had either late stage disease at diagnosis or progressed to late stage disease at some point in time. In the first group, only 4/23 (17%) patients had a single TCR gene rearrangement in the Vɣ1-8 region. In contrast, the second group had 13/20 (65%) patients with a single TCR gene rearrangement in the Vɣ1-8 region (p=0.002).

CONCLUSION

The presence of a single TCR gene rearrangement in the Vɣ1-8 region could possibly be related to a more advanced stage of MF. However, more comprehensive studies, such as next generation sequencing, with a larger cohort is necessary for a more definitive conclusion.

The Value of T-Cell Receptor γ (TRG) Clonality Evaluation by Next-Generation Sequencing in Clinical Hematolymphoid Tissues

OBJECTIVES

To evaluate feasibility of assessing T-cell receptor γ (TRG) clonality by next-generation sequencing (NGS) in hematolymphoid tissues.

METHODS

We evaluated TRG clonality using NGS and polymerase chain reaction (PCR) assays in blood, bone marrow, and formalin-fixed, paraffin-embedded tissues in 41 archived cases, including 21 benign cases with no history of any lymphoproliferative disorders (LPDs), 16 LPDs (nine mature T-cell neoplasms, seven mature B-cell neoplasms and immune dysregulation-associated LPDs), and four atypical LPDs from 22 females and 19 males with a median age of 58 (range, 9-87) years.

RESULTS

(1) NGS analyzed TRG sequence and peak ratios, and it had a greater sensitivity than PCR. (2) NGS identified small clones, including biallelic or monoallelic, and minimum clonal percentages (range, ~2.4% to ~69%) within all T cells. (3) We provide our strategy and criteria for evaluating NGS results. (4) We describe every case, with definitive evaluation of TRG clonality in 100% cases by NGS.

CONCLUSIONS

TRG clonality evaluation by NGS provides greater clinical utility than PCR.

Molecular assessment of clonality in lymphoid neoplasms

Molecular clonality assays in B- and T-cell lymphoproliferative disorders often provide critical information in establishing a diagnosis of a lymphoproliferative disorder. These assays rely on the unique genetic structures that serve as assay targets, created in the process of generating immunoglobulin and T-cell receptors during B- and T-cell development. Molecular clonality assays are generally used when flow cytometry or immunohistochemistry has not sufficiently clarified the benign or malignant nature of a lymphoid proliferation. Additionally, since molecular clonality assays are tumor specific, they allow the clinician to distinguish recurrences from second tumors, and have the sensitivity to monitor minimal residual disease. In this review, we discuss the principles underlying these tests, the current approaches to clonality testing, some of the pitfalls in their interpretation, and the future applications of next generation sequencing technology to clonality testing.

Resolution of Multifocal Epstein-Barr Virus-Related Smooth Muscle Tumor in a Patient with GATA2 Deficiency Following Hematopoietic Stem Cell Transplantation

We performed allogeneic hematopoietic stem cell transplantation in a patient with GATA2 deficiency and an Epstein-Barr virus (EBV)-related spindle cell tumor involving the liver and possibly bone. He received a matched-related donor transplant with donor peripheral blood stem cells following a myeloablative conditioning regimen. He achieved rapid and high levels of donor engraftment and had complete reversal of the clinical and immunologic phenotype of MonoMAC/GATA2 deficiency and eradication of the EBV tumors after 3 years of follow-up. Thus, allogeneic hematopoietic stem cell transplant results in reconstitution of immunologic function and cure of EBV-associated malignancy in MonoMAC/GATA2 deficiency.

Bone marrow findings in autoimmune lymphoproliferative syndrome with germline FAS mutation

Autoimmune lymphoproliferative syndrome is a rare genetic disorder characterized by defective FAS-mediated apoptosis, autoimmune disease, accumulation of mature T-cell receptor alpha/beta positive, CD4 and CD8 double-negative T cells and increased risk of lymphoma. Despite frequent hematologic abnormalities, literature is scarce regarding the bone marrow pathology in autoimmune lymphoproliferative syndrome. We retrospectively reviewed 3l bone marrow biopsies from a cohort of 240 patients with germline FAS mutations. All biopsies were performed for the evaluation of cytopenias or to rule out lymphoma. Clinical information was collected and morphological, immunohistochemical, flow cytometric and molecular studies were performed. Bone marrow lymphocytosis was the predominant feature, present in 74% (23/31) of biopsies. The lymphoid cells showed several different patterns of infiltration, most often forming aggregates comprising T cells in 15 cases, B cells in one and a mixture of T and B cells in the other seven cases. Double-negative T cells were detected by immunohistochemistry in the minority of cases (10/31; 32%); significantly, all but one of these cases had prominent double-negative T-lymphoid aggregates, which in four cases diffusely replaced the marrow space. One case showed features of Rosai-Dorfman disease, containing scattered S-100⁺ cells with emperipolesis and double-negative T cells. No clonal B or T cells were detected by polymerase chain reaction in any evaluated cases. Classical Hodgkin lymphoma was identified in three cases. Our results demonstrate that infiltrates of T cells, or rarely B cells, can be extensive in patients with autoimmune lymphoproliferative syndrome, mimicking lymphoma. A multi-modality approach, integrating clinical, histological, immunohistochemical as well as other ancillary tests, can help avoid this diagnostic pitfall. This study is registered at Clinicaltrials.gov ID # NCT00001350.

Primary CNS T-cell Lymphomas: A Clinical, Morphologic, Immunophenotypic, and Molecular Analysis

Primary central nervous system (CNS) lymphomas are relatively rare with the most common subtype being diffuse large B-cell lymphoma. Primary CNS T-cell lymphomas (PCNSTL) account for <5% of CNS lymphomas. We report the clinical, morphologic, immunophenotypic, and molecular characteristics of 18 PCNSTLs. Fifteen cases were classified as peripheral T-cell lymphoma, not otherwise specified, 2 of which were of γδ T-cell derivation and 1 was TCR silent; there was 1 anaplastic large cell lymphoma, ALK-positive and 2 anaplastic large cell lymphoma, ALK-negative. Median age was 58.5 years (range, 21 to 81 y), with an M:F ratio of 11:7. Imaging results showed that 15 patients had supratentorial lesions. Regardless of subtype, necrosis and perivascular cuffing of tumor cells were frequently observed (11/18 cases). CD3 was positive in all cases but 1; 10/17 were CD8-positive, and 5/17 were CD4-positive. Most cases studied had a cytotoxic phenotype with expression of TIA1 (13/15) and granzyme-B (9/13). Polymerase chain reaction analysis of T-cell receptor γ rearrangement confirmed a T-cell clone in 14 cases with adequate DNA quality. Next-generation sequencing showed somatic mutations in 36% of cases studied; 2 had >1 mutation, and none showed overlapping mutations. These included mutations in DNMT3A, KRAS, JAK3, STAT3, STAT5B, GNB1, and TET2 genes, genes implicated previously in other T-cell neoplasms. The outcome was heterogenous; 2 patients are alive without disease, 4 are alive with disease, and 6 died of disease. In conclusion, PCNSTLs are histologically and genomically heterogenous with frequent phenotypic aberrancy and a cytotoxic phenotype in most cases.

Epstein-Barr virus-associated inflammatory pseudotumor presenting as a colonic mass

Epstein-Barr virus (EBV)-positive inflammatory pseudotumor (IPT) commonly involves spleen and liver and has only rarely been reported in the gastrointestinal (GI) tract. The spindle cells may express myofibroblastic or follicular dendritic cell markers. We report a challenging case of EBV-positive IPT arising in the ascending colon. The lesion was composed of spindle cells positive for smooth muscle actin but negative for all follicular dendritic cell markers tested and was associated with an exuberant lymphoid proliferation containing reactive follicles, abundant plasma cells, and small lymphocytes. We further discuss pitfalls for possible misdiagnosis as ALK-positive inflammatory myofibroblastic tumor, IgG4-related disease, and peripheral T-cell lymphoma. Our case represents the first EBV-positive inflammatory pseudotumor of the GI tract in the Western literature. Awareness of this rare entity in GI tract is essential for correct diagnosis and appropriate patient management.

T-cell clonality assessment by next-generation sequencing improves detection sensitivity in mycosis fungoides

BACKGROUND

T-cell receptor (TCR) clonality assessment is a principal diagnostic test in the management of mycosis fungoides (MF). However, current polymerase chain reaction-based methods may produce ambiguous results, often because of low abundance of clonal T lymphocytes, resulting in weak clonal peaks that cannot be size-resolved by contemporary capillary electrophoresis (CE).

OBJECTIVE

We sought to determine if next-generation sequencing (NGS)-based detection has increased sensitivity for T-cell clonality over CE-based detection in MF.

METHODS

Clonality was determined by an NGS-based method in which the TCR-γ variable region was polymerase chain reaction amplified and the products sequenced to establish the identity of rearranged variable and joining regions.

RESULTS

Of the 35 MF cases tested, 29 (85%) showed a clonal T-cell rearrangement by NGS, compared with 15 (44%) by standard CE detection. Three patients with MF had follow-up testing that showed identical, clonal TCR sequences in subsequent skin biopsy specimens.

LIMITATIONS

Clonal T-cell populations have been described in benign conditions; evidence of clonality alone, by any method, is not sufficient for diagnosis.

CONCLUSION

TCR clonality assessment by NGS has superior sensitivity compared with CE-based detection. Further, NGS enables tracking of specific clones across multiple time points for more accurate identification of recurrent MF.

Lymphomatoid granulomatosis--a single institute experience: pathologic findings and clinical correlations

Lymphomatoid granulomatosis (LYG) is a rare angiocentric and angiodestructive Epstein-Barr virus (EBV)-associated B-cell lymphoproliferative disorder. It is hypothesized that these patients have dysregulated immune surveillance of EBV. We reviewed the biopsies of 55 patients with LYG who were referred for a prospective trial at the National Cancer Institute (1995 to 2010) and evaluated the histologic, immunohistochemical, in situ hybridization, and molecular findings of these biopsies in conjunction with clinical information. Grading of the lesions was based on morphologic features and the number of EBV-positive B cells. The median age was 46 years (M:F 2.2:1). Clinically, all patients had lung involvement (100%), with the next most common site being the central nervous system (38%). No patient had nodal or bone marrow disease. All patients had past EBV exposure by serology but with a low median EBV viral load. We reviewed 122 biopsies; the most common site was lung (73%), followed by skin/subcutaneous tissue (17%); other sites included kidney, nasal cavity, gastrointestinal tract, conjunctiva, liver, and adrenal gland. Histologically, the lesions showed angiocentricity, were rich in T cells, had large atypical B cells, and were positive for EBV. Grading was performed predominantly on the lung biopsy at diagnosis; they were distributed as follows: LYG grade 1 (30%), grade 2 (22%), and grade 3 (48%). Necrosis was seen in all grades, with a greater degree in high-grade lesions. Immunoglobulin gene rearrangement studies were performed, and a higher percentage of clonal rearrangements were seen in LYG grade 2 (50%) and grade 3 (69%) as compared with grade 1 (8%). LYG is a distinct entity that can usually be differentiated from other EBV-associated B-cell lymphoproliferative disorders on the basis of the combination of clinical presentation, histology, and EBV studies. Grading of these lesions is important because it dictates the treatment choice.

Chromothriptic cure of WHIM syndrome

Chromothripsis is a catastrophic cellular event recently described in cancer in which chromosomes undergo massive deletion and rearrangement. Here, we report a case in which chromothripsis spontaneously cured a patient with WHIM syndrome, an autosomal dominant combined immunodeficiency disease caused by gain-of-function mutation of the chemokine receptor CXCR4. In this patient, deletion of the disease allele, CXCR4(R334X), as well as 163 other genes from one copy of chromosome 2 occurred in a hematopoietic stem cell (HSC) that repopulated the myeloid but not the lymphoid lineage. In competitive mouse bone marrow (BM) transplantation experiments, Cxcr4 haploinsufficiency was sufficient to confer a strong long-term engraftment advantage of donor BM over BM from either wild-type or WHIM syndrome model mice, suggesting a potential mechanism for the patient's cure. Our findings suggest that partial inactivation of CXCR4 may have general utility as a strategy to promote HSC engraftment in transplantation.

Primary central nervous system extranodal NK/T cell lymphoma, nasal type, with antecedent hemophagocytic syndrome in a child

Primary central nervous system (CNS) extranodal natural killer (NK)/T-cell lymphoma, nasal type (NKTCL), is an exceedingly uncommon entity. Here, we present a case of CNS NKTCL that manifested initially as hemophagocytic syndrome 4 months earlier in a 13-year-old girl. Histological examination revealed the cerebellum mass was composed of large-sized and atypical tumor cells, with an angiocentric and angiodestructive growth pattern and prominent necrosis. The tumor cells exhibited marked pleomorphism with conspicuous nucleoli and prominent mitotic activity. Immunohistochemical staining showed the tumor cells were positive for CD45, CD2, CD3ε, CD30, CD43, CD56, and granzyme B. Epstein-Barr virus--encoded ribonucleic acid was expressed in almost all of the nuclei of the lymphoma cells. The T-cell receptor γ chain gene rearrangement study showed no evidence of a clonal rearrangement. The patient was treated with etoposide and dexamethasone and died a few days after the operation. As far as we know, this case is the 1st pediatric and female patient of primary CNS NKTCL with antecedent hemophagocytic syndrome, which highlights the clinical data and is helpful for the diagnosis of this tumor.

GATA2 deficiency-associated bone marrow disorder differs from idiopathic aplastic anemia

Germ-line GATA2 gene mutations, leading to haploinsufficiency, have been identified in patients with familial myelodysplastic syndrome/acute myeloid leukemia, monocytopenia and mycobacterial infections, Emberger syndrome, and dendritic cell, monocyte, B-, and NK-cell deficiency. GATA2 mutations have also been reported in a minority of patients with congenital neutropenia and aplastic anemia (AA). The bone marrow (BM) from patients with GATA2 deficiency is typically hypocellular, with varying degrees of dysplasia. Distinguishing GATA2 patients from those with AA is critical for selecting appropriate therapy. We compared the BM flow cytometric, morphologic, and cytogenetic features of 28 GATA2 patients with those of 32 patients being evaluated for idiopathic AA. The marrow of GATA2 patients had severely reduced monocytes, B cells, and NK cells; absent hematogones; and inverted CD4:CD8 ratios. Atypical megakaryocytes and abnormal cytogenetics were more common in GATA2 marrows. CD34(+) cells were comparably reduced in GATA2 and AA. Using these criteria, we prospectively identified 4 of 32 patients with suspected AA who had features suspicious for GATA2 mutations, later confirmed by DNA sequencing. Our results show that routine BM flow cytometry, morphology, and cytogenetics in patients who present with cytopenia(s) can identify patients for whom GATA2 sequencing is indicated.

Peripheral T-cell lymphomas of follicular T-helper cell derivation with Hodgkin/Reed-Sternberg cells of B-cell lineage: both EBV-positive and EBV-negative variants exist

Peripheral T-cell lymphomas (PTCLs) are functionally and morphologically complex. Epstein-Barr virus (EBV)-positive B cells have been reported in angioimmunoblastic T-cell lymphoma (AITL) and other PTCLs and may mimic Hodgkin/Reed-Sternberg (HRS) cells, but EBV-negative HRS-like B cells have not been described. We wished to assess the nature of the PTCL associated with HRS-like cells and to determine whether EBV-negative HRS-like cells may be seen. We identified 57 PTCL cases reported as containing HRS-like cells. These included 32 AITL, 19 PTCL, not otherwise specified (NOS), 3 PTCL-NOS, follicular variant, 1 PTCL-NOS, T-zone variant, and 2 adult T-cell leukemia/lymphoma cases. All patients were adults with a median age of 63 and presented with lymphadenopathy. The male:female ratio was 31:26 (1.2:1). Clonal TRG rearrangement was detected in 46/53 cases. Six of 38 cases had a concomitant clonal immunoglobulin gene rearrangement. In 52/57 cases the HRS cells were positive for EBV. Five cases, 3 classified as AITL and 2 as PTCL-NOS, follicular variant, contained HRS-like cells negative for EBV. All PTCLs with EBV-negative HRS cells had a T follicular helper cell immunophenotype. The neoplastic T cells expressed CD3, CD4, and PD-1 and formed rosettes around the HRS-like cells. The HRS-like cells were positive for CD20 (variable intensity), PAX5, CD30, and CD15 (4/5). We conclude that both EBV-positive and EBV-negative HRS-like B cells may occur in the background of PTCL; caution is needed to avoid misdiagnosis as classical Hodgkin lymphoma. The close interaction between the HRS-like cells and the rosetting PD-1-positive T cells suggests a possible pathogenetic role in this phenomenon and provides new insights into the abnormal B-cell proliferations that occur in the context of TFH malignancies.

Early onset, EBV− PTLD in pediatric liver-small bowel transplantation recipients: a spectrum of plasma cell neoplasms with favorable prognosis

Five cases of EBV− PTLD in pediatric recipients of combined liver and small bowel allografts are reported. The lesions were plasma cell neoplasms that resolved completely after minimal treatment.

Aberrant T-cell antigen expression in classical Hodgkin lymphoma is associated with decreased event-free survival and overall survival

Hodgkin/Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL) rarely express T-cell-associated antigens (TCA), but the clinical significance of this finding is uncertain. Fifty cHLs expressing any TCA on the HRS cells (TCA-cHL) were identified in two cohorts (National Cancer Institute, n = 38; Basel, n = 12). Diagnostic pathology data were examined in all cases with additional T-cell receptor γ rearrangements (TRG@) polymerase chain reaction (PCR) in a subset of cases. The outcome data were compared with a cohort of cHLs negative for TCA (n = 272). Primary end points examined were event-free survival (EFS) and overall survival (OS). The median age in the TCA-cHL group was 40 years (range, 10-85 years). Seventy percent presented in low stage (stage I/II) at presentation with nodular sclerosis (NS) histology predominating in 80% of cases. Among the TCA, CD4 and CD2 were most commonly expressed, seen in 80.4% and 77.4% of cases, respectively. TRG@ PCR was negative for clonal rearrangements in 29 of 31 cases. During a median follow up of 113 months, TCA expression predicted shorter OS (adjusted hazard ratio [HRadj] = 3.32 [95% confidence interval (CI): 1.61, 6.84]; P = .001) and EFS (HRadj = 2.55 [95% CI: 1.45, 4.49]; P = .001). TCA-cHL often display NS histology, lack T-cell genotype, and are independently associated with significantly shorter OS and EFS compared with TCA-negative cHLs.

Nodal involvement by cutaneous CD30-positive T-cell lymphoma mimicking classical Hodgkin lymphoma

An association between classical Hodgkin lymphoma (cHL) and mycosis fungoides (MF) or lymphomatoid papulosis has been reported in the literature. However, there can be considerable morphologic and immunophenotypic overlap between cHL and nodal involvement by CD30-positive T-cell lymphoproliferative disorders (CD30-T-LPD). To examine this potential association, biopsies from patients with a history of MF or primary cutaneous CD30-T-LPD and lymph node biopsies reported as either CD30-positive T-cell lymphoma (TCL) with Hodgkin-like cells or cHL were retrieved from the authors' institution. Of 11 cases identified, 10 were considered CD30-positive TCL with Hodgkin-like cells, whereas 1 was confirmed as cHL upon review. Five cases originally diagnosed as cHL were revised as CD30-positive TCL. Cases of CD30-positive TCL with Hodgkin-like cells showed a male predominance (M:F, 4:1) with a median age of 53 years (range, 44 to 72 y). Nearly all patients (9/10) initially presented with skin lesions. In 7/10 patients the draining lymph node was involved, whereas in 3 cases this could not be confirmed. Tumor cells morphologically resembled Hodgkin/Reed-Sternberg cells; they were uniformly strongly positive for CD30, and CD15 was expressed in 9/10 (90%) cases. A T-cell derivation was confirmed by T-cell antigen expression (7/10) and clonal rearrangement of T-cell receptor genes (9/10). In 3 cases a common T-cell clone was identified in skin and lymph node. B-cell markers (CD20/PAX5) were consistently negative. In 1 case the diagnosis of cHL followed by lymphomatoid papulosis was confirmed, with Hodgkin/Reed-Sternberg cells expressing PAX5, CD30, and CD15. In situ hybridization studies for Epstein Barr virus were negative. We show that cHL is less often associated with MF and primary cutaneous CD30-T-LPD than previously thought and that the coexpression of CD30 and CD15 in these TCLs may lead to a mistaken diagnosis of cHL.

Flow cytometric immunophenotypic assessment of T-cell clonality by Vβ repertoire analysis: detection of T-cell clonality at diagnosis and monitoring of minimal residual disease following therapy

Flow cytometric T-cell receptor (TCR)-V(β) repertoire analysis (TCR-V(β)-R) is a sensitive method for detection of T-cell clonality; however, no uniform approach exists to define clonality in neoplastic T cells. TCR-V(β)-R was evaluated in patients with a diagnosis of T-cell neoplasia in initial diagnostic specimens from 41 patients and for minimal residual disease (MRD) monitoring in 61 sequential samples from 14 patients with mature T-cell neoplasia. Gating strategies and criteria for detection of T-cell clonality were determined. In all 41 initial specimens, T-cell clonality was demonstrated via TCR-V(β)-R. The frequency of V(β) usage was consistent with random neoplastic transformation of TCR-V(β) subsets. MRD was successfully detected in follow-up samples from all 14 patients evaluated, Furthermore, MRD after therapy was quantitated in 48 peripheral blood specimens. TCR-V(β)-R analysis is a sensitive method for detection of T-cell clonality and is useful for diagnosis and MRD detection in multiple specimen types.

Myelodysplasia in autosomal dominant and sporadic monocytopenia immunodeficiency syndrome: diagnostic features and clinical implications

A novel, genetic immunodeficiency syndrome has been recently described, herein termed "MonoMAC". It is characterized by severe circulating monocytopenia, NK- and B-lymphocytopenia, severe infections with M. avium complex (MAC), and risk of progression to myelodysplasia/acute myelogenous leukemia. Detailed bone marrow analyses performed on 18 patients further define this disorder. The majority of patients had hypocellular marrows with reticulin fibrosis and multilineage dysplasia affecting the myeloid (72%), erythroid (83%) and megakaryocytic (100%) lineages. Cytogenetic abnormalities were present in 10 of 17 (59%). Despite B-lymphocytopenia, plasma cells were present but were abnormal (e.g. CD56(+)) in nearly half of cases. Increased T-cell large granular lymphocyte populations were present in 28% of patients. Chromosomal breakage studies, cell cycle checkpoint functions, and sequencing of TERT and K-RAS genes revealed no abnormalities. MonoMAC appears to be a unique, inherited syndrome of bone marrow failure. We describe distinctive bone marrow features to help in its recognition and diagnosis. (Clinicaltrials.gov identifiers: NCT00018044, NCT00923364, NCT01212055).

Assay design affects the interpretation of T-cell receptor gamma gene rearrangements: comparison of the performance of a one-tube assay with the BIOMED-2-based TCRG gene clonality assay

Interpretation of capillary electrophoresis results derived from multiplexed fluorochrome-labeled primer sets can be complicated by small peaks, which may be incorrectly interpreted as clonal T-cell receptor-γ gene rearrangements. In this report, different assay designs were used to illustrate how design may adversely affect specificity. Ten clinical cases, with subclonal peaks containing one of the two infrequently used joining genes, were identified with a tri-color, one-tube assay. The DNA was amplified with the same NED fluorochrome on all three joining primers, first combined (one-color assay) and then amplified separately using a single NED-labeled joining primer. The single primer assay design shows how insignificant peaks could easily be wrongly interpreted as clonal T-cell receptor-γ gene rearrangements. Next, the performance of the one-tube assay was compared with the two-tube BIOMED-2-based TCRG Gene Clonality Assay in a series of 44 cases. Whereas sensitivity was similar between the two methods (92.9% vs. 96.4%; P = 0.55), specificity was significantly less in the BIOMED-2 assay (87.5% vs. 56.3%; P = 0.049) when a 2× ratio was used to define clonality. Specificity was improved to 81.3% by the use of a 5× peak height ratio (P = 0.626). These findings illustrate how extra caution is needed in interpreting a design with multiple, separate distributions, which is more difficult to interpret than a single distribution assay.

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.

Cytotoxic peripheral T cell lymphoma arising in a patient with nodular lymphocyte predominant Hodgkin lymphoma: a case report

In this paper, we describe a case of nodular lymphocyte predominant Hodgkin lymphoma with the subsequent development of a peripheral T cell lymphoma. This case is unusual in that the sheets of atypical and small to intermediate-sized T cells in the diffuse component were CD8 positive and expressed cytotoxic proteins. The diagnosis of peripheral T cell lymphoma was supported by the demonstration of a clonal T cell receptor beta chain gene rearrangement by Southern blot analysis. Peripheral T cell lymphoma with a cytotoxic phenotype is a rare entity with an aggressive clinical behavior. As such, this report emphasizes the need to consider a diagnosis of coexisting peripheral T cell lymphoma in cases of nodular lymphocyte predominant Hodgkin lymphoma with atypical features, such as few or poorly defined B cell macronodules and diffuse T cell areas. The examination of both T cell receptor gamma and beta chain gene rearrangements should be performed to confirm such cases.

Interleukin-21 induces the differentiation of human umbilical cord blood CD34-lineage- cells into pseudomature lytic NK cells

Background

Umbilical cord blood (UCB) is enriched with transplantable CD34⁺ cells. In addition to CD34-expressing haematopoietic stem cells (HSC), human UCB contains a rare population of CD34^-lineage^- cells endowed with the ability to differentiate along the T/NK pathway in response to interleukin (IL)-15 and a stromal cell support. IL-21 is a crucial regulator of NK cell function, whose influence on IL-15-induced differentiation of CD34^-lineage^- cells has not been investigated previously. The present study was designed and conducted to address whether IL-21 might replace the stromal cell requirements and foster the IL-15-induced NK differentiation of human UCB CD34^-lineage^- cells.

Results

CD34^-lineage^- cells were maintained in liquid culture with Flt3-L and SCF, with the addition of IL-15 and IL-21, either alone or in combination. Cultures were established in the absence of feeder cells or serum supplementation. Cytokine-treated cells were used to evaluate cell surface phenotype, expression of molecular determinants of lymphoid/NK cell differentiation, secretion of IFN-γ, GM-CSF, TNF-α and CCL3/MIP-1α, and cytolytic activity against NK-sensitive tumour cell targets. CD34^-lineage^- cells proliferated vigorously in response to IL-15 and IL-21 but not to IL-21 alone, and up-regulated phosphorylated Stat1 and Stat3 proteins. CD34^-lineage^- cells expanded by IL-21 in combination with IL-15 acquired lymphoid morphology and killer-cell immunoglobulin-like receptor (KIR)^-CD56⁺CD16^-/+ phenotype, consistent with pseudo-mature NK cells. IL-21/IL-15-differentiated cells expressed high levels of mRNA for Bcl-2, GATA-3 and Id2, a master switch required for NK-cell development, and harboured un-rearranged TCRγ genes. From a functional standpoint, IL-21/IL-15-treated cells secreted copious amounts of IFN-γ, GM-CSF and CCL3/MIP-1α, and expressed cell surface CD107a upon contact with NK-sensitive tumour targets, a measure of exocytosis of NK secretory granules.

Conclusion

This study underpins a novel role for IL-21 in the differentiation of pseudo-mature lytic NK cells in a synergistic context with IL-15, and identifies a potential strategy to expand functional NK cells for immunotherapy.

The frequency of immunoglobulin heavy chain gene and T-cell receptor gamma-chain gene rearrangements and Epstein-Barr virus in ALK+ and ALK- anaplastic large cell lymphoma and other peripheral T-cell lymphomas

We previously identified a relatively high frequency of B-cell proliferations along with simultaneous T-cell receptor gamma-chain gene (TRG) and immunoglobulin heavy chain gene (IGH) rearrangements in a series of angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma, unspecified. Here, we report on a series of 74 peripheral T-cell lymphoma (PTCL) cases composed entirely of specific PTCL subtypes, including 28 cases of ALK+ anaplastic large-cell lymphoma (ALCL), 35 cases of ALK- ALCL, and 11 cases that represent other specific PTCL subtypes. We performed IGH and TRG gene rearrangement studies and in situ hybridization for Epstein-Barr virus (EBV) to determine the frequency of IGH clonality and to investigate the relationship between EBV, clonality, and associated B-cell proliferations. Using BIOMED-2 PCR assays, we detected TRG clones in 64 of 74 (86%) cases and IGH clones in 6 of 74 (8%) cases, with all IGH-positive cases exhibiting a concurrent TRG clone. Despite the detection of occasional IGH clones, there was no correlation between IGH clonality and EBV, and B-cell proliferations were not identified in any of the cases. These findings suggest that other factors contribute to IGH clonality and demonstrate that, in the absence of an associated B-cell proliferation, IGH clonality occurs infrequently (8%) in specific PTCL subtypes.

Extranodal marginal zone lymphoma of the dura mater with IgH/MALT1 translocation and review of literature

Primary central nervous system lymphoma (PCNSL) is an extranodal non-Hodgkin lymphoma involving brain, intraocular structures and spinal cord, without evidence of systemic disease. The majority of PCNSLs are diffuse large B-cell type. We encountered a rare case of primary dural marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) with extension into the brain in a 59-year-old man. A magnetic resonance imaging scan showed a 22-mm tumor located in the left posterior temporal lobe extending from the dura. Histopathology revealed a lymphoplasmacytic infiltration of the dura and the brain parenchyma in a perivascular pattern. Immunohistochemical and in situ hybridization studies showed a B-cell phenotype with kappa light chain restriction. Fluorescent in situ hybridization study showed a t(14;18)(q32;q21) with immunoglobulin heavy-chain/MALT1 fusion. The molecular study for immunoglobulin heavy-chain gene rearrangement by polymerase chain reaction showed a clonal gene rearrangement.

Analysis of T-cell clonality using laser capture microdissection and high-resolution microcapillary electrophoresis

Identification of clonal lymphocytic populations by polymerase chain reaction may be difficult in cases with scant cellular infiltrates or those with a heterogeneous population of cells. Here, we assessed the diagnostic utility of laser capture microdissection (LCM) and high-resolution microcapillary electrophoresis in the analysis of clonality of small biopsy specimens. Clonality was determined in 24 cases: five reactive tonsils, five reactive lymph nodes, six inflammatory skin lesions, and eight T-cell lymphomas. CD3-positive T lymphocytes were captured by LCM from paraffinized immunohistochemically stained sections. Genomic DNA was analyzed for T-cell receptor-gamma gene rearrangement by polymerase chain reaction followed by high-resolution microcapillary electrophoresis with the DNA 500 LabChip and the Agilent Bioanalyzer. In the reactive specimens, T-cell receptor-gamma polymerase chain reaction revealed monoclonal bands when 10 to 1000 cells were captured. This pattern changed to polyclonal when higher numbers of cells were microdissected (2000 to 10,000 cells). In contrast, lymphoma cells were consistently monoclonal whether low or high numbers were microdissected. Microcapillary electrophoresis coupled with LCM facilitated clonality analysis in equivocal cases. In two of eight lymphoma cases, LCM revealed diagnostic monoclonal bands, whereas routine T-cell receptor-gamma assessment of whole tissue sections with 10% polyacrylamide gel electrophoresis demonstrated only minor clonal bands. We conclude that clonality determined by LCM is cell number-dependent. Biopsy specimens containing low numbers of reactive polyclonal T cells may produce pseudomonoclonal bands and therefore should be interpreted with great caution.

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.

A novel method for interpretation of T-cell receptor gamma gene rearrangement assay by capillary gel electrophoresis based on normal distribution

T-cell receptor gamma (TRG) gene rearrangement status is useful for the differential diagnosis of T-cell lesions. The BIOMED-2 protocol that uses two sets of Jgamma and four sets of Vgamma primers in a multiplex, two-tube reaction followed by capillary gel electrophoresis is emerging as a standard assay for this application. Here, we report a computer-aided method to evaluate the significance of a peak in this TRG clonality assay. A best-fit normal distribution (ND) curve and the chi(2) error for each peak are used to determine whether a peak is significantly taller than the background (cutoff for Vgamma(1-8) is 1). Eighty clinical samples that have been previously analyzed by a GC-clamped primer polymerase chain reaction/denaturing gradient gel electrophoresis assay were reanalyzed with the BIOMED-2 assay and scored by the ND method and four previously published methods: relative peak height (RPH), relative peak ratio (RPR), height ratio (HR), and peak height ratio (Rn). A greater than 90% concordance rate was observed between RPH and ND analysis, whereas RPR, Rn, and HR had a lower threshold to call a peak positive. The advantage of the ND method is that it is more objective, reproducible, and can be automated.

Are clonal T-cell large granular lymphocytes to blame for unexplained haematological abnormalities?

Abnormalities diagnosed on routine blood work, such as mild neutropenia, anaemia, thrombocytopenia and relative lymphocytosis, often have obscure aetiologies. A series of 30 patients were evaluated for various unexplained haematological abnormalities between 1997 and 2005, and found to have circulating monoclonal T-cell large granular lymphocytes (T-LGL). These patients fit the diagnosis of T-cell clonopathy of unknown significance (TCUS), which may represent a clinical spectrum of clonal T-LGL proliferation. Our patients were characterised by a complete absence of severe neutropenia (<0.5 x 10(9)/l), absence of recurrent neutropenic infection (0%), negative rheumatoid serology (0%) and a low incidence of constitutional symptoms (20%). This overall asymptomatic clinical presentation appeared to be different from other previously reported series of TCUS or T-LGL leukaemia who typically had symptomatology and required treatment. Our series of 30 patients represented the benign end of the spectrum of clonal T-LGL proliferation, and might reflect diagnosis at earlier stages of the condition relative to other reported series. TCUS may be a heterogeneous and under-diagnosed condition. This study further broadens our understanding of the clinical and laboratory manifestations of indolent clonal T-cell proliferation, and raises our awareness of this condition. We suggest that TCUS should be considered in the diagnostic evaluation of unexplained haematological problems.

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.

Capillary electrophoresis and the clinical laboratory

Over the past 15 years, CE as an analytical tool has shown great promise in replacing many conventional clinical laboratory methods, such as electrophoresis and HPLC. CE's appeal was that it was fast, used very small amounts of sample and reagents, was extremely versatile, and was able to separate large and small analytes, whether neutral or charged. Because of this versatility, numerous methods have been developed for analytes that are of clinical interest. Other than molecular diagnostic and forensic laboratories CE has not been able to make a major impact in the United States. In contrast, in Europe and Japan an increasing number of clinical laboratories are using CE. Now that automated multicapillary instruments are commercially available along with cost-effective test kits, CE may yet be accepted as an instrument that will be routinely used in the clinical laboratories. This review will focus on areas where CE has the potential to have the greatest impact on the clinical laboratory. These include analyses of proteins found in serum and urine, hemoglobin (A1c and variants), carbohydrate-deficient transferrin, forensic and therapeutic drug screening, and molecular diagnostics.

Comparative investigations of T cell receptor gamma gene rearrangements in frozen and formalin-fixed paraffin wax-embedded tissues by capillary electrophoresis

AIM

To compare clonal T cell receptor gamma (TCRgamma) gene rearrangements in frozen and formalin-fixed paraffin wax-embedded (FFPE) tissue, using capillary electrophoresis for use in diagnostics, as T cell lymphomas may be difficult to diagnose by conventional methods.

METHODS

The DNA for PCR was extracted from frozen and FFPE tissue, cell lines and blood. PCR primers Vgamma1-8, Vgamma9, Vgamma10 or Vgamma11 (5' end labelled) combined with a mixture of JgammaP1/JgammaP/JgammaP2/Jgamma2 (unlabelled) were used. Monoclonal cases were sequenced and clonality, reproducibility, sensitivity and specificity analyses were carried out.

RESULTS

In all cases the molecular test was found to be in agreement with the histological diagnosis. Discrepancies were found between frozen and FFPE tissue in 18 of 56 (32%) tests. The method was highly reproducible. The sensitivity was found to be 0.5% for cell lines and 1% for patient specimens and the specificity 100%. The junctional region between the Vgamma and Jgamma segments was specific for each patient.

CONCLUSIONS

Capillary electrophoresis of PCR products from frozen and FFPE tissue is suitable for detecting clonal TCRgamma gene rearrangements. It is important, however, to correlate the results with conventional morphological and immunohistochemical studies.

Rapid detection of clonal T-cell receptor-beta gene rearrangements in T-Cell lymphomas using the LightCycler-polymerase chain reaction with DNA melting curve analysis

Various molecular methods have been developed to diagnose clonal T-cell receptor (TCR) gene rearrangements in clinical samples. Most polymerase chain reaction strategies for detecting clonal TCR gene rearrangements rely on either gel or capillary electrophoresis. However, a cumbersome manual transfer step separates amplification from analysis. Recently, we developed a novel polymerase chain reaction assay using the LightCycler system to detect clonal immunoglobulin heavy chain gene rearrangement. In the current study, we extend this work to include the TCR. We report that clonal TCR-beta (TCR-beta) gene rearrangements can be detected in less than 1 hour after preparing the DNA by measuring DNA melting immediately after amplification in a single closed capillary tube. We retrospectively studied 52 fresh-frozen tissue samples from patients clinically suspected of T-cell malignancy. A clonal TCR-beta gene rearrangement was detected in 14 samples by DNA melting curve analysis. When DNA melting was compared to the gold standard methods of Southern blot or denaturing gradient gel electrophoresis, it achieved a sensitivity equal to 71% and a specificity equal to 94%. We also compared melting curve analysis and polyacrylamide gel electrophoresis: melting curve analysis reached a sensitivity equal to 100% and a specificity equal to 97%. We conclude that DNA melting curve analysis in the LightCycler system has potential for clinical use as a new, ultra-fast method for the initial diagnosis of clonal TCR-beta gene rearrangements.

A comparison of multiplex and monoplex T-cell receptor gamma PCR

T-cell receptor gamma (TCRgamma) PCR is often used to detect clonal T-cell populations. Because TCRgamma contains a limited number of variable (Vgamma) and joining (Jgamma) regions, a small number of PCR primers can be used to assess T-cell clonality. The seven primers used in the current study were described previously and were split into 2 or 3 multiplex primer sets. In this study, a single 7-primer multiplex (7-plex) PCR reaction was compared with all 12 possible monoplex primer combinations on 18 samples previously analyzed for T-cell receptor rearrangements by TCRbeta Southern blot and/or TCRgamma PCR followed by temporal temperature gradient gel electrophoresis. Using fluorescent Vgamma-region primers, unlabeled Jgamma-region primers, and capillary electrophoresis, we show all TCRgamma rearrangements seen by 7-plex PCR on known positive samples were seen following monoplex PCR. However, additional TCRgamma gene rearrangements were seen in monoplex PCR reactions that were not seen in the 7-plex PCR reactions. Monoplex but not 7-plex PCR of known negative samples occasionally showed TCRgamma gene rearrangements, often with less frequently used Vgamma and Jgamma-region primers, and may have represented false positive results. In summary, the single 7-plex PCR reaction correctly identified specimens with TCRgamma clonal populations and represents an improvement over existing assays that use these same primers split into several smaller multiplex reactions. Monoplex PCR has no advantage over multiplex PCR and has the potential to lead to false positive results.