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

Analysis of immunoglobulin and T cell receptor gene rearrangement in the bone marrow of lymphoid neoplasia using BIOMED-2 multiplex polymerase chain reaction

The evaluation of bone marrow (BM) involvement is important for diagnosis and staging in patients with lymphoid neoplasia. We evaluated of immunoglobulin (Ig) and/or T-cell receptor (TCR) gene rearrangements in the BM using the standardized BIOMED-2 multiplex PCR clonality assays and compared the results with microscopic findings such as histology and CD10, CD20, CD79a, CD3 and CD5 immunohistochemistry. A total of 151 samples were enrolled; 119 B cell neoplasia, 29 T cell neoplasia, and 3 Hodgkin's lymphoma. The molecular clonality assay and microscopic diagnosis were concordant in 66.9% (n=101) and discordant in 33.1 % (n=50). Ig/TCR gene clonality assay detected 43 cases of BM involvement which was not presented in the morphology. Two cases among them turned into microscopic BM involvement during a close follow up. Clonal TCR gene rearrangements were detected in 12.6% of B cell neoplasia and Ig gene rearrangement were found in 3.4% of T cell neoplasia. This molecular clonality assay is valuable particularly in diagnosing BM involvement of lymphoid neoplasia if it is morphologically uncertain. But it should be carefully interpreted because molecular clonality may be present in the reactive lymphoproliferation. Therefore, comprehensive analysis with morphologic analysis should be important to reach a final diagnosis.

PCR-based analysis of rearranged immunoglobulin or T-cell receptor genes by GeneScan analysis or heteroduplex analysis for clonality assessment in lymphoma diagnostics

The assessment of the presence of clonal lymphoproliferations via polymerase chain reaction (PCR)-based analysis of rearranged immunoglobulin (Ig) or T-cell receptor (TCR) genes is a valuable technique in the diagnosis of suspect lymphoproliferative disorders. Furthermore this technique is more and more used to evaluate dissemination of non-Hodgkin lymphoma and/or the presence of (minimal) residual disease. In this chapter we describe an integrated approach to assess clonality via analysis of Ig heavy chain (IGH), Ig kappa (IGK), TCR beta (TCRB), and TCR gamma (TCRG) gene rearrangements. The described PCR protocol is based on the standardized multiplex PCRs as developed by the European BIOMED-2 collaborative study (Concerted Action BMH4-CT98-3936). Furthermore it also includes the pre-analytical DNA isolation step from various tissues (formalin fixed paraffin-embedded tissue, fresh tissues, body fluids, peripheral blood and bone marrow), GeneScan analysis of labeled PCR products on a genetic analyzer, heteroduplex analysis of unlabeled PCR products, and post-analytical guidelines for the interpretation of the obtained "molecular morphology" patterns.

Molecular Pathology of Malignant Lymphoma

This review focuses on practical uses of molecular testing in mature B-cell and T-cell lymphomas with a focus on those lymphomas in which molecular testing is common. Clinical findings, histology, and biomarkers, as well as diagnostic and prognostic predictive value and practical applications of molecular testing for mature B- and T-cell lymphomas are presented.

TCRβ clonality improves diagnostic yield of TCRγ clonality in refractory celiac disease

BACKGROUND

Refractory celiac disease (RCD) is a preneoplastic condition as many patients develop an enteropathy-type T-cell lymphoma, a mature T-cell receptor α-β lymphoma arising in the gut with an ominous outcome. Recently, research focused on a population of intraepithelial intestinal lymphocytes expressing the same lymphoma T-cell receptor variable region (V)γ, as shown by polymerase chain reaction (PCR) analysis and sequencing. Meanwhile, the Biomedicine and Health-2 Concerted Action has made available standardized, highly specific, and sensitive PCR assays not only for Vγ but also for Vβ.

GOALS

We verified whether analyzing both rearrangements in duodenal biopsies from RCD patients increases the diagnostic accuracy of this method.

STUDY

Duodenal biopsies were analyzed from 15 RCD patients, 21 negative controls, and 2 positive controls (enteropathy-type T-cell lymphoma complicating celiac disease). Multiplex clonality analyses were performed according to the Biomedicine and Health-2 protocols. PCR products were cloned and sequenced.

RESULTS

Monoclonal rearrangements were found in 5/15 samples from patients with RCD (both rearrangements in 2 cases, Vβ only in 2, and only 1 solitary Vγ clonality). Monoclonality was found in 4/8 of the RCD patients who subsequently died, whereas only 1/7 of the patients still alive presented a monoclonal rearrangement. Positive controls revealed both monoclonal rearrangements; rearrangements were not detected in 20 of 21 negative controls. Sequencing of the amplified fragments confirmed the results.

CONCLUSIONS

The combined analysis of both rearrangements allowed recognition of monoclonal populations in otherwise negative patients, with detection rates from 20% (Vγ only) to 33% (Vγ and Vβ), thus raising the likelihood of early identification of RCD patients at high risk of death.

Accurate detection of the tumor clone in peripheral T-cell lymphoma biopsies by flow cytometric analysis of TCR-Vβ repertoire

Multiparametric flow cytometry has proven to be a powerful method for detection and immunophenotypic characterization of clonal subsets, particularly in lymphoproliferative disorders of the B-cell lineage. Although in theory promising, this approach has not been comparably fulfilled in mature T-cell malignancies. Specifically, the T-cell receptor-Vβ repertoire analysis in blood can provide strong evidence of clonality, particularly when a single expanded Vß family is detected. The purpose of this study was to determine the relevance of this approach when applied to biopsies, at the site of tumor involvement. To this end, 30 peripheral T-cell lymphoma and 94 control biopsies were prospectively studied. Vβ expansions were commonly detected within CD4+ or CD8+ T cells (97% of peripheral T-cell lymphoma and 54% of non-peripheral T-cell lymphoma cases); thus, not differentiating malignant from reactive processes. Interestingly, we demonstrated that using a standardized evaluation, the detection of a high Vβ expansion was closely associated with diagnosis of peripheral T-cell lymphoma, with remarkable specificity (98%) and sensitivity (90%). This approach also identified eight cases of peripheral T-cell lymphoma that were not detectable by other forms of immunophenotyping. Moreover, focusing Vβ expression analysis to T-cell subsets with aberrant immunophenotypes, we demonstrated that the T-cell clone might be heterogeneous with regard to surface CD7 or CD10 expression (4/11 cases), providing indication on 'phenotypic plasticity'. Finally, among the wide variety of Vβ families, the occurrence of a Vβ17 expansion in five cases was striking. To our knowledge, this is the first report demonstrating the power of T-cell receptor-Vβ repertoire analysis by flow cytometry in biopsies as a basis for peripheral T-cell lymphoma diagnosis and precise T-cell clone identification and characterization.

EuroClonality/BIOMED-2 guidelines for interpretation and reporting of Ig/TCR clonality testing in suspected lymphoproliferations

PCR-based immunoglobulin (Ig)/T-cell receptor (TCR) clonality testing in suspected lymphoproliferations has largely been standardized and has consequently become technically feasible in a routine diagnostic setting. Standardization of the pre-analytical and post-analytical phases is now essential to prevent misinterpretation and incorrect conclusions derived from clonality data. As clonality testing is not a quantitative assay, but rather concerns recognition of molecular patterns, guidelines for reliable interpretation and reporting are mandatory. Here, the EuroClonality (BIOMED-2) consortium summarizes important pre- and post-analytical aspects of clonality testing, provides guidelines for interpretation of clonality testing results, and presents a uniform way to report the results of the Ig/TCR assays. Starting from an immunobiological concept, two levels to report Ig/TCR profiles are discerned: the technical description of individual (multiplex) PCR reactions and the overall molecular conclusion for B and T cells. Collectively, the EuroClonality (BIOMED-2) guidelines and consensus reporting system should help to improve the general performance level of clonality assessment and interpretation, which will directly impact on routine clinical management (standardized best-practice) in patients with suspected lymphoproliferations.

Analysis of T-cell receptor-γ gene rearrangements using heteroduplex analysis by high-resolution microcapillary electrophoresis

Determination of T-cell clonality has an important additional value for diagnosis of T-cell lymphomas. Various molecular methods have been developed, including polymerase chain reaction (PCR) of T-cell receptor γ (TCRγ). The detection of PCR products usually relies commonly on either GeneScan (GS) analysis or heteroduplex (HD) analysis by polyacrylamide gel electrophoresis (PAGE). These techniques have their disadvantages, being relatively time-consuming and laborious or requiring expensive equipment. Here, we propose an alternative method that combines multiplex PCR and HD analysis by microcapillary electrophoresis (ME) on the Agilent 2100 Bioanalyzer. The sensitivity of the method was determined with clonal PEER T-cell line DNA dilution in polyclonal DNA and was evaluated as 1-5%. Fifty-three samples from patients with T-cell lymphoproliferative disorders were analyzed by HD analysis using ME and GS analyses. Comparison of the two techniques showed them to be highly concordant (93% similarity). The rate of clonality detection by GS analysis was higher than HD analysis by ME, but none of the discordant patients (n=5) has yet developed lymphoma. HD analysis by ME to reveal TCRγ gene rearrangements in clinical specimens was consistent with clinical data and the outcome of patients. Detection of T-cell clonality by HD analysis with ME is sensitive, practical, safe and represents a potential alternative to PAGE and GS analysis.

Celiac disease: Management of persistent symptoms in patients on a gluten-free diet

AIM: To investigate all patients referred to our center with non-responsive celiac disease (NRCD), to establish a cause for their continued symptoms.

METHODS: We assessed all patients referred to our center with non-responsive celiac disease over an 18-mo period. These individuals were investigated to establish the eitiology of their continued symptoms. The patients were first seen in clinic where a thorough history and examination were performed with routine blood work including tissue transglutaminase antibody measurement. They were also referred to a specialist gastroenterology dietician to try to identift any lapses in the diet and sources of hidden gluten ingestion. A repeat small intestinal biopsy was also performed and compared to biopsies from the referring hospital where possible. Colonoscopy, lactulose hydrogen breath testing, pancreolauryl testing and computed tomography scan of the abdomen were undertaken if the symptoms persisted. Their clinical progress was followed over a minimum of 2 years.

RESULTS: One hundred and twelve consecutive patients were referred with NRCD. Twelve were found not to have celiac disease (CD). Of the remaining 100 patients, 45% were not adequately adhering to a strict gluten-free diet, with 24 (53%) found to be inadvertently ingesting gluten, and 21 (47%) admitting non-compliance. Microscopic colitis was diagnosed in 12% and small bowel bacterial overgrowth in 9%. Refractory CD was diagnosed in 9%. Three of these were diagnosed with intestinal lymphoma. After 2 years, 78 patients remained well, eight had continuing symptoms, and four had died.

CONCLUSION: In individuals with NRCD, a remediable cause can be found in 90%: with continued gluten ingestion as the leading cause. We propose an algorithm for investigation.

Targeting intratumoral B cells with rituximab in addition to CHOP in angioimmunoblastic T-cell lymphoma. A clinicobiological study of the GELA

BACKGROUND

In angioimmunoblastic T-cell lymphoma, symptoms linked to B-lymphocyte activation are common, and variable numbers of CD20(+) large B-blasts, often infected by Epstein-Barr virus, are found in tumor tissues. We postulated that the disruption of putative B-T interactions and/or depletion of the Epstein-Barr virus reservoir by an anti-CD20 monoclonal antibody (rituximab) could improve the clinical outcome produced by conventional chemotherapy.

DESIGN AND METHODS

Twenty-five newly diagnosed patients were treated, in a phase II study, with eight cycles of rituximab + chemotherapy (R-CHOP21). Tumor infiltration, B-blasts and Epstein-Barr virus status in tumor tissue and peripheral blood were fully characterized at diagnosis and were correlated with clinical outcome.

RESULTS

A complete response rate of 44% (95% CI, 24% to 65%) was observed. With a median follow-up of 24 months, the 2-year progression-free survival rate was 42% (95% CI, 22% to 61%) and overall survival rate was 62% (95% CI, 40% to 78%). The presence of Epstein-Barr virus DNA in peripheral blood mononuclear cells (14/21 patients) correlated with Epstein-Barr virus score in lymph nodes (P<0.004) and the detection of circulating tumor cells (P=0.0019). Despite peripheral Epstein-Barr virus clearance after treatment, the viral load at diagnosis (>100 copy/μg DNA) was associated with shorter progression-free survival (P=0.06).

CONCLUSIONS

We report here the results of the first clinical trial targeting both the neoplastic T cells and the microenvironment-associated CD20(+) B lymphocytes in angioimmunoblastic T-cell lymphoma, showing no clear benefit of adding rituximab to conventional chemotherapy. A strong relationship, not previously described, between circulating Epstein-Barr virus and circulating tumor cells is highlighted.

PCR for monitoring of minimal residual disease in hematologic malignancy

Monitoring minimal residual disease (MRD) is useful to evaluate therapeutic response and risk of relapse in patients with hematologic malignancy. Currently available quantitative MRD assays are fluorescence in situ hybridization of chromosomal aberrations; multiparameter flow cytometry of leukemia-associated immunophenotypes; and quantitative polymerase chain reaction (qPCR) analysis of fusion genes, immunoglobulin/T-cell receptor gene rearrangements, genetic alterations, or over-expressed genes. Among the PCR-based markers, genetic alterations are found in acute myelogenous leukemia patients with cytogenetically normal karyotype and can be considered as applicable targets for monitoring of MRD. Screening, confirmation and quantification procedures are important to develop the patient- or tumor-specific MRD assays using the PCR-based markers. Wild-type blocking PCR or coamplification at lower denaturing temperature-PCR is suited for screening of low-abundant genetic alterations, and allele-specific qPCR using primers including mismatched base and locked nucleic acids can quantify not only insertion and duplication of several nucleotides but also single nucleotide mutation in the presence of an excess amount of wild-type nucleotides. In addition to the well-established MRD markers, such as immunoglobulin/T-cell receptor gene rearrangements and fusion genes, utilizing potential MRD markers such as genetic alterations may expand the spectrum of patients in whom MRD can be monitored.

Pathology and biology of peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of more than 20 neoplastic entities derived from mature T cells and natural killer (NK) cells involved in innate and adaptive immunity. With few exceptions these malignancies, which may present as disseminated, predominantly extranodal or cutaneous, or predominantly nodal diseases, are clinically aggressive and have a dismal prognosis. Their diagnosis and classification is hampered by several difficulties, including a significant morphological and immunophenotypic overlap across different entities, and the lack of characteristic genetic alterations for most of them. Although there is increasing evidence that the cell of origin is a major determinant for the delineation of several PTCL entities, however, the cellular derivation of most entities remains poorly characterized and/or may be heterogeneous. The complexity of the biology and pathophysiology of PTCLs has been only partly deciphered. In recent years, novel insights have been gained from genome-wide profiling analyses. In this review, we will summarize the current knowledge on the pathobiological features of peripheral NK/T-cell neoplasms, with a focus on selected disease entities manifesting as tissue infiltrates primarily in extranodal sites and lymph nodes.

PiggyBac-mediated cancer immunotherapy using EBV-specific cytotoxic T-cells expressing HER2-specific chimeric antigen receptor

Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes (CTLs) can be modified to function as heterologous tumor directed effector cells that survive longer in vivo than tumor directed T cells without virus specificity, due to chronic stimulation by viral antigens expressed during persistent infection in seropositive individuals. We evaluated the nonviral piggyBac (PB) transposon system as a platform for modifying EBV-CTLs to express a functional human epidermal growth factor receptor 2-specific chimeric antigen receptor (HER2-CAR) thereby directing virus-specific, gene modified CTLs towards HER2-positive cancer cells. Peripheral blood mononuclear cells (PBMCs) were nucleofected with transposons encoding a HER2-CAR and a truncated CD19 molecule for selection followed by specific activation and expansion of EBV-CTLs. HER2-CAR was expressed in ~40% of T cells after CD19 selection with retention of immunophenotype, polyclonality, and function. HER2-CAR-modified EBV-CTLs (HER2-CTLs) killed HER2-positive brain tumor cell lines in vitro, exhibited transient and reversible increases in HER2-CAR expression following antigen-specific stimulation, and stably expressed HER2-CAR beyond 120 days. Adoptive transfer of PB-modified HER2-CTLs resulted in tumor regression in a murine xenograft model. Our results demonstrate that PB can be used to redirect virus-specific CTLs to tumor targets, which should prolong tumor-specific T cell survival in vivo producing more efficacious immunotherapy.

Detection of T-cell receptor gene rearrangement in children with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis using the BIOMED-2 multiplex polymerase chain reaction combined with GeneScan analysis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a serious immune disorder. Epstein-Barr virus (EBV) is the most common trigger of secondary HLH. T-cell receptor (TCR) gene rearrangement is detectable in half of patients with EBV-associated HLH using Southern blotting and conventional polymerase chain reaction (PCR) analyses. However, its clinical significance is unclear. The impact of TCR gene clonality on the outcome of patients with EBV-HLH should be evaluated using more sensitive methods. In this study, we used BIOMED-2 multiplex PCR and GeneScan analysis to evaluate TCR gene rearrangement in childhood EBV-HLH.

METHODS

Six children with EBV-HLH were enrolled in this study. EBV load in blood was quantified by real-time PCR. TCR gene rearrangement was analyzed by BIOMED-2 multiplex PCR.

RESULTS

All 6 patients showed monoclonal peaks in TCRβ and/or TCRγ at diagnosis. Serial monitoring of one patient disclosed a change in the rearrangement pattern of the TCR genes in response to immunochemotherapy.

CONCLUSION

These findings suggest that BIOMED-2 multiplex PCR, a highly sensitive method for detecting T-cell clonality, is useful for predicting the therapeutic response in childhood EBV-HLH.

A parallel comparison of T-cell clonality assessment between an in-house PCR assay and the BIOMED-2 assay leading to an efficient and cost-effective strategy

AIMS

Diagnosis of T-cell lymphoproliferation is sometimes challenging, and in certain instances pathologists rely heavily on the clonality assessment results of T-cell receptor (TCR) gene rearrangement (TCR-GR). Many investigators have designed various in-house primer sets for PCR-based study targeting different loci of TCR genes. In recent years, the commercial BIOMED-2 protocols have become available. The in-house primers are very cheap while the BIOMED-2 primers are expensive. This parallel study aimed to compare the sensitivity of the in-house TCRG primers (two reactions) and the BIOMED-2 TCR primers (six reactions) in an attempt to develop a sensitive and cost-effective strategy for TCR-GR assessment.

METHODS

PCR-based analysis was performed on 69 samples of T-lineage neoplasms including 60 formalin-fixed paraffin-embedded (FFPE) tissues, 5 samples from peripheral blood (PB) and 4 samples from bone marrow (BM) aspirate.

RESULTS

Forty-seven (78%) FFPE and all PB or BM aspirate samples yielded control DNA products suitable for clonality assessment including 4 precursor and 50 mature T-cell neoplasms. The detection rates of clonal TCR-GR were 63% (34/54) by the two in-house TCRG primers, 85% (46/54) by all six BIOMED-2 reactions, 91% (49/54) by combining the in-house and BIOMED-2 TCRG reactions and 94% (51/54) by combining the in-house and all BIOMED-2 reactions. By using the in-house and BIOMED-2 TCRG reactions with a total of four tubes, clonal TCR-GR was detected in 91% of the cases. The reagent cost for this combination was one-third of that for the six BIOMED-2 reactions and the detection rate was also higher than the latter alone (91% vs 85%).

CONCLUSIONS

As the in-house primers were custom made and are much cheaper than the commercial kits, the authors concluded that this four-tube strategy was cost-effective and efficient for TCR-GR clonality assessment.

Clonality and phenotyping analysis of alveolar lymphocytes is suggestive of pulmonary MALT lymphoma

BACKGROUND

Mucosa-associated lymphoid tissue (MALT) lymphoma, a low-grade B-cell extranodal lymphoma, is the most frequent subset of primary pulmonary lymphoma (PPL). It often associates with connective tissue disease (CTD). We aimed to evaluate the impact of concomitant CTD on diagnostic value of flow cytometry and genetic clonality analyses for the diagnostic of MALT lymphoma.

METHODS

All chest disease and pathology departments of teaching hospitals in Paris were contacted to identify patients with a histological diagnosis of PPL of the MALT subtype with or without associated CTD. We identified 44 patients in the lymphoma group; 11 had a CTD and were matched to 11 patients with CTD but without lymphoma.

RESULTS

Results of BAL analyses of MALT-PPL showed normal cellularity (370 cells/mm(3) [range 21-2300]) but increased proportion of lymphocytes (31.5% [80-2]) of the B-cell subtype (20% [1-88]). A B-cell clone was detected in 82% of cases, and specificity of clonality was 90%. Interestingly, BAL analysis results different by presence or not of a CTD. The frequency of B lymphocyte alveolitis was significantly greater in MALT patients without than with CTD (34% vs 6.5%, p = 0.007). However, BAL results for patients with CTD did not differ between those with and without lymphoma.

CONCLUSION

BAL results may be highly suggestive of pulmonary MALT lymphoma. The proportion of B-cells may vary depending on the presence of an associated CTD, but clonality analyses remained informative for the diagnostic of MALT lymphoma.

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.

The value of molecular diagnostics in primary cutaneous B-cell lymphomas in the context of clinical findings, histology, and immunohistochemistry

BACKGROUND

Primary cutaneous B-cell lymphoma (PCBCL) is classified into 3 major subtypes: primary cutaneous follicle center lymphoma (PCFCL); primary cutaneous marginal zone B-cell lymphoma (PCMZL); and primary cutaneous diffuse large B-cell lymphoma, leg type (PCLBCL, LT). Diagnosis of PCBCL is mainly based on clinical and (immuno)-histochemical grounds.

OBJECTIVE

We investigated the diagnostic value of the BIOMED-2 Concerted Action BMH4 CT98-3936 protocol in PCBCL.

METHODS

We analyzed with the BIOMED-2 Concerted Action BMH4 CT98-3936 protocol skin specimens from patients with well-defined clinical and (immuno)-histologic PCBCL (n = 18) in comparison with benign lymphocytic infiltrates (n = 9). For molecular staging we also investigated 13 extracutaneous samples from 6 patients with PCLBCL, LT. Each sample was investigated at least twice.

RESULTS

Monoclonality was detected in all of 5 PCFCL; 5 of 6 PCMZL; all of 6 PCLBCL, LT; and 2 of 9 benign lymphocytic infiltrates. In 5 of 6 patients with PCLBCL, LT, a clone corresponding to the clone detected in the skin was detected in 3 of 5 bone-marrow, 4 of 5 blood, and 1 of 3 lymph node specimens. DNA amplification using tubes A and B of IgH was not possible in PCFCL/PCMZL, benign lymphocytic infiltrates, and extracutaneous specimens of PCLBCL, LT, even after repeated analysis up to 11 times. Pseudomonoclonality was identified by repeated analyses in one case of PCMZL and in one case of benign lymphocytic infiltrate.

LIMITATIONS

A multicentric, randomized, blinded study is necessary to confirm our results.

CONCLUSION

Molecular diagnosis supports the clinical and (immuno)-histologic diagnosis in PCBCL. In PCLBCL, LT, molecular staging may be useful. Tubes C through E of IgH and Igκ analyses seem to be superior to tubes A and B of IgH. Each sample should be analyzed at least twice to assess the possibility of pseudomonoclonality.

[Synchronous detection of T-cell clonality and FIP1L1-PDGFRA fusion gene in a hypereosinophilic syndrome]

We report a 49-year-old man suffering from chronic hypereosinophilia whose biological tests revealed a gene rearrangement between FIP1L1 and PDGFRA as well as a T-cell clonality. After 1 year of therapy with imatinib mesylate (100 mg daily), the patient was clinically asymptomatic, the fusion transcript was undetectable using RTQ-PCR and no lymphoproliferative disorders occurred. This unique combination raises the question of the physiopathology of such a grey zone hypereosinophilia and their management.

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.

Molecular analysis of genetic markers for non-Hodgkin lymphomas

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

Combined use of PCR-based TCRG and TCRB clonality tests on paraffin-embedded skin tissue in the differential diagnosis of mycosis fungoides and inflammatory dermatoses

The distinction between mycosis fungoides (MF) and inflammatory dermatoses (ID) by clinicopathologic criteria can be challenging. There is limited information regarding the performance characteristics and utility of TCRG and TCRB clonality assays in diagnosis of MF and ID from paraffin-embedded tissue sections. In this study, PCR tests were performed with both TCRG and TCRB BIOMED-2 clonality methods followed by capillary electrophoresis and Genescan analysis using DNA samples from 35 MF and 96 ID patients with 69 and 133 paraffin-embedded specimens, respectively. Performance characteristics were determined for each test individually and in combination. TCRG and TCRB tests demonstrated identical sensitivity (64%) and specificity (84%) when analyzed as individual assays. The positive predictive value, negative predictive value, and change of posttest MF probability over a range of MF pretest probabilities were obtained. These data were used to construct an algorithm for sequential use of TCRG and TCRB. As single tests, commercially available BIOMED-2 PCR-based TCRG and TCRB clonality tests on paraffin-embedded tissue have no significant difference in terms of sensitivity and specificity. Combined use of the two tests in patients with intermediate pretest probabilities as proposed in the algorithm could improve test utility.

Clinicopathological characteristics of primary gastric T-cell lymphoma

AIMS

To investigate the clinicopathological characteristics of 20 primary gastric T-cell lymphoma (GTCL) cases without human T-lymphotropic virus type I infection in Japan, a non-endemic area for coeliac disease.

METHODS AND RESULTS

Fifteen cases had no history of persistent diarrhoea or severe hypoproteinaemia. Histologically, 13 cases (65%) consisted of large cell lymphoma and seven (35%) were of medium-sized cells. Intraepithelial lymphoma cell invasion was found in three cases (15%). Two of 10 surgical cases (20%) showed intramucosal tumour cell spreading with enteropathy-like features. Helicobacter pylori CagA gene was detected in three of 10 cases (30%). The lymphoma cells of all 20 cases were positive for CD3 and/or TCRbetaF1 and negative for CD56. CD4- and CD8- lymphoma was found in 11 cases (55%), CD4+ lymphoma in seven (35%) and CD8+ lymphoma in two (10%). CD30+, CD5+ and CD25+ lymphomas were detected in nine (45%), 10 (50%) and 11 (55%) cases, respectively. Five-year survival of the 16 available cases was 54%. Early clinical stage and medium-sized cell lymphoma were significantly (P < 0.05) better prognostic factors.

CONCLUSIONS

Patients with GTCL exhibit distinct clinicopathological findings and prognoses from those with enteropathy-associated T-cell lymphomas. GTCL may be mainly derived from lamina propria and parafollicular T cells.

T-cell abnormalities are present at high frequencies in patients with hypereosinophilic syndrome

BACKGROUND

A T-cell clone, thought to be the source of eosinophilopoietic cytokines, identified by clonal rearrangement of the T-cell receptor and by the presence of aberrant T-cell immunophenotype in peripheral blood defines lymphocytic variant of hypereosinophilic syndrome (L-HES).

DESIGN AND METHODS

Peripheral blood samples from 42 patients who satisfied the diagnostic criteria for HES were studied for T-cell receptor clonal rearrangement by polymerase chain reaction according to BIOMED-2. The T-cell immunophenotype population was assessed in peripheral blood by flow cytometry. The FIP1L1-PDGFRA fusion gene was detected by nested polymerase chain reaction.

RESULTS

Forty-two HES patients (18 males and 24 females) with a median age at diagnosis of 56 years (range 17-84) were examined in this study. Their median white blood cell count was 12.9 x 10(9)/L (range 5.3-121), with an absolute eosinophil count of 4.5 x 10(9)/L (range 1.5-99) and a median eosinophilic bone marrow infiltration of 30% (range 11-64). Among the 42 patients, clonal T-cell receptor rearrangements were detected in 18 patients (42.8%). Patients with T-cell receptor clonality included: T-cell receptor beta in 15 patients (35%), T-cell receptor gamma in 9 (21%) and T-cell receptor delta in 9 (21%) patients, respectively. Clonality was detected in all three T-cell receptor loci in 4 cases, in two loci in 7 patients and in one T-cell receptor locus in the remaining 7 patients. The FIP1L1-PDGFRA fusion transcript was absent in all but 2 patients with T-cell receptor clonality. Three patients out of 42 revealed an aberrant T-cell immunophenotype. In some patients, an abnormal CD4:CD8 ratio was demonstrated.

CONCLUSIONS

T-cell abnormalities are present at high frequencies in patients with HES.

Aberrant T-lymphocytes in refractory coeliac disease are not strictly confined to a small intestinal intraepithelial localization

BACKGROUND

Refractory coeliac disease (RCD) is characterized by persisting mucosal pathology in spite of a strict gluten free diet (GFD). In RCD type II, phenotypically aberrant (CD7+CD3-CD4/8-cytoplasmicCD3+) T-lymphocytes are present within the intraepitelial lymphocyte (IEL) population in the small intestine, and 50-60% of these patients develops an enteropathy associated T-cell lymphoma (EATL).

AIM

To investigate whether aberrant T-lymphocytes in RCD II can be detected in other parts of the small intestinal mucosa besides the intraepithelial compartment. Additionally, the presence of aberrant T-lymphocytes was analyzed in two RCD II patients that developed atypical skin lesions.

METHODS

Multiparameter flow cytometric immunophenotyping was performed on both IEL and lamina propria lymphocyte (LPL) cell suspensions, isolated from small bowel biopsy specimens of RCD II patients (n = 14), and on cutaneous lymphocytes isolated from skin-lesion biopsy specimens of RCD II patients (n = 2). In addition, immunofluorescence analysis of frozen RCD II derived small intestinal biopsies was performed.

RESULTS

Our results clearly show that aberrant T-lymphocytes may be present in both the IEL and the LPL compartments of RCD II derived small intestinal biopsies. Although the highest percentages are always present in the IEL compartment, aberrant LPL can exceed 20% of total LPL in half the RCD II patients. Interestingly, cutaneous lymphocytes isolated from atypical skin lesions that developed in some RCD II patients showed a similar aberrant immunophenotype as found in the intestinal mucosa.

CONCLUSIONS

In RCD II, the aberrant T-lymphocytes may also reside in the subepithelial layer of the small intestinal mucosa, in the lamina propria, and even in extraintestinal localizations including the skin. Whether this phenomenon represents a passive overflow from the intestinal epithelium or active trafficking towards other anatomical localizations remains to be elucidated. RCD II appears to be a disseminated disease, which may impose the risk of EATL development outside the intestine.