BIOMED-2 multiplex immunoglobulin/T-cell receptor polymerase chain reaction protocols can reliably replace Southern blot analysis in routine clonality diagnostics

Complete detection of FR1 to FR3 primer-based PCR patterns of immunoglobulin heavy chain rearrangement in the BIOMED-2 protocol is associated with poor prognosis in patients with diffuse large B-cell lymphoma

Somatic hypermutations (SHMs) in the variable region (VH) of the immunoglobulin heavy chain (IgH) gene are common in diffuse large B-cell lymphoma (DLBCL). Recently, IgH VH SHMs have become known as immunogenic neoantigens, but few studies have evaluated the prognostic impact of the frequency of VH SHMs in DLBCL. The BIOMED-2 protocol is the gold standard polymerase chain reaction (PCR) for clonality analysis in lymphoid malignancies, but can produce false negatives due to the presence of IgH VH SHMs. To overcome this problem, three primer sets were designed for the three framework regions (FR1, FR2, and FR3). We evaluated the predictive value of this PCR pattern in patients with DLBCL. To evaluate the prognostic impact of complete detection of the clonal amplifications (VHFR1-JH, VHFR2-JH, and VHFR3-JH) in the BIOMED-2 protocol, we retrospectively analyzed 301 DLBCL patients who were initially treated with anthracycline-based immunochemotherapy. Complete detection of the FR1 to FR3 primer-based IgH VH PCR patterns in the BIOMED-2 protocol was associated with low frequency of VH SHMs (p < 0.001). Patients who were positive for all these three PCRs (n = 79) were significantly associated with shorter 5-year overall survival (OS; 54.2% vs. 73.2%; p = 0.002) and progression-free survival (PFS; 34.3% vs. 59.3%; p < 0.001) compared to patients with other PCR patterns (n = 202). Specifically, the successful FR3-JH detection was associated with significantly worse OS (p < 0.001) and PFS (p < 0.001). PCR patterns of complete IgH rearrangement using the BIOMED-2 protocol are clinically meaningful indicators for prognostic stratification of DLBCL patients.

T-Cell Monoclonality in the Blood and the Skin Correlates With Poor Response to Treatment in Mycosis Fungoides

BACKGROUND

The prognostic value of skin and blood T-cell receptor clonality in mycosis fungoides is a matter of debate. Our aim was to ascertain the relation between the presence of a monoclonal T-cell population in the blood and in the skin with response to treatment in patients with mycosis fungoides.

PATIENTS AND METHODS

Clinical features and follow-up data were retrospectively collected and analyzed in 94 patients with mycosis fungoides seen at a cutaneous lymphoma clinic in a single tertiary center. All patients had results of polymerase chain reaction analysis of T-cell receptor gamma gene rearrangement in lesional skin and in peripheral blood at time of diagnosis. Association of response to treatment with clonality in the tissue and in the blood was assessed.

RESULTS

T-cell monoclonality was detected in the skin in 30 of 94 patients, in the blood in 12 of 94 cases and the same clone was found in both tissues in 6 of 94 patients. The presence of a polyclonal T-cell population in the circulation was associated with complete response (P = .006). Lack of response to treatment (stable disease or progression of disease) was associated with T-cell clonality in skin (P = .009), in blood (P = .002) and in both tissues (P < .001). A multivariate analysis showed that T-cell monoclonality in the skin is independently associated with lack of response of mycosis fungoides to therapy.

CONCLUSION

Blood and skin should be studied for T-cell clonality as part of the routine initial workup, even in patients with early-stage disease.

Experiencia en el uso de protocolos Biomed-2 para el estudio de reordenamientos de TCR e inmunoglobulinas en proliferaciones linfoides en el Instituto Nacional de Cancerología, Colombia

Introducción.

El consorcio europeo BIOMED-2 se creó para determinar si una población linfoide de difícil clasificación patológica es clonal. En Colombia, la implementación de estas pruebas comenzó en el 2015 en el Instituto Nacional de Cancerología E.S.E. (Bogotá).

Objetivos.

Determinar el comportamiento de las pruebas de reordenamiento clonal o clonalidad linfoide. y determinar las dificultades de su uso en nuestro medio verificando su adaptación local y los resultados en una serie retrospectiva de casos y consecutiva de proliferaciones linfoides sometidas a los protocolos BIOMED-2.

Materiales y métodos.

A partir de las historias clínicas, se recolectaron los datos clínicos e histológicos y los resultados de los análisis de los reordenamientos en todos los casos de proliferaciones linfoides sometidas a los protocolos BIOMED-2, entre febrero de 2015 y mayo de 2019.

Resultados.

Se hallaron 132 casos, de los cuales 47 se clasificaron mediante los protocolos de Biomed-2 como hiperplasias linfoides reactivas, 62 como linfomas T, 19 como linfomas B y 3 como neoplasias linfoides de linaje no establecido. Solo en un caso falló la extracción de ADN. Según estos resultados, la mayor dificultad diagnóstica para el patólogo fue el análisis de los infiltrados linfoides T, la mayoría (44) de los cuales correspondía a lesiones cutáneas.

Conclusiones.

Las pruebas de clonalidad pueden usarse en tejidos de diversa calidad en nuestro medio como ayuda en el diagnóstico de proliferaciones linfoides de difícil clasificación. Es importante hacerlas e interpretarlas de manera multidisciplinaria y considerar cada caso por separado.

Combined detection of lymphocyte clonality and MALT1 translocations in bronchoalveolar lavage fluid for diagnosing pulmonary lymphomas

Diagnosis of pulmonary lymphoma using small tissue samples is difficult and often requires surgical procedures; thus, a less invasive sampling method is desirable. We previously showed that pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma can be diagnosed by detecting MALT lymphoma translocation gene 1 (MALT1) translocations in bronchoalveolar lavage fluid (BALF) cells. Analysis of B-cell clonality based on immunoglobulin heavy chain (IGH) gene rearrangements was also reportedly useful for diagnosing pulmonary lymphoma. The aim of this prospective multicenter study was to evaluate the yet unknown diagnostic potential of combined detection of MALT1 translocations and clonality using BALF. We analyzed B- and T-cell clonality based on IGH and T-cell receptor (TCR) rearrangements together with MALT1 translocations using BALF of patients with clinically suspected pulmonary lymphomas. In total, 39 patients were evaluated and categorized into three groups: B-cell lymphoma, lymphoproliferative disorders, and other diseases. IGH rearrangement detection for B-cell lymphoma diagnosis exhibited sensitivity and specificity of 88.9% and 90.0%, respectively. TCR rearrangements were not observed in patients with B-cell lymphomas. The presence of IGH rearrangements together with the absence of TCR rearrangements indicated 96.0% specificity for the diagnosis of B-cell lymphoma. The sensitivity and specificity of MALT1 translocations for diagnosing MALT lymphoma were 28.6% and 100%, respectively. The combined detection of lymphocyte clonality and MALT1 translocations using BALF is suitable for screening and diagnosis of B-cell lymphomas. Analysis of specific genes such as MALT1 should improve the precision of B-cell lymphoma diagnosis.

Evaluation of a worldwide EQA scheme for complex clonality analysis of clinical lymphoproliferative cases demonstrates a learning effect

Clonality analysis of immunoglobulin (IG) or T-cell receptor (TR) gene rearrangements is routine practice to assist diagnosis of lymphoid malignancies. Participation in external quality assessment (EQA) aids laboratories in identifying systematic shortcomings. The aim of this study was to evaluate laboratories' improvement in IG/TR analysis and interpretation during five EQA rounds between 2014 and 2018. Each year, participants received a total of five cases for IG and five cases for TR testing. Paper-based cases were included for analysis of the final molecular conclusion that should be interpreted based on the integration of the individual PCR results. Wet cases were distributed for analysis of their routine protocol as well as evaluation of the final molecular conclusion. In total, 94.9% (506/533) of wet tests and 97.9% (829/847) of paper tests were correctly analyzed for IG, and 96.8% (507/524) wet tests and 93.2% (765/821) paper tests were correctly analyzed for TR. Analysis scores significantly improved when laboratories participated to more EQA rounds (p=0.001). Overall performance was significantly lower (p=0.008) for non-EuroClonality laboratories (95% for IG and 93% for TR) compared to EuroClonality laboratories (99% for IG and 97% for TR). The difference was not related to the EQA scheme year, anatomic origin of the sample, or final clinical diagnosis. This evaluation showed that repeated EQA participation helps to reduce performance differences between laboratories (EuroClonality versus non-EuroClonality) and between sample types (paper versus wet). The difficulties in interpreting oligoclonal cases highlighted the need for continued education by meetings and EQA schemes.

Evaluation of the polymerase chain reaction-based T-cell receptor β clonality test in the diagnosis of early mycosis fungoides

BACKGROUND

T-cell receptor (TCR) clonality may help establish a diagnosis of mycosis fungoides (MF). Routine clonality analysis is performed by using a polymerase chain reaction TCR- gamma assay, yet with this method, 10% to 50% of T-cell lymphomas escape detection. TCR- beta gene rearrangement is an additional assay. Data about its efficacy are controversial.

OBJECTIVE

To evaluate the role of TCR-β assay in the diagnosis of early MF.

METHODS

A retrospective study of 61 skin biopsies, 20 from patients with MF, 30 from patients suspected to have early MF, and 11 from patients with chronic inflammatory skin disease.

RESULTS

Monoclonality was detected in 16 of 20 (80%) MF cases: 15 (75%) with TCR-β and 12 (60%) with TCR-γ assay. Of the 30 suspected cases of early MF, 14 showed monoclonality with TCR-β, and only 5 of 14 showed monoclonality with TCR-γ assay. None of the chronic inflammatory condition samples showed monoclonality. Therefore, TCR-β clonality assay was more sensitive than TCR-γ in early MF (83% vs 43%; P = .002).

LIMITATIONS

This was a retrospective, relatively small study.

CONCLUSION

TCR-β showed a higher sensitivity rate compared with TCR-γ in early-stage MF. The combined use of the TCR-β and TCR-γ clonality tests can significantly improve the diagnosis rate of early-stage MF.

A Systematic Approach to the Cutaneous Lymphoid Infiltrates: A Clinical, Morphologic, and Immunophenotypic Evaluation

CONTEXT.—

The evaluation of cutaneous lymphoid infiltrates, both neoplastic and inflammatory, occurs very frequently in routine dermatopathologic examination and consultation practices. The "tough" cutaneous lymphoid infiltrate is feared by many pathologists; skin biopsies are relatively small, whereas diagnostic possibilities are relatively broad. It is true that cutaneous lymphomas can be difficult to diagnose and that in many circumstances multiple biopsies are required to establish a correct diagnostic interpretation. As a reminder, one should understand that low-grade cutaneous lymphomas are indolent disorders that usually linger for decades and that therapy does not result in disease cure. It is also important to remember that in most circumstances, those patients will die from another process that is completely unrelated to a diagnosis of skin lymphoma (even in the absence of specific therapy).

OBJECTIVE.—

To use a clinicopathologic, immunophenotypic, and molecular approach in the evaluation of common lymphocytic infiltrates.

DATA SOURCES.—

An in-depth analysis of updated literature in the field of cutaneous lymphomas was done, with particular emphasis on updated terminology from the most recent World Health Organization classification of skin and hematologic tumors.

CONCLUSIONS.—

A diagnosis of cutaneous lymphoid infiltrates can be adequately approached using a systematic scheme following the proposed ABCDE system. Overall, cutaneous T- and B-cell lymphomas are rare and "reactive" infiltrates are more common. Evaluation of lymphoid proliferations should start with a good sense of knowledge of the clinical presentation of the lesions, the clinical differential considerations, and a conscientious and appropriate use of immunohistochemistry and molecular tools.

Detection of immunoglobulin and T-cell receptor gene rearrangements in angioimmunoblastic T-cell lymphoma

Objective: To assess the value of immunoglobulin and T-cell receptor gene rearrangements in the diagnosis and differential diagnosis of angioimmunoblastic T-cell lymphoma. Methods: We selected 55 cases of angioimmunoblastic T-cell lymphoma confirmed by histopathology and 15 cases of reactive lymph node hyperplasia. Using the IdentiClone gene rearrangement detection kit, BIOMED-2 primer system, and GeneScanning analysis, we tested for immunoglobulin and T-cell receptor gene rearrangements. Results: Among all 55 angioimmunoblastic T-cell lymphoma cases, 1 (2%) displayed the first type of angioimmunoblastic T-cell lymphoma, which has an intact lymphoid follicle structure. Five cases (9%) displayed the second type, which has an intact segmental lymphatic follicular structure. Forty-nine cases (89%) displayed the third type, which is characterized by a complete obliteration of the lymphatic follicular structure. Fifty-two cases (95%) had tumor cells that were positive for CD3, 50 cases (91%) were positive for CD4, 33 cases (60%) were positive for Bcl-6, 20 cases (36%) were positive for CD10, 44 cases (80%) were positive for CXCL13 to different degrees, and 53 cases (96%) showed a strong positive expression of CD21. Ki67 expression intensity was 30-80% in tumor T cells. Clonal gene rearrangements were identified in 48 of the 55 angioimmunoblastic T-cell lymphoma cases (87%), of which 30 (55%) displayed IG gene rearrangements, including IGHA (7 cases; 13%), IGHB (6 cases; 11%), IGHC (2 cases; 4%), IGKA (22 cases; 40%), IGKB (6 cases; 11%), and IGL (20 cases; 36%). TCR gene rearrangements were observed in 32 cases (58%), including TCRBA (6 cases; 11%), TCRBB (5 cases; 9%), TCRBC (10 cases; 18%), TCRD (7 cases; 13%), TCRGA (22 cases; 40%), and TCRGB (16 cases; 29%). IG and TCR gene rearrangements were concurrently observed in 14 cases (25%). Immunoglobulin or TCR clonal gene rearrangements were not detected in the 15 cases of reactive hyperplasia. Conclusions: Angioimmunoblastic T-cell lymphomas may be positive for immunoglobulin or T-cell receptor clone gene rearrangements or may express double rearrangements. The assessment of clonal gene rearrangements is valuable for the diagnosis and differential diagnosis of angioimmunoblastic T-cell lymphoma.

Macrophage Activation Syndrome

Hemophagocytic lymphohistiocytosis (HLH), or termed macrophage activation syndrome (MAS) when associated with rheumatic disorders, is a frequently fatal complication of infections, rheumatic disorders, and hematopoietic malignancies. Clinically, HLH/MAS is a life-threatening condition that is usually diagnosed among febrile hospitalized patients (children and adults) who commonly present with unremitting fever and a shock-like multiorgan dysfunction scenario. Laboratory studies reveal pancytopenia, elevated liver enzymes, elevated markers of inflammation (ESR, CRP), hyperferritinemia, and features of coagulopathy. In about 60% of cases, excess hemophagocytosis (macrophages/histiocytes engulfing other hematopoietic cell types) is noted on biopsy specimens from the bone marrow, liver, lymph nodes, and other organs. HLH/MAS has been hypothesized to occur when a threshold level of inflammation has been achieved, and genetic and environmental risk factors are believed to contribute to the hyperinflammatory state. A broad variety of infections, from viruses to fungi to bacteria, have been identified as triggers of HLH/MAS, either in isolation or in addition to an underlying inflammatory disease state. Certain infections, particularly by members of the herpesvirus family, are the most notorious triggers of HLH/MAS. Treatment for infection-triggered MAS requires therapy for both the underlying infection and dampening of the hyperactive immune response.

Idiopathic hypereosinophilia is clonal disorder? Clonality identified by targeted sequencing

Idiopathic hypereosinophilia (IHE)/idiopathic hypereosinophilic syndrome (IHES) has been defined by a persistent elevation of the blood eosinophil count exceeding 1.5×10³/μL, without evidence of reactive or clonal causes. While T-cell clonality assessment has been recommended for unexplained hypereosinophilia, this approach is not often applied to routine practice in the clinic. We hypothesized that the clonality would exist in a subset of IHE/IHES patients. We aimed to investigate the candidate mutations and T-cell clonality in IHE/IHES and to explore the role of mutations in eosinophil proliferation. We performed targeted capture sequencing for 88 genes using next-generation sequencing, T-cell receptor (TCR) gene rearrangement assays, and pathway network analysis in relation to eosinophil proliferation. By targeted sequencing, 140 variants in 59 genes were identified. Sixteen out of 30 patients (53.3%) harbored at least one candidate mutation. The most frequently affected genes were NOTCH1 (26.7%), SCRIB and STAG2 (16.7%), and SH2B3 (13.3%). Network analysis revealed that our 21 candidate genes (BIRC3, BRD4, CSF3R, DNMT3A, EGR2, EZH2, FAT4, FLT3, GATA2, IKZF, JAK2, MAPK1, MPL, NF1, NOTCH1, PTEN, RB1, RUNX1, TET2, TP53 and WT1) are functionally linked to the eosinophilopoietic pathway. Among the 21 candidate genes, five genes (MAPK1, RUNX1, GATA2, NOTCH1 and TP53) with the highest number of linkages were considered major genes. A TCR assay revealed that four patients (13.3%) had a clonal TCR rearrangement. NOTCH1 was the most frequently mutated gene and was shown to be a common node for eosinophilopoiesis in our network analysis, while the possibility of hidden T cell malignancy was indwelling in the presence of NOTCH1 mutation, though not revealed by aberrant T cell study. Collectively, these results provide new evidence that mutations affecting eosinophilopoiesis underlie a subset of IHE/IHES, and the candidate genes are inferred to act their potential roles in the eosinophilopoietic pathway.

The value of detecting immunoglobulin gene rearrangements in the diagnosis of B-cell lymphoma

Objective

To discuss the clinical value of immunoglobulin gene rearrangements in the diagnosis of B-cell lymphoma.

Methods

A total of 209 cases of B-cell lymphomas and 35 cases of reactive lymphoid hyperplasia were selected for DNA extraction and PCR amplification using the BIOMED-2 primer system. Gel electrophoresis of heteroduplexes was used to analyze immunoglobulin gene rearrangements.

Results

A total of 209 cases of B-cell lymphoma, including 69 extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue, 63 diffuse large B-cell lymphomas, 39 follicular lymphomas, 15 small lymphocytic lymphomas, 6 plasmacytomas, 6 mantle cell lymphomas, 7 nodal marginal zone B-cell lymphomas, and 4 lymphoplasmacytoid lymphomas, were examined. Immunoglobulin gene rearrangements were found in all 209 cases, with 93 IGHA, 122 IGHB, 98 IGHC, 167 IGK, 100 IGL, 167 IGHA/B/C, 204 IGH/IGK, 209 IGH/IGK/IGL, 129 IGH+IGK, 81 IGH+IGL, 83 IGK+IGL and 68 IGH+IGK+IGL gene rearrangements. Immunoglobulin gene rearrangements were not found in the 35 cases of reactive lymphoid hyperplasia. IGH and IGK gene rearrangements were mainly found in mantle cell lymphomas, small lymphocytic lymphomas, extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue and diffuse large B-cell lymphomas. The IGH gene rearrangement was mainly found in lymphoplasmacytoid lymphomas and follicular lymphomas. IGK and IGL gene rearrangements were mainly found in plasmocytoma, and the IGK gene rearrangement was mainly found in nodal marginal zone B-cell lymphomas.

Conclusions

The BIOMED-2 standardized immunoglobulin gene rearrangement detection system is an important tool in B-cell lymphoma diagnosis. Analysis of IGH, IGK and IGL gene rearrangements is valuable in confirming the classification of B-cell NHL.

Determination of VH Family Usage in B-Cell Malignancies via the BIOMED-2 IGH PCR Clonality Assay

OBJECTIVES

To determine whether V H family usage in B-cell lymphoproliferative disorders can be deduced from polymerase chain reaction (PCR) product-length information obtained through the BIOMED-2 (Invivoscribe, San Diego, CA) clonality assay.

METHODS

We develop an algorithm that uses the sizing information of the BIOMED-2 immunoglobulin heavy chain (IGH) clonality assay to deduce V H family usage. PCR with family-specific primers on 51 clinical samples containing 54 rearranged alleles were used to validate the algorithm.

RESULTS

The clonal PCR products in different framework reactions contain the same NDN segment (because they are from the same allele). Subtracting the size of the framework III product from the size of the framework I and II products yields the relative position of the framework primer binding sites for the V H segment used. The V H family can be assigned with these relative positions because they are V H family specific in the BIOMED-2 assay. The V H family assigned by the algorithm was concordant with family-specific PCR results for 49 (96%) of the 51 specimens.

CONCLUSIONS

We have developed an algorithm that can correctly assign V H family usage when all three BIOMED-2 framework reactions produced clonal products. Given the wide adoption of BIOMED-2 assay, the algorithm can facilitate collection of IGH V H usage data without additional cost to the laboratories.

Synchronous Microscopic Epstein-Barr Virus-Positive Diffuse Large B-Cell Lymphoma of the Adrenal and Lymphoplasmacytic Lymphoma: De Novo Disease or Transformation?

Lymphomas arising in the adrenal are rare, and to our knowledge, 2 cases of Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphomas (DLBCL) in an adrenal pseudocyst have been reported. We report an incidental EBV-positive DLBCL arising in an adrenal pseudocyst in a 58-year-old man with a 7-year history of lymphoplasmacytic lymphoma (LPL). The DLBCL was present in the fibrinous exudate, while the LPL resided in the cyst wall. The patient underwent de-roofing of the same cyst 3 years previously; review of histology revealed foci of LPL in the cyst wall, but not of DLBCL. There have been reports of similar microscopic EBV-positive DLBCLs within enclosed cystic spaces. However, all these cases were incidental extranodal primary DLBCLs. Since residual LPL was present alongside DLBCL, with similar light chain restriction, we propose that this may represent transformation, rather than a de novo primary EBV-driven lymphoma.

Methodologic Considerations in the Application of Next-Generation Sequencing of Human TRB Repertoires for Clinical Use

Next-generation sequencing (NGS) of immune receptors has become a standard tool to assess minimal residual disease (MRD) in patients treated for lymphoid malignancy, and it is being used to study the T-cell repertoire in many clinical settings. To better understanding the potential clinical utility and limitations of this application outside of MRD, we developed a BIOMED-2 primer-based NGS method and characterized its performance in controls and patients with graft-versus-host disease (GVHD) after allogeneic hematopoietic transplant. For controls and patients with GVHD, replicate sequencing of the same T-cell receptor β (TRB) libraries was highly reproducible. Higher variability was observed in sequencing of different TRB libraries made from the same DNA stock. Variability was increased in patients with GVHD compared with controls; patients with GVHD also had lower diversity than controls. In the T-cell repertoire of a healthy person, approximately 99.6% of the CDR3 clones were in low abundance, with frequency <10^-3. A single library could identify >93% of the clones with frequency ≥10^-3 in the repertoire. Sequencing in duplicate increased the average detection rate to >97%. This work demonstrates that NGS reliably and robustly characterizes TRB populations in healthy individuals and patients with GVHD with frequency ≥10^-3 and provides a methodologic framework for applying NGS immune repertoire methods to clinical testing applications beyond MRD.

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography evaluation of subcutaneous panniculitis-like T cell lymphoma and treatment response

Subcutaneous panniculitis-like T cell lymphoma (SPTCL) is a very rare variant of non-Hodgkin’s lymphoma. Currently, there is no standard imaging method for staging of SPTCL nor for assessment of treatment response. Here, we describe our use of fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for staging and monitoring of treatment response in 3 cases of SPTCL. Primary staging by PET/CT showed that all 3 patients had multiple foci in the subcutaneous fat tissue, with SUVmax from 10.5 to 14.6. Involvement of intra-abdominal fat with high SUVmax was identified in 2 of the patients. Use of the triple drug regimen of gemcitabine, cisplatin and methylprednisolone (commonly known as “GEM-P”) as first-line therapy or second-line therapy facilitated complete metabolic response for all 3 cases. FDG PET/CT provides valuable information for staging and monitoring of treatment response and can reveal occult involvement of the intra-abdominal visceral fat. High FDG uptake on pre-treatment PET can identify patients with aggressive disease and help in selection of first-line therapy.

Biomarkers in Hematological Malignancies: A Review of Molecular Testing in Hematopathology

BACKGROUND

Molecular interrogation of genetic information has transformed our understanding of disease and is now routinely integrated into the workup and monitoring of hematological malignancies. In this article, a brief but comprehensive review is presented of state-of-the-art testing in hematological disease.

METHODS

The primary medical literature and standard textbooks in the field were queried and reviewed to assess current practices and trends for molecular testing in hematopathology by disease.

RESULTS

Pertinent materials were summarized under appropriate disease categories.

CONCLUSION

Molecular testing is well entrenched in the diagnostic and therapeutic pathways for hematological malignancies, with rapid growth and insights emerging following the integration of next-generation sequencing into the clinical workflow.

Hemophagocytic Lymphohistiocytosis in Children: Pathogenesis and Treatment

Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder in children that is characterized by persistent fever, splenomegaly with cytopenia, hypertriglyceridemia, and hypofibrinogenemia. Increased levels of various cytokines and soluble interleukin-2 receptor are biological markers of HLH. HLH can be classified into two major forms: primary and secondary. Familial hemophagocytic lymphohistiocytosis (FHL), a type of primary HLH, is an autosomal recessive disorder that typically occurs in infancy and can be classified into five different subtypes (FHL types 1-5). In Japan, >80% of patients with FHL have either PRF1 (FHL type 2) or UNC13D (FHL type 3) defects. FHL is considered to be a disorder of T-cell function because the activity of NK cells or cytotoxic T lymphocytes as target cells is usually impaired. Moreover, Epstein-Barr virus-associated HLH (EBV-HLH) is considered a major subtype of secondary HLH. Any genetic background could have an effect on the pathogenesis of secondary HLH because EBV-HLH is considered to be particularly prevalent in Asian countries. For primary HLH, hematopoietic stem cell transplantation is the only accepted curative therapy, although cord blood transplantation with a reduced-conditioning regimen has been used with superior outcomes. For secondary HLH, including EBV-HLH, immunochemotherapy based on the HLH-2004 protocol has been used. In the near future, the entire mechanism of HLH should be clarified to establish less toxic therapies, including cell therapy and gene targeting therapy.

Invivoscribe BIOMED-2 primer mixes in B-cell immunoglobulin gene rearrangement studies: experience of a molecular diagnostics laboratory in a major tertiary care center

AIMS

To determine the frequency of positive reactions obtained using the Invivoscribe BIOMED-2 kit for B-cell gene rearrangement studies in leukemias and lymphomas.

MATERIALS AND METHODS

We reviewed the gel patterns for 192 samples tested, using the above-mentioned kit and matched the positive signal with the corresponding mix available in the assay kit.

RESULTS

92.2% had immunoglobulin heavy-chain clonality, of which 74% were detected by the IgH VH-FR1+JH primer set, 75.5% by IgH VH-FR2+JH primer set, 65.1% by IgH VH-FR3+JH primer set, 26% by IgH DH+JH primer set, and 2.1% by IgH DH7+JH primer set. In addition, 55.7% had clonality in the kappa light chain, where 33.3% were positive by the IgK Vκ +Jκ primer set and 39.6% by IgK Vκ and INTR+Kde primer sets. Clonality in the lambda light chain of immunoglobulins was detected in 17.7% of specimens tested using the IgL Vλ +Jλ primer set.

CONCLUSION

All primer mixes provided by the assay were positive. Thus, the Invivoscribe BIOMED-2 B-cell gene rearrangement kit is very reliable in adequately covering all targets represented by the master mixes. This assay is an integral part of the differential diagnosis of clonal populations of cells. Our report is the first in the literature that describes the full range of coverage of the BIOMED-2 primer mixes provided in this assay.

Increased expression of interferon signaling genes in the bone marrow microenvironment of myelodysplastic syndromes

Introduction

The bone marrow (BM) microenvironment plays an important role in the pathogenesis of myelodysplastic syndromes (MDS) through a reciprocal interaction with resident BM hematopoietic cells. We investigated the differences between BM mesenchymal stromal cells (MSCs) in MDS and normal individuals and identified genes involved in such differences.

Materials and Methods

BM-derived MSCs from 7 MDS patients (3 RCMD, 3 RAEB-1, and 1 RAEB-2) and 7 controls were cultured. Global gene expression was analyzed using a microarray.

Result

We found 314 differentially expressed genes (DEGs) in RCMD vs. control, 68 in RAEB vs. control, and 51 in RAEB vs. RCMD. All comparisons were clearly separated from one another by hierarchical clustering. The overall similarity between differential expression signatures from the RCMD vs. control comparison and the RAEB vs. control comparison was highly significant (p = 0), which indicates a common transcriptomic response in these two MDS subtypes. RCMD and RAEB simultaneously showed an up-regulation of interferon alpha/beta signaling and the ISG15 antiviral mechanism, and a significant fraction of the RAEB vs. control DEGs were also putative targets of transcription factors IRF and ICSBP. Pathways that involved RNA polymerases I and III and mitochondrial transcription were down-regulated in RAEB compared to RCMD.

Conclusion

Gene expression in the MDS BM microenvironment was different from that in normal BM and exhibited altered expression according to disease progression. The present study provides genetic evidence that inflammation and immune dysregulation responses that involve the interferon signaling pathway in the BM microenvironment are associated with MDS pathogenesis, which suggests BM MSCs as a possible therapeutic target in MDS.

Improving the cytological diagnosis of intraocular lymphoma from vitreous fluid

AIMS

To improve the cytological diagnosis of retinal lymphoma on vitreous fluid using improved cell collection and systematic analyses.

METHODS AND RESULTS

Since October 2010, we have developed and optimized in our department a method with which to perform the diagnosis of retinal lymphoma. The vitreous sample was collected in a tube containing RPMI-1640 medium, decomplemented fetal bovine serum, and gentamicin. The transport and technical steps were performed at 4°C. Systematically, cytological examination with May-Grünwald-Giemsa staining and immunocytochemistry (mainly anti-CD3, anti-CD20 and anti-CD68 antibodies) were performed on cytospins. Whenever possible, determination of B-cell clonality, flow cytometry and determination of the interleukin (IL)-10/IL-6 ratio were performed. From October 2010 to June 2013, with this optimized protocol, 38 vitreous cytological samples from 32 patients were analysed, and a final diagnosis was possible, avoiding a biopsy, in all cases except one.

CONCLUSION

The preservation of vitreous fluid cells on culture medium led to the diagnosis of retinal lymphoma in 10 of 12 cases, and exclusion of this diagnosis in 26 cases. This protocol may be applied even when the delay in shipping from the surgery to the pathology departments exceeds 1 h.

Frequency, interobserver reproducibility and clinical significance of equivocal peaks in PCR clonality testing using Euroclonality/BIOMED-2 primers

AIMS

PCR studies for lymphoid clonality are now widely employed, especially using Euroclonality/BIOMED-2 primers. Criteria for interpretation as a clonal result, however, have proven controversial. This study examines the frequency and clinical significance of equivocal amplification patterns and measures the interobserver reproducibility of clonality interpretations.

METHODS

At our institution, results of each primer set are first classified as clonal, non-clonal or abnormal (equivocal peak on polyclonal background). Final results for all primer sets are then collectively reported as positive (≥1 clonal result), negative (non-clonal results) or indeterminate (≥1 abnormal result) for a clonal population. Results of 274 consecutive clonality cases were reviewed, and the interobserver reproducibility of individual primer set reactions and final results was determined in a subset of 30 cases.

RESULTS

44/161 (27%) B-cell and 50/163 (31%) T-cell cases contained at least one abnormal peak. Of these, 29 (64%) and 31 (62%), respectively, showed clonal results in another primer set. Interobserver reproducibility was excellent for most primer sets and for final interpretations, but only fair to good for IGK V-J and TCRB D-J1+2 primer sets. A definitive diagnosis of lymphoma was rendered in 93%, 20% and 6% of B-cell cases and 90%, 42%, and 14% of T-cell cases positive, indeterminate or negative for a clonal population, respectively.

CONCLUSIONS

Using a subjective approach, abnormal (equivocal) peaks are frequently observed in routine practice. However, most cases with abnormal peaks contain clonal rearrangements in other primer sets, facilitating overall interpretation of final results with excellent interobserver reproducibility.

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

Background

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

Materials and methods.

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

Results

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

Conclusions

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

Infectious mononucleosis accompanied by clonal proliferation of EBV-infected cells and infection of CD8-positive cells

A 22-year-old male was admitted for a sustained fever of 2 months, lymphadenopathy, and liver dysfunction. Anti-VCA-IgM antibody was positive, with elevated Epstein-Barr virus (EBV)-DNA load in the peripheral blood. Liver biopsy revealed infiltration of CD8-positive and EBV-positive cells. Most peripheral blood mononuclear cells (PBMCs) were also positive for CD8, and showed detectable levels of EBV-DNA. Monoclonal proliferation of EBV-infected cells was detected in the PBMCs by Southern blotting for EBV-terminal repeat (EBV-TR). Although EBV-positive T-cell lymphoproliferative disease (EBV-T-LPD) was suspected, the symptoms spontaneously resolved within 12 months. Anti-VCA-IgM antibody and the clonal band of EBV-TR were negative 1 year after the onset, while anti-EBNA antibody was positive. The final diagnosis was thus confirmed as infectious mononucleosis (IM). Our results indicate that EBV-infected CD8-positive cells and clonal proliferation of EBV-infected cells may be temporally detected in IM. EBV-T-LPDs should be carefully excluded in such cases.

Successive B-cell lymphomas mostly reflect recurrences rather than unrelated primary lymphomas

OBJECTIVES

To address whether successive B-cell lymphomas, diagnosed within a 5- to 15-year interval, are recurrences or unrelated primary lymphomas.

METHODS

Immunoglobulin heavy and κ light chain gene rearrangements were studied using multiplex polymerase chain reaction fragment assays and sequence analysis in 61 patients.

RESULTS

Clonal patterns of the multiple lymphomas from 36 patients were determined and classified accordingly: 30 recurrences, 2 possible recurrences, 2 different clones with a common origin, and 2 unrelated primary lymphomas.

CONCLUSIONS

Regardless of subtype, 89% to 94% of late B-cell lymphoma relapses were recurrences of the primary tumor. Therefore, routinely investigating the possible clonal relationship between successive lymphomas may not be warranted except for specific lymphoma subtypes such as diffuse large B-cell lymphomas.

Network properties derived from deep sequencing of human B-cell receptor repertoires delineate B-cell populations

The adaptive immune response selectively expands B- and T-cell clones following antigen recognition by B- and T-cell receptors (BCR and TCR), respectively. Next-generation sequencing is a powerful tool for dissecting the BCR and TCR populations at high resolution, but robust computational analyses are required to interpret such sequencing. Here, we develop a novel computational approach for BCR repertoire analysis using established next-generation sequencing methods coupled with network construction and population analysis. BCR sequences organize into networks based on sequence diversity, with differences in network connectivity clearly distinguishing between diverse repertoires of healthy individuals and clonally expanded repertoires from individuals with chronic lymphocytic leukemia (CLL) and other clonal blood disorders. Network population measures defined by the Gini Index and cluster sizes quantify the BCR clonality status and are robust to sampling and sequencing depths. BCR network analysis therefore allows the direct and quantifiable comparison of BCR repertoires between samples and intra-individual population changes between temporal or spatially separated samples and over the course of therapy.

Dysregulated RasGRP1 responds to cytokine receptor input in T cell leukemogenesis

Enhanced signaling by the small guanosine triphosphatase Ras is common in T cell acute lymphoblastic leukemia/lymphoma (T-ALL), but the underlying mechanisms are unclear. We identified the guanine nucleotide exchange factor RasGRP1 (Rasgrp1 in mice) as a Ras activator that contributes to leukemogenesis. We found increased RasGRP1 expression in many pediatric T-ALL patients, which is not observed in rare early T cell precursor T-ALL patients with KRAS and NRAS mutations, such as K-Ras(G12D). Leukemia screens in wild-type mice, but not in mice expressing the mutant K-Ras(G12D) that encodes a constitutively active Ras, yielded frequent retroviral insertions that led to increased Rasgrp1 expression. Rasgrp1 and oncogenic K-Ras(G12D) promoted T-ALL through distinct mechanisms. In K-Ras(G12D) T-ALLs, enhanced Ras activation had to be uncoupled from cell cycle arrest to promote cell proliferation. In mouse T-ALL cells with increased Rasgrp1 expression, we found that Rasgrp1 contributed to a previously uncharacterized cytokine receptor-activated Ras pathway that stimulated the proliferation of T-ALL cells in vivo, which was accompanied by dynamic patterns of activation of effector kinases downstream of Ras in individual T-ALLs. Reduction of Rasgrp1 abundance reduced cytokine-stimulated Ras signaling and decreased the proliferation of T-ALL in vivo. The position of RasGRP1 downstream of cytokine receptors as well as the different clinical outcomes that we observed as a function of RasGRP1 abundance make RasGRP1 an attractive future stratification marker for T-ALL.

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.

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.

Early posttransplant lymphoproliferative disease: clinicopathologic features and correlation with mTOR signaling pathway activation

Early posttransplant lymphoproliferative disorders (EPTLDs) represent the first changes in posttransplant lymphoproliferative disorders (PTLDs) morphologic spectrum. EPTLD data are available mostly from case reports and series that include other types of PTLD. Fifteen EPTLDs were reviewed retrospectively. Clinical data, histopathology, clonality, and Epstein- Barr virus (EBV) status were correlated with staining intensity to an antibody for phosphorylated S6 (pS6) ribosomal protein, a downstream effector of mammalian target of rapamycin (mTOR). Median time from transplantation to EPTLD was 50 months (range, 7-135 mo). EPTLDs involved tonsil and/or adenoids (n = 11) and lymph nodes (n = 4), all of which were nonclonal and EBV-encoded RNA-positive. Most (n = 11) were plasmacytic hyperplasia and florid follicular hyperplasia (n = 4). All regressed with reduced immunosuppression, and had increased pS6 staining compared with normal tonsil (P = .002, F test). EPTLDs developed later than previously reported, involved mostly tonsils/adenoids, were EBV-encoded RNA (EBER) positive, showed increased pS6, and had excellent clinical outcome with reduction of immunosuppression.

Diagnostic significance of TCR gene clonal rearrangement analysis in early mycosis fungoides

Mycosis fungoides (MF), the most common type of cutaneous T-cell lymphoma, has various unspecific clinical and histological characteristics. Its early diagnosis is challenging. The application of T-cell receptor (TCR) gene clonal rearrangement to the diagnosis of MF has been widely studied. In this study, we used polymerase chain reaction (PCR) to investigate the diagnostic significance of detecting TCR-γ and -β gene clonal rearrangement in the early diagnosis of mycosis fungoides. PCR for TCR-γ and TCR-β gene rearrangement was performed on 19 patients with suspected early MF, 6 with typical MF, and 6 with chronic dermatitis. Of the 19 patients with suspected early MF, 13 had TCR-γ gene clonal rearrangement, whereas none had TCR-β gene clonal rearrangement. All patients with typical MF had TCR gene clonal rearrangement, in which 4 showed TCR-γ clonal rearrangement, 1 showed TCR-β gene clonal rearrangements, and 1 showed both. No patients with chronic dermatitis had TCR gene clonal rearrangement. These results indicate that TCR gene clonal rearrangement analysis is a useful tool in diagnosing early MF. TCR-γ gene is recommended to the routine analysis, whereas TCR-β gene has potential in combination toward intractable cases.

Application of flow cytometric in situ hybridization assay to Epstein-Barr virus-associated T/natural killer cell lymphoproliferative diseases

Epstein-Barr virus (EBV) infects various types of lymphocytes and is associated with not only B cell-origin lymphoma, but also T or natural killer cell lymphoproliferative diseases (T/NK LPD). Recently, we established a novel assay to identify EBV-infected cells using FISH. Using this assay, dual staining with antibodies to both surface antigens and an EBV-encoded small RNA (EBER) probe can be performed. In the present study, we applied this recently developed FISH assay to EBV-associated T/NK LPD to confirm its diagnostic utility. Using FISH, we prospectively analyzed peripheral blood from patients with suspected EBV-associated T/NK LPD. The results were compared with those obtained using immunobead sorting followed by quantitative PCR. In all, 26 patients were included study. Using FISH, 0.15-67.0% of peripheral blood lymphocytes were found to be positive for EBER. Dual staining was used to determine EBER-positive cell phenotypes in 23 of 26 subjects (88.5%). In five of seven patients with hydroa vacciniforme-like lymphoma (an EBV-positive cutaneous T cell lymphoma), EBER-positive cells were identified as CD3(+) CD4(-) CD8(-) TCRγδ(+) T cells. Furthermore, in a 25-year-old male patient with systemic EBV-positive T cell LPD, two lymphocyte lineages were positive for EBER: CD4(+) CD8(-) and CD4(-) CD8(+) T cells. Thus, we confirmed that our newly developed assay is useful for quantifying and characterizing EBV-infected lymphocytes in EBV-associated T/NK LPD and that it can be used not only to complement the pathological diagnosis, but also to clarify the pathogenesis and to expand the spectrum of EBV-associated diseases.

Clonality in sarcoidosis, granuloma annulare, and granulomatous mycosis fungoides

The histological discrimination of granulomatous cutaneous T-cell lymphomas (CTCLs) from reactive granulomatous disorders such as sarcoidosis and granuloma annulare (GA) may be difficult due to overlapping histological features. We analyzed the T-cell receptor gene rearrangement in sarcoidosis and GA to investigate the value of the detection of clonal T cells as an adjunctive diagnostic marker in the differentiation between sarcoidosis and GA versus granulomatous CTCLs. Rearrangement of T-cell receptor γ genes was examined by the use of automated high-resolution polymerase chain reaction fragment analysis in 35 cases of sarcoidosis and 15 cases of GA and compared with a series of 19 cases of granulomatous CTCLs. A monoclonal T-cell population was found in none of the cases of sarcoidosis and in 2 of 15 cases of GA (13%). In granulomatous CTCLs, a neoplastic T-cell clone was detected in 94%. Presence of clonal T cells argues in favour of a granulomatous CTCL, while a polyclonal T-cell population makes the presence of a sarcoidosis or a GA more likely. The analysis of T-cell clonality is a useful diagnostic adjunct in the differentiation between sarcoidosis and GA from granulomatous CTCLs.

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.

A simple and efficient method for DNA extraction from skin and paraffin-embedded tissues applicable to T-cell clonality assays

PCR-based clonality assay of rearranged T-cell receptor genes gamma and beta (TCRG and TCRB) in a number of cases could be essential to discriminate between cutaneous T-cell lymphomas and reactive lymphoproliferative lesions in the skin. However, extraction of good-quality DNA from skin specimens (especially formalin-fixed paraffin-embedded) remains a challenge. Common procedures, being labour-intensive and time-consuming and requiring toxic solvents such as phenol and chloroform, still may end up with DNA sample of insufficient quality. We herewith present a simple and efficient method for DNA isolation based on ammonia extraction of tissue, followed by neutralization and simultaneous salting out of proteins with acetic acid. We have analysed 30 samples - 24 fresh (16 skin, two spleen and six lymph node) and six paraffin-embedded. Standard procedure (proteinase K digestion, followed by phenol/chloroform extraction) has been carried out simultaneously. We observed good PCR signal for TCRG rearrangements in 30 samples processed with the new protocol and only in 20 extracted with proteinase K/phenol/chloroform. For TCRB, the success rate was 29 of 30 with the new protocol, compared to 11 of 30 with conventional protocol. The proposed method of DNA extraction should improve the value of T-cell clonality assay, because insufficient DNA quality and quantity may bias analysis towards monoclonality and therefore cause false-positive results.

Molecular cytogenetics of lymphoma: where do we stand in 2010?

For the past 20 years most malignant lymphomas have been classified as clinicopathological entities, each with its own combination of clinical, morphological, immunophenotypic and molecular genetic characteristics. Molecular and cytogenetic abnormalities can be detected by a wide range of techniques, ranging from conventional karyotyping to single nucleotide polymorphism analysis. In this review, we consider the common genetic abnormalities found in lymphoma and discuss the advantages and disadvantages of individual techniques used in their detection. Finally, we discuss briefly possible novel developments in the field of lymphoma diagnostics.

Treatment of mucosa-associated lymphoid tissue lymphoma in Sjogren's syndrome: a retrospective clinical study

OBJECTIVE

To retrospectively analyze the clinical course of patients with mucosa-associated lymphoid tissue (MALT)-type lymphoma of the parotid gland and associated Sjögren's syndrome (SS).

METHODS

All consecutive patients with SS and MALT lymphoma (MALT-SS) diagnosed in the University Medical Center Groningen between January 1997 and January 2009 were analyzed. Clinical course and treatment outcome of SS and MALT lymphoma were evaluated.

RESULTS

From a total of 329 patients with SS, 35 MALT-SS patients were identified, with a median followup of 76 months (range 16-153 mo). MALT lymphoma was localized in the parotid gland in all cases. Treatment consisted of "watchful waiting" (n = 10), surgery (n = 3), radiotherapy (n = 1), surgery combined with radiotherapy (n = 2), rituximab only (n = 13), or rituximab combined with chemotherapy (n = 6). Complete response was observed in 14 patients, partial response in 1 patient, and stable disease in 20 patients. In 6 of 7 patients with initially high SS disease activity (M-protein, cryoglobulins, IgM rheumatoid factor > 100 KIU/l, severe extraglandular manifestations), MALT lymphoma progressed and/or SS disease activity increased after a median followup of 39 months (range 4-98 mo), necessitating retreatment. Only 1 patient with MALT who had low SS disease activity showed progression of lymphoma when left untreated.

CONCLUSION

An initially high SS disease activity likely constitutes an adverse prognostic factor for progression of lymphoma and/or SS. Such patients may require treatment for both MALT lymphoma and SS. In SS patients with localized asymptomatic MALT lymphoma and low SS disease activity, a "watchful waiting" strategy seems justified.

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.