Immunoglobulin Gene Rearrangement Analysis Research Articles

Bilateral development of biclonal ocular adnexal marginal zone lymphoma at a 2-year interval.

Ocular adnexal marginal zone B-cell lymphoma (OAMZL) of the mucosa-associated lymphoid tissue is a distinct subtype of B-cell lymphoma. OAMZL occasionally occurs on both sides with a varied sequence in the time course. However, few case reports have described clonal analysis of bilateral OAMZ. Here we present a case of biclonal OAMZL, that developed bilaterally at a 2-year interval. A 38-year-old woman was diagnosed with OAMZL in the right lower eyelid conjunctiva and received local radiation therapy, resulting in the disappearance of the tumor. Two years later, she developed another tumor in the left lower eyelid and was diagnosed with relapse of OAMZL. She was re-treated successfully with radiation therapy. Analysis of immunoglobulin (Ig) gene rearrangement in the bilateral tumor samples showed different clonotypic VDJ recombination within the Ig heavy chain gene and different patterns of rearrangement of the Ig light chain genes. The results indicated that independent B-cell clones causing the specific subtype of lymphoma had generated in both eyes. The biclonal nature of the lymphoma that developed sequentially in the same anatomic site in this case suggests that underlying inherent or environmental factors may lead to ongoing emergence of new tumor clones.

Assessment of Bone Marrow Involvement in B-Cell non-Hodgkin Lymphoma Using Immunoglobulin Gene Rearrangement Analysis with Next-Generation Sequencing.

Assessment of bone marrow involvement (BMI) in non-Hodgkin lymphoma (NHL) is crucial for determining patient prognosis and treatment strategy. We assessed the prognostic value of next-generation sequencing (NGS)-based immunoglobulin (Ig) gene clonality analysis as an ancillary test for BMI evaluation in NHL. A retrospective cohort of 124 patients newly diagnosed with B-cell NHL between 2019 and 2022 was included. NGS-based Ig clonality analysis was conducted using LymphoTrak IGH FR1 Assay and IGK Assay (Invivoscribe Technologies, San Diego, CA, USA) on BM aspirate samples, and the results were compared with those of histopathological BMI (hBMI). Among the 124 patients, hBMI was detected in 16.9% (n = 21). The overall agreement of BMI between Ig clonality analyses and histopathological analysis for IGH, IGK, and either IGH or IGK was 86.3%, 92.7%, and 90.3%. The highest positive percent agreement was observed with clonal rearrangements of either IGH or IGK gene (90.5%), while the highest negative percent agreement was observed with clonal rearrangement of IGK gene (96.1%). For the prediction of hBMI, positive prediction value ranged between 59.1% and 80.0% and the negative prediction value ranged between 91.3% and 97.9%. NGS-based clonality analysis is an analytic platform with a substantial overall agreement with histopathological analysis. Assessment of both IGH and IGK genes for the clonal rearrangement analysis could be considered for the optimal diagnostic performance of BMI detection in B-cell NHL.

Comparison of Measurable Residual Disease in Pediatric B-Lymphoblastic Leukemia Using Multiparametric Flow Cytometry and Next-Generation Sequencing.

Measurable residual disease (MRD) testing, a standard procedure in B-lymphoblastic leukemia (B-ALL) diagnostics, is assessed using multiparametric flow cytometry (MFC) and next-generation sequencing (NGS) analysis of immunoglobulin gene rearrangements. We evaluated the concordance between eight-color, two-tube MFC-MRD the LymphoTrack NGS-MRD assays using 139 follow-up samples from 54 pediatric patients with B-ALL. We also assessed the effect of hemodilution in MFC-MRD assays. The MRD-concordance rate was 79.9% (N=111), with 25 (18.0%) and 3 (2.2%) samples testing positive only by NGS-MRD (MFC-NGS+MRD) and MFC-MRD (MFC+NGS-MRD), respectively. We found a significant correlation in MRD values from total nucleated cells between the two methods (r=0.736 [0.647-0.806], P<0.001). The median MRD value of MFC-NGS+MRD samples was estimated to be 0.0012% (0.0001%-0.0263%) using the NGS-MRD assays. Notably, 14.3% of MFC-NGS+MRD samples showed NGS-MRD values below the limit of detection in the MFC-MRD assays. The percentages of hematogones detected in MFC-MRD assays significantly differed between the discordant and concordant cases (P<0.001). MFC and NGS-MRD assays showed relatively high concordance and correlation in MRD assessment, whereas the NGS-MRD assay detected MRD more frequently than the MFC-MRD assay in pediatric B-ALL. Evaluating the hematogone percentages can aid in assessing the impact of sample hemodilution.

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.

Direct-acting antiviral agents in lymphoproliferative disorders: more complex than expected.

Direct-acting antiviral agents in lymphoproliferative disorders: more complex than expected.

Outcomes of patients with childhood B-cell precursor acute lymphoblastic leukaemia with late bone marrow relapses: long-term follow-up of the ALLR3 open-label randomised trial

SummaryBackgroundThe ALLR3 trial investigated outcomes of children with B-cell precursor acute lymphoblastic leukaemia who had late bone marrow relapses. We analysed long-term follow-up outcomes of these patients.MethodsALLR3 was an open-label randomised clinical trial that recruited children aged 1–18 years with B-cell precursor acute lymphoblastic leukaemia who had late bone marrow relapses. Eligible patients were recruited from centres in Australia, Ireland, the Netherlands, New Zealand, and the UK. Patients were randomly assigned from Jan 31, 2003, to Dec 31, 2007, and the trial closed to recruitment on Oct 31, 2013. Randomly assigned patients were allocated to receive either idarubicin or mitoxantrone in induction by stratified concealed randomisation; after randomisation stopped in Dec 31, 2007, all patients were allocated to receive mitoxantrone. After three blocks of therapy, patients with high minimal residual disease (≥10−4 cells) at the end of induction were allocated to undergo allogeneic stem-cell transplantation and those with low minimal residual disease (<10−4 cells) at the end of induction were allocated to receive chemotherapy. Minimal residual disease level was measured by real-time quantitative PCR analysis of immunoglobulin and T-cell receptor gene rearrangements. The primary endpoint of the original ALLR3 clinical trial was progression-free survival of randomly assigned patients. The primary endpoint of this long-term follow-up analysis was progression-free survival of patients with late bone marrow relapses stratified by minimal residual disease level. Outcomes were correlated with age, site, time to recurrence, and genetic subtypes, and analysed by both intention to treat and actual treatment received. This trial is registered on the ISRCTN registry, number ISRCTN45724312, and on ClinicalTrials.gov, number NCT00967057.FindingsBetween Feb 2, 2003, and Oct 28, 2013, 228 patients with B-cell precursor acute lymphoblastic leukaemia and late bone marrow relapses were treated. After a median follow-up of 84 months (IQR 48–109), progression-free survival of all randomly assigned patients was 60% (95% CI 54–70). 220 patients achieved second complete remission, and minimal residual disease was evaluable in 192 (87%). 110 patients with late bone marrow relapses and high minimal residual disease at the end of induction were allocated to undergo stem-cell transplantation, and 82 patients with low minimal residual disease at the end of induction were allocated to receive chemotherapy. In the patients allocated to undergo stem-cell transplantation, four relapses and three deaths were reported before the procedure, and 11 patients were not transplanted. Of the 92 patients transplanted, 58 (63%) remained in second complete remission, 13 (14%) died of complications, and 21 (23%) relapsed after stem-cell transplantation. In patients allocated to receive chemotherapy, one early treatment-related death was reported and 11 patients were transplanted. Of the 70 patients who continued on chemotherapy, 49 (70%) remained in second complete remission, two (3%) died of complications, and 19 (27%) relapsed. Progression-free survival at 5 years was 56% (95% CI 46–65) in those with high minimal residual disease and 72% (60–81) in patients with low minimal residual disease (p=0·0078). Treatment-related serious adverse events were not analysed in the long-term follow-up.InterpretationPatients with B-cell precursor acute lymphoblastic leukaemia with late bone marrow relapses and low minimal residual disease at end of induction had favourable outcomes with chemotherapy without undergoing stem-cell transplantation. Patients with high minimal residual disease benefited from stem-cell transplantation, and targeted therapies might offer further improvements in outcomes for these patients.FundingBloodwise (Formerly Leukaemia and Lymphoma Research) UK, Cancer Research UK, Sporting Chance Cancer Foundation, National Health and Medical Research Council Australia, KindreneKankervrij Netherlands, European Union Seventh Framework Programme, India Alliance Wellcome DBT Margdarshi Fellowship.

Primary adrenal diffuse large B cell lymphoma: a clinicopathological and molecular study from China.

Primary adrenal lymphoma is a rare entity that, in most cases, is derived from B cells. The most commonly seen primary adrenal lymphoma is diffuse large B cell lymphoma (DLBCL). To better understand the clinicopathological and molecular features of these tumors, we studied 14 Chinese patients with DLBCL who initially presented with an adrenal tumor. The clinicopathological features of the 14 primary adrenal DLBCL cases were retrospectively reviewed using immunohistochemistry, immunoglobulin gene rearrangement analysis, evaluation of Epstein-Barr virus status, and fluorescence in situ hybridization. Patient age ranged from 43 to 69years, with a mean age of 58years. The patients most commonly presented with abdominal pain and adrenal mass. Ten patients exhibited bilateral adrenal masses, and four had unilateral adrenal masses (three left, one right). Thirteen of 14 DLBCLs were DLBCL not otherwise specified, and one was an intravascular large B cell lymphoma. According to the algorithm of Hans et al. (Blood 103:275-282, 2004), 13 and 1 cases were classified as the non-germinal center B-cell-like subtype and the germinal center B-cell-like subtype, respectively. The Ki-67 index ranged from 35 to 80%. Epstein-Barr virus-encoded RNA was detected by in situ hybridization in 6 of the 12 available cases. Two patients showed BCL-6 rearrangements. The follow-up period ranged from 1 to 87months. During the follow-up period, four patients died of the disease, five were alive with the disease, four were alive without disease, and one was lost during the follow-up period. In summary, most primary adrenal lymphomas are non-germinal-center B-cell-like subtype DLBCLs, which have high proliferative activity and a poor prognosis.

Molecular pathology diagnosis of diffuse large B cell lymphoma using BIOMED-2 clonal gene rearrangements.

Clonality testing for immunoglobulin gene rearrangement analysis could be implemented effectively as a useful technique for conventional diagnosis of lymphoma. The European Biomedicine and Health Concerted Action Project BMH4-CT98-3936 (BIOMED-2) have been suggested a gold standard method to clonality detection. We tested empirically clonality rearrangements of IGH and incomplete IGH D-J, on formalin-fixed, paraffin embedded (FFPE) tissue of patients with diffuse large B cell lymphoma (DLBCL). This appraisal was conveyed on 50 sequential FFPE specimens of patients with DLBCL. We carried out a standard multiplex PCR and heteroduplex techniques to analysis of IGH and incomplete IGH D-J clonal gene rearrangements. In our investigation, we were identified a total positive monoclonality of 96% (48/50) for IGH and 58% (29/50) for incomplete IGH D-J. The percentage of positive clonality was detected in three frameworks (FRI, II, III) of IGH revealed 50% (25/50), 28% (14/50) and 18% (9/50) to FRIII, FRII and FRI, respectively. Analysis of incomplete IGH D-J showed 34% (17/50) and 24% (12/50) rates of positive clonality for DH1-6-JH and DH7-JH, respectively. In the 4% (2/50) of cases was no detected any gene rearrangements in both of IGH and incomplete IGH D-J genes. Analysis of molecular clonality gene rearrangements on FFPE tissues disclosed that using BIOMED-2 protocols, could be improvement significant clinicopathological diagnosis of DLBCL. Clonality testing is believable that to suggest as a helpful and credible technique for clonality detection in the routine diagnosis of DLBCL and other lymphoproliferative disorders.

Establishment of a novel human lymphoblastic cell strain with the long arm of chromosome 11 aberration without MLL rearrangement

At present, all cell strains derived from acute lymphoblastic leukemia (ALL) patients with the long arm of chromosome 11 aberration are accompanied with mixed lineage leukemia (MLL) gene rearrangement. In this study, we established a permanent ALL cell strain CHH-1 with the long arm of chromosome 11 aberration and without MLL rearrangement, hoping that it could be used for the research of ALL with such genetic abnormality. CHH-1 cell strain was certified through morphology, immunophenotype, genetics and immunoglobulin (Ig) gene rearrangement analysis. Cell characteristics including tumorigenic ability, semisolid colony forming ability, telomerase activity, autocrine and invasion were further detected. Cells were with an add(11)(q23) structural abnormality without MLL rearrangement, and were consistent with the genetic abnormality of the patient. In addition, these cells had features of tumor-forming ability, high colony forming capacity, unique cytokine autocrine mode, high telomerase activity, and high invasion ability. CHH-1 may prove to be a useful cell model for the research of human leukemia with genetic aberration in chromosome 11, and help explore the role of such genetic abnormality in the pathogenesis, progression and prognosis of ALL, and in developing new target drugs.

Hodgkin's lymphoma as a rare variant of Richter's transformation in chronic lymphocytic leukemia: A case report and review of the literature.

Richter's transformation induces an aggressive clinical course in chronic lymphocytic leukemia (CLL). In the majority of cases, Richter's transformation manifests itself as a high-grade B-cell non-Hodgkin's lymphoma (B-NHL). However, other histological types, such as classical Hodgkin lymphoma (cHL), lymphoblastic lymphoma, hairy cell leukemia and high-grade T-cell NHL have been described previously. The present study reports a rare case of CLL with transformation into classical Hodgkin's lymphoma (cHL). The common clonal origin of CLL and cHL was documented by immunoglobulin gene rearrangement analysis performed using multiplex polymerase chain reaction. Following a review of the literature, treatment of secondary Hodgkin's lymphoma is discussed, and prognosis is often poor.

Clonality Analysis of Immunoglobulin Gene Rearrangement by Next-Generation Sequencing in Endemic Burkitt Lymphoma Suggests Antigen Drive Activation of BCR as Opposed to Sporadic Burkitt Lymphoma.

Objectives: Recent studies using next-generation sequencing (NGS) analysis disclosed the importance of the intrinsic activation of the B-cell receptor (BCR) pathway in the pathogenesis of sporadic Burkitt lymphoma (sBL) due to mutations of TCF3/ID3 genes. Since no definitive data are available on the genetic landscape of endemic Burkitt (eBL), we first assessed the mutation frequency of TCF3/ID3 in eBL compared with sBL and subsequently the somatic hypermutation status of the BCR to answer whether an extrinsic activation of BCR signaling could also be demonstrated in Burkitt lymphoma.Methods: We assessed the mutations of TCF3/ID3 by RNAseq and the BCR status by NGS analysis of the immunoglobulin genes (IGs).Results: We detected mutations of TCF3/ID3 in about 30% of the eBL cases. This rate is significantly lower than that detected in sBL (64%). The NGS analysis of IGs revealed intraclonal diversity, suggesting an active targeted somatic hypermutation process in eBL compared with sBL.Conclusions: These findings support the view that the antigenic pressure plays a key role in the pathogenetic pathways of eBL, which may be partially distinct from those driving sBL development.

Abstract 5164: Lacking clonal relationship in 20% of relapsing diffuse large B-cell lymphomas

Abstract Introduction: Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma in adults. Nearly half of the patients can be cured with standard therapeutic regimens. However, a substantial number of patients experience a recurrence. In general, lymphoma recurrences are considered to represent a relapse of the original neoplasm, but this concept has been recently challenged by demonstration of clonally unrelated relapses by immunoglobulin (heavy chain) gene (IGH) rearrangement analysis. Although being the most widely used method for clonality testing, IGH fragment length analysis has a very limited output of information not giving any insight about tumor heterogeneity and evolution in time. Also, the result is based only on a single gene in the whole genome, and therefore it can be error-prone. We applied a genome-wide clonality testing on 17 paired primary and relapsed DLBCL aiming to provide an unambiguous answer about the existence of clonally unrelated recurrences in this entity. Additionally, we profiled 10 cases of non-relapsing DLBCL searching for genetic markers at diagnosis which could predict lymphoma relapse. Methods: Genomic DNA extracted from formalin-fixed paraffin-embedded tissue with at least 70% tumor content was used for the analysis. Array-comparative genomic hybridization was utilized to detect chromosomal copy number aberrations and to determine clonal relationship status of each primary-relapse pair. This result was then verified by IGH gene fragment length analysis. Directed deep-sequencing was performed on a custom hot-spot panel consisting of most frequently mutated genes in DLBCL. Results: Among 17 cases of recurring DLBCL, 3 relapses (17%) were identified which were clonally unrelated to the primary disease by copy number aberration and IGH fragment length analysis. Different modes of tumor progression could be detected within clonally related set of relapses, providing evidence of a common early progenitor cell population in some patients. Moreover, some DLBCL exhibit substantial intra- and inter- tumoral heterogeneity, which is probably a source of variation in patient outcomes and clonal progression. Comparison of copy number aberration and point mutation profiles between relapsing and non-relapsing tumors yielded significant differences, which could be useful for understanding the genetic basis of DLBCL recurrence. Conclusions: We provide a clear evidence for the existence of clonally unrelated relapses in DLBCL. The existence of clonally unrelated relapses might be of clinical importance since relapses are usually treated more aggressively than primary neoplasms with a significant treatment-related morbidity, and this may be by-passed in the former instances. Moreover, the high definition clonal analyses provide new insights into the molecular profiles of tumors in vivo, and therefore might contribute to the development of more personalized approaches for cancer treatment. Citation Format: Darius Juskevicius, Alexander Rufle, Christian Ruiz, Stephan Dirnhofer, Alexandar Tzankov. Lacking clonal relationship in 20% of relapsing diffuse large B-cell lymphomas. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5164. doi:10.1158/1538-7445.AM2014-5164

Chronic lymphocytic leukemia presenting with ascites diagnosed by clonality analysis via gene rearrangement assay: A case report.

The diagnosis of chronic lymphocytic leukemia (CLL) presenting with ascites is predominantly based on the morphological and immunophenotypic characteristics, which are comparable to peripheral blood and bone marrow cells. However, it is relatively difficult to diagnose CLL due to the pleomorphism of the lymphocytes in ascites. The current study presents an 80-year-old male with a prior diagnosis of CLL who developed large ascites. Predominant T lymphocytes rendered morphological and immunophenotypic diagnosis difficult. Clonality analysis of immunoglobulin (Ig) gene rearrangements was performed on the lymphocytes from the ascites to diagnose the involvement of CLL, a laparotomy and biopsy from the peritoneal node confirmed the involvement of small lymphocytic lymphoma/CLL. The clonality analysis of Ig gene rearrangements may provide a powerful and accurate method for diagnosing CLL presenting with ascites.

Human herpesvirus 8+ polyclonal IgMλ B‐cell lymphocytosis mimicking plasmablastic leukemia/lymphoma in HIV‐infected patients

Multicentric Castleman disease (MCD) is a distinct lymphoproliferative disorder characterized by inflammatory symptoms, lymphadenopathy, splenomegaly, and cytopenia. Kaposi's sarcoma-associated herpesvirus (KSHV), also called human herpesvirus-8 (HHV-8), is the cause of virtually all cases of MCD occurring in patients with HIV infection. MCD lesions characteristically contain HHV-8-infected polyclonal IgMλ plasmablasts. A high frequency of HHV-8-related non-Hodgkin lymphoma has been reported in these patients. We now report on three patients who presented with severe symptoms of MCD, extreme splenomegaly, and rapid expansion of B-cell lymphocytosis (44-81%) attributable to circulating HHV-8 positive plasmablasts. The circulating plasmablastic cells shared the phenotype (IgMλ, CD19+, CD20- CD138-) of HHV-8-infected cells from MCD lesions, mimicking the leukemic phase of large B-cell lymphoma occurring in HHV-8-related MCD. These patients displayed a very high HHV-8 viral load in blood (>7 logs HHV-8 DNA copies/ml) and high levels of serum vIL-6, the viral homolog of human interleukin 6. Serum IL-6 and IL-10 were also abnormally elevated. HHV-8-infected cells were demonstrated by immunoglobulin gene rearrangement analysis, to be polyclonal and likely represent an expansion of HHV-8-infected cells similar to those found in MCD lesions. Thus, the spectrum of HHV-8-related plasmablastic lymphoproliferative disorders in patients with HIV infection is expanded to include HHV-8+ polyclonal IgMλ B-cell lymphocytosis. At onset, this lymphoproliferative disorder may mimic plasmablastic leukemia/lymphoma. Recognizing this unusual complication may have important implications in treatment decision avoiding unnecessary toxicity to the patients.

Nævus géant congénital

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

Plasmablastic lymphoma of the stomach in an HIV‐negative patient

Plasmablastic lymphoma (PBL) is a rare B-cell neoplasm with an aggressive clinical behavior that predominantly occurs in the oral cavity of human immunodeficiency virus (HIV)-positive patients. However, it has recently been recognized that PBLs can also affect individuals without HIV infection, and suggested that these neoplasms show different clinicopathological characteristics between HIV-positive and -negative patients. Herein we describe a case of gastric PBL in a female HIV-negative patient. The tumor was composed of a diffuse and cohesive proliferation of large neoplastic cells, which resembled immunoblasts or plasmablasts with a starry sky appearance. Immunophenotypically, the neoplastic cells were diffusely positive for CD138, MUM1, IgM, and BOB-1, and negative for CK, LCA, CD3, CD20, CD79a, Pax5, kappa, lambda, CD30, ALK, S-100, HMB-45, MPO, and HHV-8. The MIB-1 index was nearly 100%. Epstein-Barr virus-encoded RNA in situ hybridization was negative. A monoclonal immunoglobulin heavy chain gene rearrangement was detected in polymerase chain reaction (PCR) and heteroduplex analyses. A combination of PCR-based analysis of immunoglobulin gene rearrangement and immunohistochemistry can be useful to substantiate the diagnosis by utilizing routine paraffin-embedded tissue sections, because PBL in the setting of extra-oral localization and immunocompetence is a diagnostic challenge, given its rarity, morphology, and absence of CD20 expression.

Under Scope of the Current Redefinition Process of Optimal Response in Multiple Myeloma: Assesment of Molecular Response by Fluorescent PCR of Ig Genes Has Similar Applicability and Prognosis Impact to Immunophenotypic Response. (A GEM/PETHEMA study),

Abstract 3951▪▪This icon denotes a clinically relevant abstract Aim:The aims of this study were on one hand, to evaluate the significance of achieving molecular response (MR) by fluorescent-PCR (F-PCR) of Ig genes in a prospective way, particularly in patients with singular cytogenetics’ features. On the other hand, to compared MR with immunophenotypic response (IR) and complete remission by immunofixation (CR). Patients: 130 new MM patients who had achieved CR or VGPR were analyzed by PCR, multiparametric flow cytometry (MFC) and immunofixation at diagnosis, and after induction therapy or transplantation: 48 patients received conventional chemotherapy as induction therapy followed with ASCT and were included in the GEM2000 trial and the other 82 patients were enrolled in the GEM2005 clinical trials in which the induction and maintenance therapy were based on Bortezomib and/or Thalidomide. Methods: The molecular analysis of Immunoglobulin (Ig) gene rearrangements at diagnosis was carried out by fluorescent PCR in DNA from bone marrow samples according to the Biomed-2 protocols. Briefly three different multiplex PCRs: DHJ; Ig Kappa light chain (IGK) rearrangements K-VJ and Kappa deleting element (KDE). DHJ and light chain rearrangements detected at the diagnosis were used in the follow-up. The sensitivity of PCR was between 1/103 and 1/104 as Martínez P. et al previously published in BJH, 2008. Regarding MFC the following monoclonal antibody combinations (FITC/PE/PerCP-Cy5.5/APC) were used at the diagnosis to identify different aberrant plasma cells phenotypes which were used as patient-specific probes for Minimal Residual Disease. Results: 64 patients had negative F-PCR and 66 patients had positive F-PCR after induction therapy. The OS was 77.32% and 59.18%, respectively and the medians OS were 116 and 67 months for each group (P= 0.03). Regarding the PFS, 28 of the 64 F-PCR negative patients relapsed while there were 44 relapses in the group of positive F-PCR. The 5y PFS was 56.44% and 27.43% respectively; the medians PFS were 60 and 36 months respectively (P= 0.0005). The multivariate analysis showed that achieving molecular response by F-PCR had a independent prognostic value in PFS (P=0.003, HR 2.3). Interestingly amongst patients who achieved CR, F-PCR identified a population of patient with a better PFS, figure A (P= 0.04, HR 2.179).The applicability of the F-PCR was almost equivalent to that observed by MFC (91.5 vs. 92%). Nevertheless we found discordant results between these two response criteria. Approximately the 20% of patients who had achieved a MR no obtained IR. The opposite pattern also was observed (IR/noMR) in 10% of the patients. In order to see if the PCR showed differences in terms of survival in patients with high or low risk cytogenetics features at the diagnosis, we made two independent analysis: in one hand we analyzed 14 patients with high-risk cytogenetics [t(4;14), t(14;16) and/or del(17p)] and on the other hand 72 patients with standard-risk cytogenetics. In the former analysis, 4 of the 8 who had negative F-PCR relapsed after the induction therapy while the totality of the other six with positive F-PCR did. The medians PFS were 32 and 17 months respectively (P= 0.0002). In connection with the 72 patients with standard-risk cytogenetics, 13 of the 34 who had negative F-PCR relapsed while 24 of the 38 with positive F-PCR did. The medians PFS times were 75 and 38 months respectively, figure B (P= 0.01). Conclusion: F-PCR of IgH rearrangements is a simple, cheap and feasible method for evaluating response in MM patients after induction therapy or transplantation. Additionally achieving MR provides a similar prognostic value to IR in patients differentially treated, and particularly in patients with singular cytogenetics’ features as well as in patients with CR by immunofixation. Disclosures:Paiva:Jansen-Cillag: Honoraria; Celgene: Honoraria. Rosiñol:Janssen: Honoraria; Celgene: Honoraria. Alegre:Janssen: Honoraria; Celgene: Honoraria. Blade:Centocor Ortho Biotech Research & Development: Research Funding. San Miguel:Janssen-Cilag: Honoraria; Celgene: Honoraria. Lahuerta:Celgene: Honoraria; Janssen: Honoraria.

3.28 Trompe L'Oeil Not Only in Painting: CLL Concomitant with Hairy Cell Leukemia is Not Rare

The coexistence of chronic lymphocytic leukemia (CLL) and hairy cell leukemia (HCL) has already been reported in the literature, but as an exceedingly rare event, because the presentation (clinical and laboratory) is generally CLL-like and HCL is discovered ‘by the way’. To prove that the concomitance between these two diseases is not as rare as previously believed, we have to think ‘semantically’: the question is not how many CLL cases are concomitant with HCL, but how many HCL cases are concomitant with CLL. CLL originates from antigen-stimulated mature B lymphocytes and is the most common type of leukemia in older adults, accounting for 25% of all leukemia cases. HCL is also a chronic lymphoproliferative disorder originating from mature B lymphocytes. HCL accounts for 2-3% of all leukemia cases. The male to female ratio is approximately 4:1. The etiology is not known. CLL and HCL have distinct clinical, morphological and immunophenotyping features. The occurrence of second neoplasm, especially non-Hodgkin’s lymphomas, is well known in HCL patients. In the past 10 years we have diagnosed in our hemato-oncologic clinic 22 cases of HCL, 4 of them (18% of all cases of HCL diagnosed during this period) concomitant with CLL. We did not perform immunoglobulin gene rearrangement analysis, so we cannot know whether the origin is from different B cell clones or not; we can only affirm that the same light chain type was present on the membranes of both CLL and HCL cells. All cases of lymphoproliferative disorders (LPD) are systematically screened in our lab for the presence of an additional monoclonal B-cell population. Conclusion: the concept that concomitant CLL and HCL is a rare event is challenged. It is a mere ‘trompe l’oeil’, due to the rarity of HCL.

Analysis of Immunoglobulin Gene Rearrangement: Comparison between BIOMED-2 Multiplex PCR and Conventional Nested PCR

Analysis of Immunoglobulin Gene Rearrangement: Comparison between BIOMED-2 Multiplex PCR and Conventional Nested PCR

Minimal residual disease detection using real-time quantitative PCR analysis of immunoglobulin and T-cell receptor gene rearrangements in the non-MRD-based ALL IC-BFM 2002 protocol for childhood ALL: Slovak experience.

Acute lymphoblastic leukemia is the most common form of cancer in children. The 10-year event-free survival ranged from 77 to 85% after having achieved complete remission rates of 93% or higher. The main cause of treatment failure is relapse arising from outgrowth of residual leukemic cells that are refractory to therapy. An intense effort has been made to develop methods to determine the degree of minimal residual leukemia cells present in patients considered to be in morphological remission. Because of the strong correlation between minimal residual disease (MRD) levels and risk of relapse, monitoring of MRD provides unique information regarding treatment response. The MRD monitoring based on real-time quantitative PCR detection of patient-specific immunoglobulin and T-cell receptor (Ig/TCR) gene rearrangements is currently considered to be the most reliable tool for MRD-based diagnosis in ALL. Because the significance of MRD monitoring has been strongly supported by several studies and because it has been implemented in the latest protocols, there has been a significant effort to develop MRD monitoring in the Slovak Republic since 2005. Between October 2006 and December 2009, 50 children with ALL who were treated at three Slovak centers were included in the RQ PCR MRD pilot project. A total of 40 patients with BCP-ALL ( B cell precursor ALL) and 4 patients with T ALL were analyzed for Ig/TCR rearrangement. We identified 106 different rearrangements in the 44 ALL patients analyzed. Based on MRD stratification, we identified 26 patients who were stratified into the HRG ( high risk group) (n = 3; 11.5%), IRG ( intermediate risk group) (n = 14; 54%) and SRG ) standard risk group) (n = 9; 34.5%). Morphology-based risk stratification allows the identification of most HRG patients identified also by MRD-based stratification, but fails to discriminate the IRG assigned to therapy reduction. Patients in the SRG and the IRG could profit from MRD-based risk assignment