Search

Primary cutaneous posttransplant lymphoproliferative disorders (PTLDs) after allogeneic hematopoietic stem cell transplant (allo-HSCT) are exceedingly rare, with only 6 published cases, all of them consisting in T-cell neoplasms. In this report, we present for the first time a donor-derived B-cell PTLD consisting in a primary, cutaneous, B-cell, marginal zone, lymphoproliferative disorder (PCMZLPD). The patient, a 37-year-old woman with a history of Hodgkin lymphoma received an allo-HSCT from her healthy, matched, related father, achieving complete host chimerism in the bone marrow and peripheral blood. However, 8 years after the allo-HSCT, she presented asymptomatic skin lesions consisting in oval, well-defined, slightly raised erythematous plaques, located on the arms, trunk, and legs. Skin biopsies of 2 lesions demonstrated a class-switched IgG+, EBV-, PCMZLPD, showing kappa light chain restriction and monoclonal rearrangement of the IgH gene. Microsatellite genotyping and 2-color fluorescence in situ hybridization (X and Y chromosomes) confirmed that the origin of the neoplastic cells was the donor graft. The lesions showed an indolent behavior, good response to topical corticosteroids, and no need for systemic treatment. Our case broadens the spectrum of PTLD, a diverse group of lymphoid and/or plasmacytic proliferations with variable clinical presentations and histopathological features.

Acute myeloid leukemias (AMLs) are currently genomically characterized by karyotype, fluorescence in situhybridization (FISH), real-time quantitative PCR, and DNA sequencing. Next-generation sequencing offers the promise of detecting all genomic lesions in a single run. However, technical limitations have hampered the detection of chromosomal rearrangements, so most studies are limited to somatic mutation assessment or require the use of RNA-based strategies. To overcome these limitations, we designed a targeted-DNA capture next-generation sequencing approach associated with easy-to-perform public bioinformatic tools for one-step identification of translocations, inversions, and somatic mutations in AML. Thirty well-characterized newly diagnosed myeloid leukemia patients (27 AML and 3 chronic myeloid leukemia) were tested with the panel. Twenty-three of 24 known rearrangements, as well as one novel fusion gene that could not be detected by karyotype/fluorescence in situhybridization/real-time quantitative PCR, were detected. This strategy also identified all chromosomal breakpoints as potential targets for future high-sensitive minimal residual disease studies. In addition, mutation analysis revealed the presence of missense protein-coding alterations in at least 1 of the 32 genes evaluated in 21 of 30 patients (70%). This strategy may represent a time- and cost-effective diagnostic method for molecular characterization in AML.

The presence of mutations in the TP53gene is a powerful prognostic and predictive marker in chronic lymphocytic leukemia (CLL). Widespread use of NGS has enabled the detection of variants ≤10 % variant allelic frequency (low-VAF variants); however, the overall reliability and reproducibility of NGS techniques to identify such variants have been questioned repeatedly. Individual studies using sensitive, custom NGS-based assays have mostly demonstrated the shortened overall survival (OS) and event-free survival in patients with low-VAF TP53variants treated with chemoimmunotherapy (CIT) regimens with median survival ranging between that of TP53 variants >10 % VAF (high-VAF) and wild-type TP53(wt- TP53).

Identification and characterization of genetic alterations are essential for diagnosis of multiple myeloma and may guide therapeutic decisions. Currently, genomic analysis of myeloma to cover the diverse range of alterations with prognostic impact requires fluorescence in situhybridization (FISH), single nucleotide polymorphism arrays, and sequencing techniques, which are costly and labor intensive and require large numbers of plasma cells. To overcome these limitations, we designed a targeted-capture next-generation sequencing approach for one-step identification of IGHtranslocations, V(D)J clonal rearrangements, the IgH isotype, and somatic mutations to rapidly identify risk groups and specific targetable molecular lesions. Forty-eight newly diagnosed myeloma patients were tested with the panel, which included IGHand six genes that are recurrently mutated in myeloma: NRAS, KRAS, HRAS, TP53, MYC,and BRAF. We identified 14 of 17 IGHtranslocations previously detected by FISH and three confirmed translocations not detected by FISH, with the additional advantage of breakpoint identification, which can be used as a target for evaluating minimal residual disease. IgH subclass and V(D)J rearrangements were identified in 77% and 65% of patients, respectively. Mutation analysis revealed the presence of missense protein-coding alterations in at least one of the evaluating genes in 16 of 48 patients (33%). This method may represent a time- and cost-effective diagnostic method for the molecular characterization of multiple myeloma.

MYD88L265P mutation has been reported in ∼90 of Waldenström’s Macroglobulinemia (WM) patients and immunoglobulin M (IgM) monoclonal gammopathies of uncertain significance (MGUS), as well as in some cases of lymphoma and chronic lymphocytic leukemia. The present study aimed to develop a real-time allele-specific oligonucleotide PCR (ASO-RQ-PCR) to detect the MYD88L265P mutation. We first evaluated the reproducibility and sensitivity of the technique with a diluting experiment of a previously known positive sample. Then, we evaluated the applicability of the methodology by analyzing 30 selected patients (10 asymptomatic WM, 10 symptomatic WM, and 10 IgM MGUS) as well as 10 healthy donors. The quantitative ASO-PCR assay could detect the MYD88L265P mutation at a dilution of 0.25, showing an inverse correlation between the tumor cell percentage and the cycle threshold (CT) value, thus allowing for tumor burden quantitation. In addition, mutated cases were distinguished from the unmutated by >10 cycles of difference between CTs. To sum up, ASO-RQ-PCR is an inexpensive, robust, and optimized method for the detection of MYD88L265P mutation, which could be considered as a useful molecular tool during the diagnostic work-up of B-cell lymphoproliferative disorders.

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease influenced by genetic and environmental factors. The role of the HLA system in tumor antigen presentation could be involved in susceptibility and disease control. We analyzed the phenotypic frequencies of HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1 in 250 DLBCLs, comparing them with 1940 healthy individuals. We also evaluated the influence of HLA polymorphisms on survival in those patients treated with curative intention using cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP)-like regimen without (n = 64, 26%) or with (n = 153, 61%) rituximab. DLBCL patients have a higher phenotypic frequency of HLA-DRB1*01 (29% vs 19.5%, P = .0008, Pc = .0104) and a lower frequency of HLA-C*03 (6.4% vs 17.9%, P < .0005, Pc = .007) compared with healthy individuals. Irrespective of the age-adjusted International Prognostic Index, those patients receiving a CHOP-like plus rituximab regimen and carrying the HLA-B44 supertype had worse 5-year progression-free (54% vs 71%, P = .019) and 5-year overall (71% vs 92%, P = .001) survival compared with patients without this supertype. Our data suggest that some HLA polymorphisms influence the development and outcome of DLBCL, allowing the identification of an extremely good-risk prognostic subgroup. However, these results are preliminary and need to be validated in order to exclude a possible population effect.

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease influenced by genetic and environmental factors. The role of the HLA system in tumor antigen presentation could be involved in susceptibility and disease control. We analyzed the phenotypic frequencies of HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1 in 250 DLBCLs, comparing them with 1940 healthy individuals. We also evaluated the influence of HLA polymorphisms on survival in those patients treated with curative intention using cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP)-like regimen without (n = 64, 26%) or with (n = 153, 61%) rituximab. DLBCL patients have a higher phenotypic frequency of HLA-DRB1*01 (29% vs 19.5%, P= .0008, Pc= .0104) and a lower frequency of HLA-C*03 (6.4% vs 17.9%, P< .0005, Pc= .007) compared with healthy individuals. Irrespective of the age-adjusted International Prognostic Index, those patients receiving a CHOP-like plus rituximab regimen and carrying the HLA-B44 supertype had worse 5-year progression-free (54% vs 71%, P= .019) and 5-year overall (71% vs 92%, P= .001) survival compared with patients without this supertype. Our data suggest that some HLA polymorphisms influence the development and outcome of DLBCL, allowing the identification of an extremely good-risk prognostic subgroup. However, these results are preliminary and need to be validated in order to exclude a possible population effect.

The pathogenesis of diffuse large B-cell lymphoma (DLBCL) remains partially unknown. The analysis of the B-cell receptor of the malignant cells could contribute to a better understanding of the DLBCL biology. We studied the molecular features of the immunoglobulin heavy chain (IGH) rearrangements in 165 patients diagnosed with DLBCL not otherwise specified. Clonal IGH rearrangements were amplified according to the BIOMED-2 protocol and PCR products were sequenced directly. We also analyzed the criteria for stereotyped patterns in all complete IGHV-IGHD-IGHJ (V-D-J) sequences. Complete V-D-J rearrangements were identified in 130 of 165 patients. Most cases (89%) were highly mutated, but 12 sequences were truly unmutated or minimally mutated. Three genes, IGHV4-34, IGHV3-23, and IGHV4-39, accounted for one third of the whole cohort, including an overrepresentation of IGHV4-34(15.5% overall). Interestingly, all IGHV4-34rearrangements and all unmutated sequences belonged to the nongerminal center B-cell–like (non-GCB) subtype. Overall, we found three cases following the current criteria for stereotyped heavy chain VH CDR3 sequences, two of them belonging to subsets previously described in CLL. IGHV gene repertoire is remarkably biased, implying an antigen-driven origin in DLBCL. The particular features in the sequence of the immunoglobulins suggest the existence of particular subgroups within the non-GCB subtype.

We have evaluated 9 new molecular markers (ERG, EVI1, MLL-PTD, MN1, PRAME, RHAMM, and WT1gene-expression levels plus FLT3and NPM1mutations) in 121 de novo cytogenetically normal acute myeloblastic leukemias. In the multivariate analysis, high ERGor EVI1and low PRAMEexpressions were associated with a shorter relapse-free survival (RFS) and overall survival (OS). A 0 to 3 score was given by assigning a value of 0 to favorable parameters (low ERG, low EVI1, and high PRAME) and 1 to adverse parameters. This model distinguished 4 subsets of patients with different OS (2-year OS of 79%, 65%, 46%, and 27%; P= .001) and RFS (2-year RFS of 92%, 65%, 49%, and 43%; P= .005). Furthermore, this score identified patients with different OS (P= .001) and RFS (P= .013), even within the FLT3/NPM1intermediate-risk/high-risk subgroups. Here we propose a new molecular score for cytogenetically normal acute myeloblastic leukemias, which could improve patient risk-stratification.

We have evaluated 9 new molecular markers (ERG, EVI1, MLL-PTD, MN1, PRAME, RHAMM, and WT1 gene-expression levels plus FLT3 and NPM1 mutations) in 121 de novo cytogenetically normal acute myeloblastic leukemias. In the multivariate analysis, high ERG or EVI1 and low PRAME expressions were associated with a shorter relapse-free survival (RFS) and overall survival (OS). A 0 to 3 score was given by assigning a value of 0 to favorable parameters (low ERG, low EVI1, and high PRAME) and 1 to adverse parameters. This model distinguished 4 subsets of patients with different OS (2-year OS of 79%, 65%, 46%, and 27%; P = .001) and RFS (2-year RFS of 92%, 65%, 49%, and 43%; P = .005). Furthermore, this score identified patients with different OS (P = .001) and RFS (P = .013), even within the FLT3/NPM1 intermediate-risk/high-risk subgroups. Here we propose a new molecular score for cytogenetically normal acute myeloblastic leukemias, which could improve patient risk-stratification.

Recent studies suggest the potential involvement of common antigenic stimuli on the ontogeny of monoclonal T-cell receptor (TCR)–αβ+/CD4+/NKa+/CD8−/+dim T-large granular lymphocyte (LGL) lymphocytosis. Because healthy persons show (oligo)clonal expansions of human cytomegalovirus (hCMV)–specific TCRVβ+/CD4+/cytotoxic/memory T cells, we investigate the potential involvement of hCMV in the origin and/or expansion of monoclonal CD4+ T-LGL. Peripheral blood samples from patients with monoclonal TCR-αβ+/CD4+ T-LGL lymphocytosis and other T-chronic lymphoproliferative disorders were evaluated for the specific functional response against hCMV and hEBV whole lysates as well as the “MQLIPDDYSNTHSTRYVTVK” hCMV peptide, which is specifically loaded in HLA-DRB1*0701 molecules. A detailed characterization of those genes that underwent changes in T-LGL cells responding to hCMV was performed by microarray gene expression profile analysis. Patients with TCR-αβ+/CD4+ T-LGL displayed a strong and characteristic hCMV-specific functional response, reproduced by the hCMV peptide in a subset of HLA-DRB1*0701+ patients bearing TCRVβ13.1+ clonal T cells. Gene expression profile showed that the hCMV-induced response affects genes involved in inflammatory and immune responses, cell cycle progression, resistance to apoptosis, and genetic instability. This is the first study providing evidence for the involvement of hCMV in the ontogeny of CD4+ T-LGL, emerging as a model disorder to determine the potential implications of quite a focused CD4+/cytotoxic immune response.

Recent studies suggest the potential involvement of common antigenic stimuli on the ontogeny of monoclonal T-cell receptor (TCR)–αβ+/CD4+/NKa+/CD8−/+dimT-large granular lymphocyte (LGL) lymphocytosis. Because healthy persons show (oligo)clonal expansions of human cytomegalovirus (hCMV)–specific TCRVβ+/CD4+/cytotoxic/memory T cells, we investigate the potential involvement of hCMV in the origin and/or expansion of monoclonal CD4+T-LGL. Peripheral blood samples from patients with monoclonal TCR-αβ+/CD4+T-LGL lymphocytosis and other T-chronic lymphoproliferative disorders were evaluated for the specific functional response against hCMV and hEBV whole lysates as well as the “MQLIPDDYSNTHSTRYVTVK” hCMV peptide, which is specifically loaded in HLA-DRB1*0701 molecules. A detailed characterization of those genes that underwent changes in T-LGL cells responding to hCMV was performed by microarray gene expression profile analysis. Patients with TCR-αβ+/CD4+T-LGL displayed a strong and characteristic hCMV-specific functional response, reproduced by the hCMV peptide in a subset of HLA-DRB1*0701+patients bearing TCRVβ13.1+clonal T cells. Gene expression profile showed that the hCMV-induced response affects genes involved in inflammatory and immune responses, cell cycle progression, resistance to apoptosis, and genetic instability. This is the first study providing evidence for the involvement of hCMV in the ontogeny of CD4+T-LGL, emerging as a model disorder to determine the potential implications of quite a focused CD4+/cytotoxic immune response.

We have explored the potential role of genetics in the development of osteonecrosis of the jaw (ONJ) in multiple myeloma (MM) patients under bisphosphonate therapy. A genome-wide association study was performed using 500 568 single nucleotide polymorphisms (SNPs) in 2 series of homogeneously treated MM patients, one with ONJ (22 MM cases) and another without ONJ (65 matched MM controls). Four SNPs (rs1934951, rs1934980, rs1341162, and rs17110453) mapped within the cytochrome P450-2C gene (CYP2C8) showed a different distribution between cases and controls with statistically significant differences (P = 1.07 × 10−6, P = 4.231 × 10−6, P = 6.22 × 10−6, and P = 2.15 × 10−6, respectively). SNP rs1934951 was significantly associated with a higher risk of ONJ development even after Bonferroni correction (P corrected value = .02). Genotyping results displayed an overrepresentation of the T allele in cases compared with controls (48% vs 12%). Thus, individuals homozygous for the T allele had an increased likelihood of developing ONJ (odds ratio 12.75, 95% confidence interval 3.7-43.5).

We have explored the potential role of genetics in the development of osteonecrosis of the jaw (ONJ) in multiple myeloma (MM) patients under bisphosphonate therapy. A genome-wide association study was performed using 500 568 single nucleotide polymorphisms (SNPs) in 2 series of homogeneously treated MM patients, one with ONJ (22 MM cases) and another without ONJ (65 matched MM controls). Four SNPs (rs1934951, rs1934980, rs1341162, and rs17110453) mapped within the cytochrome P450-2C gene (CYP2C8) showed a different distribution between cases and controls with statistically significant differences (P= 1.07 × 10−6, P= 4.231 × 10−6, P= 6.22 × 10−6, and P= 2.15 × 10−6, respectively). SNP rs1934951 was significantly associated with a higher risk of ONJ development even after Bonferroni correction (Pcorrected value = .02). Genotyping results displayed an overrepresentation of the T allele in cases compared with controls (48% vs 12%). Thus, individuals homozygous for the T allele had an increased likelihood of developing ONJ (odds ratio 12.75, 95% confidence interval 3.7-43.5).

Detection of recipient versus donor disparities in microsatellite DNA regions (short tandem repeats STR) allows for sensitive and specific monitorization of the degree of hematopoietic chimerism. It is well known that disparities between donor and recipient in various polymorphic systems (mainly human leukocyte antigen HLA) are associated with an increased incidence of graft-versus-host disease (GvHD). However, the possible biological role of STR discrepancies in GvHD development has not yet been well established.

We analyzed patients with hairy cell leukemia (HCL) to achieve a better understanding of the differentiation stage reached by HCL cells and to define the key role of the diversification of cell surface makers, especially CD25 expression.

Despite the key role of memory T‐cells specific for human cytomegalovirus (hCMV) in protecting against hCMV‐reinfection early after immunodeficiency episodes, the precise characterization and definition of the essential components of a protective CD4 T‐cell response still remain to be established.We analyzed by flow cytometry hCMV‐specific immune responses driven by peripheral blood antigen‐presenting cells (APC) and CD4 memory T‐cells at both the cellular and soluble levels, and their cooperation in priming and sustaining the effector function of specific CD8 T cells in adult healthy individuals using a hCMV whole viral lysate stimulatory model.Overall, activated T‐cells showed a heterogeneous phenotype, with a marked predominance of CD45RA−/CCR7+/− memory CD4+ T‐cells. Despite this, cytoplasmic expression of granzyme B was found in both the CD45RA+/effector and CD45RA−/memory T‐cell compartments of the two major CD4+ and CD8+ activated T‐cell subpopulations, further confirming the presence of circulating antigen experienced cytotoxic CD4+ T cells in hCMV‐seropositive individuals. Moreover, we observed that both CD4+ and CD8+ hCMV‐specific T‐cells included relatively restricted numbers of TCR‐Vβ family members. Interestingly, we found a significant association between some HLA Class II and Class I haplotypes and the presence of specifically expanded TCR‐Vβ clones of anti‐hCMV T cells.These results indicate that hCMV‐specific memory T‐cells are phenotypically heterogeneous, their TCR‐Vβ repertoire shaped through the interaction between hCMV epitopes and the HLA haplotype. © 2007 Clinical Cytometry Society.

Monoclonal TCRαβ+/CD4+T-large granular lymphocyte (T-LGL) lymphocytosis is a T-cell disorder with a restricted TCR-Vβ repertoire. In the present study we explored the potential association between the expanded TCR-Vβ families, the CDR3 sequences of the TCR-Vβ gene, and the HLA genotype of patients with monoclonal TCRαβ+/CD4+T-LGL lymphocytosis. For that purpose, 36 patients with monoclonal TCRαβ+/CD4+T-LGL lymphocytosis (15 TCR-Vβ13.1 versus 21 non–TCR-Vβ13.1) were selected. For each patient, both the HLA (class I and II) genotype and the DNA sequences of the VDJ-rearranged TCR-Vβ were analyzed. Our results show a clear association between the TCR-Vβ repertoire and the HLA genotype, all TCR-Vβ13.1+cases being HLA-DRB1*0701 (P= .004). Interestingly, the HLA-DR7/TCR-Vβ13.1–restricted T-cell expansions displayed a highly homogeneous and strikingly similar TCR arising from the use of common TCR-Vβ gene segments, which shared (1) unique CDR3 structural features with a constantly short length, (2) similar combinatorial gene rearrangements with frequent usage of the Jβ1.1 gene, and (3) a homolog consensus protein sequence at recombination junctions. Overall, these findings strongly support the existence of a common antigen-driven origin for monoclonal CD4+T-LGL lymphocytosis, with the identification of the exact peptides presented to the expanded T cells deserving further investigations.

Monoclonal TCRαβ+/CD4+ T-large granular lymphocyte (T-LGL) lymphocytosis is a T-cell disorder with a restricted TCR-Vβ repertoire. In the present study we explored the potential association between the expanded TCR-Vβ families, the CDR3 sequences of the TCR-Vβ gene, and the HLA genotype of patients with monoclonal TCRαβ+/CD4+ T-LGL lymphocytosis. For that purpose, 36 patients with monoclonal TCRαβ+/CD4+ T-LGL lymphocytosis (15 TCR-Vβ13.1 versus 21 non–TCR-Vβ13.1) were selected. For each patient, both the HLA (class I and II) genotype and the DNA sequences of the VDJ-rearranged TCR-Vβ were analyzed. Our results show a clear association between the TCR-Vβ repertoire and the HLA genotype, all TCR-Vβ13.1+ cases being HLA-DRB1*0701 (P = .004). Interestingly, the HLA-DR7/TCR-Vβ13.1–restricted T-cell expansions displayed a highly homogeneous and strikingly similar TCR arising from the use of common TCR-Vβ gene segments, which shared (1) unique CDR3 structural features with a constantly short length, (2) similar combinatorial gene rearrangements with frequent usage of the Jβ1.1 gene, and (3) a homolog consensus protein sequence at recombination junctions. Overall, these findings strongly support the existence of a common antigen-driven origin for monoclonal CD4+ T-LGL lymphocytosis, with the identification of the exact peptides presented to the expanded T cells deserving further investigations.

Indolent natural killer (NK) cell lymphoproliferative disorders include a heterogeneous group of patients in whom persistent expansions of mature, typically CD56+, NK cells in the absence of any clonal marker are present in the peripheral blood. In the present study we report on the clinical, hematological, immunophenotypic, serological, and molecular features of a series of 26 patients with chronic large granular NK cell lymphocytosis, whose NK cells were either CD56−or expressed very low levels of CD56 (CD56−/+dimNK cells), in the context of an aberrant activation-related mature phenotype and proved to be monoclonal using the human androgen receptor gene polymerase chain reaction-based assay. As normal CD56+NK cells, CD56−/+dimNK cells were granzyme B+, CD3−, TCRαβ/γδ−, CD5−, CD28−, CD11a+bright, CD45RA+bright, CD122+, and CD25−and they showed variable and heterogeneous expression of both CD8 and CD57. Nevertheless, they displayed several unusual immunophenotypic features. Accordingly, besides being CD56−/+dim, they were CD11b−/+dim(heterogeneous), CD7−/+dim(heterogeneous), CD2+(homogeneous), CD11c+bright(homogeneous), and CD38−/+dim(heterogeneous). Moreover, CD56−/+dimNK cells heterogeneously expressed HLA-DR. In that concerning the expression of killer receptors, CD56−/+dimNK cells showed bright and homogeneous CD94 expression, and dim and heterogeneous reactivity for CD161, whereas CD158a and NKB1 expression was variable. From the functional point of view, CD56−/+dimshowed a typical Th1 pattern of cytokine production (interferon-γ+, tumor necrosis factor-α+). From the clinical point of view, these patients usually had an indolent clinical course, progression into a massive lymphocytosis with lung infiltration leading to death being observed in only one case. Despite this, they frequently had associated cytopenias as well as neoplastic diseases and/or viral infections. In summary, we describe a unique and homogeneous group of monoclonal chronic large granular NK cell lymphocytosis with an aberrant activation-related CD56−/+dim/CD11b−/+dimphenotype and an indolent clinical course, whose main clinical features are related to concomitant diseases.

Leukemic B-chronic lymphoproliferative disorders (B-CLPDs) are generally believed to derive from a monoclonal B cell; biclonality has only occasionally been reported. In this study, we have explored the incidence of B-CLPD cases with 2 or more B-cell clones and established both the phenotypic differences between the coexisting clones and the clinicobiologic features of these patients. In total, 53 B-CLPD cases with 2 or more B-cell clones were studied. Presence of 2 or more B-cell clones was suspected by immunophenotype and confirmed by molecular/genetic techniques in leukemic samples (n = 42) and purified B-cell subpopulations (n = 10). Overall, 4.8% of 477 consecutive B-CLPDs had 2 or more B-cell clones, their incidence being especially higher among hairy cell leukemia (3 of 13), large cell lymphoma (2 of 10), and atypical chronic lymphocytic leukemia (CLL) (4 of 29). In most cases the 2 B-cell subsets displayed either different surface immunoglobulin (sIg) light chain (n = 37 of 53) or different levels of the same sIg (n = 9 of 53), usually associated with other phenotypic differences. Compared with monoclonal cases, B-CLL patients with 2 or more clones had lower white blood cell (WBC) and lymphocyte counts, more frequently displayed splenomegaly, and required early treatment. Among these, the cases in which a CLL clone coexisted with a non-CLL clone were older and more often displayed B symptoms, a monoclonal component, and diffuse infiltration of bone marrow and required early treatment more frequently than cases with monoclonal CLL or 2 CLL clones.

Leukemic B-chronic lymphoproliferative disorders (B-CLPDs) are generally believed to derive from a monoclonal B cell; biclonality has only occasionally been reported. In this study, we have explored the incidence of B-CLPD cases with 2 or more B-cell clones and established both the phenotypic differences between the coexisting clones and the clinicobiologic features of these patients. In total, 53 B-CLPD cases with 2 or more B-cell clones were studied. Presence of 2 or more B-cell clones was suspected by immunophenotype and confirmed by molecular/genetic techniques in leukemic samples (n = 42) and purified B-cell subpopulations (n = 10). Overall, 4.8% of 477 consecutive B-CLPDs had 2 or more B-cell clones, their incidence being especially higher among hairy cell leukemia (3 of 13), large cell lymphoma (2 of 10), and atypical chronic lymphocytic leukemia (CLL) (4 of 29). In most cases the 2 B-cell subsets displayed either different surface immunoglobulin (sIg) light chain (n = 37 of 53) or different levels of the same sIg (n = 9 of 53), usually associated with other phenotypic differences. Compared with monoclonal cases, B-CLL patients with 2 or more clones had lower white blood cell (WBC) and lymphocyte counts, more frequently displayed splenomegaly, and required early treatment. Among these, the cases in which a CLL clone coexisted with a non-CLL clone were older and more often displayed B symptoms, a monoclonal component, and diffuse infiltration of bone marrow and required early treatment more frequently than cases with monoclonal CLL or 2 CLL clones.

Large granular lymphocyte (LGL) leukemia is a well-recognized disease of mature T-CD8+or less frequently natural killer cells; in contrast, monoclonal expansions of CD4+T-LGL have only been sporadically reported in the literature. In the present article we have explored throughout a period of 56 months the incidence of monoclonal expansions of CD4+T-LGL in a population of 2.2 million inhabitants and analyzed the immunophenotype and the pattern of cytokine production of clonal CD4+T cells of a series of 34 consecutive cases. Like CD8+T-LGL leukemias, CD4+T-LGL leukemia patients have an indolent disease; however, in contrast to CD8+T-LGL leukemias, they do not show cytopenias and autoimmune phenomena and they frequently have associated neoplasias, which is usually determining the clinical course of the disease. Monoclonal CD4+T-LGLshowed expression of TCRαβ, variable levels of CD8 (CD8−/+dim) and a homogeneous typical cytotoxic (granzyme B+, CD56+, CD57+, CD11b+/−) and activated/memory T cell (CD2+bright, CD7−/+dim, CD11a+bright, CD28−, CD62L−HLA-DR+) immunophenotype. In addition, they exhibited a Th1 pattern of cytokine production [interferon-γ++, tumor necrosis factor-α++, interleukin (IL-2)−/+, IL-4−, IL-10−, IL-13−]. Phenotypic analysis of the TCR-Vβ repertoire revealed large monoclonal TCR-Vβ expansions; only a restricted number of TCR-Vβ families were represented in the 34 cases analyzed. These findings suggest that monoclonal TCRαβ+/CD4+/NKa+/CD8−/+dimT-LGL represent a subgroup of monoclonal LGL lymphoproliferative disorders different from both CD8+T-LGL and natural killer cell-type LGL leukemias. Longer follow-up periods are necessary to determine the exact significance of this clonal disorder.

At present, a major challenge in the initial diagnosis of leukemia of large granular lymphocytes (LGLs) is to establish the clonal nature of the expanded population. In the present study we have analyzed by flow cytometry immunophenotyping the TCR-Vβ repertoire of 98 consecutive cases of persistent expansions of CD4+or CD8+brightCD3+/TCR-αβ+LGLs and compared the results with those obtained in molecular studies of TCR-β gene rearrangements. Fifty-eight cases were considered to be monoclonal in molecular studies whereas in the remaining 40 cases there was no evidence for monoclonality (11 cases were considered oligoclonal and 29 polyclonal). The TCR-Vβ repertoire was biased to the preferential use of one or more TCR-Vβ families in 96% of cases, a total of 124 TCR-Vβ expansions being diagnosed: one TCR-Vβ expansion in 71 cases and two or more TCR-Vβ expansions in 23 cases. The highest TCR-Vβ expansion observed in each case was higher among monoclonal (74 ± 19%) as compared to nonmonoclonal cases (24 ± 14%) (P= 0.001), as did the fraction of LGLs that exhibited a TCR-Vβ-restricted pattern (86 ± 16% and 42 ± 23%, respectively;P= 0.0001); by contrast, the proportion of cases displaying more than one TCR-Vβ expansion was higher in the latter group: 7%versus48%, respectively (P= 0.001). Results obtained in oligoclonal cases were intermediate between those obtained in polyclonal and monoclonal cases and similar results were observed for CD4+as for CD8+brightT-cell expansions. TCR-Vβ familiesexpressed in CD8+brightT-cell-LGL proliferations showed a pattern of distribution that mimics the frequency at which the individual TCR-Vβ families are represented in normal peripheral blood T cells. Assuming that a given proliferation of LGLs is monoclonal whenever there is an expansion of a given TCR-Vβ family of at least 40% of the total CD4+or CD8+brightT-cell compartment, we were able to predict clonality with a sensitivity of 93% and a specificity of 80%. By increasing the cut-off value to 60%, sensitivity and specificity were of 81% and 100%. In summary, our results suggest that flow cytometry immunophenotypic analysis of the TCR-Vβ repertoire is a powerful screening tool for the assessment of T-cell clonality in persistent expansions of TCR-αβ+LGLs.

Puig: Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria. Ocio:Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Seattle Genetics: Consultancy; Pharmamar: Consultancy; AbbVie: Consultancy; Novartis: Consultancy, Honoraria; Sanofi: Research Funding; BMS: Consultancy; Amgen: Consultancy, Honoraria, Research Funding; Mundipharma: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Array Pharmaceuticals: Research Funding. Mateos:Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Lahuerta:Amgen: Honoraria; Janssen: Honoraria; Celgene: Honoraria. San-Miguel:Celgene: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; MSD: Consultancy; Novartis: Consultancy; Takeda: Consultancy; Amgen: Consultancy; Brystol-Myers Squibb: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees. García-Sanz:Incyte: Consultancy; Amgen Inc.: Research Funding; Gilead: Research Funding; Spanish Government: Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding; BMS: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses.

Introduction

INTRODUCTION:Infection complications are important cause of morbidity and non-relapse mortality after allogeneic hematopoietic stem cell transplantation (allo-SCT), even in HLA-identical sibling donors. Although there are many studies associating single nucleotide polymorphisms (SNPs) and allo-SCT evolution, these are mainly related with graft versus host disease (GVHD) and/or transplant related mortality (TRM), with few focused on post-allo-SCT infections. This multicentric study analyzes the potential implication of SNPs with cytomegalovirus (CMV) reactivation and fungal infection (FI) development in allo-SCT with reduced intensity conditioning (RIC).

We report a patient who developed up to three different lymphomas with the same clonal IGH rearrangement. She was first diagnosed of splenic zone marginal lymphoma and relapsed for the first time with Hodgkin lymphoma histology and later with diffuse large B-cell lymphoma histology. Subsequent biopsies and analysis of clonally rearranged IGH genes helped to elucidate the clonal relationship between the three histologies and to confirm a common origin from the three tissue histologies. An integrated diagnosis should always be performed in order to achieve the most accurate diagnosis and be able to choose the best therapeutic options for our patients.

Mateos: Celgene: Consultancy, Honoraria; Takeda: Consultancy; Onyx: Consultancy; Janssen-Cilag: Consultancy, Honoraria. Ocio:Array BioPharma: Consultancy, Research Funding; Celgene: Consultancy, Honoraria; Amgen/Onyx: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy; Mundipharma: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; MSD: Research Funding; Pharmamar: Consultancy, Research Funding; Janssen: Honoraria. Puig:Janssen: Consultancy; The Binding Site: Consultancy.

Background:Waldenström's macroglobulinemia (WM) is a rare immunoproliferative neoplasia with indolent characteristics that shows important variability, involving three different stages of presentation: IgM Monoclonal Gammopathy of Undetermined Significance (IgM-MGUS), asymptomatic WM (AWM), and Symptomatic WM (SWM). Whole-genome sequencing and some specific approaches have identified MYD88L265P (90%) and CXCR4(29%) mutations as the most recurrent somatic mutations in WM. However, other genetic abnormalities under as well as the mechanisms responsible for this clinical heterogeneity still remain to be clarified. Therefore, our aim was to analyze the genomic landscape of WM, distinguishing between the three stages of the disease, by using a targeted next generation sequencing (NGS) strategy.

No relevant conflicts of interest to declare.

Multiple myeloma (MM) pathogenesis has been explained for many years by the cancer biology dogma introduced by Peter Nowell: first, a single plasma cell would be immortalized by an error in the immunoglobulin genes rearrangement process; then, a progressive stepwise acquisition of somatic cell mutations would induce a sequential selection and domination by the fittest clone. In line with this idea of “myeloma stability”, SNP arrays studies in diagnostic-relapse paired samples have revealed the presence of common clonal characteristics. Biologically, the M-protein remains usually constant across MM evolution and further, the variable domain of the rearranged immunoglobulin heavy chain genes (or CDR3 region) has been used as a patient-specific myeloma fingerprint in minimal residual disease (MRD) studies. However, massive genome studies with Next Generation Sequencing (NGS) have challenged this concept, showing a significant intraclonal heterogeneity at diagnosis with the possible presence of several clonal progenitors or tumor-initiating cells.

Acquired potentially N-glycosylation sites are produced by somatic hypermutation (SHM) in the immunoglobulin (Ig) variable region. This phenomenon is produced in ∼9% of normal B-cells and seems to be related to certain B-cell lymphoproliferative disorders (B-LPDs) such as follicular lymphoma (FL, 79%), endemic Burkitt lymphoma (BL, 82%) and diffuse large B-cell lymphoma (DLBCL, 41%). These data suggest that new potential N-glycosylation sites could be related to germinal center B (GCB)-LPDs. By contrast, in other B-LPDs, such as chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), MALT lymphoma, Waldenström macroglobulinemia (WM) or multiple myeloma (MM), these modifications have not been analyzed in deep.To evaluate the acquisition of potential N-glycosylation sites in B-LPDs, including immunohystochemical DLBCL subtypes (GCB and non-GCB) and specific non-GCB-LPDs, such as hairy cell leukemia (HCL), splenic marginal-zone lymphoma (SMZL), CLL, MCL, ocular extranodal marginal zone lymphoma (OAEMZL), MM and WM.A total of 953 sequences (203 from our group and 750 previously published sequences) of B-LPDs were included. Diagnosis distribution was as follows: DLBCL (n=235), MCL (n=235), CLL (n=166), MM (n=96), OAEMZL (n=82), SMZL (n=68), WM (n=38) and HCL (n=33).Acquired N-glycosylation sites were counted according to the sequence Asn-X-Ser/Thr, where X could be any amino acid except Pro. Natural motifs in germline sequences of IGHV1–08, IGHV4–34 e IGHV-5a were not considered. Fisher test was used to perform comparisons between groups. To distinguish DLBCL biological subtypes (GCB and non-GCB DLBCL), Hans' algorithm was used.A total of 83 out of the 235 DLBCL cases acquired at least a new N-glycosylation site, a higher value than in normal B-cells (35% vs. 9%, p<0.0001). Higher incidence of these motifs in the group of GCB as compared to non-GCB DLBCL were observed (52% vs. 20%, p<0.0001). Those cases diagnosed of HCL, CLL, MCL, MM, WM, OAEMZL and SMZL presented a reduced number of new N-glycosylation sites, showing similar values than normal B-cells (range 3–18%, p=ns).We described for the first time the pattern of N-glycosylation in HCL, SMZL, OAEMZL and in the immunohystochemical DLBCL subtypes, where the GCB-DLBCL showed a higher number of new N-glycosylation sites with respect to non-GCB DLBCL and other non-GCB-LPDs. The presence of novel N-glycosylation sites in FL, BL and in GCB-DLBCL strongly suggests that these motifs are characteristic of the germinal center B-LPDs.No relevant conflicts of interest to declare.

The Human Leukocyte Antigen (HLA) system plays an important role in antitumor immune response. In the last years, different genome-wide association studies have suggested that 6p21.3 (which include HLA system), is a risk region for lymphoma susceptibility. It has been also reported that specific alleles could modify the prognosis in patients diagnosed of lymphoma, including diffuse large B cell lymphoma (DLBCL), treated without Rituximab.Our hypothesis is that HLA system could play an essential role in disease control of DLBCL. Here, we have evaluated the effect of HLA Class I (A, B and C) and II (DRB1 and DQB1) alleles in DLBCL incidence and survival.A total of 251 patients diagnosed of DLBCL according to the 2008 WHO classification were analyzed (68% of them received Rituximab-based regimens). Control population consisted in 1940 healthy donor individuals analyzed for HLA-A, B, and DRB1 alleles and 200 for HLA-C and HLA-DQB1.Overall survival (OS) was calculated from diagnosis until death for any cause. Event-free survival (EFS) was calculated from diagnosis until event defined as death for any cause, relapse or progression of the disease.Allele frequencies and Hardy-Weinberg equilibrium were estimated using the Arlequin software package, version 3.5.1.2. Comparison of allele and phenotype frequencies between populations was performed with the two-sided Fisher's exact test or χ2 test using GraphPad Prism 4.0 (GraphPad Software, Inc. San Diego, CA, USA) or SPSS software (SPSS 15.0, Inc. Chicago, IL, USA). P-value was adjusted applying a Bonferroni correction (Pc).The effect of biological and clinical variables on OS and EFS at five years was analyzed by univariate (two-sided log-rank test) and multivariate (Cox multivariate analysis) methods. Differences were considered to be statistically significant when P< 0.05.HLA specificities frequencies in patients and controls (Alcoceba et al, Tissue Antigens 2011) were consistent in all cases with the Hardy-Weinberg equilibrium.Phenotypic frequencies showed significant differences in DLBCL patients compared to control population. DRB1*01 frequency was increased in DLBCL patients (28.9% vs. 19.5%, p=0.0009, Pc=0.0117, OR: 1.68; 95% CI: 1.24–2.26). By contrast, DLBCL patients showed a lower frequency in C*03 allele as compared to the control population (6.4% vs. 18.3, p=0.0005, Pc=0.007, OR: 3.2, 95% CI: 1.62–6.3).As far as the outcome of patients was concerned, the presence of B*18 and/or B*44 was significantly associated with a worse EFS (32% vs. 60%, p<0.001 and 53% vs. 72%, p=0.025, respectively) and OS (41% vs. 78%, p<0.001, and 53% vs. 86%, p=0.006, respectively). These statistical differences were also observed in the group of patients receiving Rituximab-based regimens. The Cox multivariate analysis identified high International Prognostic Index and the presence of any B*18 or B*44 as independent adverse prognostic factors for EFS and OS.Our data revealed that HLA specificities could influence the incidence (DRB1*01 and C*03) and outcome (B*18 and B*44) of DLBCL. These results suggest a role for HLA in the immune-surveillance of DLBCL and, also open possibilities for future investigations to answer how a specific HLA allele could affect in DLBCL.No relevant conflicts of interest to declare.

Abstract 1589

Abstract 2680

So far, none of the high-density microarray studies in acute myeloid leukemia (AML) have provided a useful approach with relevant diagnostic and prognostic value for the routine clinical practice. We aimed to assess the clinical utility of a small combination of genes and fusion genes included in a microfluidic card by means of real-time quantitative PCR (RQ-PCR) in AML patients.Ninety-six clinically relevant markers were analyzed simultaneously using TaqMan® Low Density Arrays (TLDAs) (Applied Biosystems, Foster City, CA). This plataform includes: 3 control genes (ABL1, GADPH and GUS), 36 AML specific fusion transcripts described, NPM1 mutations and 55 genes which RNA expression levels have been associated with prognosis or pathogenic process in AML. To assess the feasibility of the designed TLDA we evaluated the gene expression profile of 191 leukemia patients at diagnosis: 167 AML (inv(16): n=11, t(8;21): n=9, t(15;17): n=7, with 11q23 abnormalities: n=27, with other cytogenetic abnormalities: n=20 and normal karyotype n=93), 16 pre-B-ALL, 5 T-ALL and 3 CML with rare BCR-ABL fusions (b2a3, b3a3 and e19a2).We observed a high correlation between TLDA results for fusion transcripts and those obtained by gold standard techniques (RQ-PCR based on Europe against Cancer protocols). Indeed, we identified 89 patients with different fusion transcripts, including 18 cases previously reported as negative by cytogenetics or FISH approach. Patients with a favorable karyotype showed a distinctive gene expression profile. Thus, inv(16) AML overexpressed: MYH11, CLIP3, CTNNB1, SPARC, SNAI1 and MN1; t(8;21) AML expressed high levels of ETO, POU4F1, CAV1, CD34, FOXO3A, PRAME and BAALC, and t(15;17) AML showed upregulation of HGF, FGF13, WT1 and PRAME. Further, the 51 NPM1 mutated patients (38 A, 5 B, 6 D and 2 DD1, confirmed by sequencing) also showed a specific gene profile, showing high NPM1, CD34, ABCB1, ABCG2, BAALC, PROM1 or BCL2 RNA levels and low HOXA7, HOXA9 and MEIS1 RNA levels. In contrast, AML with 11q23 abnormalities or with FLT3-ITD mutations did not exhibit a characteristic pattern. Several genes (EVI1, BAALC, ERG, PRAME or PIM1) showed prognostic significance in AML with normal karyotype and AML with NPM1 mutations, thus confirming TLDA as a useful approach for risk assessment in AML. Interestingly, PIM1 overexpression was an independent predictor for shorter relapse-free (RFS) and overall survival (OS) in patients with normal karyotype (p=0.012 and p<0.001, respectively) and patients harboring NPM1 mutations (p=0.004 and p=0.002). Moreover, patients with FLT3-ITD mutations and high levels of PIM1 showed an extremely poor prognosis (2-year RFS 26% and OS 30%). These results were confirmed in multivariate analyses.We showed the diagnostic and prognostic value of the designed TLDA platform for evaluation of AML patients. Furthermore, in our series PIM1 has been identified as the most important prognostic marker and thus this oncogene could be used for a more accurate risk classification of AML patients.Gutiérrez: Janssen Cilag: Honoraria; Celgene: Honoraria. Díaz-Mediavilla:Janssen-Cilag: Honoraria; Celgene: Honoraria.

Abstract 1620

Several mutations and aberrant gene expression have been proposed as prognostic factors in cytogenetically normal acute myeloid leukemia (CN-AML), but few studies have analyzed the clinical value of several genes in a large group of CN-AML patients. In 121 de novo CN-AML included into the Spanish PETHEMA therapeutic protocols, we evaluated FLT3and NPM1mutations and BAALC, ERG, EVI1, MLL-PTD, MN1, PRAME, RHAMMand WT1RNA levels. Ninety-one patients achieved CR with standard induction therapy while 20/111 (16.5%) were refractory to treatment. This latter subgroup showed higher ERG(media 1.0±0.8 vs. 0.6±0.6;p=0.012) and lower PRAME(media 28.8±52.9 vs. 1640.6±6102.0;p=0.014) levels than no-refractory patients. Moreover, high ERGexpression (defined by median value) was associated with shorter OS at 2-years (38% vs. 61%;p=0.012) and RFS at 2-years (38% vs. 60%;p=0.005). By contrast, high PRAMElevels (defined by 75thpercentile) was related to longer OS (61% vs. 48%;p=0.029) and RFS (74% vs. 43%;p=0.016). Additionally, high EVIexpression (defined by 75thpercentile) was associated with a poorer OS (37% vs. 56%;p=0.049). The same results in OS were observed in patients with high BAALCRNA levels (median value; 41% vs. 62%; p=0.049). Interestingly, ERG, EVI1and PRAMEmarkers improved the current prognostic classification of CN-AML based on FLT3and NPM1status. Therefore, intermediate risk patients (FLT3-ITD/NPM1mutand FLT3wt/NMP1wt) with low ERG, low EVI1or high PRAMEachieved long OS and RFS, similar to the favorable FLT3wt/NPM1mut subgroup. By contrast, the opposite expression subgroup (high ERG, high EVI1or low PRAME) showed OS and RFS similar to the adverse FLT3-ITD/NPM1wt subset. These results allowed identify clearly two risk-subgroups for OS and RFS, based on three molecular markers (FLT3, NPMand one of the 3 proposed genes). In conclusion, we demonstrated that ERG, EVI1and PRAMEare relevant prognostics markers in CN-AML and they could improve their risk-stratification.

Several mutations and aberrant gene expression have been proposed as prognostic factors in cytogenetically normal acute myeloid leukemia (CN-AML), but few studies have analyzed the clinical value of several genes in a large group of CN-AML patients. In 121 de novo CN-AML included into the Spanish PETHEMA therapeutic protocols, we evaluated FLT3 and NPM1 mutations and BAALC, ERG, EVI1, MLL-PTD, MN1, PRAME, RHAMM and WT1 RNA levels. Ninety-one patients achieved CR with standard induction therapy while 20/111 (16.5%) were refractory to treatment. This latter subgroup showed higher ERG (media 1.0±0.8 vs. 0.6±0.6;p=0.012) and lower PRAME (media 28.8±52.9 vs. 1640.6±6102.0;p=0.014) levels than no-refractory patients. Moreover, high ERG expression (defined by median value) was associated with shorter OS at 2-years (38% vs. 61%;p=0.012) and RFS at 2-years (38% vs. 60%;p=0.005). By contrast, high PRAME levels (defined by 75th percentile) was related to longer OS (61% vs. 48%;p=0.029) and RFS (74% vs. 43%;p=0.016). Additionally, high EVI expression (defined by 75th percentile) was associated with a poorer OS (37% vs. 56%;p=0.049). The same results in OS were observed in patients with high BAALC RNA levels (median value; 41% vs. 62%; p=0.049). Interestingly, ERG, EVI1 and PRAME markers improved the current prognostic classification of CN-AML based on FLT3 and NPM1 status. Therefore, intermediate risk patients (FLT3-ITD/NPM1mut and FLT3wt/NMP1wt) with low ERG, low EVI1 or high PRAME achieved long OS and RFS, similar to the favorable FLT3wt/NPM1mut subgroup. By contrast, the opposite expression subgroup (high ERG, high EVI1 or low PRAME) showed OS and RFS similar to the adverse FLT3-ITD/NPM1wt subset. These results allowed identify clearly two risk-subgroups for OS and RFS, based on three molecular markers (FLT3, NPM and one of the 3 proposed genes). In conclusion, we demonstrated that ERG, EVI1 and PRAME are relevant prognostics markers in CN-AML and they could improve their risk-stratification.

Waldenstro¨m Macroglobulinemia (WM) is characterized by monoclonal IgM paraprotein and bone marrow (BM) infiltration by lymphoplasmacytic lymphoma. The normal counterpart of WM malignant cell seems to be a post germinal centre IgM B-cell, which tumoral transformation occurs after cessation of somatic mutation (SM) but prior to Class switch recombination (CSR). However, recently has been reported that CSR can be possible “ex-vivo”, since clonotypic transcripts encoding post-switch isotypes have been observed in some WM cells cultured with CD40L/IL-40. However, this process has not been shown to occur “in vivo” until now. #3754, a 51-year-old woman, was diagnosed in 2001 of WM with a M-IgM spike (46 g/L), anemia (Hb 9·6 g/dL), 76% lymphoplasmacytic monoclonal B-cells in BM and normal cytogenetics. In April 2005, an important IgG increase was observed (23 g/L). Immunofixation demonstrated an IgG-k paraprotein in the mid g-region and a monoclonal IgM-k paraprotein at the b-region corresponding to the two monoclonal peaks detected on serum electrophoresis. After 6-mercaptoethanol treatment, a single band was seen at the line stained with kappa, suggesting the presence of a single clone. Other causes of IgG monoclonal components were excluded considering clinical factors, immunophenotype analyses (San Miguel et al, 2003), quantity of DNA and cell cycle analyses (Ocio et al, 2005). However, the definitive proof for a unique monoclonal population was provided through molecular analysis. A single clonotypic rearrangement was detected by amplifying the complete VDJH fragment at diagnosis moment, according to the protocol describes in Biomed II (Leukemia2003; 17.2257–2317). Method describes from Billadeu et al (Billadeau et al, 1993) was used for isotype identification. So, cDNA monoclonal amplification was observed at tubes corresponding to Cm, Cd and Cg. All monoclonal PCR products were directly sequenced in an automated ABI 377 DNA sequencer. VH, DH & JH segments identification, as well as SH recognition was made using the V-BASE sequence directory alignment program, and the CH regions were compared at BLAST. All sequences obtained showed the same clonotypic CDR3 sequence (VH4-59/JH6) as well as the same SH (10,75%) pattern that monoclonal amplification at diagnosis, indicating the presence of the same clone at that moment (Figure 1). In conclusion, we report for the first time a WM case in which tumor cells were able to carry out CSR, showing IgG and IgM clonotypic amplification, as well as producing both paraprotein components. This constitutes the first in vivo demonstration that CSR is possible in WM cells, and are able to develop a fully functional isotype class switch recombination not only in vitro but also in vivo. Figure 1: Deduced amino acid sequence of tumor-derived VDJH gene with the three heavy chain isotypes (A: Cµ, B: Cd C: C?). Sequences indicates the somatic mulation pattern. Comparison for WM are made with the closest germline VH gone; uppercase, replacement (R) mutation; lower case, silent (S) mutation. Each mutation was defined by nuclieotide exchanges in a single codon, with successive mutations leading in some cases to 2 or 3 distinct R or S events. These are shown as aligned amino acid changes at specific sites. Figure 1:. Deduced amino acid sequence of tumor-derived VDJH gene with the three heavy chain isotypes (A: Cµ, B: Cd C: C?). Sequences indicates the somatic mulation pattern. Comparison for WM are made with the closest germline VH gone; uppercase, replacement (R) mutation; lower case, silent (S) mutation. Each mutation was defined by nuclieotide exchanges in a single codon, with successive mutations leading in some cases to 2 or 3 distinct R or S events. These are shown as aligned amino acid changes at specific sites.

Waldenström Macroglobulinemia (WM) is characterized by monoclonal IgM paraprotein and bone marrow (BM) infiltration by lymphoplasmacytic lymphoma. The normal counterpart of WM malignant cell seems to be a post germinal centre IgM B-cell, which tumoral transformation occurs after cessation of somatic mutation (SM) but prior to Class switch recombination (CSR). However, recently has been reported that CSR can be possible “ex-vivo”, since clonotypic transcripts encoding post-switch isotypes have been observed in some WM cells cultured with CD40L/IL-40. However, this process has not been shown to occur “in vivo” until now.

The detection of PML-RARa by real-time PCR (RQ-PCR) is becoming an important tool for monitoring minimal residual disease (MRD) in acute promyelocytic leukemia (APL) patients; however, the clinical value of using a RQ-PCR approach remains to be determined. Our aim was to analyze the correlation between relapse risk and MRD levels assessed by RQ-PCR at different phases of treatment, and to compare these data with conventional qualitative RT-PCR. Follow-up samples from 145 APL patients treated with the PETHEMA protocols were analyzed by RQ-PCR protocol from Europe Against Cancer program and by RT-PCR method from European BIOMED-1 Concerted Action. After induction therapy, no association was found between the presence of a RQ-PCR positive result and relapse. After the third consolidation course, three cases remained positive by RQ-PCR assays and two of them (67%) relapsed. By contrast, only 16 out of 119 (13%) patients with negative RQ-PCR relapsed. During maintenance therapy and out-of treatment, a significant correlation between a RQ-PCR positive result and a poor relapse-free survival was observed (p < 0.0001). All patients with > 10 PML-RARa normalized number copies (NCN) at maintenance or out-of therapy relapsed (n=19), while all patients with < 1 NCN within out-of treatment group remained in hematological remission (n=75). 8 patients with < 1 NCN during maintenance therapy finally relapsed, but all of them appeared beyond the end of treatment. In addition, in the intermediate group of patients (NCN 1–10) (n=18) relapse probability of 40% at 5 years was observed. All hematological relapses were predicted if a follow-up sample had been obtained within the previous 4 months. Based on the information provided by RQ-PCR in samples obtained after the end of consolidation and subsequently, a relapse risk stratification could be established for APL patients.

The detection of PML-RARaby real-time PCR (RQ-PCR) is becoming an important tool for monitoring minimal residual disease (MRD) in acute promyelocytic leukemia (APL) patients; however, the clinical value of using a RQ-PCR approach remains to be determined. Our aim was to analyze the correlation between relapse risk and MRD levels assessed by RQ-PCR at different phases of treatment, and to compare these data with conventional qualitative RT-PCR. Follow-up samples from 145 APL patients treated with the PETHEMA protocols were analyzed by RQ-PCR protocol from Europe Against Cancer program and by RT-PCR method from European BIOMED-1 Concerted Action. After induction therapy, no association was found between the presence of a RQ-PCR positive result and relapse. After the third consolidation course, three cases remained positive by RQ-PCR assays and two of them (67%) relapsed. By contrast, only 16 out of 119 (13%) patients with negative RQ-PCR relapsed. During maintenance therapy and out-of treatment, a significant correlation between a RQ-PCR positive result and a poor relapse-free survival was observed (p < 0.0001). All patients with > 10 PML-RARanormalized number copies (NCN) at maintenance or out-of therapy relapsed (n=19), while all patients with < 1 NCN within out-of treatment group remained in hematological remission (n=75). 8 patients with < 1 NCN during maintenance therapy finally relapsed, but all of them appeared beyond the end of treatment. In addition, in the intermediate group of patients (NCN 1–10) (n=18) relapse probability of 40% at 5 years was observed. All hematological relapses were predicted if a follow-up sample had been obtained within the previous 4 months. Based on the information provided by RQ-PCR in samples obtained after the end of consolidation and subsequently, a relapse risk stratification could be established for APL patients.

Gene Expression Profiling through RNA arrays has provided new clues to Multiple Myeloma pathogenesis and prognostic pattern evaluation. Recently, ZHX2, CHC1L & RAN expression have been highlighted as key elements in MM. In the present paper, we have evaluated theses genes by real time quantitative RT-PCR (RQ-PCR) in purified plasma cells from 74 patients with plasma cell discrasias. MATERIAL AND METHODS: Purified Bone Marrow cells were obtained from the following patients: 6 MGUS, 7 smoldering MM, 59 newly diagnosed symptomatic MM patients and 2 Plasma cell leukemia (PCL). After RNA extraction, RQ-PCR of CHC1L(C), RAN(R) and ZHX2 (Z) genes was carried out using the standard protocol from TaqMan® gene expression Assays-on-Demand in an ABI-PRISM 7700 Sequence Detection System (Applied Biosystems, Foster City, CA, USA). Expression levels were normalized with ABL gene and expressed in n-fold times compared to the expression in a pool of RNA from mononuclear cells from healthy donors. The expression level of the different genes was evaluated for correlation with the diagnosis, clinical characteristics and prognosis of the patients. RESULT AND CONCLUSIONS: None of these genes displayed a clear relationship with the different stages of disease pathogenesis, although ZHX2 gene was slightly more expressed in the indolent forms of the proliferative disorders (MGUS and SMM). Within symptomatic MM patients, several interesting associations were observed. Thus, in hyperdiploid MM cases, CHC1L expressions observed were fewer than in those with a normal DNA index, confirming the participation of the gene product in chromosomal condensation during the mitosis. No other important associations were observed for this gene, although patients with the lowest expression displayed a very good prognosis, but without reaching statistically significant differences. As expected, RAN expression was related to S-Phase PC, since patients with high S phase values (>1.8 %) displayed higher levels of RAN transcripts. This, however, only resulted in a marginal impact on survival. ZHX2 provided the most interesting results, whereby decreased levels of ZHX2 were related to unfavorable prognostic indicators such as B2 microglobulin >4 mg/L and Hemoglobin levels <10.5 g/dl. This was significantly associated with a shorter survival. As such, patients with a level of ZHX2 expression lower than twice the expression of controls were associated with a very low survival (median of 6 months vs not reached, p=0.019). If we take into account the survival prediction value of these three genes, the following prognosis groups were defined: very good prognosis (Z+ C−), poor prognosis (Z− C+) and intermediate (the remaining patients). SUMMARY: From this study we can confirm that RAN, CHC1L and especially ZHX2 genes play a role in the pathogenesis and behavior of MM, this could be helpful in predicting survival of patients.

p15 and p14/p16 tumor suppressor genes, have been reported to be frequently inactivated by various mechanisms in haematological malignancies such us MM. Alterations of these cell cycle inhibitors in MM display a close correlation with the cell cycle and clinical outcome. We have evaluated by real time quantitative RT-PCR (RQ-PCR) the expression of the p14/p16 and p15 genes in purified bone marrow plasma cells (PBMPC) from MM patients in order to evaluate the possible clinical, biological and prognostic significance of these cell cycle regulators. RNA extracted from purified BMPC from 53 untreated symptomatic MM and a pool of buffy coat from healthy donors (reference value) was analyzed by RQ-PCR using Assays-on-Demand gene expression mixes specific for p14/p16 and p15 genes in an ABI PRISM 7700 SDS (Applied Biosystems, Foster City, CA, USA). Values were corrected with a control gene (ABL). The relative quantification of gene expression was performed through the cycle threshold (CT) increment method. Patients were classified into different groups depending on gene expression values. Thus, according to p15 expression, 29% of patients (n=14) showed higher levels than the control and this group was characterized by the presence of good prognostic markers such us low Lactato dehidrogenase levels (LDH), low b2-microglobulin (B2M) and C-Reactive Protein (CRP) serum levels and absence of monoclonal proteinuria. Similar results were found for p14/p16 expression. Fifteen patients (28%) displayed a high p14/p16 expression and the group was also characterized by good prognostic features: low CRP, B2M and LDH levels. When p14/p16 and p15 genes were simultaneously analyzed, clinical and biological parameters showed a statistically significant correlation with gene expression. Thus patients with low gene expression had a high B2M (≥3 mg/dl) and high C-reactive protein (≥3 mg/dl). As far as survival was concerned, patients with a high p15 expression had a longer overall survival of 100% vs. 58% at 30 months (p=0,01), with the additional value that no deaths have been observed in any such patients. Similar results were observed for the group of patients displaying a high p14/p16 expression since they displayed a much better OS (100% vs. 63% at 30 months, p=0,02). Again, we should note that no deaths have been presented in this group. All these findings were much more evident when the three genes were simultaneously considered. Thus, within the group of 21 patients with at least one of the two genes overexpressed there have been no deaths vs. 11 among the 27 patients with low levels. This resulted in quite different OS curves for the two groups of patients (Figure 1) of 100% vs. 49% at 30 months (p=0,00). In conclusion, these genes significantly determine patients’ outcome thanks to their ability to classify them into different groups with different clinical, biological and outcome characteristics.

Introduction: Waldenström’s Macroglobulinemia (WM) is an uncommon lymphoproliferative disorder characterized by bone marrow infiltration of the lymphoplasmocytic cells and IgM monoclonal gammopathy. The normal counterpart of the WM malignant cell is believed to be a post germinal-center B cell. However, the low frequency of WM has hampered investigation into Immunoglobulin Heavy Chain (IgH) rearrangements in large series of patients and whether preferential use of specific genetic segments or non-functional rearrangements exits. Aim: Molecular characterization in a large cohort of WM patients analyzing their functional, complete VDJH, and non-functional, incomplete DJH, IgH rearrangements, the pattern of somatic hypermutation (SHM) and gene segment usage. Patients and methods: 47 patients with unequivocal diagnosis of WM were included in the study. Bone Marrow samples (always with more than 10% of tumor cell) were used for amplification of clonal rearrangements employing the Biomed-2 strategy (Leukemia2003; 17; 2257), followed by direct automated sequencing in ABI 377 DNA sequencer using Big-Dye terminators (Applied Biosystems, Foster City, CA). Results: All patients showed a monoclonal amplification of at least one VDJH or DJH rearrangement. VDJH monoclonal rearrangements were detected in 42/47 (89.3%) patients while DJH were observed in 20 (42.5%) patients. VH, DH and JH gene segment usage: VH3 gene segment was the most commonly represented family (76,2%) while the other gene segments were scarcely detectable, and VH5 was totally absent. In the complete VDJH rearrangements, DH6 was the family most commonly represented while DH2 (45%) and DH4 (30%) were the most common in the incomplete DJH rearrangement. Regarding JH elements, JH4 (38%) was the most represented in the complete rearrangements and JH5 (46%) in the incomplete rearrangements. Somatic hypermutation: SHM were observed in all except two of the cases (94%, 34 of 36 cases), in which the study could be performed. (median 9,38; range2.9–16.6). In the remaining clonal cases (6 cases, 14.3%) no amplification of FR1 region was obtained, also suggesting the presence of SHM. Conclusions: In this series of patients, we observed the presence of incomplete rearrangements with an incidence similar (44%) to that described in multiple myeloma. The preferential usage for determined families of genetic segments, in VDJH and in DJH, suggests the presence of positive and negative selection processes. Finally, the majority, (94 %) of the cases, presented SHM, although the presence of two patients lacking in SHM suggests a pre-follicular origin for some WM cases.

Gene Expression Profiling through RNA arrays has provided new clues to Multiple Myeloma pathogenesis and prognostic pattern evaluation. Recently, ZHX2, CHC1L & RAN expression have been highlighted as key elements in MM. In the present paper, we have evaluated theses genes by real time quantitative RT-PCR (RQ-PCR) in purified plasma cells from 74 patients with plasma cell discrasias.

p15and p14/p16tumor suppressor genes, have been reported to be frequently inactivated by various mechanisms in haematological malignancies such us MM. Alterations of these cell cycle inhibitors in MM display a close correlation with the cell cycle and clinical outcome. We have evaluated by real time quantitative RT-PCR (RQ-PCR) the expression of the p14/p16and p15genes in purified bone marrow plasma cells (PBMPC) from MM patients in order to evaluate the possible clinical, biological and prognostic significance of these cell cycle regulators.