B-cell Differentiation Markers Research Articles

DSMZCellDive: Diving into high-throughput cell line data

Human and animal cell lines serve as model systems in a wide range of life sciences such as cancer and infection research or drug screening. Reproducible data are highly dependent on authenticated, contaminant-free cell lines, no better delivered than by the official and certified biorepositories. Offering a web portal to high-throughput information on these model systems will facilitate working with and comparing to these references by data otherwise dispersed at different sources. We here provide DSMZCellDive to access a comprehensive data source on human and animal cell lines, freely available at celldive.dsmz.de. A wide variety of data sources are generated such as RNA-seq transcriptome data and STR (short tandem repeats) profiles. Several starting points ease entering the database via browsing, searching or visualising. This web tool is designed for further expansion on meta and high-throughput data to be generated in future. Explicated examples for the power of this novel tool include analysis of B-cell differentiation markers, homeo-oncogene expression, and measurement of genomic loss of heterozygosities by an enlarged STR panel of 17 loci. Sharing the data on cell lines by the biorepository itself will be of benefit to the scientific community since it (1) supports the selection of appropriate model cell lines, (2) ensures reliability, (3) avoids misleading data, (4) saves on additional experimentals,and (5) serves as reference for genomic and gene expression data.

DSMZCellDive: Diving into high-throughput cell line data

Human and animal cell lines serve as model systems in a wide range of life sciences such as cancer and infection research or drug screening. Reproducible data are highly dependent on authenticated, contaminant-free cell lines, no better delivered than by the official and certified biorepositories. Offering a web portal to high-throughput information on these model systems will facilitate working with and comparing to these references by data otherwise dispersed at different sources. We here provide DSMZCellDive to access a comprehensive data source on human and animal cell lines, freely available at celldive.dsmz.de. A wide variety of data sources are generated such as RNA-seq transcriptome data and STR (short tandem repeats) profiles. Several starting points ease entering the database via browsing, searching or visualising. This web tool is designed for further expansion on meta and high-throughput data to be generated in future. Explicated examples for the power of this novel tool include analysis of B-cell differentiation markers, homeo-oncogene expression, and measurement of genomic loss of heterozygosities by an enlarged STR panel of 17 loci. Sharing the data on cell lines by the biorepository itself will be of benefit to the scientific community since it (1) supports the selection of appropriate model cell lines, (2) ensures reliability, (3) avoids misleading data, (4) saves on additional experimentals, and (5) serves as reference for genomic and gene expression data.

DSMZCellDive: Diving into high-throughput cell line data.

Human and animal cell lines serve as model systems in a wide range of life sciences such as cancer and infection research or drug screening. Reproducible data are highly dependent on authenticated, contaminant-free cell lines, no better delivered than by the official and certified biorepositories. Offering a web portal to high-throughput information on these model systems will facilitate working with and comparing to these references by data otherwise dispersed at different sources. We here provide DSMZCellDive to access a comprehensive data source on human and animal cell lines, freely available at celldive.dsmz.de. A wide variety of data sources are generated such as RNA-seq transcriptome data and STR (short tandem repeats) profiles. Several starting points ease entering the database via browsing, searching or visualising. This web tool is designed for further expansion on meta and high-throughput data to be generated in future. Explicated examples for the power of this novel tool include analysis of B-cell differentiation markers, homeo-oncogene expression, and measurement of genomic loss of heterozygosities by an enlarged STR panel of 17 loci. Sharing the data on cell lines by the biorepository itself will be of benefit to the scientific community since it (1) supports the selection of appropriate model cell lines, (2) ensures reliability, (3) avoids misleading data, (4) saves on additional experimentals,and (5) serves as reference for genomic and gene expression data.

Poster: HL-325: A Case Report of Classic Hodgkin Lymphoma with Unusually Abundant Tumor Cell Expression of B-Cell Markers: A Diagnostic Dilemma and Treatment Challenge

Context The diagnosis of classic Hodgkin Lymphoma (cHL) appears quite straightforward, as it is built upon extended histological and immunophenotypic assessment. Hodgkin and Reed-Sternberg cells reflect monoclonal cell proliferation, presumably originating from germinal center B-cells. In general, these cells lose the B-cell phenotype, yet one-third of cHL cases express at least one B-cell marker, which in some instances leads to diagnostic difficulties in distinguishing cHL from B-Cell Lymphomas (BCL). Objective We present a diagnostically complex case of cHL CD30+/CD15+ in a 21-year-old male. Immunohistochemistry demonstrated unusual, strong expression of markers of B-cell differentiation and positivity for Epstein-Barr Virus (EBV), which brought out serious constraints in the differential diagnosis of an EBV-positive Diffuse Large BCL. Patient Case Report A previously healthy 21-year-old male presented at our institution with neck lymphadenopathy. He experienced no B-symptoms. Except for a slightly elevated sedimentation rate, blood analyses were within normal ranges. Initial PET-CT scan identified stage II disease involving supradiaphragmatic lymph nodes. Fine needle aspiration of the lymph node was suggestive of HL. However, histological examination of the surgically extirpated lymph node was puzzling. The atypical lymphoid cells expressed classical Hodgkin phenotype CD30+/CD15+, but they showed strong CD20+ co-expression. The tumor cells were strongly positive for EBV, and a diagnosis of EBV-associated BCL was assumed. In addition, high EBV loads in blood were confirmed. PCR studies for B- and T-cell gene rearrangements were negative. The tumor tissue was sent for consultative opinion in three centers independently. Immunostains were consistent; lymphoma cells were strongly positive for CD30, CD15, EBV, and EBV receptor CD21, as well as the B-cell markers CD20, Bcl-6, and MUM1. Finally, next-generation sequencing for B-cell rearrangement was negative. In absence of sufficient diagnostic criteria for EBV-positive BCL and all things considered, the diagnosis of classic HL was concluded. Conclusions In consensus with reported literature, treatment was initiated with R-ABVD regimen. Complete regression of tumor masses became evident after the first cycle. An interim PET scan is planned for further evaluation.

Differential Expression of BCL-6, CD138/Syndecan-1, and Epstein-Barr Virus–Encoded Latent Membrane Protein-1 Identifies Distinct Histogenetic Subsets of Acquired Immunodeficiency Syndrome–Related Non-Hodgkin's Lymphomas

AbstractThis study was aimed at defining the histogenesis of the pathologic spectrum of acquired immunodeficiency syndrome–related non-Hodgkin's lymphomas (AIDS-NHL), including AIDS-related small noncleaved cell lymphoma (AIDS-SNCCL), AIDS-related large noncleaved cell lymphoma (AIDS-LNCCL), AIDS-related large cell immunoblastic lymphoma plasmacytoid (AIDS-IBLP), and AIDS-related primary effusion lymphoma (AIDS-PEL). Forty-six cases of AIDS-NHL were investigated for the expression pattern of BCL-6, a protein specifically expressed by germinal center (GC) B-cells, and CD138/syndecan-1 (syn-1), a marker of post-GC B-cell differentiation. Expression of BCL-6 and syn-1 segregated two major phenotypic patterns among AIDS-NHL: (1) the BCL-6+/syn-1− pattern associated with AIDS-SNCCL and AIDS-LNCCL; (2) the BCL-6−/syn-1+ pattern associated with AIDS-IBLP and AIDS-PEL. Among systemic AIDS-NHL infected by Epstein-Barr virus (EBV), expression of the EBV-encoded latent membrane protein-1 (LMP-1) preferentially associated with the BCL-6−/syn-1 + profile. Analysis of nonneoplastic lymph nodes showed that the two phenotypic patterns detected in AIDS-NHL correspond to physiologic stages of B-cell development, ie, GC B-cells (BCL-6+/syn-1−) and preterminally differentiated post-GC B-cells (BCL-6−/syn-1+). Thus, BCL-6+/syn-1− AIDS-NHL reflects a GC stage of differentiation, whereas AIDS-NHL which are BCL-6−/syn-1+, and LMP-1+when infected by EBV, derive from B cells that have entered post-GC plasmacell differentiation. These findings are relevant for the pathogenesis and differential diagnosis of AIDS-NHL.

ML-04 PROGNOSTIC SIGNIFICANCE OF IMMUNOHISTOCHEMICAL SUBTYPES BASED ON THE STAGE OF B-CELL DIFFERENTIATION IN PRIMARY CNS LYMPHOMA

PURPOSEPrimary central nervous system lymphoma (PCNSL) has been immunohistochemically classified into two subtypes, germinal center (GC) B-cell and non-GC B-cell, but prognostic impact of these subtypes remains debated. We investigated clinical features and prognostic significance of newly defined immunohistochemical subtypes that were identified by expression patterns of three B-cell differentiation markers in PCNSL. In addition, we analyzed a factor related to responsiveness to high-dose methotrexate (HD-MTX) chemotherapy.METHODSTumors from 32 PCNSL patients were immunohistochemically evaluated regarding expression of CD10, BCL-6, and MUM-1 and classified into subtypes according to the expression patterns of these markers. Clinical features and prognostic outcome of these subtypes were investigated.RESULTSTwenty-three patients were treated with HD-MTX-based chemotherapy followed by whole-brain radiation therapy (WBRT), and nine were treated with WBRT alone. Three immunohistochemical subtypes were identified, including A-type expressing CD10, BCL-6, and MUM-1 (12 patients), B-type expressing BCL-6 and MUM-1 (12 patients) and C-type expressing MUM-1 only (8 patients). Response rate in the HD-MTX therapy group was 57.1% (4/7) in A-type, 87.5% (7/8) in B-type, and 75% (6/8) in C-type. C-type with the lowest metabolic activity showed significantly longer overall survival than A-type with the higher uptake of methionine (71.6 versus 39.6 months).CONCLUSIONSImmunohistochemical identification of PCNSL based on the B-cell differentiation stage revealed three types of tumors, showing different metabolic activity and survival time. Refined immunohistochemical classification of PCNSL subtypes may become a useful tool for predicting more accurate prognosis and accessing the sensitivity to HD-MTX therapy.

T-cell mitochondrial dysfunction and lymphopenia in DOCK2-deficient patients

This study delineates the mitochondrial defects in DOCK2-deficient T cells contributing to the T cell lymphopenia characteristic of this primary immunodeficiency.

Rituximab as a Therapeutic Option for Steroid-Sensitive Minimal Change Nephrotic Syndrome in Adults.

Minimal change nephrotic syndrome (MCNS) usually responds to steroids but frequently relapses, requiring additional treatment with immunosuppressive agents. Rituximab is a chimeric murine/human monoclonal immunoglobulin G1 antibody that targets CD20, a B-cell differentiation marker. B-cell recovery begins at approximately 6 months following the completion of treatment. Rituximab has a beneficial effect, with the sustained remission or reduction of proteinuria in patients with steroid-dependent MCNS. Relapses are thought to be associated with an increase in CD19 cells. The mean serum half-life of rituximab was reported to be 10-15 days in patients with steroid-dependent MCNS. Only infusion reactions, such as rash and chills, occurred after single-dose rituximab infusion and can be managed by pre-medication or infusion rate adjustments. Even though severe adverse effects of rituximab are not expected, we must be aware of potentially life-threatening adverse effects. Controlled randomized trials that include adult patients with steroid-dependent MCNS are required to prove the efficacy and safety of rituximab and to evaluate the cost-effectiveness of rituximab treatment. In this review, we highlight recent studies and discuss the effects of these studies on the management of patients with MCNS in adults.

B-cell populations are expanded in breast cancer patients compared with healthy controls

BackgroundHistorically, humoral immunity was considered unimportant in anti-tumor immunity, and the differentiation and anti-tumor activity of B cells in breast cancer are poorly understood. However, it was recently discovered that B cells participate in tumor immunity through both antibody production and immunosuppressive mechanisms. We analyzed the expression of B-cell differentiation markers in detail using fluorescence-activated cell sorting to investigate the relationship between B-cell subsets and breast cancer etiology.MethodsBlood samples were taken from breast cancer patients and healthy donors, and peripheral blood mononuclear cells were collected. B cells at various stages of differentiation were identified by the expression of combinations of the cell surface markers CD5, CD19, CD21, CD24, CD27, CD38, CD45, and IgD. Statistical analysis of the proportions of each B-cell subtype in the different patient groups was then performed.ResultsTwenty-seven breast cancer patients and 12 controls were considered. The proportion of total B cells was significantly higher in cancer patients than in controls (11.51 ± 2.059 vs 8.905 ± 0.379%, respectively; p = 0.001). Breast cancer patients were then classified as High-B or Low-B for further analysis. A significantly higher proportion of memory B cells was found in the High-B group than in the Low-B or control groups (p = 0.003 and p = 0.043, respectively).ConclusionsBreast cancer patients generally have a higher proportion of B cells than healthy controls, but this is highly variable. Analysis of the major B-cell surface markers indicates that memory B cells in particular are significantly expanded, or more robust, in breast cancer patients.

Effect of B Cell Differentiation Markers on the Prognosis of Primary Central Nervous System Lymphoma

To investigate the value of B-cell differentiation markers in prognosis evaluation of 119 patients with primary CNS lymphoma(PCNSL). The expressions of BCL-2, BCL-6, CD10 and MUM1/IRF4 protein were determined by immunohistochemistry, and their relationship with the prognosis of primary central nervous system lymphoma was analyzed. Univariate analysis showed that BCL-6 positive means shorter PFS (P=0.047) and OS (P=0.035). Multivariate analysis showed that BCL-6 positive expression was related with shorter PFS (hazard ratio:1.95, 95% CI: 1.22- 3.12, P=0.005), but did not relate with OS (hazard ratio: 1.85, 95% CI: 0.71- 4.80, P=0.21). Classification based on Hans algorithm and expression status of the single B-cell markers BCL-2, CD10 and MUM1/IRF4 did not correlate with prognosis. BCL-6 may be an unfavorable prognostic biomarker for PCNSL.

High Resolution Mapping of Human Lymphopoiesis Reveals a Common Lymphoid Progenitor (CLP) Population

In vivo reconstitution studies have established the phenotype of murine CLP, a progenitor population with restricted developmental potential for T, NK, B lymphoid and plasmacytoid dendritic cell (pDC) lineages. Co-transplantation of murine CLP with purified HSC more rapidly restores lymphopoiesis, immune function and resistance to viral challenge in experimental models of HSC transplantation. Thus, the identification of human CLP would have translational impact in clinical HSCT. Based on the expression of IL-7Rα (CD127) as a key distinguishing marker of murine CLP, we studied the CD127+ subset of immature CD34+ Lin- CD38+ cells for lymphoid committed progenitors, comprising approximately 0.1-0.2% of total marrow. Like murine CLP, the CD34+ Lin- CD38+ CD127+ cells also expressed Kit and Flt3. OP9 stromal cells were transduced with a vector expressing a doxycycline inducible delta-like ligand 1 (dll1) gene to test the differentiation potential in a single-well switch culture. Progenitors co-cultured with uninduced OP9Δdll1 cells can differentiate into B and myeloid cells; after induction of dll1, the culture is permissive for T and NK differentiation in the same well. In the presence of Kit and Flt3 ligands, erythromyeloid growth factors (IL-6, IL-3, GM-CSF, EPO, TPO) and lymphoid factors (IL-7, IL-15), CD34+ Lin- CD38- CD127- HSC generated erythroid (E), myelomonocytic (MM), myeloid DC (mDC), T, NK, and B lymphocytes and pDC. In contrast, CD34+ Lin- CD38+ CD127+ cells generated T/NK/B/pDC progeny, distributed in varying proportions, but did not generate E/MM/mDC. Singly plated CD34+ Lin- CD38+ CD127+ cells generate T/NK/B cells in the same well, consistent with these cells being human CLP. CD34+ Lin- CD38+ CD127- "non-CLP" generated E/MM/mDC, but not T/NK/B/pDC progeny. Limiting dilution analyses under lymphoid conditions demonstrated that the CD34+ Lin- CD38+ CD127+ CLP had approximately 2-3-fold greater efficiency of lymphocyte generation than HSC under the same conditions. Transcriptional profiling of the human CLP showed patterns of gene expression distinct from that of HSC, CD34+ Lin- CD38+ CD127- progenitors and immature CD3-CD4-CD8- thymocytes. Approximately 50% of the CD34+ Lin- CD38+ CD127+ CLP also express CD10, a subpopulation which CyTOF analyses revealed to have other markers of B-cell commitment and/or differentiation, e.g., CD179a. Human CD34+ Lin- CD38+ CD127+ marrow cells are a unique multipotent, lymphoid-restricted progenitor population for T/NK/B/pDC cell development, and within which subsets of cells biased for individual lymphoid lineages may exist. Identification of human CLP will permit further analyses of lymphoid specification, commitment to lymphoid lineages, and potential adoptive transfer as a short-term source of polyclonal lymphocytes. DisclosuresNolan:Fluidigm: Consultancy.

Prognostic impact of B-cell lymphoma 6 in primary CNS lymphoma.

We investigated the prognostic significance of B-cell differentiation status and common B-cell differentiation markers in a post hoc analysis of 119 patients with primary CNS lymphoma (PCNSL) homogeneously receiving high-dose methotrexate (HDMTX)-based chemotherapy within the prospective G-PCNSL-SG1 trial. We evaluated protein expression of B-cell lymphoma 2 (BCL2), BCL6, CD10, and multiple myeloma oncogene 1/interferon regulatory factor 4 (MUM1/IRF4) by immunohistochemistry and analyzed the association with survival. The median follow-up of all patients was 67.5 months. Median progression-free survival (PFS) was 10.61 months (95% CI: 4.23-17.00). Median overall survival (OS) was 28.85 months (95% CI: 17.96-39.73). Eighty-nine tumors expressed BCL2 (92.7%), 24 (20.5%) expressed CD10, 60 (54.1%) expressed BCL6, and 87 (79.0%) expressed MUM1/IRF4. On the basis of the Hans algorithm, 80 tumors (73.4%) were classified to the non-germinal center B group, suggesting a post-germinal center origin of PCNSL. Expression of BCL6 (cutoff point 30%), but none of the other markers, was associated with shorter PFS (P = .047) and OS (P = .035). On multivariate analysis, BCL6 expression was associated with shorter PFS (hazard ratio: 1.95, 95% CI: 1.22-3.12, P = .005) but not OS (hazard ratio: 1.85, 95% CI: 0.71-4.80, P = .21). Classification according to Hans algorithm and expression status of the single B-cell markers BCL2, CD10, and MUM1/IRF4 did not correlate with prognosis. The findings are limited by the fact that only 23% of all G-PCNSL-SG1 patients could be included in the analysis. If validated in an independent cohort, BCL6 may assume clinical relevance as an unfavorable prognostic biomarker in PCNSL.

A Genome-Wide RNAi Screen to Identify Novel Genes Involved in Clonal Maintenance of ALL

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children and adolescents where treatment is associated with significant morbidity. Novel therapeutic approaches to improve treatment outcome and minimize side-effects are therefore required. We have previously shown a lack of stem cell hierarchy and a high frequency of leukemic stem cells in ALL. Based on these findings, we have postulated that malignant self-renewal in ALL may be similar to lymphoid, but distinct from hematopoietic stem cell (HSC) self-renewal thereby providing new therapeutic targets for diseases affecting the lymphoid system. To identify targets and pathways involved in ALL self-renewal, we have performed a genome-wide RNAi screen in the ALL cell line SEM, which carries the translocation t(4;11) and expresses the MLL/AF4 fusion gene.SEM cells were lentivirally transduced using the Decode™ pGIPZ negative selection library consisting of 7 pools of 10,000 shRNA constructs each. The pGIPZ vector allows for Pol II-dependent shRNA expression, GFP-based cell sorting and selection for puromycin resistance. Self-renewal was addressed by replating of transduced cells on puromycin-resistant murine stromal bone marrow feeder cells (M2-10B4), which mimics a niche environment in vitro. SEM cells were selected with puromycin and seeded at low cellular-density under serum-starved conditions to ensure adherence-dependent growth. SEM cells were replated onto new feeders and the puromycin selective pressure was kept throughout the experiments to minimize silencing of shRNA expression. Cells were harvested after the second plating (F2, ~30 days after transduction) and the prevalence of shRNA constructs in F2 was compared to samples harvested 6 days after transduction (baseline, BL) using next generation sequencing of genomic DNA.Initial sequencing results obtained from one out of seven pools show that constructs targeting 637 different genes were differentially expressed (2 –fold change, padj <0.05). For instance, shRNAs targeting genes associated with lymphoid differentiation such as IKZF3 (B-cell progenitor differentiation) and CD20 (marker of B-cell differentiation) were enriched, whereas constructs targeting genes important for proliferation and survival such as BCL2 (survival), BRD4 (epigenetic reader, therapeutic target in leukemia), MAX (partner of MYC), BMI1 (polycomb complex 1 member, required for self-renewal) or POT1 (telomere integrity) were depleted. Furthermore, constructs targeting MAPK9/JNK2 and JUN in the mitogen-activated protein kinase pathway were depleted whilst the construct targeting DUSP10 (inhibitor of MAPK9/JNK2) was enriched, further proving that our screen has functional relevance within a biological context. Interestingly, the construct targeting the aryl hydrocarbon receptor (AHR) involved in B-cell maturation was also increased, which is in line with published data showing that inhibition of AHR drives stem cell maintenance.These results demonstrate the feasibility of our approach where we have established a robust screening protocol that can identify genes involved in survival and self-renewal. Sequencing data from the additional six pools are currently being analyzed. These analyses are expected to provide important information about the key mechanisms by which leukemic blasts maintain their “stemness” in ALL. DisclosuresNo relevant conflicts of interest to declare.

PROGNOSTIC FACTORS FOR PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMAS TREATED WITH HIGH-DOSE METHOTREXATE-BASED CHEMO-RADIOTHERAPY

BACKGROUND: Chemotherapy with high-dose methotrexate (HD-MTX) followed by whole brain radiotherapy (WBRT) is a conventional approach to treat primary central nervous system lymphomas (PCNSL), but some tumors relapse early leading to unfavorable outcome. Several biomarkers have been identified as prognostic factors in PCNSL, however, the correlation of both clinical factors including those related to MTX metabolism and B-cell differentiation and oncogenic biomarkers with response to and outcome by therapy is yet unclear. METHODS: We investigated 32 immunocompetent patients (19 males, 13 females) with PCNSL (all diffuse large B-cell type) treated with HD-MTX based therapy with or without WBRT since 2000 in our institution. Paraffin-embedded formalin-fixed tumor tissue sections were stained immunohistochemically with antibodies against following factors: B-cell differentiation markers (CD10, Bcl-6, Mum-1, CD138); MTX metabolism-related (MRP family, LRP, DHFR); cell cycle-related (p27KIP1, MIB-1); drug resistance-related (MGMT, MLH1, MSH2, MSH6, PMS2); and oncogenes (Myc, Bcl-2). Correlation between positivity of these factors and clinical outcomes were evaluated using logrank test and cox regression analysis. RESULTS: Among these factors, complete response to HD-MTX was significantly associated with longer progression-free survival (PFS)(P = 0.0012), while Bcl-6 expression as well as histological subtype (non-germinal center B-cell, non-GCB) was closely correlated with shorter PFS. Age (>60) (P = 0.006) and MSH2 expression (P = 0.017) were found to be better predictor for overall survival (OS), but in multivariate analysis, they were no longer significant. Other factors involved in MTX metabolism, DNA repair enzymes, and oncogenes did not affect outcome. CONCLUSIONS: Non-GCB subtype and Bcl-6 expression may be associated with worse outcome in patients with PCNSL treated with HD-MTX, while MTX-metabolism related factors did not influence prognosis. Further investigation is needed to assess Bcl-6 as a potential prognostic factor in PCNSL. SECONDARY CATEGORY: Clinical Neuro-Oncology.

Abstract 4490: Molecular characteristics of diffuse large B-cell lymphoma in HIV-positive and HIV-negative patients

Abstract Introduction: HIV-infected patients are at elevated risk of non-Hodgkin lymphoma (NHL), especially diffuse large B-cell lymphoma (DLBCL), compared with the general population. Because DLBCL is a molecularly and clinically heterogeneous disease, we compared frequencies and prognostic significance of molecular characteristics in HIV+ and HIV- DLBCLs. Methods: Archived formalin-fixed paraffin-embedded tissue specimens from 175 patients with primary DLBCL diagnosed during 1977-2003 were obtained from the Los Angeles County SEER Residual Tissue Repository. Immunohistochemistry was used to evaluate expression of key markers of B-cell differentiation, and fluorescence in situ hybridization was used to detect common NHL-associated translocations involving BCL2, BCL6, and c-Myc [t(14;18)(q32;q21), (t(3;14)(q27;q32), and t(8;14)(q24;q32), respectively]. DLBCLs were distinguished by cell of origin into germinal center B-cell (GCB)-DLBCL and activated B-cell (ABC)-DLBCL according to expression of CD10, GCET1, MUM1, FoxP1, and LMO2 based on the Tally algorithm (Meyer et al., J Clin Oncol 2011). Multivariate Cox regression compared survival according to HIV, cell of origin, and translocation status, adjusting for race/ethnicity, sex, socioeconomic status, age, Los Angeles residence, and initial course of treatment (immunochemotherapy and/or radiotherapy). Results: We identified 54 HIV+ and 121 HIV- patients with DLBCL. All HIV+ patients were male with a median age at diagnosis of 37 years (range 25-58 years) and median year of diagnosis of 1992 (range 1987-1998), whereas HIV- patients were evenly divided by sex with a median age at diagnosis of 65 years (range 16-90 years) and median year of diagnosis of 1992 (range 1977-2003). Among HIV-patients, 104 (86%) were deceased whereas all 54 HIV+ patients were deceased. HIV+ patients had worse prognosis compared to HIV- patients (hazard ratio (HR)=7.55, 95% confidence interval (CI) 4.34-13.12). Compared with patients with HIV-DLBCL, HIV+ patients were more likely to have ABC-DLBCL (HIV-: 46%, HIV+: 71%, p=0.0053), and less likely to have translocations of BCL2 (HIV-: 24%, HIV+: 0%, p&amp;lt;0.0001) and BCL6 (HIV-: 18%, HIV+: 5%, p=0.076). Among both HIV+ and HIV- patients, ABC-DLBCL was associated with adverse prognosis compared with GCB-DLBCL (HIV-: ABC HR=1.76, 95% CI 1.10-2.82, HIV+: ABC HR=2.00, 95% CI 0.93-4.33). In contrast, the presence of BCL2 and BCL6 translocations was associated with adverse prognosis in HIV- patients only (BCL2 HR=1.79, 95% CI 1.09-2.93, BCL6 HR=2.07, 95% CI 1.08-3.64). Conclusions: HIV+ and HIV- DLBCLs differ significantly with respect to key molecular characteristics, supporting biologic differences in the lymphomagenic process in the presence of HIV. The well-recognized adverse prognosis among HIV+ patients with DLBCL may be due in part to the higher proportion of ABC-DLBCLs compared to HIV- patients with DLBCL. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4490. doi:1538-7445.AM2012-4490

Rituximab and minimal change nephrotic syndrome: a therapeutic option

Minimal change nephrotic syndrome (MCNS) usually responds to steroids but frequently relapses, requiring additional treatment with immunosuppressive agents. Rituximab is a chimeric murine/human monoclonal immunoglobulin G1 antibody that targets CD20, a B-cell differentiation marker. B-cell recovery begins at approximately 6months following the completion of treatment. Rituximab has a beneficial effect, with the sustained remission or reduction of proteinuria in patients with steroid-dependent MCNS. Relapses are thought to be associated with an increase in CD19 cells. The mean serum half-life of rituximab was reported to be 10-15days in patients with steroid-dependent nephrotic syndrome. Only infusion reactions, such as rash and chills, occurred after single-dose rituximab infusion and can be managed by pre-medication or infusion rate adjustments. Even though severe adverse effects of rituximab are not expected, physicians must be aware of potentially life-threatening adverse effects. Controlled randomized trials that include adult patients with steroid-dependent or steroid-resistant MCNS are required to prove the efficacy and safety of rituximab and to evaluate the cost-effectiveness of rituximab treatment.

Biological Characterization of Nodal versus Extranodal Presentation of Diffuse Large B-Cell Lymphoma using Immunohistochemistry

Diffuse large B cell lymphoma (DLBCL) of primary nodal (PN) or primary extranodal (PEN) origin may differ immunophenotypically, in that PEN lymphoma cells may originate from activated rather than germinal center B (GCB) cells. We evaluated the relationship between DLBCL clinicopathological features, including expression of B-cell differentiation markers, and primary tumor site. Expression of CD10, Bcl-6, Bcl-2, and MUM1 was determined in paraffin-embedded tissues from 123 patients with DLBCL. Of the 123 patients with DLBCL, 40 (32.5%) had the GCB and 83 (67.5%) had the non-GCB phenotype. Fifty-one patients (42%) showed disease involvement at PEN sites, including 29 with disease in the gastrointestinal (GI) tract (14 in the stomach, 15 in the intestine). Of these 51 patients, 16 (31.4%) were classified with the GCB and 35 (68.5%) with the non-GCB subtype. There were no differences in the frequencies of GCB and non-GCB subtypes among primary sites. Of the 72 patients with PN DLBCL, 22 (31%) had the GCB and 50 (69%) had the non-GCB subtype. There were no differences in the frequencies of GCB and non-GCB subtypes between patients with PN and PEN DLBCL. Although lactate dehydrogenase (LDH) concentration > normal, stage >II, and rituximab-cyclophosphamide, doxorubicin, vincristine, and prednisone (RCHOP) treatment were independent predictors of overall survival (OS), GCB subtype, and presence of PEN disease failed to predict survival upon multivariate analysis. There was no difference in GCB and non-GCB phenotypes between patients with PN and PEN DLBCLs. Additional studies are needed to further assess molecular differences between the two groups.

Atypical familial hemophagocytic lymphohistiocytosis due to mutations in UNC13D and STXBP2 overlaps with primary immunodeficiency diseases

Familial hemophagocytic lymphohistiocytosis is a genetic disorder of lymphocyte cytotoxicity that usually presents in the first two years of life and has a poor prognosis unless treated by hematopoietic stem cell transplantation. Atypical courses with later onset and prolonged survival have been described, but no detailed analysis of immunological parameters associated with typical versus atypical forms of familial hemophagocytic lymphohistiocytosis has been performed. We analyzed disease manifestations, NK-cell and T-cell cytotoxicity and degranulation, markers of T-cell activation and B-cell differentiation as well as Natural Killer T cells in 8 patients with atypical familial hemophagocytic lymphohistiocytosis due to mutations in UNC13D and STXBP2. All but one patient with atypical familial hemophagocytic lymphohistiocytosis carried at least one splice-site mutation in UNC13D or STXBP2. In most patients episodes of hemophagocytic lymphohistiocytosis were preceded or followed by clinical features typically associated with immunodeficiency, such as chronic active Epstein Barr virus infection, increased susceptibility to bacterial infections, granulomatous lung or liver disease, encephalitis or lymphoma. Five of 8 patients had hypogammaglobulinemia and reduced memory B cells. Most patients had a predominance of activated CD8(+) T cells and low numbers of Natural Killer T cells. When compared to patients with typical familial hemophagocytic lymphohistiocytosis, NK-cell cytotoxicity and NK-cell and CTL degranulation were impaired to a similar extent. However, in patients with an atypical course NK-cell degranulation could be partially reconstituted by interleukin-2 and cytotoxic T-cell cytotoxicity in vitro was normal. Clinical and immunological features of atypical familial hemophagocytic lymphohistiocytosis show an important overlap to primary immunodeficiency diseases (particularly common variable immunodeficiency and X-linked lymphoproliferative syndrome) and must, therefore, be considered in a variety of clinical presentations. We show that degranulation assays are helpful screening tests for the identification of such patients.

Low rather than high Ki-67 protein expression is an adverse prognostic factor in diffuse large B-cell lymphoma

The prognostic role of overexpression of Ki-67 protein in diffuse large B-cell lymphoma (DLBCL) is still unclear. Furthermore, immunohistochemical studies have suggested a correlation between markers of proliferation, B-cell differentiation and apoptosis, but the prognostic relevance of these findings has not been clarified. To investigate the prognostic impact of Ki-67, in the context of this correlation, a retrospective immunohistochemical study was performed on 199 DLBCL patients treated with curative intent. Patients with low Ki-67 expression (<49%) had significantly worse progression-free (PFS) and overall (OS) survival, independent of clinical risk factors. In addition, low Ki-67 correlated to bcl-2 expression but not to non-germinal centre B-cell-like (non-GCB) phenotype. Each of these factors had negative impact on PFS and OS, but low Ki-67 expression also remained as an adverse prognostic factor independent of non-GCB phenotype and bcl-2 expression. Together, these results suggest that low rather than high Ki-67 protein expression is of prognostic importance in DLBCL.

Bcl‐6 predicts improved prognosis in primary central nervous system lymphoma

In systemic non-Hodgkin lymphoma (NHL), tumors that resemble germinal center B-cells are less aggressive than tumors that resemble postgerminal center B-cells. However, the value of B-cell differentiation markers in primary central nervous system lymphoma (PCNSL) is less clear. The objectives of this study were to characterize the immunophenotypes of PCNSL samples and to determine their utility in predicting clinical outcomes. The immunohistochemical staining profile of PCNSL was determined from 66 immunocompetent patients. Then, the authors evaluated whether the expression of these proteins was associated with progression-free or overall survival. Only 8% of PCNSL samples were positive for the cluster designation (CD) germinal center marker CD10. Another germinal center marker, bcl-6, was positive in 47% of samples. Ninety-four percent of samples expressed significant levels of the postgerminal center marker melanoma-associated antigen (MUM-1). In univariate analyses, only bcl-6 staining had a significant effect on progression-free survival (median, 20.5 months in bcl-6-positive patients vs 10.1 months in bcl-6-negative patients; P = .02). There was a nonsignificant trend toward improved overall survival in patients who had bcl-6 expressing tumors. Older age and poorer performance status, as observed previously, were associated with reduced survival. Bcl-6 expression was associated with a better prognosis in patients with PCNSL.