CD23 expression in mediastinal large B-cell lymphomas

AIMS: Mediastinal large B-cell lymphoma (MLBCL) is a subtype of diffuse large B-cell lymphoma (DLBCL) in the WHO classification with peculiar features, such as female prevalence, young patient age and bulky presentation. It shows a B-cell phenotype with variable expression of surface immunoglobulin, negative CD21 and CD10 and positive CD30 in a large number of cases. An origin from activated thymic B cells has been suggested in several studies. A subpopulation of large, dendritic cells (asteroid cells) strongly expressing CD23 has been identified amongst thymic B cells and these could represent the normal cellular counterpart for this type of primary mediastinal large cell lymphoma. METHODS AND RESULTS: To explore this possibility, we immunostained 24 cases of primary mediastinal lymphomas and 100 cases of non-mediastinal, nodal and extranodal, DLBCLs for CD23 in routinely processed paraffin-embedded tissues. CONCLUSIONS: Our results show that a vast majority (70%) of mediastinal lymphomas strongly express CD23 whilst the same antigen is expressed in only 15% of non-mediastinal nodal DLBCLs and 9% of non-mediastinal extranodal DLBCLs. These results support the hypothesis that most cases of MLBCL arise from activated dendritic thymic B cells. We also suggest that CD23 should be included in the panel of antibodies currently used to characterize this subtype of DLBCL.     

MUM1蛋白在弥漫性大B细胞淋巴瘤中的表达及意义

目的 探讨弥漫大B细胞淋巴瘤(diffuse large B-cell lymphoma,DLBCL)中活化的B细胞相关蛋白MUM1的表达与临床病理特征之间的关系.方法 利用组织微阵列免疫组化检测60例DLBCL石蜡包埋组织中MUM1、bcl-6和CD10的表达.结果 60例DLBCL被分为两种抗原表达表型:一种为活化的B细胞表型(A型)表达MUM1;另一种为生发中心B细胞表型(B型),表达CD10和(或)bcl-6但不表达MUM1.60例DLBCL中61.67%为A型,31.67%为B型,其中59.25%中心母细胞型,3/4免疫母细胞型,2/2间变性大B细胞型均为A型.A型在结外和结内DLBCL中分别占61.76%和61.54%,而在胃肠道DLBCL中的比例(47%)显著低于在其他结外DLBCL中的比例(80%,P=0.079).在MUM-1( )/bcl-6( )/CD10( /-)的病例中,75.00%(12/16)为结外DLBCL,高于在MUM-1( )/bcl-6(-)/CD10(-)病例中的比例43.75%(7/16),但差异没有显著性(P=0.149).结论 A型(表达MUM1)在DLBCL中的比例较高,提示MUM1表达很可能与DLBCL组织学变异有关,联合检测CD10和bcl-6,可协助DLBCL分型诊断.     

Prognostic clinicopathologic factors, including immunologic expression in diffuse large B-cell lymphomas

The aim of this study was to assess the clinical significance and potential prognostic value of the expression of a panel of surface markers, proliferating, suppressor and oncogenic proteins in diffuse large B-cell lymphomas (DLBCL). Biopsies were collected from 158 patients with DLBCL and analyzed immunohistochemically for p53, p21/WAF1, bcl-2, cyclin-D1, bcl-6, mdr, CD5, CD30, epithelial membrane antigen (EMA), Ki-67 and c-myc positive tumor cells. Among these, 76 young and middle-aged patients (20-65 years) were selected to investigate the relationship between protein expression, clinical features, and survival. Survival analysis showed that advanced stage, high lactic dehydrogenase level, and high International Prognostic Index (IPI) were poor prognostic factors associated with a shorter overall survival (OS) and disease-free survival (DFS) times. A high p53 expression and low bcl-6 expression were associated with a shorter DFS time. The histological variant type, cyclin-D1+ CD5+ DLBCL, positive epithelial membrane antigen (EMA+) CD30- DLBCL, high bcl-2 expression, and low Ki-67 proliferation activity tended to be associated with worse survival, but the correlations were not statistically significant. In the multivariate analysis, the most significant factors were age, followed by IPI and last p53. The expression of p21/WAF1, mdr, and c-myc proteins did not influence OS and DFS. The expression of p53 and bcl-6 proteins may be useful prognostic indicators in DLBCL. Cyclin-D1+ CD5+ or EMA+ CD30- DLBCL tended to predict a worse survival and may probably bear a significant prognostic value worthy of consideration. Overall, clinical factors appeared to be more important than biologic parameters in determining the prognosis of diffuse large B-cell lymphomas.     

CD10 expression in diffuse large B-cell lymphomas does not influence survival

CD10 expression is considered as a marker of centrofollicular-derived diffuse large B-cell lymphomas (DLBCL). The aim of our study was to determine retrospectively among 98 patients with DLBCL, enrolled in the LNH93 trial of the Groupe dEtude des Lymphomes de lAdulte (GELA) and homogeneously treated with high-dose cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP)-like regimen [doxorubicin, cyclophosphamide, vindesine, bleomycin and prednisone (ACVBP)], the expression of CD10 using immunohistochemistry and its correlation with morphological features and clinical parameters. Of the 98 patients studied, 33 (34%) expressed CD10. There was no correlation among clinical parameters, International Prognostic Index risk groups and CD10 expression, with the exception of lactic dehydrogenase levels, which were lower in CD10-negative cases (P=0.005). There was no significant correlation between CD10 expression and morphological subtyping of DLBCL. Indeed, centrofollicular-derived DLBCL may present with numerous immunoblasts or as an immunoblastic lymphoma. Overall survival rate and event-free survival were not significantly different according to CD10 expression (P=0.44 and P=0.34 respectively). Therefore, it appears that CD10 expression does not influence survival or event-free survival in DLBCL.     

High frequency and strong prognostic relevance of O6-methylguanine DNA methyltransferase silencing in diffuse large B-cell lymphomas from the Middle East

Several clinically relevant molecular classifiers of diffuse large B-cell lymphoma (DLBCL) have recently been demonstrated in Western populations. However, substantial molecular differences have recently been shown between tumors derived from different ethnic groups. To investigate prevalence and interrelationship of recently suggested molecular prognostic markers in Middle East DLBCL, we analyzed coexpression of CD10/Bcl6 (by immunohistochemistry), t(14;18) translocations (by fluorescence in situ hybridization), and methylation of the gene encoding the DNA repair enzyme O(6)-methylguanine DNA methyltransferase (MGMT) in a series of 190 DLBCL patients from Saudi Arabia with clinical follow-up data. Coexpression of CD10/Bcl6 (germinal center-like immunophenotype) was found in 13%, t(14;18) translocations in 17.9%, and MGMT methylation in 75.9% of cases. There was a trend toward better prognosis (although statistically insignificant) in tumors with coexpression of CD10/Bcl6. MGMT methylation were significantly related to good prognosis. The combined analysis of both parameters revealed that MGMT methylation was independent of immunophenotype and remained a significant predictor of prognosis in nongerminal center-like DLBCL subgroup. t(14;18) was significantly associated with CD10/Bcl6 coexpression (46.7%) but infrequent in CD10-/Bcl6-negative lymphomas (9.4%; P = .0073). However, t(14;18) was unrelated to clinical outcome. In summary, our data suggest a strong prognostic importance of MGMT methylation independent of DLBCL immunophenotype. Based on previous data from Western patients, the rate of MGMT hypermethylation was higher, and the portion of germinal center-like DLBCL was lower than expected. These results provide evidence for molecular differences between Saudi Arabian and Western DLBCL.     

Clinical relevance of CD10, BCL-6 and multiple myeloma-1 expression in diffuse large B-cell lymphomas in Malaysia

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma, and it is recognized to constitute a heterogenous group of neoplasms. It can be divided into germinal center B-cell-like (GCB) and non-GCB subgroups. The aim of the present study was to evaluate the utility of immunophenotype subgrouping of DLBCL in a cohort of multi-ethnic Asian patients. A total of 84 reconfirmed de novo DLBCL were immunostained for the expression of CD10, BCL-2, BCL-6 and multiple myeloma-1. Thirty-three (39.3%) had the GCB phenotype, and the remainder (60.7%), the non-GCB phenotype. The results concur with most reports using a similar method of stratification. Forty-five patients had complete demographic and phenotype studies and 42 patients did not have rituximab treatment and had sufficient data for survival rate analysis. Similar to other studies, patients with combined low and low–intermediate International Prognostic Index score had better overall survival ( P  = 0.006). But patients with GCB phenotype did not have better prognosis, and BCL-2 expression was not associated with better prognosis. The expression of BCL-6 was associated with lower overall survival rate ( P  = 0.038). No apparent difference in overall and disease-free survival was noted between patients with GCB and non-GCB disease. BCL-6 expression by tumor cells appears to be associated with poorer prognosis.     

Common and HIV-related diffuse large B-cell lymphomas differ in their immunoglobulin gene mutation pattern

HIV-infected patients are at high risk of developing diffuse large B-cell lymphomas (DLBCL). It is currently unclear whether these lymphomas represent Epstein-Barr virus (EBV)-driven lymphoproliferations that develop in the setting of immunodeficiency, or whether these tumours are more closely related to the DLBCL seen in the general population. To clarify this issue, 12 HIV-related DLBCL from 11 patients were analysed for the presence of clonally rearranged and somatically mutated immunoglobulin heavy chain (IgH) genes and their association with EBV was determined. Eleven of the 12 tumour samples displayed monoclonal rearrangements of the IgH genes, with or without a moderate number of somatic mutations in the CDRII and in the FWIII regions (average four mutations). One patient presented two successive lesions; whereas the initial tumour showed an oligoclonal IgH rearrangement, the lymphoma at relapse proved to harbour a monoclonal B-cell population. Ten of 12 tumour samples expressed the EBV encoded small RNAs (EBERs), and six of these EBV-positive cases displayed, in addition, an expression of the EBV encoded nuclear antigen 2 (EBNA-2). The results obtained from HIV-related DLBCL are at variance to those described for DLBCL occurring in the general population, since the latter contain significantly more somatic IgH mutations in the CDRII and in the FWIII regions and are only rarely associated with EBV. It is concluded from these findings that HIV-related DLBCL represent a distinct group of B-cell lymphomas, a significant fraction of which most likely originates from EBV-driven lymphoproliferations, and that half of the cases derive from pre-germinal centre B-cells. Copyright © 1999 John Wiley & Sons, Ltd.     

CD3-positive diffuse large B-cell lymphoma relapses as CD3-negative large B-cell lymphoma: Loss of aberrant antigen expression in B-cell lymphoma after chemotherapy

Aberrant expression of CD3 on diffuse large B-cell lymphoma (DLBCL) is rare, and its mechanism and biological significance are currently unclear. Herein we report a case of Epstein-Barr virus-negative, CD3-positive DLBCL in a 53?year-old male, who had a remote history of renal transplantation. After standard chemotherapy, the patient was in clinical remission. He relapsed three years later, but at this time with apparent loss of CD3 expression. PCR-based IGK gene rearrangement studies demonstrated clonal amplicons with an identical nucleotide size between the primary and secondary DLBCL, confirming the clonal relationship despite their phenotypic differences. To our knowledge, this is the first case of CD3-positive DLBCL that demonstrated a loss of aberrant CD3 on relapse. The chronologic change in phenotype seen in this case suggests that the source of the patient’s lymphoma relapse may arise from either a quiescent subclone without CD3 expression, or from an upstream neoplastic precursor cell.     

CD10 and Bcl10 expression in diffuse large B-cell lymphoma: CD10 is a marker of improved prognosis

AIMS: Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, is clinically and pathologically heterogeneous. The Bcl10 gene was recently isolated from the breakpoint region of t(1;14)(p22;q32) in mucosa-associated lymphoid tissue (MALT) lymphomas, and is considered to be an apoptosis-associated gene. CD10 is considered to be a marker of follicular centre B-cell differentiation. To assess the clinical significance and roles of CD10 and Bcl10 in DLBCL, we analysed 138 cases, using immunohistochemical methods. METHODS AND RESULTS: CD10 expression was limited to the cytoplasm, whereas Bcl10 expression was detected in the cytoplasm and/or nuclei. CD10 expression was detected in 39 of 138 cases (28.2%), cytoplasmic Bcl10 in 68 cases (49.2%), and nuclear Bcl10 in 34 cases (24.6%). Nuclear Bcl10 was detected in 14 of 28 cases (50%) of extranodal DLBCL, but only 20 of 110 cases (18.2%) of nodal DLBCL. Cytoplasmic Bcl10 was detected in 19 of 28 cases (67.8%) of extranodal DLBCL and 49 of 110 cases (44.5%) of nodal DLBCL. CD10 expression closely correlated with improved survival (68% overall survival (OS) vs. 48% OS), but not with site of disease. A high International Prognostic Index (IPI) was considered to be a poor prognostic factor associated with a shorter OS. CD10 expression was detected in 27 of 84 cases (32.1%) with low-risk IPIs, and in 12 of 54 cases (22.2%) with high-risk IPIs. In the low-risk group, cases expressing CD10 carried a better prognosis than CD10- cases (93% OS vs. 71% OS), whereas this was not the case in the high-risk group (25% vs. 20%). CONCLUSIONS: Bcl10 expression was associated with extranodal DLBCL, but not with prognosis. CD10 expression was closely associated with improved survival, but not with risk as predicted by IPI. Overall, our results suggest that CD10 expression may be useful, in combination with clinical parameters, for determining the prognosis of DLBCL.     

CD26/dipeptidyl peptidase IV expression in human lymphomas is restricted to CD30-positive anaplastic large cell and a subset of T-cell non-Hodgkin's lymphomas

CD26 is identical to the cell surface ectoenzyme dipeptidyl peptidase IV (DPPIV). is associated with T-cell activation and proliferation and also may function as an auxiliary adhesion factor. Although has been previously studied on lymphoid populations and on leukemias/lymphomas of B- and T-cell phenotype, little is known about its expression and functional role in some specific types of lymphomas, such as CD30-positive anaplastic large cell (ALC) lymphomas and Hodgkin's disease (HD). A series of 81 lymphoma samples, including 23 cases of HD, 17 cases of CD30-positive ALC lymphomas, 41 cases of other non-Hodgkin's lymphomas (NHL), and a panel of HD- or ALC lymphoma-derived human cell lines were evaluated for expression by enzyme histochemistry and immunohistochemistry on frozen sections and cell smears. protein was expressed on neoplastic cells in 12 of 17 (71%) ALC lymphomas irrespective of their antigenic phenotype and in seven of 15 (47%) T-cell NHLs. In contrast, we did not detect expression in tumor cells from 26 cases of B-cell NHL other than ALC lymphomas or in Reed Sternberg (RS) cells and variants of 21 of 23 HD cases. Accordingly, expression was maintained on the CD30-positive ALC lymphoma cell line Karpas 299, but the molecule was not detected on HD-derived cell lines of B, T, or non-B non-T phenotype. These results may support a new potential tool for the phenotypic separation of ALC lymphomas from HD based on the differential expression of the molecule. Moreover, given the demonstration that is identical to the human adenosine deaminase (ADA) binding protein, it could be speculated that also may function by interacting with ADA to regulate the growth of expressing neoplastic cells in ALC lymphomas.     

弥漫大B细胞淋巴瘤中CD27的表达及临床意义

目的探讨弥漫大B细胞淋巴瘤(diffuse large B cell lymphoma, DLBCL)中CD27的表达及其临床意义。方法采用免疫组化EnVision法检测143例DLBCL组织中CD27蛋白的表达;应用FISH技术检测DLBCL组织中MYC、BCL-2、BCL-6基因重排情况。结果 143例DLBCL中,CD27蛋白阳性者46例,阳性率为32.2%。CD27阳性组中BCL-2重排阳性率(17.4%)明显高于CD27阴性组(4.1%),差异有统计学意义(P<0.01)。CD27阳性组病死率(30.4%)明显高于CD27阴性组(15.5%),差异有统计学意义(χ²=4.326,P=0.038)。CD27阳性者与阴性者的Kaplan-Meier生存曲线差异有显著性(χ²=4.485,P=0.034),阳性组生存期较短。结论 CD27高表达与DLBCL预后密切相关,可作为临床预后评价的指标之一。     

A tree-based decision rule for identifying profile groups of cases without predefined classes: application in diffuse large B-cell lymphomas

In this paper, we examined the utility of a forward growing classification tree as a supplement to cluster analysis for deriving a decision rule for the identification of profile groups when the cases do not belong to predefined classes. The technique was applied for the identification of low and high proliferation profile groups of diffuse large B-cell lymphomas according to the immunohistochemical expression levels of proliferation proteins. In a forward growing classification tree method, the size of the tree is controlled by the improvement (threshold value) in the apparent misclassification rate after each split. The classes used in the tree were defined using k-means clustering. The decision rule consisted of the splitting points of the split variables used. The methodology was applied to the histology data from 79 cases of diffuse large B-cell lymphomas. Ten classes of individual cases were derived from k-means clustering. Then, a classification tree with a threshold of 2% was used to derive the decision rule. Branches at the left side of the tree consisted of individuals with a low proliferation profile and branches at the right side of the tree consisted of cases with a high proliferation profile. The classification tree, as a supplement method, not only identified but also provided decision rules for identifying profile groups. Finally, it also allowed for exploration of the data structure.     

Primary diffuse large B-cell lymphomas of the bone: prognostic relevance of protein expression and clinical factors

Diffuse large B-cell lymphomas can be considered primary bone tumors if they are monostotic or polyostotic, affecting multiple skeletal sites without visceral or lymph node involvement. They are rarely considered as extranodal lymphomas or as bone tumors, respectively. To elucidate the prognostic relevance of clinicopathologic characteristics in such disease, we collected a cohort of primary diffuse large B-cell lymphomas of the bone and retrospectively investigated 33 patients. The cohort encompassed the years 1975 to 2004. Protein expression patterns were identified by immunohistochemistry applied to a tissue microarray. The patients included 23 males (mean age, 37 years) and 10 females (mean age, 54 years). Disease stage was I and II in 30 and IV in 3 patients. Within the mean follow-up of 28 months, 6 patients died. Median overall survival was reached after 78 months. Clinical factors favoring a good prognosis were age younger than 53 and administration of chemotherapy. Of the phenotypic markers analyzed (CD10, CD44s, CD138, Bcl-2, Bcl-6, MUM1, and Ki-67), MUM1 expression in more than 10% of the tumor cells and CD10 expression in less than 55% as well as a nongerminal center signature substantiated adverse outcome in a univariate model. In summary, poor survival in PB-DLBCL was clearly predicted in patients older than 53, who had not received chemotherapy, and who demonstrated MUM1 expression and nongerminal center phenotype.     

Expression of TCL1 and CD27 in primary cutaneous B-cell lymphomas

AIMS: To investigate by immunohistochemical analysis the expression of the TCL1 oncogene product and of CD27 in 25 cases of primary cutaneous B-cell lymphomas (PCBCL) classified according to the World Health Organization-European Organization for Research and Treatment of Cancer classification of cutaneous lymphomas. In B-cell ontogenesis TCL1 is mainly expressed by 'naive' B lymphocytes and by a subset of germinal centre B cells, whereas CD27 is expressed by a subset of germinal centre B cells, 'memory' B lymphocytes and plasma cells, suggesting that their expression in physiological conditions is mutually exclusive. METHODS AND RESULTS: Overall, TCL1 was expressed in 5/25 cases (20%) and CD27 in 15/25 cases (60%). Furthermore, 7/25 cases (28%) were TCL1- and CD27- and 2/25 cases (8%) were TCL1+ and CD27+. In particular, primary cutaneous follicle-centre lymphomas (10 cases) showed a variable expression of both TCL1 and CD27, whereas primary cutaneous marginal-zone B-cell lymphomas (eight cases) showed, with the exception of a single case, a definite CD27+/TCL1- profile. CONCLUSIONS: These findings indicate: (i) the TCL1 oncogene product is uncommonly expressed in PCBCL (20% of cases, mainly of the follicle-centre subtype); (ii) in contrast, CD27 is often expressed in PCBCL (60% of cases), mainly of the marginal-zone subtype; (iii) the coexpression of TCL1 and CD27 may be seldom observed in PCBCL (8% of cases); (iv) PCBCL does not seem to show, in terms of either TCL1 or CD27 expression, significant differences compared with its systemic counterparts.     

Clinicopathological study of gene rearrangement and microRNA expression of primary central nervous system diffuse large B-cell lymphomas

We studied the clinicopathological and imaging characteristics of primary central nervous system diffuse large B-cell lymphomas (PCNS-DLBCL). Imaging, pathologic histology, and immunohistochemical staining characteristics were analyzed, and the immunoglobulin heavy and light chain gene rearrangement of 25 PCNS-DLBCL cases was examined. MicroRNA was extracted from 10 cases each of PCNS-DLBCL, extracerebral germinal center DLBCL (GC-DLBCL), and extracerebral non-GC-DLBCL (NGC-DLBCL); we conducted chip hybridization and comparatively analyzed the difference among the three. PCNS-DLBCLs typically involved no less than two cerebral lobes (10/25); the frontal lobe was affected most often (6/25). Target-shaped structures were observed in all PCNS-DLBCLs due to the proliferation of centroblast-like large lymphocytes surrounding the vessels. There was strong and diffuse immunostaining for CD20 and CD79a, and negative immunostaining for CD3, CD5, CD23, and cyclin D1 for all PCNS-DLBCLs. The percentage of cells with nuclear positivity for anti-Ki67 antibody ranged 50-90% (mean, 80%). Three, 19, and 22 PCNS-DLBCLs were CD10-, Bcl-6-, and melanoma ubiquitous mutated 1-positive, respectively. Twenty-four PCNS-DLBCLs were B-cell monoclonal. MicroRNA hybridization showed that 788 PCNS-DLBCL microRNAs/segments increased to at least twice that of NGC-DLBCLs, and 401 PCNS-DLBCL microRNAs/segments declined to less than half of that of NGC-DLBCLs. Six hundred and eleven PCNS-DLBCL microRNAs/segments increased to at least twice that of GC-DLBCLs, and 229 PCNS-DLBCL microRNAs/segments declined to less than half of that in GC-DLBCLs. PCNS-DLBCL typically affected multiple sites, tended to occur in older men, arose from activated B cells, had high B-cell monoclonality; its microRNA expression differed from that of NGC-DLBCL and GC-DLBCL.     

Identification of oligoclonal CD4 T cells in diffuse large B cell lymphomas

Human B cell lymphomas often contain CD4 T cells. Here we show that, in diffuse large B cell lymphomas (DLCL), such T cells are oligoclonal. The CDR3 lengths and nucleotide sequences of oligoclonal TCRBV of CD4 T cells in an original and relapsed lymphoma from one patient were compared. Three BV23 sequences were identical (12/17 and 16/16 clones in primary and relapsed lymphomas, respectively), but were absent in CD4 T cells from another patient's DLCL. Two of the repetitive BV23 sequences were found in peripheral blood CD4 T cells (5/17 clones); gamma-irradiated DLCL from this patient stimulated syngeneic BV23 response in CD4 cells (92% of BV23 had the same CDR3 length). Skew in TCRBV representation was observed in CD4 T cells from all the DLCL. One DLCL, with overrepresentation of BV13S1 in CD4 cells, stimulated the same TCR in CD4 cells from three unrelated individuals. These findings support the conclusion that there is clonal selection of CD4 T cells in DLCL.     

Detection of germinal center B-cell lymphoma in archival specimens: critical evaluation of Bcl-6 protein expression in diffuse large B-cell lymphoma of the tonsil

Expression of Bcl-6 and CD10, markers for the tumor of the germinal center (GC) B-cell derivation, has been studied in primary diffuse large B-cell lymphomas (DLBCLs) of the lymph node, gastrointestinal tract, and mediastinum. In these studies, the coexpression rate of CD10 and Bcl-6 was relatively constant at 30% approximately 40%, but the frequency of Bcl-6+ tumors varied from 55% to 100%, raising doubts about the usefulness of Bcl-6 expression in identifying the tumor of GC B-cell derivation. Because the expression of Bcl-6 in tumors of non-GC B-cell origin has recently been reported, we critically evaluated the expression of Bcl-6 and CD10 in primary DLBCLs of the tonsil, a relatively common tumor in Japan and Korea. The cases (n = 51) represented a consecutive series for any recent 2-year period at several teaching hospitals in Korea and Japan. Formalin-fixed, paraffin-embedded specimens were used for immunostaining. Staining for Bcl-6 and CD10 was positive in 44 (86%) and 22 cases (45%), respectively. However, among those positive for Bcl-6 (>10% Bcl-6+ tumor cells), 2 basic patterns were recognized: uniform and nonuniform. The uniform pattern was characterized by a dense population (>75%) and a consistent density in any given area, resembling the staining pattern observed in GC or follicular lymphoma (FL) (the "GC/FL" pattern). In contrast, the nonuniform pattern exhibited a varying density from area to area, as well as a less-dense population (<75%). The uniform pattern was observed in 26 cases (51%). All but 1 (95%) of the CD10+ tumors coexpressed Bcl-6, with most (82%) displaying the uniform pattern. We conclude that tumors showing a uniform pattern of Bcl-6 expression should be distinguished from those showing a nonuniform pattern, because the former most likely represent tumors of GC B-cell derivation and the latter most likely represent tumors of non-GC derivation. GC B-cell lymphoma thus defined accounted for 51% of tonsillar DLBCL, a proportion comparable to that of the nodal DLBCL. CD10 expression correlated with the "GC/FL" pattern, but appeared to be not essential for the identification of GC B-cell lymphoma. This study suggests that a significant proportion of tonsillar DLBCLs in Asia is of GC B-cell origin rather than of mucosa-associated lymphoid tissue origin. This finding may have significance for clinical management of these lymphomas.     

De novo CD5 positive diffuse large B-cell lymphomas with bone marrow involvement in Korean

In CD5 positive (CD5+) mature B-cell lymphomas, newly recognized CD5+ diffuse large B-cell lymphoma (DLBCL) has been characterized by aggressive features. We studied twenty-five cases with CD5+ lymphomas involving bone marrow. Eleven cases were diagnosed as chronic lymphocytic leukemia, six cases were diagnosed as mantle cell lymphoma (MCL), and three cases with morphologic characteristics of MCL and without both the cyclin D1 expression and IGH/CCND1 rearrangement were unclassifiable. The remaining five cases, showing large to medium-sized lymphoid cells with prominent nucleoli and a moderate amount of cytoplasm, were diagnosed as DLBCL. Five DLBCL cases were positive for CD5, CD20, surface immunoglobulin, but negative for CD23. Patients with CD5+ DLBCL showed a high age of onset (median, 68 yr) and two patients expired one month after the diagnosis. Since CD5+ DLBCL forms a distinct subgroup of DLBCL, a study of CD5 expression in DLBCL would be helpful to predict prognosis and to determine future therapeutic strategy. To the best of our knowledge, this is the first report on de novo CD5+ DLBCL in Koreans.     

Haemodialysis monocytopenia: differential sequestration kinetics of CD14+CD16+ and CD14++ blood monocyte subsets

In peripheral blood the majority of circulating monocytes present a CD14highCD16- (CD14++) phenotype, while a subpopulation shows a CD14lowCD16+ (CD14+CD16+) surface expression. During haemodialysis (HD) using cellulosic membranes transient leukopenia occurs. In contrast, synthetic biocompatible membranes do not induce this effect. We compared the sequestration kinetics for the CD14+CD16+ and CD14++ monocyte subsets during haemodialysis using biocompatible dialysers. Significant monocytopenia, as measured by the leucocyte count, occurred only during the first 30 min. However, remarkable differences were observed between the different monocyte subsets. CD14++ monocyte numbers dropped to 77 +/- 13% of the predialysis level after 15 min, increasing to > or = 93% after 60 min. In contrast, the CD14+CD16+ subset decreased to 33 +/- 15% at 30 min and remained suppressed for the course of dialysis (67 +/- 11% at 240 min). Approximately 6 h after the end of HD the CD14+CD16+ cells returned to basal levels. Interestingly, the CD14+CD16+ monocytes did not show rebound monocytosis while a slight monocytosis of CD14++ monocytes was occasionally observed during HD. A decline in CD11c surface density paralleled the sequestration of CD14+CD16+ monocytes. Basal surface densities of important adhesion receptors differed significantly between the CD14+CD16+ and CD14++ subsets. In conclusion, during HD the CD14+CD16+ subset revealed different sequestration kinetics, with a more pronounced and longer disappearance from the blood circulation, compared with CD14++ monocytes. This sequestration kinetics may be due to a distinct surface expression of major adhesion receptors which facilitate leucocyte-leucocyte, as well as leucocyte-endothelial, interactions.     

Effects of human placental lactogen on the expression of CD163 and CD14 on human monocytes in culture

The effect of human placental lactogen (hPL), a member of the somatomammotrophin family, on the regulation of the scavenger receptor molecules CD14 and CD163 on human monocytes cultured for 48h was investigated. Cells were cultured in the presence or absence of the hormone and also in the presence or absence of IFN-gamma and dexamethasone. Monocytes cultured in the presence of hPL showed a significant increase in the expression of CD14 in both males and females compared to background. When IFN-gamma and dexamethasone were added to the cultures, CD14 expression was decreased and was not rescued by the presence of hPL. hPL alone had no effect on the expression of CD163 on cultured monocytes from either gender, although cells cultured in the presence of IFN-gamma and dexamethasone showed a profound increase in their expression of CD163. This expression was augmented further by the presence of hPL in the cultures over a 48-h period. These results support the hypothesis of a potential role of this hormone in the regulation of the innate immune response.