Interleukin-6-producing Intravascular Large B-cell Lymphoma with Lymphadenopathy Mimicking the Histology of Multicentric Castleman Disease

An inguinal lymph node biopsy of a woman with a one-month history of a progressive fever, fatigue, dyspnea, skin rash, and lymphadenopathy revealed a well-preserved basic structure, hyperplastic germinal centers, and an interfollicular region containing polyclonal plasma cell sheets, suggesting plasma cell-type multicentric Castleman disease (MCD). We initiated prednisolone and anti-interleukin (IL)-6 antibody (tocilizumab), without success. A biopsy specimen re-evaluation detected CD20-positive atypical large B cells infiltrating the small vessels within and around the lymph node and its capsule. We diagnosed her with intravascular large B-cell lymphoma (IVLBCL). Lymphoma cells were weakly positive for IL-6 by immunohistochemical staining. IL-6 from lymphoma cells may have caused the MCD-like presentation as a paraneoplastic etiology. Malignant lymphoma should be excluded before diagnosing MCD.     

Evolving abundance and clonal pattern of human germinal center B cells during childhood

Childhood is a critical period for the development of the memory B-lymphocyte repertoire necessary in protective humoral immunity. This study addressed the natural history of memory B cells based on the previous identification of germinal center and mantle zone cells as the probable precursor and mature memory cell populations, respectively. Using flow cytometric quantitation of these B-cell subpopulations in human tonsil, we found that germinal center cells were abundant (70% of tonsil B cells) during early childhood (2 to 3 years), but decline by early adolescence (8 to 14 years) to a low level (33%, P = .0003). To study the clonal evolution of these B-cell subpopulations, germinal center and mantle zone B cells were isolated using a preparative magnetic immunobead method, and analyzed using a novel polymerase chain reaction-based quantitative assay to measure the abundance of B-cell clones bearing certain rearranged VH subfamilies. Two VH subfamilies were informative: VH1N clones were uniquely deficient in germinal center B cells at the early age period, but became abundant in later childhood; and VH3L clones were absent among germinal center cells regardless of age. In contrast, B-cell clones bearing each VH subfamily were abundant in the mantle zone subpopulation throughout childhood. These findings suggest that the abundance and clonal pattern of germinal center B cells evolves during childhood, presumably due to changing antigenic or ontogenic processes. Moreover, the distinct clonal pattern of germinal center versus mantle zone B cells suggests that a major phase of clonal selection occurs after germinal center emigration.     

B-cell development in progressively transformed germinal centers: similarities and differences compared with classical germinal centers and lymphocyte-predominant Hodgkin disease

Progressively transformed germinal centers (PTGCs) are histologic structures mainly composed of small resting B cells and intermingled proliferating centroblast-like cells. The B-cell differentiation processes within PTGCs and their relation to classical germinal centers (GC) and to lymphocyte-predominant Hodgkin disease (LPHD), with which PTGCs are often associated, are largely unknown. To address these issues, single small resting (Ki67-) and proliferating (Ki67+) centroblast-like cells were isolated from 7 PTGCs of 5 lymph nodes, and rearranged immunoglobulin genes were amplified and sequenced. Most small resting B cells were clonally unrelated, and most carried unmutated immunoglobulin gene rearrangements resembling mantle zone B cells. Small resting B cells with mutated immunoglobulin gene rearrangements may represent centrocytes, memory B cells, or both. Among the centroblast-like Ki67+ cells, expanded B-cell clones were observed in 6 of 7 PTGCs analyzed. Clonally related V region genes showed extensive intraclonal diversity, and the mutation pattern indicated stringent selection of the cells for the expression of functional antigen receptors. Thus, somatic hypermutation, clonal expansion, and selection occur also in the disorganized PTGC microenvironment, as in classical GCs. In lymph nodes affected by PTGCs, no clonal expansion across the borders of individual PTGCs was observed, distinguishing PTGCs from LPHD.     

IgG4-producing marginal zone B-cell lymphoma

IgG4-related disease is a recently proposed clinical entity with several unique clinicopathological features. A chronic inflammatory state with marked fibrosis, which can often be mistaken for malignancy, especially by clinical imaging analyses, unifies these features. Little is known about lymphomagenesis in the context of IgG4-related disease, we recently first reported the ocular adnexal marginal zone B-cell lymphomas arising from IgG4-related disease. To the best of our knowledge, no existing study has ever established the neoplastic potential of IgG4-producing cells. In the present report, we describe the first IgG4-producing lymphoma. The patient was a 72-year-old male who was being followed for an asbestos-related pleural plaque. During follow-up, computed tomography revealed bilateral renal masses and multiple swollen retroperitoneal lymph nodes. A retroperitoneal lymph node biopsy was performed. Histologically, the interfollicular areas were expanded by medium to large plasmacytoid cells. These plasmacytoid cells showed nuclear pleomorphism and had prominent Russell bodies. Immunohistochemistry and double immunofluorescence staining of these cells revealed IgG4 positivity and monotypic lambda-light chain predominance. A portion of these cells were partially positive for CD20, negative for CD3, and somewhat faintly positive for CD138. In addition, serum IgG4 was elevated. Southern blot analysis of the lymph node specimen detected immunoglobulin heavy chain gene rearrangement. The present study indicates that, not only can malignant lymphomas occur in the setting of IgG4-related disease, but IgG4-producing cells can also be neoplastic.     

A new human B-lymphocyte surface antigen (BL 2) detectable by a hybridoma monoclonal antibody: distribution on benign and malignant lymphoid cells

A hybridoma-derived monoclonal antibody, produced by immunization with the Burkitt's tumor-derived B-lymphoblastoid cell line, B35M, was previously shown to detect a 68,000 dalton surface membrane protein, BL2, on the surface of peripheral blood B cells, which is absent from thymocytes, T cells, and granulocytes. In this study, we investigated the expression and distribution of BL2 on benign and malignant human lymphoid cells. Indirect immunofluorescent assay with this monoclonal antibody demonstrated that BL2 is expressed by cells within the fetal liver and by a variable proportion of lymph node, tonsil, and spleen B cells, but not by T cells. The neoplastic cells isolated from 18 T-cell malignancies were BL2- . BL2 was was heterogeneously expressed by a variable proportion of the malignant cells in 29/32 cases of B-chronic lymphocytic leukemia and 33/38 cases of B-cell lymphomas, but appeared to be lost in the terminal stages of B-cell differentiation, as myeloma plasma cells were BL2- . BL2 expression was not limited to B cells of a particular surface immunoglobulin isotype. Immunofluorescent staining for BL2 in cryostat tissue sections demonstrated that the majority, but not all, germinal center and interfollicular Ia+ (non-T) cells are BL2+. These findings suggest that BL2 is a B-cell lineage-specific differentiation marker that may be useful in the study of B-cell ontogeny and in defining subgroups of the B-cell malignancies.     

Topographical dissociation of BCL-2 messenger RNA and protein expression in human lymphoid tissues

Immunohistochemistry and in situ hybridization with a synthetic oligonucleotide probe were used to compare the topographical distribution of BCL-2 proto-oncogenic protein with that of its messenger RNA (mRNA) in normal lymphoid tissues, follicular lymphomas, and lymphoma-derived cell lines. In normal lymph nodes, BCL-2 protein was most abundant in the small lymphocytes of primary lymphoid follicles and the mantle zones of secondary follicles, virtually absent within germinal centers, and of variable abundance in many interfollicular cells. In contrast, the distribution of BCL-2 mRNA was roughly reciprocal to that of the protein with intense hybridization signal in germinal centers and almost none in mantle zones. Discordant BCL-2 RNA and protein levels were also observed in tonsillar epithelial cells and cortical thymocytes. Concordant and abundant expression of BCL-2 mRNA and protein was detected in biopsy tissues and cell lines from t(14;18)-carrying lymphomas. The contrasting distributions of BCL- 2 protein and RNA in normal lymphoid tissues suggest that translational and posttranslational control mechanisms play a significant role in regulating BCL-2 protein levels in germinal center cells, epithelial cells, and cortical thymocytes. Concordant BCL-2 mRNA and protein levels in follicular lymphomas suggest that translational control mechanisms may be disrupted as part of the sequence of genetic changes that transforms normal lymphoid cells into neoplastic follicular lymphoma cells.     

A VH clonal deficit in human immunodeficiency virus-positive individuals reflects a B-cell maturational arrest [published erratum appears in Blood 1991 Oct 1;78(7):1899]

A major feature of human immunodeficiency virus (HIV) infection is disordered B-cell function, which paradoxically includes both pathologic overactivity (elevated serum antibodies, lymphadenopathy, and increased risk for lymphoma) and underactivity (impaired antibody immunity, particularly to bacterial polysaccharide antigens). B-cell immune dysfunction contributes significantly to HIV-related morbidity and also represents an obstacle to eventual definitive treatment by anti-HIV immunization. Our laboratory has recently identified in normal B-cell populations certain VH gene subfamilies with a developmentally regulated pattern of utilization. In particular, B cells bearing rearranged VH3L were rare in the germinal center but uniformly abundant in the blood and lymphoid mantle zone. We used this index gene subfamily as a clonal criterion for the pattern of B-cell development in lymphocytes of HIV-positive individuals. In a series of 19 HIV- positive subjects, a striking deficit of VH3L B cells was observed; in contrast, none of the 16 normal subjects showed this abnormality. Other VH subfamilies (VH1N, VH4/6, and VH5N) were unaffected in the HIV- positive patients. This VH3L clonal deficit and other recent phenotype and histopathologic findings suggest that the general B-cell dysfunction in HIV is due to a discreet maturational arrest at the germinal center stage.     

IRTAs: a new family of immunoglobulinlike receptors differentially expressed in B cells

The IRTA1 and IRTA2 genes encode immunoglobulinlike cell surface receptors expressed in B cells and involved in chromosome 1q21 translocations in B-cell malignancy. We have now characterized and comparatively analyzed the structure and expression pattern of the entire family of IRTA genes, which includes 5 members contiguously located on chromosome 1q21. The IRTA messenger RNAs are expressed predominantly in the B-cell lineage within discrete B-cell compartments: IRTA1 is specific to the marginal zone, IRTA2 and IRTA3 are found in the germinal center light zone and in intraepithelial and interfollicular regions, and IRTA4 and IRTA5 are expressed predominantly in the mantle zone. All IRTA genes code for transmembrane receptors that are closely related to Fc receptors in their most amino-terminal extracellular domains and that possess cytoplasmic domains containing ITIM (immunotyrosine inhibition motifs)- and, possibly, ITAM (immunotyrosine activation motifs)-like motifs. These structural features suggest that the IRTA receptors may play a role in regulating activation of normal B cells and possibly in the development of neoplasia.     

The relative resistance of HIV type 1-infected chimpanzees to AIDS correlates with the maintenance of follicular architecture and the absence of infiltration by CD8+ cytotoxic T lymphocytes

Lymphoid tissues are the focus of critical events in HIV pathogenesis. Persistent and high levels of virus production, extensive trapping of virus particles in germinal centers, and progressive degenerative changes in lymph node architecture are characteristics of progressive HIV-1 infection. Infiltrates of granzyme B- and TIA-expressing CD8+ "cytotoxic" T lymphocytes (CTLs) precede involution of germinal centers in humans who develop AIDS. Similar to humans, HIV-1 infection in chimpanzees is active and persistent. However, in contrast to humans, they remain relatively resistant to AIDS. Lymph node biopsies from chimpanzees infected with HIV-1 or a related chimpanzee lentivirus were studied for the level and pattern of virus expression, changes in lymphoid architecture, CD8+ T cell infiltrates and the presence or absence of CTL markers. In stark contrast to HIV-1-infected humans, lymph nodes from infected chimpanzees had little virus deposition in germinal centers and a paucity of virus-expressing cells. Although some of the lymph nodes examined from infected animals had moderate follicular hyperplasia with infiltrating CD8+ T cells, none had evidence of follicular fragmentation. Most importantly, in marked contrast to infected humans, CD8+ T cells infiltrating the germinal center were negative for the CTL marker granzyme B. This evidence suggests that the infiltration of CD8+ CTLs into the germinal centers of lymph nodes may be a key determinant in AIDS pathogenesis.     

Chronic lymphocytic leukemia progenitor cells carry the antigens T65, BA-1, and Ia

CLL B cells may be induced to form B-cell colonies in vitro. Colonies formed are monoclonal and appear to reflect the circulating malignant B- cell clone in vitro. Using hybridoma-produced monoclonal antibodies (MAB) and an in vitro B-cell colony assay, we have provided a characterization of the antigenic phenotype of the clonogenic CLL B cell. B-cell colony growth in both patients and normals was not altered by prior incubation with either MAB or complement (C') alone. CLL B- cell colony formation was markedly reduced after treatment with T101 and C', while normal colonies were unaffected (8 +/- 2 versus 107 +/- 10). None of the residual CLL B-cell colonies after T-101 and C' treatment reacted with T-101. However, BA-1 and la reactivity were still seen in residual CLL B-cell colonies following T-101 treatment. In contrast, a similar percentage reduction of B-cell colony growth was seen for both normals and CLL patients following treatment with BA-1 (76% versus 81%) and Q5/13 (89% versus 92%). These studies suggest that the CLL progenitor cell is characterized by the phenotype la+, BA-1+, T- 101+. Better definition of the CLL progenitor cell has potential implications with regards to clinical utilization of MAB in the treatment of CLL.     

CD1c but neither CD1a nor CD1b molecules are expressed on normal, activated, and malignant human B cells: identification of a new B-cell subset

The CD1 cluster of monoclonal antibodies (MoAbs) CD1a, CD1b, and CD1c, identifies molecules that are differentially expressed on hematopoietic and nonhematopoietic tissues. Our earlier finding that the mantle zone (MZ) but not the germinal center (GC) of normal lymph nodes (LN) is CD1c+, CD1a-, and CD1b- prompted us to further investigate the expression of these molecules on normal, activated, and malignant B cells. We report that blood and spleen contain CD1c+ B cells that account for 49% +/- 20.4% (mean +/- SD) and 50.9% +/- 4.4% of the total B cell population, respectively. CD1a- and CD1b-specific MoAbs are unreactive with both B and T cells; these latter are CD1c- as well. When CD1c+ and CD1c- B cells are activated in vitro, the CD1c molecule is upregulated in the former subset and induced de novo in the latter. Conversely, activated blood T cells remain CD1c-. Neither CD1a nor CD1b molecules are detected on activated T and B lymphocytes. At ultrastructural level, the CD1c+ B cells exhibit distinctive features, namely, condensed chromatin with or without a nucleolus and a unique cluster of cytoplasmic vesicles and organelles; the number of nucleolated cells is higher in the spleen (95%) than in the tonsil (40%) or blood (5%). These findings further confirm the similarity between blood and MZ B cells. The CD1c expression assessed on 27 B-cell chronic lymphocytic leukemias (B-CLL) and 46 B non-Hodgkin's lymphomas (B-NHL) was detected on 41% and 32% of cases, respectively; the latter comprised four follicular and 11 diffuse histotypes. The Burkitt's lymphomas were CD1c-negative. The B-cell neoplasms were all CD1a- and, except for four with a weak cytoplasmic staining, all CD1b- as well. The clear-cut CD1c distribution in normal LN (MZ+, GC-) contrasted with the evidence that some B-NHL cells of GC origin (eg, follicular with predominantly small cleaved cells) were CD1c+. Overall, the finding that CD1c expression is restricted to a fraction of B cells present in lymphoid organs and in peripheral blood indicates that CD1c is a powerful marker for the identification and dissection of B-cell subsets whose functional properties can now be evaluated.     

Characterization of a monoclonal antibody that reacts with an activation antigen on human B cells: reactions on mitogen-stimulated blood lymphocytes and cells of normal lymph nodes

We describe a monoclonal antibody that reacts with human B-lymphoid cells. We have characterized the reactions of this antibody on normal blood lymphocytes, with and without pokeweed mitogen stimulation, bone marrow lymphocytes, and on frozen sections of normal lymph nodes. The antibody, B532, appears to recognize an activation antigen on human B cells. This activation antigen can apparently be induced both by infection with Epstein-Barr virus and by stimulation with antigens and mitogens, but it is lost on plasma cells. In normal lymph nodes, the antigen is confined to germinal center cells and some of the cells of the "mantle" that surrounds germinal centers. The antigen is not present on T cells.     

Expression of activation-induced cytidine deaminase in human B-cell non-Hodgkin lymphomas

Activation-induced cytidine deaminase (AID) induces somatic hypermutation (SHM), class switch recombination (CSR), and immunoglobulin gene conversion in B-lymphocytes. Here we report for the first time the expression of AID in healthy human B-lymphocytes and in B-cell non-Hodgkin lymphomas (B-NHL). AID mRNA expression in humans is restricted to the CD19(+)CD38(+)IgD(-) germinal center cells, namely the CD19(+)CD38(+)CD44(-) centroblasts. After in vitro stimulation of naive human B cells by CD40-L and IL-4, AID mRNA is strongly induced for only 48 hours. In a survey of human B-NHL AID was found to be constitutively expressed in follicular lymphoma and in diffuse large B-cell lymphoma but to be absent in B-precursor lymphoblastic leukemia, in mantle cell lymphoma, and in plasma cell myeloma. In B-cell chronic lymphatic leukemia, in immunocytoma, and in extranodal marginal zone B-cell lymphoma of MALT, AID mRNA was expressed only in some samples. In follicular lymphoma and diffuse large B-cell lymphoma, the expression of AID mRNA was coincident with the presence of SHM in the variable region exons of the immunoglobulin heavy-chain gene. In human B-NHL, the AID mRNA is spliced into 4 different variants but does not contain point mutations. Thus AID, which is highly regulated during healthy B-cell development, is constitutively expressed in human germinal center B-NHL and in subsets of nongerminal center B-NHL. This constitutive expression of AID may promote illegitimate DNA recombinations and somatic mutations in B-NHL.     

The t(14;18) defines a unique subset of diffuse large B-cell lymphoma with a germinal center B-cell gene expression profile

Recently we have identified subgroups of de novo primary diffuse large B-cell lymphoma (DLBCL) based on complementary DNA microarray-generated gene expression profiles. To correlate the gene expression profiles with cytogenetic abnormalities in these DLBCLs, we examined the occurrence of the t(14;18)(q32;q21) in the 2 distinctive subgroups of DLBCL: one with the germinal center B-cell gene expression signature and the other with the activated B cell-like gene expression signature. The t(14;18) was detected in 7 of 35 cases (20%). All 7 t(14;18)-positive cases had a germinal center B-cell gene expression profile, representing 35% of the cases in this subgroup, and 6 of these 7 cases had very similar gene expression profiles. The expression of bcl-2 and bcl-6 proteins was not significantly different between the t(14;18)-positive and -negative cases, whereas CD10 was detected only in the group with the germinal center B-cell expression profile, and CD10 was most frequently expressed in the t(14;18)-positive cases. This study supports the validity of subdividing DLBCL into 2 major subgroups by gene expression profiling, with the t(14;18) being an important event in the pathogenesis of a subset of DLBCL arising from germinal center B cells. CD10 protein expression is useful in identifying cases of DLBCL with a germinal center B-cell gene expression profile and is often expressed in cases with the t(14;18).     

Nodal monocytoid B-cell lymphoma (nodal marginal-zone B-cell lymphoma).

Benign monocytoid B cells are seen in lymph nodes in different types of lymphadenitis and they occur in the form of clusters within and around sinuses and in the interfollicular areas, but rarely completely surround benign follicles to produce a marginal-zone pattern. The cytologic hallmark of these cells is the presence of abundant pale to clear cytoplasm; these cells usually are of medium size, and they have a rather bland-appearing, irregular nuclei with inconspicuous nucleoli. Malignant monocytoid B-cell proliferations in a lymph node have been classified as monocytoid B-cell lymphomas (MBCL), which are now called nodal marginal-zone B-cell lymphoma (MZL) in the World Health Organization (WHO) classification. In the recently published clinical evaluation of the International Lymphoma Study Group classification of non-Hodgkin's lymphoma, 25 of 1,378 cases (1.8%) were classified as primary MZL, whereas four times as many cases (105 or 7.6%) were classified as low-grade mucosa-associated lymphoid tissue (MALT)-type lymphoma. Transformation to large-cell lymphoma at the time of diagnosis was seen in five of 25 (20%) cases of nodal MZL and in 32 of 105 (30%) cases of MALT-type lymphoma. Comparison of the clinical findings at presentation and the survival results indicate that nodal MZL is more aggressive clinically than low-grade MALT-type lymphoma. For example, patients with nodal MZL had a significantly higher incidence of advanced-stage disease, including peripheral and paraaortic lymphadenopathy, than those with MALT-type lymphoma. Moreover, patients with nodal MZL had lower 5-year overall survival and failure-free survival than patients with MALT type lymphoma. When analysis was restricted to those patients with zero to three adverse risk factors in the International Prognostic Index, patients with nodal MZL still had a significantly lower overall and failure-free survival at 5 years than patients with MALT-type lymphoma. We conclude that nodal MZL is a distinctive disease entity and is similar to other low-grade nodal lymphomas, such as the follicular or small lymphocytic lymphomas, but different than MALT-type lymphoma.     

Hodgkin's disease with a B-cell phenotype often shows a VDJ rearrangement and somatic mutations in the VH genes

The nature of Hodgkin and Reed-Sternberg (HRS) cells remains in question. Immunophenotypic studies favor a relation to the lymphoid lineage with the existence of B- and T-cell types. However, studies on the detection of antigen (Ag) receptor gene rearrangements provided inconsistent results. They concur in that rearranged Ig and T-cell receptor (TCR) genes are not demonstrable in most Hodgkin's disease (HD) cases. To clarify whether this is because of the insensitivity of the method of detection or a real absence of clonal Ig heavy chain (IgH) rearrangements, a polymerase chain reaction (PCR) method with high sensitivity was applied, allowing the detection of less than 50 cells with clonally rearranged IgH genes in a mixture of 100,000 germline or individually rearranged cells. In 67 cases of HD, most of those (67%) with B-Ag+ HRS cells express clonal VDJ rearrangements of the IgH gene. No cases with T-cell Ag+ HRS cells harbored detectable clonal VDJ rearrangements. Of 10 sequenced rearranged IgH genes, the VH segment of six contained considerable somatic mutations. These results suggest that the demonstrated VDJ rearrangements stem from the HRS cells themselves and that the HRS cells of cases with rearranged IgH genes are B-cell related and correspond in their differentiation stage either to naive pregerminal center B cells or (more commonly) to germinal center/postgerminal center-derived memory B cells.     

Antigenic phenotype and functional characterization of human tonsil B cells

Human tonsil cells were labeled with anti-leu-16, a monoclonal antibody (MoAb) that recognizes the CD20 antigen and that is specific for B cells. Two populations of B cells were identified by flow cytometry on the basis of antigen density. One labeled brightly with anti-Leu-16, and the other labeled at a level comparable to blood B cells. These two populations were characterized with a panel of MoAbs in two- and three-color flow cytometric studies and appeared to correspond to germinal-center and mantle-zone B cells. The pattern of staining of anti-Leu-16 on sections of frozen tonsil supported this characterization. Anti-Leu-16 labeled germinal center cells more intensely than mantle zone cells and stained a few scattered B cells in the interfollicular zone. The ability of each Leu-16+ population to secrete IgG and IgM in response to mitogens was measured in a particle immunofluorescence assay. Dim Leu-16+ B cells (small, resting B cells and a subpopulation of preactivated cells) secreted IgG and IgM in response to pokeweed mitogen (PWM) but only IgG in response to B cell growth factor (BCGF). Bright Leu-16+ B cells (small to large activated cells and possibly memory cells) did not respond to PWM but secreted IgG in response to BCGF. The functional responses of dim Leu-16+ and bright Leu-16+ B cells were consistent with their identification as mantle-zone and germinal-center B cells. Phenotypic identification and functional studies of mantle-zone and germinal-center B cells may help clarify the differentiation pathway within the germinal center.