Radioimmunotherapy with iodine-131 tositumomab in patients with low-grade non-Hodgkin's B-cell lymphoma does not induce loss of acquired humoral immunity against common antigens.

Thirty-one previously untreated patients with follicular low-grade B-cell non-Hodgkin's lymphoma expressing the CD20 antigen were treated with iodine-131 tositumomab therapy between 1996 and 1998. The therapy led to a temporary depletion of peripheral blood B-lymphocytes. Recovery of B-cells occurred in most cases by 3 to 6 months and in all patients by 12 months posttherapy. A temporary decline in T-cell subpopulations, but no reduction in serum immunoglobulin levels, could be observed. ELISA techniques were used to detect specific antibodies against rubella, mumps, varicella zoster, measles, and tetanus. Almost all patients remained seropositive against the different antigens during the 1- to 2-year follow-up. No significant reduction in antibody concentrations to tetanus or measles could be detected. The data show that acquired humoral immunity against common antigens appears to be preserved despite a temporary loss of B-lymphocytes.     

Comparative clinicopathological study of primary CNS diffuse large B-cell lymphoma and intravascular large B-cell lymphoma

Primary CNS diffuse large B-cell lymphoma (CNS DLBCL) is confined to the CNS, and constitutes a distinct entity. In the present study a series of 40 Japanese patients with CNS DLBCL who presented with neurological, but not systemic symptoms, was reviewed. Median survival was 18.7 months. CD5, CD10, Bcl-6, MUM-1, and Bcl-2 were positive in 30%, 10%, 84%, 100%, and 93% of patients, respectively. All CD10-negative patients had non-germinal center B-cell type. There was no significant difference in survival among the immunophenotypic subgroups. CNS DLBCL appeared to be homogenous as a group, which prompted the comparison with another distinct extranodal entity, intravascular large B-cell lymphoma (IVLBCL) in Japanese patients. CNS DLBCL patients did not differ in age, sex, or immunophenotype, including CD5 positivity, from IVLBCL patients, but were significantly less likely to have poor prognostic parameters than IVLBCL patients: the international prognostic index score was low or low–intermediate in 86% of CNS DLBCL patients and high or high–intermediate in 98% of IVLBCL patients. Notably, despite this difference, their survival curves almost overlapped. The present study highlights the issue of clinical distinctiveness of aggressive extranodal lymphomas, the peculiar migration and localization of which should be further clarified.     

Mechanisms of killing by anti-CD20 monoclonal antibodies

CD20 is a cell-surface marker expressed on mature B cells and most malignant B cells, but not stem or plasma cells. It is an ideal target for monoclonal antibodies (mAb), such as rituximab and ofatumumab, as it is expressed at high levels on most B-cell malignancies, but does not become internalized or shed from the plasma membrane following mAb treatment. This allows mAb to persist on the cell surface for extended periods and deliver sustained immunological attack from complement and FcR-expressing innate effectors, particularly macrophages. CD20 can also generate transmembrane signals when engaged by certain mAb which, although unproven, might provide an important element of the therapeutic success of anti-CD20 mAb. These favourable characteristics have led to anti-CD20 mAb being developed and exploited for use in immunotherapy, where they have proven remarkably efficacious in both the treatment of malignant disease and autoimmune disorders by deleting malignant or normal B cells, respectively. In this review, we discuss how these mAb have driven research in the immunotherapy field over the last decade, detail their likely modes of action and their limitations in terms of effector exhaustion, and explore ways in which they might be enhanced and further exploited in the future.     

Large B-cell lymphoma with IRF4 rearrangement

Large B-cell lymphoma with IRF4 rearrangement (LBCL-IRF4) is a new provisional entity in the WHO Classification of Tumours of Haematopoietic Neoplasms (revised 4th edition, 2017). It shows diffuse or follicular infiltrates of medium to large neoplastic B cells with an aberrant germinal centre phenotype with IRF4 positivity on immunohistochemistry and IRF4 gene rearrangements found on fluorescence in situ hybridization (FISH). Here, we report a case of LBCL-IRF4 in a 30 year old female with asymmetrical tonsils. Microscopy showed partial infiltration by a diffuse, vaguely nodular proliferation of medium-to-large, highly proliferative B-cells and a background of follicular hyperplasia. The lesional cells were positive on immunohistochemistry for CD79, CD20, BCL2, BCL6 and IRF4, weak patchy positive for CD10 and had a high proliferative index. An IRF4 rearrangement was found on analysis by FISH. We have also included the pathological features of LBCL-IRF4 cases diagnosed in the Leeds Haematological Malignancy Diagnostic Service from 2017 to 2021.     

Primary hepatic marginal zone B-cell lymphoma with mantle cell lymphoma phenotype

We report a rare case of primary hepatic lymphoma, Stage II disease, in a 48-year-old male who had a solitary hepatic tumour measuring 4×4.5×3 cm. The tumour showed a nodular growth pattern and lymphoepithelial lesions with bile ducts. Some neoplastic nodules had a non-neoplastic atrophic germinal centre and/or a thin mantle cell layer. Morphologically, the neoplastic cells were centrocyte-like cells or intermediate lymphocytes. They expressed L26(CD20)⁺/LN-1(CDw75)^±/LN-2(CD74)⁺/cyclin D1^– and had a monotypic immunoglobulin of cytoplasmic IgM () on paraffin sections. The neoplastic cells or neoplastic nodules expressed surface IgM⁺/surface IgD^±/Leu-1(CD5)⁺/DRC-1⁺/alkaline phosphatase⁺/B1(CD20)⁺/B4(CD19)^– on fresh frozen sections. We therefore diagnosed this case as primary hepatic marginal zone B-cell lymphoma with mantle cell lymphoma phenotype. We confirm that it is difficult to differentiate extranodal marginal zone B-cell lymphoma (low grade B-cell lymphoma of mucosa-associated lymphoid tissue type; MALT lymphoma) and mantle cell lymphoma.     

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.     

Diffuse large B-cell lymphoma arising in a composite lymphoma with biclonality by flow cytometry and one monoclonal band by PCR

Composite lymphoma (CL) refers to the presence of two or more distinct types of lymphomas in a single organ or tissue. CL is an infrequent finding and may be due to the existence of two genetically related neoplasms, i.e. transformation of a single lymphoma into another lymphoma, or be due to the presence of two clonally unrelated lymphomas. CL composed of more than two lymphomas is even rare. Herein we describe a case of diffuse large B-cell lymphoma (DLBCL) arising in a CL of follicular lymphoma (FL) and small lymphocytic lymphoma (SLL) in an inguinal lymph node of an 85 year old woman. The three lymphomas were morphologically and immunophenotypically distinct while flow cytometry detected two monoclonal B-cell populations. Karyotyping and Polymerase Chain Reaction (PCR) for B-cell clonality each detected a single monoclonal B-cell population. The morphology findings may suggest DLBCL being transformed from FL while Richter transformation from SLL appears to be less likely in our case. Due to the single clone by chromosome study and PCR study, the precise relationships of the three lymphomas are unknown.     

Monocytes mediate shaving of B-cell-bound anti-CD20 antibodies

Anti-CD20 monoclonal antibodies are promising for the treatment of B-cell malignancies such as chronic lymphocytic leukaemia and autoimmune diseases where auto-antibodies play an important role. Anti-CD20 such as rituximab (RTX) mediates B-cell depletion through mechanisms such as complement-mediated cytotoxicity and antibody-dependent cellular cytotoxicity. However, in haematological malignancies, such effector mechanisms can be saturated and result in release of malignant B cells with reduced levels of CD20. It has been hypothesized that this is the result of monocyte-mediated shaving of the CD20/RTX complex from the B-cell surface. Here, we confirm, that in vitro co-culture of human monocytes and RTX-labelled syngeneic B cells results in reduced expression of CD20/RTX complex on the B cell surface. This shaving mechanism was the result of active protease activity because EDTA and PMSF were able to mediate partial inhibition. Also, a series of alternative anti-CD20 antibodies representing both type I and type II antibodies were tested for their ability to induce the shaving reaction. These results demonstrate that a monocyte-mediated shaving reaction can lead to complete loss of most anti-CD20 antibodies from the surface of B cells even from healthy donors and this is an important obstacle for antibody-mediated immune therapy. The findings demonstrate the necessity of developing novel antibodies that maintain high effector functions without enabling activation of the shaving reaction.     

Morphological variability of tumour cells in T-cell-rich B-cell lymphoma

T-cell-rich B-cell lymphoma (TCRBCL) is an unusual lymphoma which is difficult to diagnose. A majority of reactive T-cells and numerous histiocytes mask the few large neoplastic B-cells. Fourteen cases of TCRBCL were studied in order to identify the main histological and cytological features useful for this diagnosis. Neoplastic cells are atypical and sometimes difficult to classify. Several types are seen; they are mostly centroblasts, which represent more than 50% of the tumour cells but are sometimes multilobated, immunoblasts- or Reed-Sternberg-like cells. Interestingly, at least two, and often three, types of tumour cell are present in all the cases. Epithelioid cells and histiocytes are always found and are often numerous. Hypervascularization and fibrosis are present in the majority of cases, but without annular bands. Necrosis is absent. All tumour cells express CD20 but EMA is expressed in less than half the cases. In two cases, the association of a diffuse large B-cell lymphoma in one site and a TCRBCL in another suggests that TCRBCL may be considered as a peculiar pattern of a diffuse large B-cell lymphoma with a strong stroma reaction. TCRBCL may not represent a clinicopathological entity.     

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.     

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。     

Multilobated B-cell lymphoma, a variant of centroblastic lymphoma. Report of four cases

Four cases of multilobated B-cell lymphoma, one follicular and three diffuse, are described. Many of the lymphoma cells show marked lobulation of the nuclei, and possess multiple prominent nucleoli. There are admixed classical centrocytes, classical centroblasts, and cells with morphology intermediate between classical centroblasts and multilobated cells. Multilobated cells are also observed in small numbers in germinal centres of lymph nodes showing reactive follicular hyperplasia. We believe that the multilobated B-cell may represent one form of centroblast during transition between the centroblastic and centrocytic stages. Multilobated B-cell lymphoma may be its neoplastic counterpart in which the nuclear lobulation is further exaggerated.     

体外研究抗CD20单克隆抗体对骨髓瘤细胞的细胞毒性作用

目的:体外探讨上调多发性骨髓瘤(MM)细胞表面CD20抗原表达后,抗CD20单克隆抗体美罗华对骨髓瘤细胞的细胞毒性作用。方法:将浓度为(0-800)×10³U/L的重组人干扰素γ(hrγ-IFN),分别与10例初治(初治组)和10例复发难治(难治组)的MM患者瘤细胞共同培养,流式细胞仪测定培养前后瘤细胞表面CD20的表达;应用MTT比色法分析不同浓度美罗华对CD20抗原表达上调后瘤细胞的抗体依赖性细胞介导的细胞毒作用(ADCC)和补体依赖性细胞毒作用(CDC)。结果:hrγ-IFN浓度分别≥5×10⁴U/L或≥1×10⁵U/L,可明显增加初治组或难治组瘤细胞表面CD20的表达,在用8×10⁵U/Lhrγ-IFN上调瘤细胞表面CD20抗原的表达后,12mg/L和16mg/L的美罗华分别能显著介导初治组和难治组效应细胞对MM瘤细胞的ADCC和激活CDC。结论:体外hrγ-IFN上调MM瘤细胞表面CD20的表达后、抗CD20单克隆抗体美罗华具有对瘤细胞的ADCC和CDC效应。     

Clear cell variant of diffuse large B-cell lymphoma: a case report and review of the literature

Diffuse large B cell lymphoma (DLBCL) is a diffuse proliferation of large neoplastic B lymphoid cells with nuclear size equal to or exceeding that of normal macrophage nuclei. The DLBCL morphological variants are centroblastic, immunoblastic, T-cell- and histiocyte-rich, anaplastic, plasmablastic, anaplastic lymphoma kinase-positive, and primary mediastinal large B-cell lymphoma (PMBCL). These histopathologically-recognized morphological variants respond differently to treatment and have distinct prognoses. We report a case of a 43-year-old patient who presented pain in the lower abdomen that had begun four months prior. Ultrasound-guided biopsy revealed epithelial cell features and a partial alveolar growth pattern. We discovered large diffuse areas comprising large cells with slightly irregular nuclei and very clear cytoplasm. These features were similar to those of clear cell carcinoma in renal tissue, suggesting the possibility of an epithelial neoplasm. To test this possibility, immunohistochemistry for cluster designation markers was performed, but the diffuse areas were found to be positive only for CD45. Additional immunohistochemistry was performed, and the diffuse areas were found to be positive for CD20, CD79a, P53, and Mum-1. Based on these characteristics, a diagnosis of a clear cell variant of DLBCL was made, and the patient was treated with chemotherapy. Precise histological diagnosis is crucial for clinical management and ultimately for patient survival. There has been one additional report of a case of clear cell DLBCL, in outside the mediastinum. The features we identified can be used to define a new subtype of DLBCL. The expression of P53 and Mum-1 suggest a poor prognosis.     

Anaplastic lymphoma kinase-positive large B-cell lymphoma with complex karyotype and novel ALK gene rearrangements

Anaplastic lymphoma kinase–positive large B-cell lymphoma is a rare non–Hodgkin lymphoma that exhibits a characteristic immunoblastic/plasmablastic morphology and is frequently associated with t(2;17)(p23;q23) and expression of Clathrin–anaplastic lymphoma kinase fusion protein. Here, we report a refractory anaplastic lymphoma kinase–positive large B-cell lymphoma in a 49-year-old human immunodeficiency virus–positive man. The neoplastic cells expressed CD138, epithelial membrane antigen, CD45, and perforin, and showed a strong granular cytoplasmic anaplastic lymphoma kinase staining pattern. Conventional chromosome analysis revealed a clone with multiple anomalies and a chromosome count of 76 to 79. Fluorescence in situ hybridization studies showed 5 copies of the ALK gene with 2 intact signals and 3 signals resulting from 2 independent, previously unreported, rearrangements. One rearrangement, seen in 2 copies, involved translocation of ALK sequences to chromosome Xq21. The second rearrangement involved translocation of ALK sequences to chromosome 12q24.1. This case broadens the cytogenetic alterations in anaplastic lymphoma kinase–positive large B-cell lymphoma, and it also demonstrates the high genetic instability of this tumor.     

Large B-cell lymphoma with Hodgkin's features

AIMS: To describe the features of a series of nine cases of diffuse large B-cell lymphoma (DLBCL) showing morphological and immunophenotypic features that are intermediate with Hodgkin's lymphoma (HL). METHODS AND RESULTS: Most cases (6/9) presented as mediastinal tumours affecting young males, while the other three cases arose in extramediastinal locations. Histopathologically, tumours showed diffuse large cell areas in a polymorphous background, with pleomorphic cytology and the common presence of Hodgkin's and Reed-Sternberg cells. Immunophenotypically, tumours shared features of DLBCL and classical HL, with expression of CD30, CD15 (6/9), and a full B-cell profile including CD45RB, CD20, CD79a and OCT2. Epstein-Barr virus-latent membrane protein expression was found in 2/9 cases. The majority of tumours had immunohistochemical features consistent with activation of the NF-(kappa)B pathway, including nuclear location of the c-REL/p65 subunit, overexpression of phosphorylated I(kappa)B(alpha), and overexpression of NF-(kappa)B targets. Finally, 2/9 cases showed 3q27 (BCL6) rearrangement, and 1/9 had p53 gene mutations, both of which are rarely detected in classical HL. CONCLUSIONS: These findings suggest that DLBCLs with HL features constitute a distinctive subgroup of aggressive lymphomas whose neoplastic growth and peculiar characteristics could be facilitated by a particular microenvironment found in the mediastinum.     

Intravascular large B-cell lymphoma presenting with fulminant pseudomembranous colitis

Intravascular large B-cell lymphoma is a rare entity that usually presents in late stages with non-specific symptoms. We present a case of an incidentally discovered intravascular large B-cell lymphoma in a 78-year-old man who underwent colectomy for medically refractory pseudomembranous colitis. The malignant lymphocytes were preferentially localized to small colonic submucosal vasculature, without any evidence of an extravascular tumor mass. The gastrointestinal system is an exceeding rare initial diagnostic site for intravascular lymphoma, and presentation with pseudomembranous colitis has not been previously reported. We discuss the current definition of intravascular lymphoma, clinicopathological variants, differential diagnoses, as well as current therapy.     

Bone marrow infiltration of CD20-negative follicular lymphoma after rituximab therapy: a histological mimicker of hematogones and B-cell acute lymphoblastic leukemia/lymphoma

Rituximab is a monoclonal antibody against CD20. Rituximab combined with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy, termed R-CHOP, have improved the overall survival of patients with B-cell lymphoma in comparison with that of CHOP therapy. However, as with other molecularly-targeted therapies, resistance to rituximab could emerge sooner or later after rituximab administration. A number of mechanisms for rituximab resistance have been proposed, including downregulation of CD20 protein expression. Differential diagnosis of B-cell proliferation with reduced or lost CD20 expression includes not only B-cell lymphomas with CD20 downregulation, but also other tumorous and non-tumorous lesions. These include precursor B-cell neoplasms such as B acute lymphoblastic leukemia/lymphoblastic lymphoma (B-ALL/LBL) and hematogones, a normal precursor B-cell proliferation during regeneration of hematopoiesis, typically observed following bone marrow suppression by chemotherapy. It is important to distinguish these possibilities because distinct therapies are required for each. In this paper, we report a case where bone marrow infiltration of follicular lymphoma histopathologically mimicked hematogones or B-ALL/LBL when CD20 expression was downregulated in follicular lymphoma after R-CHOP therapy.