Immunologic Markers in Non-Hodgkin’s Lymphoma

Current targeted therapies in lymphomas

Purpose

This article summarizes current targeted therapies that have received regulatory approval for the treatment of B- and T-cell lymphomas.

Summary

Over the last 20 years, new drug therapies for lymphomas of B cells and T cells have expanded considerably. Targeted therapies for B-cell lymphomas include: (1) monoclonal antibodies directed at the CD20 lymphocyte antigen, examples of which are rituximab, ofatumumab, and obinutuzumab; (2) gene transfer therapy, an example of which is chimeric antigen receptor–modified T-cell (CAR-T) therapy directed at the CD19 antigen expressed on the cell surface of both immature and mature B cells; and (3) small-molecule inhibitors (ibrutinib, acalabrutinib, copanlisib, duvelisib, and idelalisib) that target the B-cell receptor signaling pathway. Of note, brentuximab vedotin is an antibody–drug conjugate that targets CD30, another lymphocyte antigen expressed on the cell surface of both Hodgkin lymphoma (a variant of B-cell lymphoma) and some T-cell lymphomas. Although aberrant epigenetic signaling pathways are present in both B- and T-cell lymphomas, epigenetic inhibitors (examples include belinostat, vorinostat, and romidepsin) are currently approved by the Food and Drug Administration for T-cell lymphomas only. In addition, therapies that target the tumor microenvironment have been developed. Examples include mogamulizumab, bortezomib, lenalidomide, nivolumab, and pembrolizumab. In summary, the efficacy of these agents has led to the development of supportive care to mitigate adverse effects, due to the presence of on- or off-target toxicities.

Conclusion

The therapeutic landscape of lymphomas has continued to evolve. In turn, the efficacy of these agents has led to the development of supportive care to mitigate adverse effects, due to the presence of on- or off-target toxicities. Further opportunities are warranted to identify patients who are most likely to achieve durable response and reduce the risk of disease progression. Ongoing trials with current and investigational agents may further elucidate their place in therapy and therapeutic benefits.

Dysregulated B-cell TLR2 expression and elevated regulatory B-cell frequency precede the diagnosis of AIDS-related non-Hodgkin lymphoma

OBJECTIVES

In antiretroviral therapy (ART)-treated patients, to determine if AIDS-related non-Hodgkin lymphoma (AIDS-NHL) is preceded by: elevated frequency of potentially malignant abnormal activated/germinal center-like B cells, elevated serum prevalence of B-cell stimulatory Toll-like receptor (TLR) ligands resulting from HIV infection-associated microbial translocation, dysregulated B-cell TLR expression/signaling, and perturbations in the frequency of immunoregulatory cells.

DESIGN

A case-control study nested with a cohort study of HIV-infected women.

METHODS

Prediagnostic AIDS-NHL cases (n = 12, collected 1-12 months before diagnosis) and controls (n = 42) from the Women's Interagency HIV Study cohort, were matched for HIV and ART status, age, race, and CD4 lymphocyte count. Serum levels of TLR ligands, the prevalence of malignancy-associated abnormal activated/germinal center-like (CD19CD10CD71CD86AID) B cells, TLR2 expression on B cells, expression of TLR2-modulating micro-RNA, and the frequency of regulatory T and B cells were assessed.

RESULTS

Diagnosis of AIDS-NHL was preceded by a significantly elevated frequency of activated/germinal center-like CD19CD10CD71CD86AID B cells (P = 0.0072), elevated serum prevalence of the TLR2 ligand, and significantly elevated B-cell TLR2 expression (P = 0.0015), positively correlating with the frequency of activated/germinal center-like B cells (rho = 0.7273, P = 0.0144). In cases, a purified subset of activated/germinal center-like B cells exhibited decreased expression of microRNAs that modulate TLR2 signaling, including miR-21, 146a, 146b, and 155. Finally, cases also exhibited significantly elevated frequencies of antitumor immunity inhibitory regulatory B cells (P = 0.0024), but not regulatory T cells.

CONCLUSIONS

Our findings suggest that increased microbial translocation and dysregulated TLR expression/signaling, coupled with an elevated frequency of regulatory B cells, precede the diagnosis of AIDS-NHL in HIV-infected ART-treated patients.

TLR2-activated B cells are phenotypically similar to the abnormal circulating B cells seen preceding the diagnosis of AIDS-related NHL diagnosis

BACKGROUND

AIDS-related non-Hodgkin lymphoma (AIDS-NHL) is a common AIDS-defining cancer. Prior studies suggest that chronic B-cell activation precedes AIDS-NHL diagnosis. Activation of B cells by multiple factors, including Toll-like receptor (TLR) signaling, leads to the expression of activation-induced cytidine deaminase (AID), a DNA mutating molecule that can contribute to oncogene translocations/mutations, leading to NHL. The goal of this study was to determine whether surface markers expressed on activated and/or germinal center B cells, and AID expression, were elevated on circulating B cells preceding AIDS-NHL and to determine if TLR signaling contributes to this activated B-cell phenotype.

METHODS

Stored viable peripheral blood mononuclear cell specimens, obtained before AIDS-NHL diagnosis, were assessed by multicolor flow cytometry. Additionally, B cells isolated from peripheral blood mononuclear cell were exposed to TLR ligands in vitro, after which B-cell phenotype was assessed by flow cytometry.

RESULTS

An elevated fraction of B cells expressing CD10, CD71, or CD86 was seen in those who went on to develop AIDS-NHL. AID expression was detected in some who developed AIDS-NHL, but not in HIV+ or HIV- controls. TLR2-stimulated purified B cells exhibited the activated B-cell phenotype observed in HIV+ subjects before AIDS-NHL diagnosis.

CONCLUSIONS

These results indicate that an elevated fraction of B cells display an activated/germinal center phenotype in those HIV+ subjects who go on to develop AIDS-NHL and suggest that TLR2-mediated activation may play a role in HIV infection-associated B-cell activation, potentially contributing to the genesis of AIDS-NHL.

Rituximab-induced inhibition of antiapoptotic cell survival pathways: implications in chemo/immunoresistance, rituximab unresponsiveness, prognostic and novel therapeutic interventions

Rituximab (chimeric anti-CD20 monoclonal antibody) is the first Food and Drug Administration approved antitumor antibody and is used in the treatment of B-non-Hodgkin's lymphoma (B-NHL). It is used as single monotherapy or in combination with chemotherapy and has improved the treatment outcome of patients with B-NHL. The in vivo mechanisms of rituximab-mediated antitumor effects include antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cell cytotoxicity (CDC), growth-inhibition and apoptosis. A subset of patients does not initially respond to rituximab and several responsive patients develop resistance to further rituximab treatment. The mechanism of rituximab unresponsiveness is not known. Besides the above-postulated mechanisms, rituximab has been shown to trigger the cells via CD-20. Studies performed with B-NHL cell lines as model systems revealed several novel mechanisms of rituximab-mediated effects that are involved in chemo/immunosensitization and the development of resistance to rituximab. Rituximab has been shown to inhibit the p38 mitogen-activated protein kinase, nuclear factor-kappaB (NF-kappaB), extracellular signal-regulated kinase 1/2 (ERK 1/2) and AKT antiapoptotic survival pathways, all of which result in upregulation of phosphatase and tensin homolog deleted on chromosome ten and Raf kinase inhibitor protein and in the downregulation of antiapoptotic gene products (particularly Bcl-2, Bcl-(xL) and Mcl-1), and resulting in chemo/immunosensitization. Further, rituximab treatment inhibits the overexpressed transcription repressor Yin Yang 1 (YY1), which negatively regulates Fas and DR5 expression and its inhibition leads to sensitization to Fas ligand and tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis. Rituximab-resistant clones were generated as model to examine the mechanism of in vivo rituximab unresponsiveness. These clones showed reduced expression of CD20 and hyperactivation of the above antiapoptotic signaling pathways and failure of rituximab to trigger the cells leading to inhibition of ADCC, CDC and chemo/immunosensitization. Interference with the hyperactivated pathways with various pharmacological and proteasome inhibitors reversed resistance. Furthermore, the above findings have identified several gene products that can serve as new prognostic/diagnostic biomarkers as well as targets for therapeutic intervention in B-NHL.

Development of a murine model for blastoid variant mantle-cell lymphoma

Blastoid-variant mantle-cell lymphoma (MCL-BV), unlike most B-cell non-Hodgkin lymphomas (NHL-Bs), is refractory to conventional chemotherapy and associated with a very poor prognosis. Development of new therapies has been hampered by the lack of valid animal models. We have developed a novel murine model of MCL-BV by crossing interleukin 14alpha (IL-14alpha) transgenic mice with c-Myc transgenic mice (double transgenic [DTG]). IL-14alpha is a B-cell growth factor that is expressed in a number of high-grade lymphomas, including MCL-BV. Ninety-five percent of IL-14alpha transgenic mice develop CD5(+) large B-cell lymphomas by 18 months of age. Sixty percent of c-Myc transgenic mice develop pre-B-cell lymphomas by 12 months of age. Close to 100% of DTG mice develop an aggressive, rapidly fatal lymphoma at 3 to 4 months of age that is CD5(+), CD19(+), CD21(-), CD23(-), sIgM(+). The tumor is found in the blood, bone marrow, liver, spleen, lymph nodes, gastrointestinal tract, and lungs and rarely in the brain, similar to the involvement seen in human MCL-BV. Immunoglobulin gene rearrangements document the monoclonality of the tumor. Cyclin D1 is highly expressed in these tumors, as it is in MCL-BV. DTG represents a novel model for MCL-BV that should reveal important insights into the pathogenesis of the lymphoma and contribute to the development of new forms of therapy.

Molecular Analysis of T-Cell Receptor β Genes in Cutaneous T-Cell Lymphoma Reveals Jβ1 Bias

Molecular characterization of T-cell receptor junctional region sequences in cutaneous T-cell lymphoma had not been previously reported. We have examined in detail the features of the T-cell receptor beta (TCRB) gene rearrangements in 20 individuals with well-defined stages of cutaneous T-cell lymphoma (CTCL) comprising 10 cases with early-stage mycosis fungoides (MF) and 10 cases with late-stage MF or Sezary syndrome. Using BIOMED-2 PCR primers, we detected a high frequency of clonally rearranged TCR gamma and TCRB genes (17/20 and 15/20 cases, respectively). We carried out sequencing analysis of each complete clonal variable (V)beta-diversity (D)beta-joining(J)beta fingerprint generated by PCR amplification, and determined the primary structure of the Vbeta-Dbeta-Jbeta junctional regions. We observed considerable diversity in the T-cell receptor Vbeta gene usage and complementarity-determining region 3 loops. Although we found that TCRB gene usage in CTCL and normal individuals share common features, our analysis also revealed preferential usage of Jbeta1 genes in all cases with advanced stages of disease.

Rituximab (chimeric anti-CD20) sensitizes B-NHL cell lines to Fas-induced apoptosis

Rituximab (chimeric anti-CD20 monoclonal antibodies) is currently being used in the treatment of B non-Hodgkin's lymphoma (NHL). We have recently reported that rituximab triggers and modifies various intracellular signaling pathways in NHL B-cell lines, resulting in reverting the chemoresistant phenotype to a sensitive phenotype. This study investigated whether rituximab also modifies intracellular signaling pathways resulting in the sensitization of NHL cells to Fas-induced apoptosis. Treatment of the Fas-resistant NHL cell lines (2F7, Ramos and Raji) with rituximab sensitized the cells to CH-11 (FasL agonist mAb)-induced apoptosis and synergy was achieved. Fas expression was upregulated by rituximab as early as 6 h post-treatment as determined by flow cytometry, reverse transcriptase-polymerase chain reaction and Western blot. Rituximab inhibited both the expression and activity of the transcription repressor Yin-Yang 1 (YY1) that negatively regulates Fas transcription. Inhibition of YY1 resulted in the upregulation of Fas expression and sensitization of the tumor cells to CH-11-induced apoptosis. The downregulation of YY1 expression was the result of rituximab-induced inhibition of both the p38 mitogen-activated protein kinase (MAPK) signaling pathway and constitutive nuclear factor kappa of B cells (NF-kappaB) activity. The involvement of NF-kappaB and YY1 in the regulation of Fas expression was corroborated by the use of Ramos cells with a dominant-active inhibitor of NF-kappaB (Ramos IkappaB-estrogen receptor (ER) mutant) and by silencing YY1 with YY1 siRNA, respectively. Further, the role of rituximab-mediated inhibition of the p38 MAPK/NF-kappaB/YY1 pathway in the regulation of Fas and sensitization to CH-11-induced apoptosis was validated by the use of specific chemical inhibitors of this pathway and which mimicked rituximab-mediated effects. These findings provide a novel mechanism of rituximab-mediated activity by sensitizing NHL cells to Fas-induced apoptosis.

Rituximab inhibits p38 MAPK activity in 2F7 B NHL and decreases IL-10 transcription: pivotal role of p38 MAPK in drug resistance

We have recently reported that Rituximab (anti-CD20) sensitizes drug-resistant 2F7 and 10C9 B Non-Hodgkin's lymphoma (NHL) cell lines to the apoptotic effects of various chemotherapeutic drugs by downregulation of IL-10 and Bcl-2 expression. The mechanism by which Rituximab induces downregulation of IL-10 was examined. We hypothesized that Rituximab may inhibit p38 MAPK activity that regulates IL-10 expression via Sp1. Treatment of 2F7 cells with Rituximab or the p38 inhibitor SB203580 inhibited the constitutive p38 MAPK activity and resulted in the inhibition of Sp1, IL-10, STAT3, and Bcl-2. Inhibition of the Src-family PTKs, Lyn, and Src-family PTKs upstream signaling molecules of the p38MAPK pathway, by PP2, a specific Src-family kinase inhibitor, resulted in the inhibition of p38MAPK and IL-10 expression. In addition to p38 MAPK, Rituximab also inhibited NF-kappaB activity. Inhibition of the Src PTKs, MAPK, and NF-kappaB activities by Rituximab or by specific chemical inhibitors sensitized the cells to CDDP-mediated apoptosis. The above signaling-mediated effects by Rituximab were observed with similar kinetics beginning at 1 h following treatment. Thus, altogether, these results demonstrate that signaling by Rituximab results in the inhibition of the p38MAPK pathway, which in turn inhibits the transcription of IL-10 via Sp1. Inhibition of the IL-10 autocrine/paracrine loop results in the inhibition of STAT3 activity and, consequently, inhibition of Bcl-2 expression and sensitization to drugs-apoptosis. Further, Rituximab-mediated signaling identifies several new intracellular targets in NHL that may be of potential therapeutic interest for the development of new drugs in the treatment of drug-refractory NHL tumor cells.

Polyclonal expansion of T cells with the TCR Vbeta type of the tumour cell in lesions of cutaneous T-cell lymphoma: evidence for possible superantigen involvement

The involvement of superantigens in the pathology of cutaneous T-cell lymphomas (CTCL) has been suggested before, but without unequivocal evidence for superantigen activity in the patients. Seeking evidence for superantigen activity we analysed clones and microdissected single cells isolated from the epidermis of early-stage lesions of a CTCL patient for their T-cell receptor (TCR) V beta expression and TCR V gamma gene rearrangements. The vast majority of these T cells expressed the TCR V beta family type of the tumour. From their TCR gamma gene rearrangements, however, these cells were polyclonal. The tumour cell clone accounted for about 60% of these cells, about 40% were of heterogeneous origin. This dominance of a single V beta family in the polyclonally expanded dermal T-cell populations implies superantigen activity in the CTCL lesions.

Immunophenotyping lymphomas in dogs: a comparison of results from fine needle aspirate and needle biopsy samples

The reliability of utilizing cytologic samples for immunophenotyping canine lymphomas was evaluated by a systematic comparison of results from fine needle aspirate (FNA) to needle biopsy specimens stained by immunochemical methods. The specific reactivity of a selected panel of 12 antibodies to cell surface markers and intermediate filaments was assessed in 11 dogs by comparing cytologic to histologic samples. There was excellent correlation of results between immunostained cytologic and histologic samples. FNA sampling is a simple, noninvasive method for determining the lymphoid phenotype in canine lymphoma. In addition, this technique may be useful as a cytodiagnostic aid in differentiating lymphoid from non-lymphoid tumors and in assessing neoplastic vs. reactive or hyperplastic processes.

Sporadic Burkitt's lymphoma of the head and neck in the pediatric population

Burkitt's lymphoma (BL) is one of the fastest growing malignancies in the pediatric population in the United States. BL is a high-grade B-cell Non-Hodgkin's lymphoma (NHL) which exists in endemic, sporadic, and human immunodeficiency-associated subtypes. The African, or endemic, variant usually involves the maxilla and other facial bones while head and neck manifestations in non-endemic BL are rare. We present three unusual present ations of sporadic BL stemming from Waldeyer's ring and the orbit. The clinical and pathologic features of BL are reviewed.

Establishment and characterization of a Kaposi's sarcoma-associated herpesvirus- and Epstein-Barr virus-negative malignant lymphoma cell line (OHK) with primary effusion lymphoma immunophenotype

A novel cell line, designated OHK, was established from ascites of a 59-year-old Japanese woman with diffuse large B-cell lymphoma showing a peculiar serosal tropism, as seen in primary effusion lymphomas (PEL). OHK exhibited a large pleomorphic morphology with irregular nuclei and distinct nucleoli, and included immunoblastic and Reed-Sternberg-like giant cells. On ultrastructural examination, rich intermediate filaments, and well-developed Golgi apparati and rough endoplasmic reticulum, were seen. Immunophenotypically, OHK lacked T and B cell-associated antigens, and had CD10, CD30, CD33 and CD138 antigens. Although OHK cells did not express immunoglobulin (Ig) protein, Southern blot analysis demonstrated clonal rearrangements of Ig heavy and light chain genes. These observations suggest that OHK cells are derived from preterminally differentiated B cells, and that they have features of PEL. Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus were not detected. OHK displayed hyperploid karyotypes with multiple structural abnormalities, and produced some cytokines such as macrophage-colony-stimulating factor (M-CSF), granulocyte-CSF, interleukin 6 and transforming growth factor beta 1. In particular, vascular endothelial growth factor (VEGF), whose stimulation of vascular permeability is thought to be critical to the pathogenesis of PEL, was also produced in large quantities. These results indicate that OHK may be a useful tool for the investigation of PEL.

Immunophenotyping large B-cell lymphomas. Flow cytometric pitfalls and pathologic correlation

Large cell lymphomas often challenge the diagnostic flow cytometrist. The purposes of this study were to improve our protocols for diagnosing large cell lymphomas and to correlate flow cytometric (FC) data with demographic and histologic features. We identified 63 cases of large B-cell lymphoma between January 1, 1995, and July 30, 1999, and reviewed the diagnostic slides and FC light scatter and staining patterns. The 51 lymphomas with adequate material for systemic review fell into 2 light scatter patterns: "clear cut," with large abnormal cells (high forward scatter relative to normal lymphocytes), 17 cases (33%); and "complex," 34 cases (67%). Clear-cut cases were more mitotically active (average of 42 vs 25 per 10 high-power fields), with higher cellularity. Apoptosis, geographic necrosis, and sclerosis were present histologically in many cases, regardless of FC findings. We conclude that morphologic features of large cell lymphomas do not predict which cases will be difficult to diagnose by FC. Gating strategies can be critical to improve the diagnostic yield.

Immunophenotyping of leukemia

Modern immunophenotyping of hematological malignancies by flow cytometry is assisted by a wide array of easily accessible monoclonal antibodies, by antibodies conjugated to diverse fluorochromes, and by reliable techniques for cell membrane permeabilization. Simultaneous assessment of multiple surface and intracellular markers at diagnosis reduces the number of cells required, helps the identification of the malignant cells and determines the degree of immunophenotypic heterogeneity of the malignant cell population. A few critical markers are sufficient to establish the lineage association in the majority of cases of acute and chronic leukemias and lymphomas. More extensive immunophenotyping can provide information about the cells' stage of differentiation, assess the expression of prognostically important features, and determine clonality. The identification of leukemia-associated immunophenotypes can be used for monitoring minimal residual disease during therapy. The presence of cells expressing these phenotypes in patients who are in clinical remission is associated with an increased risk of relapse.

Precursor B-cell lymphoblastic lymphoma in childhood and adolescence: clinical features, treatment, and results in trials NHL-BFM 86 and 90

BACKGROUND

Precursor B-cell lymphoblastic lymphoma (PBLL) is a rare subtype of childhood non-Hodgkin lymphoma (NHL). The purpose of our study was to investigate frequency and clinicopathological features of PBLL in children and to test prospectively the efficacy of an ALL-type therapy for treatment of these patients.

PROCEDURE

From October, 1986, to March, 1995, 1,075 patients up to 18 years of age suffering from all kinds of NHL were registered in the two consecutive multicenter studies NHL-BFM 86 and 90. Of these, 27 patients were diagnosed with PBLL. Twenty-one PBLL patients were treated according to a BFM-ALL-type protocol: an eight-drug induction over 9 weeks was followed by an 8-week consolidation including methotrexate 5 g/m(2) x4. Patients in stages I and II continued with maintenance up to a total therapy duration of 24 months, whereas patients in stages III and IV received an additional eight-drug intensification and cranial radiotherapy (12 Gy for prophylaxis) after consolidation. Six PBLL patients were treated according to the BFM-protocol for B-NHL, stratified according to stage and tumor load and consisiting of two to six 5-day courses of chemotherapy.

RESULTS

The median age of the 27 patients with PBLL (18 boys, 9 girls) was 6.2 (range 0.7-15) years. Stages (St. Jude) were: I (n = 3), II (n = 7), III (n = 9), and IV (n = 8). Twenty-one PBLL patients had nodal disease, 6 patients had subcutaneous manifestations, and 8 patients had bone marrow disease (<25% blasts). All patients achieved remission. With a median follow-up time of 4. 25 years, the estimated probability for event-free survival (pEFS) at 10 years for the total group was 0.73 (SE 0.10). Five patients (2, 1, 1, and 1 patients at stages I, II, III, and IV, respectively) relapsed: 2 of 21 patients who were treated according to the ALL strategy and 3 of 6 who were treated according to the B-NHL-protocol.

CONCLUSIONS

PBLL accounts for 2.5% of childhood NHL. An ALL-type therapy strategy appears to be superior to a short-pulse B-NHL protocol.

Why do B cell lymphoma fail to elicit clinically sufficient T cell immune responses?

There is no doubt that human B cell lymphoma does not elicit a clinically sufficient T cell mediated immune response that results in tumor rejection. However, the mechanisms leading to this lack of T cell recognition and effector function are still not fully understood. Many potential mechanisms such as "ignorance" including "antigen silencing", "tolerance" including "infectious tolerance" and "anergy" or "immunosuppression" have been identified in different model systems and all these could, in part, account for the lack of immune recognition in B cell lymphoma. Malignant B cells are poor antigen presenting cells and T cells in close proximity to the malignant cells are hyporesponsive with detects in T cell receptor signaling and cytotoxic effector function. This review will discuss recent in vitro findings in context of in vivo data in murine model systems relevant to B cell lymphoma. Understanding these complex defects of anti-lymphoma immune responses should allow us to redefine our immunotherapeutic strategies to overcome these detects and induce clinically sufficient T cell mediated immune responses.

The difference in NK-cell activity between patients with non-Hodgkin's lymphomas and Hodgkin's disease

Natural killer (NK) cells play an important role in immune surveillance against malignant diseases. Considering the lymphoid origin of malignant lymphomas, as well as scarce data concerning NK-cell function in these neoplasms, we evaluated NK-cell activity in 49 patients with non-Hodgkin's lymphomas (NHL) and 47 patients with Hodgkin's disease (HD), prior to therapy. Using the recommended International Working Formulation and the Ann Arbor staging system for classification of lymphomas we found, by the LDH release cytotoxicity assay, that decreased NK-cell activity (P < 0.05) in NHL patients was essentially related to unfavourable histology (13 indolent lymphomas, 25 intermediate and 11 very aggressive lymphomas were included), but that within these categories clinical stage of the disease also contributed to the degree of NK-cell dysfunction. In contrast, in HD, NK-cell activity was persistently decreased (P< 0.05), compared to controls, irrespective of histological type and clinical stage. It is of interest also that the most profound NK-cell dysfunction that is present and persistent from the onset of HD, and which appears in very aggressive NHL was associated with the phenomenon of increased spontaneous lactate acid dehydrogenase (LDH) release activity from the separated PBMC of these patients. The difference in the level of NK-cell impairment between patients with various histological grades of malignancy in NHL and HD suggests different initial participation of innate immune reactions in these diseases.

Cytokeratin-positive large-cell lymphomas of B-cell lineage. A study of five phenotypically unusual cases verified by polymerase chain reaction

Five cases of clinically aggressive, keratin-positive malignant lymphomas of B-cell type with unusual immunophenotypes were studied. All cases were extranodal: two from the stomach, one from soft tissue, one from the skin, and one from the spleen. These tumors were undifferentiated large-cell neoplasms that showed reactivity for low-molecular-weight keratin 8, but they were negative for keratin 19; three cases were also positive for epithelial membrane antigen. The immunohistochemical diagnosis was complicated by the fact that two of these cases lacked reactivity for leukocyte common antigen and three were CD20 negative. These findings simulated the immunophenotype of a carcinoma and led to an initial misdiagnosis of carcinoma. Although only two cases showed immunohistochemical evidence of B-cell lineage (CD20+), all five cases were documented as B-cell lymphomas on the basis of the clonal immunoglobulin heavychain gene rearrangement, as demonstrated by polymerase chain reaction (PCR) in all the cases and by Southern blot hybridization in three cases; all cases were negative for T-cell markers, and three cases showed germline configuration for T-cell receptor beta-chain. One case was strongly CD30 positive and represented large-cell anaplastic lymphoma of B-cell type. Our results show that some B-cell lymphomas can have unusual and confusing immunophenotypes, including keratin positivity and leukocyte antigen negativity. Use of PCR-based molecular genetic demonstration of clonal immunoglobulin heavychain gene rearrangement is helpful in establishing the correct diagnosis in such cases.

Correlation between immunophenotypic diversity and clinical features in B-cell lymphoblastic lymphoma

Lymphoblastic lymphoma (LBL) is a highly malignant subtype of non-Hodgkin's lymphoma (NHL) and generally carries a T-cell phenotype with mediastinum or central nervous system (CNS) involvement. However, only a small proportion of LBL exhibit a B-cell phenotype (B-LBL), and these frequently present at the head and neck without mediastinum or CNS involvement. Three immunological subgroups may exist. The most predominant CD10-positive pre-B-cell type, corresponding to a precursor B-cell neoplasm, frequently involves the head and neck. The second, CD10-negative or mature B-cell type, defined by the absence of CD10 or presence of surface membrane immunoglobulins combined with expression of CD19 or CD20, often involves the mediastinum. The final group is a CD5-positive B-cell type corresponding to a blastic variant of mantle cell lymphoma (MCL). Its clinical course is less aggressive, patients are often older, and nodal lesions are more frequent than extranodal involvement. Thus, B-LBL is immunologically diverse, but its biological behavior correlates with the immunophenotype.

The usefulness of a rapid PCR methodology to detect rearranged Ig heavy chain genes in lymphoproliferative disease in a diagnostic setting

Polymerase chain reaction (PCR) was used to amplify the DNA fragments of the framework 3 region (FR3) of the immunoglobulin heavy (IgH) chain genes, from the tissue of 66 patients with B-lymphoproliferative diseases and 74 patients with other malignant diseases, reactive or normal tissue. The assay performed with 77% sensitivity, 100% specificity and 89% efficacy. In addition, the PCR assay cost less than 25% of the cost performing Southern blot analysis of tumor DNA, which has been the test performed to date, and had a turn around time of 24 hrs rather than the 7-14 days required to obtain a result from Southern blot analysis. These results suggest that PCR analysis of B-cell lymphoproliferative disease is superior to Southern blot analysis, in the setting of a diagnostic laboratory.

Novel tumor-associated accessory molecules involved in the gamma/delta cytotoxic T-lymphocyte-Burkitt's lymphoma interaction

BACKGROUND

Tumor specific cytotoxic T lymphocytes (CTL) recognize antigen via the T-cell receptor (TCR). In addition, recognition requires accessory molecules involved in adhesion and signal transduction. The authors previously have characterized an autologous, Burkitt's lymphoma specific CTL line that uses the gamma-delta TCR to recognize antigen in a nonclassical context. The current study was undertaken to identify novel accessory molecules involved in this unusual TCR-tumor cell interaction.

METHODS

A panel of monoclonal antibodies was generated against a Burkitt's lymphoma cell line and was screened for inhibition of autologous, tumor specific, cytolysis by a gamma-delta CTL line. Proteins identified by these monoclonal antibodies were further characterized by fluorescent-activated cell sorter analysis, Western blot and immunoprecipitation.

RESULTS

Three known (CD5, CD43, and CD11a/CD18) and three novel (BAM-1, BAM-2, and BAM-3) cell surface molecules involved in the gamma-delta CTL-Burkitt's lymphoma interaction were identified and characterized.

CONCLUSIONS

This study identifies and provides a preliminary characterization of three novel Burkitt's lymphoma-associated molecules involved in the gamma-delta CTL-tumor cell interaction and demonstrates that CD5, CD43, and CD11a/CD18 are involved in this interaction. It is likely that other unidentified accessory molecules are also involved in this and other effector cell-tumor interactions. Identification of such molecules may be useful in the design of new immunotherapeutic approaches.

Characteristic clinicopathologic features of adult B-cell lymphoblastic lymphoma with special emphasis on differential diagnosis with an atypical form probably of blastic lymphocytic lymphoma of intermediate differentiation origin

BACKGROUND

Lymphoblastic lymphoma is typically of thymic T-cell phenotype. Lymphoblastic lymphoma of B-cell origin (B-lymphoblastic lymphoma) has been relatively poorly described. Whether B-lymphoblastic lymphoma should be managed like its T-cell counterpart remains to be clarified.

METHODS

From 1983 to 1991, 10 adult patients were diagnosed as having B-lymphoblastic lymphoma at National Taiwan University Hospital by using the histomorphologic criteria of international working formulation. B-cell phenotype was determined by the immunohistochemistry method. Clinicopathologic features of these 10 patients were reviewed.

RESULTS

Seven patients were grouped as typical type and were characterized by an aggressive clinical course with lymph node (7 of 7), bone marrow (6 of 7), liver (3 of 7), spleen (3 of 7), and central nervous system (2 of 7) involvement. The median survival time was 8 months. In contrast, three patients had an atypical clinical picture. They were older patients (64-73 years) and were characterized by a relatively less aggressive course with predominantly bulky nodal involvement. Two of these three patients are alive (31 and 49 months, respectively) and well at this report, with one of them being repeatedly experiencing disease remission with the use of simple salvage chemotherapeutic regimens. Further studies revealed that tumor tissues of these three atypical cases had strong expression of CD5 (Leu-1) marker.

CONCLUSION

B-lymphoblastic lymphoma diagnosed by histomorphologic criteria should be further distinguished from a relatively favorable subtype, which probably represents a variant of blastic lymphocytic lymphoma of intermediate differentiation as described by Lardelli et al. Clinical features of typical B-lymphoblastic lymphoma, except for the lack of mediastinal involvement, is similar to its T-cell counterpart.

Recent developments in radioimmunotherapy

With the advent of monoclonal antibody techniques, there has been renewed interest in RIT as a treatment modality in patients with a variety of tumour types. There has been a considerable research effort to increase understanding of the scientific basis of such therapy at all levels. Antibody, chelator and radioisotope factors are all the subject of research aimed at producing a potent effector system capable of maximal target cell kill with acceptable normal tissue toxicity. Improved knowledge of the host and tumour factors which limit access to the target cell offers the possibility of optimizing targeting and increasing the therapeutic index. Target cell factors that influence response to low dose rate RIT have been elucidated and provide an opportunity to integrate the treatment modality into radical therapy regimens. A number of Phase I and II trials have now been performed in various tumour types. The results have been promising but, as yet, the prospect of radical RIT remains a research goal. Before it can be achieved it will be necessary to improve specific tumour cell targeting and to increase both the initial dose rates and the total dose delivered to tumour deposits. Until such time, it is likely that RIT will be incorporated into multimodality protocols to deliver a moderate (10-20 Gy) tumour boost, or in an adjuvant setting in patients with minimal residual disease.

Non-Hodgkin's lymphoma in the older person: a review

OBJECTIVE

To study the epidemiology of non-Hodgkin's Lymphoma (NHL) in the older person and to explore treatment strategies for older persons with NHL.

DESIGN

Review of the English literature.

MEASUREMENTS

Incidence of NHL in patients of different ages; prevalence of NHL of different grades and stages in persons of different ages; and response to treatment, disease free survival, and survival, for patients of different ages.

RESULTS

The incidence of NHL in the aged has increased approximately 80% since 1970, and approximately one-half of the 40,000 annual new cases occur in persons aged 60 and older in the USA. The 2-4 phenoxy pesticides may be partly responsible for this increment. The treatment of low grade lymphoma is mostly palliative and well tolerated by the aged. Age may have an adverse effect on the prognosis of intermediate grade lymphomas, and the prevalence of poor prognostic factors and comorbidity increases with age. Among persons aged 65-75, the complete response rate (CRR) of intermediate grade NHL to chemotherapy is approximately 50%, and approximately one-third of complete responders remain alive and free of disease 5 years from diagnosis. Among those aged 75 and older, the CRR to chemotherapy is approximately 40%, and the median duration of response is 16 months. Strategies aimed to ameliorate treatment-related toxicity include lower doses of chemotherapy, choice of drugs better tolerated by older individuals, and prevention of chemotherapy-induced toxicity.

CONCLUSIONS

NHL are an increasingly common problem for older persons. Approximately 80% of older patients with low grade lymphomas and 40%-50% of those with intermediate grade lymphomas may benefit from chemotherapy. Individualized treatment, based on life expectancy and comorbidity, is the key to effective management.

Immunohistochemistry in tumour diagnosis

Immunohistochemistry has become an everyday tool in diagnostic pathology to increase the accuracy in tumour typing. The most important recent developments include availability of antibodies to leukocyte CD-antigens to nearly comprehensive lymphoma typing in paraffin sections, use of certain leukocyte antigens in typing of solid tumours, e.g. neoplastic endothelial cells (CD31 and CD34) and neural and neuroendocrine cells (CD56, CD57). Also, antibodies selective to individual keratin polypeptides promise to be helpful in the subtyping of carcinomas. Antibodies to nuclear proliferation antigens have already proven helpful in the characterization of tumour cell proliferation. Technical optimization, using enzymatic and non-enzymatic antigen retrieval modalities, is also important.

The usefulness of cell surface markers in predicting the prognosis of non-Hodgkin's lymphomas

The Working Formulation for classification of non-Hodgkin's lymphomas provides useful prognostic information. Since this scheme was published in 1982, many studies have investigated the prognostic significance of various cell surface markers in lymphoma cases. This article reviews the value of distinguishing T cells from B cells, CD5+ B cells, immunoglobulin light chain types, proliferation antigens such as Ki 67, other markers of B-cell differentiation, and chromosomal anomalies. Each of these contributes some further prognostic significance to that already determined by the Working Formulation.