Richard J. Ford

Antibiotic Treatment of Gastric Lymphoma of Mucosa-Associated Lymphoid Tissue: An Uncontrolled Trial

Gastric low-grade B-cell lymphoma is related to Helicobacter pylori infection according to histopathologic, epidemiologic, and clinical characteristics. Although normal gastric mucosa does not contain organized lymphoid tissue, lymphoid follicles develop with H. pylori infection (1) and with autoimmune diseases, such as the Sjgren syndrome (2). Low-grade B-cell lymphoma has been postulated to arise within this mucosa-associated lymphoid tissue (MALT) and is often called low-grade MALT lymphoma (3, 4). The incidence of gastric low- and high-grade MALT lymphoma is increased in populations with a high prevalence of H. pylori infection, and H. pylori infection has been reported in up to 90% of patients with low-grade MALT lymphoma (4-6). In addition, investigators have shown that growth of this tumor may depend on antigenic stimulation by H. pylori: They demonstrated that the proliferation of lymphoma B cells in cell culture can be stimulated by H. pylori-specific T cells and related cytokines in the presence of H. pylori (7). On the basis of these findings, trials of antibiotic treatment of gastric low-grade MALT lymphoma have been initiated, and the regression of lymphoma after cure of H. pylori infection has been reported in a high proportion of patients with low tumor burden (8-13). Data on patients with significant tumor infiltration are still forthcoming (13, 14). Because MALT lymphoma has only recently been approached as a distinct clinicopathologic entity (15, 16), its natural history and clinical course are not fully defined. Current data suggest that it is often an indolent tumor with long periods of mild activity and confinement to the stomach. Patients often present with nonspecific upper intestinal discomfort, ulcer-associated symptoms, or gastric bleeding. The endoscopic appearance may suggest benign gastritis, and extensive biopsies may be required for diagnosis. Progression to significant tumor mass, dissemination, or transformation to high-grade, aggressive lymphoma occur in an undefined subset of patients, who may present with early satiety or weight loss. Spontaneous remissions are rare (17-20). Because low-grade MALT lymphoma is an uncommon, often indolent form of cancer with few clinical findings and because the risk for progression to high-grade MALT lymphoma is still unknown (15, 16), definitive data on cure require long-term follow-up of large cohorts from standardized clinical trials. This report presents an interim analysis of an ongoing trial designed to determine the long-term response of low-grade gastric MALT lymphoma to antibiotic treatment and to define criteria for treatment and follow-up. Methods Patients Patients with gastric MALT lymphoma restricted to the stomach and perigastric lymph nodes (modified Ann Arbor stage I and II N1) were eligible for the study. The University of Texas, M.D. Anderson Cancer Center (MDACC), Internal Review Board approved the study, and all patients provided written informed consent. The National Cancer Institute and the institutional review boards of participating institutions approved the multi-institutional protocol. To enable a follow-up period of at least 18 months, only patients treated before May 1997 were included in this analysis. Study Design and Treatment The interim data are derived from an ongoing, prospective, uncontrolled treatment trial with third-party patient registry. Patients were studied at four participating centers. Pathologic diagnosis and resolution of MALT lymphoma were confirmed at MDACC, and all but one patient were examined endoscopically at MDACC. Study design included 1) tumor staging with bilateral bone marrow biopsies and aspirates and computed tomography of the abdomen and pelvis done at baseline and yearly; 2) endoscopy at baseline, at weeks 6 to 8, at 3- to 4-month intervals thereafter until resolution of MALT lymphoma was seen on two consecutive endoscopies, at 6-month intervals thereafter for 2 years, and then yearly thereafter; and 3) endoscopic ultrasonography at baseline and at each endoscopy until resolution of masses or infiltration of the muscularis propria, if present (defined as thickness>2 mm or obliteration of wall architecture), and then at 6- to 12-month intervals. The treatment protocol consisted of two of the following three oral antibiotic regimens1] amoxicillin, 750 mg three times daily, and clarithromycin, 500 mg three times daily; 2) tetracycline, 500 mg four times daily, and clarithromycin, 500 mg three times daily; or 3) tetracycline, 500 mg four times daily, and metronidazole, 500 mg three times dailyadministered sequentially for 21 days at baseline and at 8 weeks along with a proton-pump inhibitor (lansoprazole, 30 mg twice daily [n=29], or omeprazole, 20 mg twice daily [n=5]), and bismuth subsalicylate, two tablets four times daily. Patients who were allergic to penicillin received the tetracycline-based regimens. Tumor Staging Tumors were staged endoscopically to separate superficial gastritis from significant ulcers and infiltration and from mass lesions. A modified Ann Arbor staging system that incorporated changes proposed by Blackledge, Musshoff, and Rohatiner and their coworkers was used initially (21-23). The TNM (tumor, node, metastasis) classification of the American Joint Committee on Cancer and Union Internationale Contre le Cancer (24, 25), which corresponds to the modified Ann Arbor staging, was subsequently adapted and applied (Table 1). The extent of tumor (T) infiltration through the stomach wall and to adjacent organs corresponds to T staging of gastric cancer. Modified Ann Arbor stage I corresponds to stage I T1-4 N0 M0. Modified Ann Arbor stage II1 (22) (involvement of perigastric lymph nodes) corresponds to stage II T1-4 N1 M0. Modified Ann Arbor stage II2 (22) (involvement of distant lymph nodes caudal to the diaphragm, including para-aortic and retroperitoneal lymph nodes) corresponds to stage II T1-4 N2 M0. Ann Arbor stage III (lymph node involvement on both sides of the diaphragm) is designated by stage III T1-4 N3 M0. Ann Arbor stage IV (organ metastasis or involvement of a second extranodal site) is designated by stage IV T1-4 N0-3 M1. Table 1. Staging of Gastric Lymphoma of Mucosa-Associated Lymphoid Tissue Criteria for Response Response to treatment was evaluated at 3- to 4-month intervals beginning with the fifth month after treatment. Treatment was considered to have failed if patients did not meet criteria for improvement; these patients were removed from the study. In stage I T2, I T3, and II N1 tumors, improvement was defined as regression to a lower stage, 30% reduction in abnormal wall thickness, or 30% reduction in the size of the tumor mass (product of the greatest diameters). These patients remained in the study if sequential improvement was evident at each 3-month interval. Patients with persistent mucosal disease (stage I T1) documented by histopathology were formally reviewed at 12-month intervals; a consensus on withdrawal from or continuation in the study was based on clinical considerations, current knowledge, and patient preference. Initially, patients with persistent stage I T1 disease were withdrawn from the study at 12 months (n=2). Subsequently, patients with persistent stage I T1 disease were observed for more than 36 months if improvement was documented at 12-month intervals. Criteria for improvement in stage I T1 disease included reduction in the number of affected gastric sites or affected biopsy specimens or improved histologic score (8), endoscopic appearance of progressive atrophy and scarring, or resolution of abnormal wall thickness on endoscopic ultrasonography. Complete remission was defined as the absence of histopathologic evidence of lymphoma and an endoscopic appearance of gastritis or better. Partial remission was defined as a reduction in endoscopic stage in stage I T2 disease or at least 50% reduction in the size of the mass lesions in stage I T3 or II T3 N1 disease. In stage I T1 disease, partial remission was defined as at least 75% reduction in the number of gastric sites or biopsy specimens showing lymphoma. Treatment was considered to have failed in patients who met criteria for failure or who were withdrawn from the study before complete remission occurred. Endoscopy and Biopsies The gastric mapping protocol included 2 or more maximum-capacity biopsies from each of 7 to 12 areas of the gastric map (26) and at least 6 biopsies from 2 or more of the most abnormal areas. The more extensive mapping was done at baseline and at clinically relevant time points. Studies, done at defined intervals, included routine histopathology, H. pylori testing by Genta stain, rapid urease test (CLO-test, Delta West, Bentley, Australia) or serology, Southern blot or polymerase chain reaction (PCR) for immunoglobulin gene rearrangement analysis, and immunoglobulin light-chain immunocytochemistry. Diagnostic Criteria Low-grade B-cell MALT lymphoma was diagnosed by established histologic criteria [15, 27], including 1) a dense diffuse infiltrate of marginal-zone centrocyte-like B cells with round to slightly irregular nuclear contours, often with abundant pale cytoplasm; 2) presence of lymphoepithelial lesions, characterized by infiltration and disruption of gastric glands or crypts by groups of neoplastic lymphoid cells; and 3) absence of any areas where large cells predominate. Minor criteria supporting but not essential for diagnosis included presence of immunoglobulin light-chain restriction; presence of residual secondary follicle centers with or without intact mantles; and presence of follicular colonization, defined as replacement of follicle centers by neoplastic lymphoid cells. Immunophenotypic expression of pan-B-cell antigens, such as CD20, and lack of expression of CD5 or CD10 supported the diagnosis. Patients with foci of large-cell transformation were excluded from the study. Southern Blot and Polymerase Chain Reaction High-molec

Mantle cell lymphoma cells express high levels of CXCR4, CXCR5, and VLA-4 (CD49d): importance for interactions with the stromal microenvironment and specific targeting.

Mantle cell lymphoma (MCL) is characterized by an early, widespread dissemination and residual disease after conventional treatment, but the mechanisms responsible for lymphoma cell motility and drug resistance are largely unknown. There is growing evidence suggesting that chemokine receptors and adhesion molecules are critical for malignant B-cell trafficking and homing to supportive tissue microenvironments, where they receive survival and drug resistance signals. Therefore, we examined chemokine receptor and adhesion molecule expression and function in MCL cells and their importance for migration and adhesion to marrow stromal cells (MSCs). We found that MCL cells display high levels of functional CXCR4 and CXCR5 chemokine receptors and VLA-4 adhesion molecules. We also report that MCL cells adhere and spontaneously migrate beneath MSCs in a CXCR4- and VLA-4-dependent fashion (pseudoemperipolesis). Moreover, we demonstrate that MSCs confer drug resistance to MCL cells, particularly to MCL cells that migrate beneath MSC. To target MCL-MSC interactions, we tested Plerixafor, a CXCR4 antagonist, and natalizumab, a VLA-4 antibody. Both agents blocked functional responses to the respective ligands and inhibited adhesive interactions between MCL cells and MSCs. These findings provide a rationale to further investigate the therapeutic potential of these drugs in MCL.

A CD40 Signalosome anchored in lipid rafts leads to constitutive activation of NF-κB and autonomous cell growth in B cell lymphomas

B cell lineage non-Hodgkins lymphomas (NHL-B) are neoplastic B cells that show dysregulated B lymphocyte growth characteristics. Unlike normal B cells, aggressive NHL-B cells show constitutive expression of nuclear NF-kappaB by maintaining an assembled, scaffold-like signaling platform, called a Signalosome within the lipid raft microdomain, extending from the cell membrane. The CD40 Signalosome appears to be initiated through autochthonous production and cognate binding of CD154 (CD40L, gp39) to CD40 by the lymphoma cell. Constitutive expression of NF-kappaB in NHL-B can be downregulated by treatment with antibodies to CD40 or CD154 that disrupt Signalosomes, inhibit lymphoma cell growth, and induce cell death. CD40 Signalosomes may provide a potentially vulnerable target for therapeutic intervention in NHL-B cells.

Lenalidomide treatment promotes CD154 expression on CLL cells and enhances production of antibodies by normal B cells through a PI3-kinase–dependent pathway

Chronic lymphocytic leukemia (CLL) involves a profound humoral immune defect and tumor-specific humoral tolerance that directly contribute to disease morbidity and mortality. CD154 gene therapy can reverse this immune defect, but attempts to do this pharmacologically have been unsuccessful. The immune-modulatory agent lenalidomide shows clinical activity in CLL, but its mechanism is poorly understood. Here, we demonstrate that lenalidomide induces expression of functional CD154 antigen on CLL cells both in vitro and in vivo. This occurs via enhanced CD154 transcription mediated by a Nuclear Factor of Activated T cells c1 (NFATc1)/Nuclear Factor-kappaB (NF-kappaB) complex and also through phosphoinositide-3 (PI3)-kinase pathway-dependent stabilization of CD154 mRNA. Importantly, CD154-positive CLL cells up-regulate BID, DR5, and p73, become sensitized to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis, and promote costimulatory activation of normal B cells to produce antibodies. In CLL patients receiving lenalidomide, similar evidence of CD154 activation is observed including BID, DR5, and p73 induction and also development of anti-ROR1 tumor-directed antibodies. Our data demonstrate that lenalidomide promotes CD154 expression on CLL cells with subsequent activation phenotype, and may therefore reverse the humoral immune defect observed in this disease. This study is registered at http://clinicaltrials.gov as NCT00466895.

Differential expression of BCL-2 family proteins in ALK-positive and ALK-negative anaplastic large cell lymphoma of T/null-cell lineage

Anaplastic large-cell lymphoma (ALCL) of T- or null-cell lineage, as defined in the revised European-American lymphoma classification, includes a subset of tumors that carry the t(2;5)(p23;q35) resulting in overexpression of anaplastic lymphoma kinase (ALK). Patients with ALK+ ALCL are reported to have a better prognosis than patients with ALK- ALCL. Because the mechanisms for this survival difference are unknown, we investigated the hypothesis that apoptotic pathways may be involved. We therefore assessed expression levels of the anti-apoptotic proteins BCL-2 and BCL-XL and the pro-apoptotic proteins BAX and BCL-XS in T/null-cell ALCL using immunohistochemical methods and correlated the findings with ALK expression and apoptotic rate (AR), the latter assessed by a modified Tdt-mediated dUTP nick-end labeling assay. ALK was detected in 21 of 66 (31.8%) ALCLs. BCL-2 was not detected in 21 ALK+ ALCLs but was present in 26 of 45 (57.8%) ALK- ALCLs (P < 0.0001). ALK+ and ALK- ALCLs also showed significant differences in expression of BCL-XL, BAX, and BCL-XS. ALK+ tumors less commonly had a high level of BCL-XL (1 of 17 versus 14 of 35, P = 0.01), and more commonly had high levels of BAX (13 of 18 versus 15 of 36, P = 0.05), and BCL-XS (11 of 16 versus 12 of 31, P = 0.05) compared with ALK- tumors. ALK+ tumors also had a higher mean AR than ALK- tumors (3.4% versus 1.1%, P = 0.0002). Differential expression of BCL-2 family proteins may be responsible for the higher AR observed in ALK+ ALCL and provides a possible biological explanation for the better prognosis reported for patients with ALK+ ALCL.

The use of primers from highly conserved pol regions to identify uncharacterized retroviruses by the polymerase chain reaction

Two degenerate oligonucleotide primers derived from regions of pol conserved among retroviruses have been synthesized. Polymerase chain reactions utilizing these primers amplify a 135-bp pol fragment in every retrovirus DNA tested to date. The polymerase chain reaction has been linked to a reverse transcriptase step so that a pol-specific DNA fragment can be obtained from a moderate amount of a purified retrovirus or viral RNA. The identity of an unknown retrovirus can be determined by sequencing of the amplified fragment following molecular cloning. This procedure was tested on an unidentified (non-HIV) retrovirus expressed by a B-cell lymphoma line obtained from an AIDS patient. Our PCR assay identified the retrovirus as being highly similar to Mason-Pfizer monkey virus (MPMV) and simian retrovirus 1, which are closely related immunosuppressive type D viruses that cause simian AIDS.

BAFF-R promotes cell proliferation and survival through interaction with IKKβ and NF-κB/c-Rel in the nucleus of normal and neoplastic B-lymphoid cells

BLyS and its major receptor BAFF-R have been shown to be critical for development and homeostasis of normal B lymphocytes, and for cell growth and survival of neoplastic B lymphocytes, but the biologic mechanisms of this ligand/receptor-derived intracellular signaling pathway(s) have not been completely defined. We have discovered that the BAFF-R protein was present in the cell nucleus, in addition to its integral presence in the plasma membrane and cytoplasm, in both normal and neoplastic B cells. BAFF-R interacted with histone H3 and IKKbeta in the cell nucleus, enhancing histone H3 phosphorylation through IKKbeta. Nuclear BAFF-R was also associated with NF-kappaB/c-Rel and bound to NF-kappaB targeted promoters including BLyS, CD154, Bcl-xL, IL-8, and Bfl-1/A1, promoting the transcription of these genes. These observations suggested that in addition to activating NF-kappaB pathways in the plasma membrane, BAFF-R also promotes normal B-cell and B-cell non-Hodgkin lymphoma (NHL-B) survival and proliferation by functioning as a transcriptional regulator through a chromatin remodeling mechanism(s) and NF-kappaB association. Our studies provide an expanded conceptual view of the BAFF-R signaling, which should contribute a better understanding of the physiologic mechanisms involved in normal B-cell survival and growth, as well as in the pathophysiology of aggressive B-cell malignancies and autoimmune diseases.

JunB expression is a common feature of CD30+ lymphomas and lymphomatoid papulosis

JunB is a member of the Jun family of proteins that are components of the AP-1 transcription factor complex. AP-1 is involved in cell proliferation and apoptosis. Recent evidence suggests that Hodgkin and Reed–Sternberg cells overexpress JunB and that JunB facilitates constitutive CD30 expression by binding to an AP-1 site in the CD30 promoter. In this study we surveyed JunB expression in a variety of CD30+ lymphoma types including 42 cases of anaplastic large cell lymphoma, 36 classical Hodgkin lymphoma, 15 cutaneous anaplastic large cell lymphoma, and 11 CD30+ diffuse large B-cell lymphoma. In addition, seven cases of nodular lymphocyte-predominant Hodgkin lymphoma and 42 diffuse large B-cell lymphoma, known to be CD30−, were analyzed. JunB expression was assessed using tissue microarrays, immunohistochemistry and a monoclonal antibody specific for JunB. Expression of JunB was observed in 41 of 42 cases of anaplastic large cell lymphoma, including all 21 cases positive for anaplastic lymphoma kinase and 20 of 21 (95%) negative for anaplastic lymphoma kinase. JunB was also expressed in all cases of classical Hodgkin lymphoma, cutaneous anaplastic large cell lymphoma and CD30+ diffuse large B-cell lymphoma, and in lymphomatoid papulosis. By contrast, all nodular lymphocyte-predominant Hodgkin lymphomas and diffuse large B-cell lymphomas that were CD30− were also JunB−. We conclude that JunB is expressed in virtually all CD30+ lymphomas and is a potential target for experimental therapy in patients with these tumors.

Development of Autoimmunity in IL-14α-Transgenic Mice

Multiple genetic loci contribute to the development of systemic lupus erythematosus (SLE). In murine models for SLE, various genes on chromosome four have been implicated. IL-14 is a cytokine originally identified as a B cell growth factor. The il14 gene is located on chromosome 4. IL-14α is a cytokine encoded by the plus strand of the IL-14 gene using exons 3–10. The expression of IL-14α is increased in (NZB × NZW)F1 mice. In this study, we produced IL-14α-transgenic mice to study the role of IL-14α in the development of autoimmunity. At age 3–9 mo, IL-14α-transgenic mice demonstrate increased numbers of B1 cells in the peritoneum, increased serum IgM, IgG, and IgG 2a and show enhanced responses to T-dependent and T-independent Ags compared with littermate controls. At age 9–17 mo, IL-14α-transgenic mice develop autoantibodies, sialadenitis, as in Sjögren’s syndrome, and immune complex-mediated nephritis, as in World Health Organization class II SLE nephritis. Between the ages 14–18 mo, 95% of IL-14α-transgenic mice developed CD5+ B cell lymphomas, consistent with the lymphomas seen in elderly patients with Sjögren’s syndrome and SLE. These data support a role for IL-14α in the development of both autoimmunity and lymphomagenesis. These studies may provide a genetic link between these often related disorders.

Nuclear Localization in the Biology of the CD40 Receptor in Normal and Neoplastic Human B Lymphocytes

CD40 is a tumor necrosis factor (TNF) receptor superfamily, (TNFR; TNFRSF-5) member, that initiates important signaling pathways mediating cell growth, survival, and differentiation in B-lymphocytes. Although CD40 has been extensively studied as a plasma membrane-associated growth factor receptor, we demonstrate here that CD40 is present not only in the plasma membrane and cytoplasm but also in the nucleus of normal and neoplastic B-lymphoid cells. Confocal microscopy showed that transfected CD40-green fluorescent fusion protein entered B-cell nuclei. The CD40 protein contains a nuclear localization signal sequence that, when mutated, blocks entry of CD40 into the nucleus through the classic karyopherins (importins-α/β) pathway. Nuclear fractionation studies revealed the presence of CD40 protein in the nucleoplasm fraction of activated B cells, and chromatin immunoprecipitation assays demonstrated that CD40 binds to and stimulates the BLyS/BAFF promoter, another TNF family member (TNFSF-13B) involved in cell survival in the B cell lineage. Like other nuclear growth factor receptors, CD40 appears to be a transcriptional regulator and is likely to play a larger and more complex role than previously demonstrated in regulating essential growth and survival pathways in B-lymphocytes.