Splenic large B-cell lymphoma in patients with hepatitis C virus infection

Splenic Lymphomas: A Tertiary Care Center Experience and Review of Literature

Primary splenic lymphomas are rare with the majority of lymphomas in spleen being secondary to an extra-splenic lymphoma. We aimed to analyze the epidemiological profile of the splenic lymphoma and review the literature. This was a retrospective study including all splenectomies and splenic biopsies from 2015 to September 2021. All the cases were retrieved from Department of Pathology. Detailed histopathological, clinical and demographic evaluation was done. All the lymphomas were classified according to WHO 2016 classification. A total of 714 splenectomies were performed for a variety of benign causes, as part of tumor resections and for the diagnosis of lymphoma. Few core biopsies were also included. A total of 33 lymphomas diagnosed in the spleen, primary splenic lymphomas constituted 84.84% (n = 28) of the cohort with 5 (15.15%) having the primary site elsewhere. The primary splenic lymphomas constituted 0.28% of all the lymphomas arising at various sites. Adult population (19-65 years) formed the bulk (78.78%) with a slight male preponderance. Splenic marginal zone lymphomas (n = 15, 45.45%) comprised of major proportion of cases followed by primary splenic diffuse large B-cell lymphoma (n = 4, 12.12%). Splenectomy was the main course of treatment for SMZL with a good overall outcome, with chemotherapy ± radiotherapy forming the mainstay in other lymphomas. Lymphomas in spleen can be infiltrative or a primary, hence proper clinic-radiological and pathological evaluation is required. Appropriate management is guided by the precise and detailed evaluation by the pathologist, requiring understanding of the same.

Rare Causes of Isolated and Progressive Splenic Lesions: Challenges in Differential Diagnosis, Evaluation, and Treatment of Primary Splenic Lymphomas

The spleen is among the most common extranodal sites for Hodgkin and non-Hodgkin lymphomas (NHLs); however, among lymphomas arising from the spleen, primary splenic lymphomas (PSLs) are rare. The group of PSLs includes primary splenic diffuse large B-cell lymphoma (PS-DLBCL), splenic red pulp small B-cell lymphoma, splenic marginal zone lymphoma (SMZL), and a splenic hairy cell leukemia variant. Delineating between the PSL variants can be challenging, especially as fine-needle aspirate and core needle biopsy of the spleen are not routinely offered at most medical centers. Herein, we describe the clinical course of 2 representative patients who presented with non-specific gastrointestinal symptoms, the first who was diagnosed with PS-DLBCL and the second who was diagnosed with SMZL. We review and contrast the clinical presentations, imaging techniques, and laboratory findings of these discrete lymphoma variants and offer strategies on how to delineate between these varied splenic processes. We also examine the use of splenectomy and splenic needle biopsy as diagnostics and, in the case of splenectomy, a therapeutic tool. Finally, we also briefly review treatment options for these varied lymphoma sub-types while acknowledging that randomized trials to guide best practices for PSLs are lacking.

Clinicopathologic characteristics of follicular lymphoma in hepatitis C virus-infected patients

Follicular lymphoma (FL) is the most common subtype of indolent non-Hodgkin lymphoma. It has been hypothesized that chronic hepatitis C virus (HCV) infection stimulates IGH-BCL2 clone proliferation, leading to development of FL. Furthermore, regression of FL after antiviral treatment without chemotherapy has been reported in HCV-infected patients. To clarify the relationship between HCV and FL, we compared the prevalence of IGH-BCL2 translocation and other clinicopathologic characteristics between HCV-infected and HCV-uninfected FL patients and determined the impact of HCV eradication on the oncologic outcomes of HCV-infected FL patients. The study included HCV-infected patients (cases) with FL seen at our institution during 2004-2018. Cases were matched with HCV-uninfected FL patients (controls) according to year of lymphoma diagnosis, sex, and hepatitis B serology. We studied 19 cases and 57 controls. More cases than controls had splenic involvement of FL (26% vs 5%, P = 0.02), higher histologic grade (grade 3 in 56% vs 24%, P = 0.01), absent or weak CD10 expression (42% vs 11%, P = 0.005), and absent BCL2 expression (33% vs 4%, P = 0.004). Compared to controls, cases had a lower rate of detection of IGH-BCL2 translocation (31% vs 68%, P = 0.02). Finally, cases with a sustained virologic response (virologic cure of HCV) had a better 10-year overall survival rate than did cases not treated with antivirals or controls (P = 0.001). In conclusion, HCV-infected patients with FL have unique clinicopathologic characteristics including improved overall survival with HCV eradication. The pathogenesis of FL in HCV-infected patients seems unrelated to antiapoptotic effect of IGH-BCL2 rearrangement.

Clinicopathological features of HCV-positive splenic diffuse large B cell lymphoma

The hepatitis C virus (HCV) is a single-stranded RNA virus which is thought to be involved in the onset of B cell lymphoma. HCV-positive diffuse large B cell lymphoma (DLBCL) has been reported to clinically manifest in extranodal lesions (e.g., in the liver, spleen, and stomach). Here, we investigated HCV-positive and -negative primary splenic DLBCL (p-spDLBCL) and non-primary splenic DLBCL (ordinary DLBCL). Furthermore, to examine HCV lymphomagenesis, RNA in situ hybridization (ISH), RT-PCR (reverse-transcription polymerase chain reaction), and NS3 immunostaining of HCV viral nonstructural proteins were performed. HCV-positive p-spDLBCL patients presented fewer B symptoms (asymptomatic) and better performance status, with elevated presence of splenic macronodular lesions and more germinal center B cell (GCB) sub-group cases than HCV-negative p-spDLBCL patients. However, HCV-positive ordinary DLBCL patients were found to have more non-GCB sub-group cases than HCV-negative ordinary DLBCL patients. HCV-positive DLBCL patients showed 20.6% (7/34) NS3 positivity, 16.7% (1/6) HCV-RNA in situ positivity, and 22.2% (2/9) detection of HCV-RNA in tumor tissue by RT-PCR. Splenic samples were found to have a higher frequency of HCV detection than lymph node samples, thus suggesting that HCV may be closely related to lymphomagenesis, especially in splenic lymphoma.

Extrahepatic cancers and chronic HCV infection

Infectious agents, such as HCV, account for ∼15% of human cancers. HCV infects not only hepatocytes but also extrahepatic cells. Chronic HCV infection can induce chronic inflammation with qualitative and quantitative alterations of the immune repertoire and tissue microenvironment, which could induce various neoplasias. Epidemiological studies and meta-analyses suggest an increased rate of extrahepatic cancers in patients with chronic HCV infection along with a higher risk of intrahepatic cholangiocarcinoma, pancreatic cancer and non-Hodgkin lymphoma (NHL), highlighting the need to screen for HCV infection in patients with these cancers. Development of B cell NHL has been associated with HCV infection, with a relative risk of ∼1.5. Direct transformation related to the presence of the virus and chronic antigenic stimulation are the two major non-exclusive mechanisms involved in HCV-related lymphomagenesis. HCV infection alters survival of patients with lymphoma, and sustained virologic response (SVR) substantially improves prognosis. Antiviral treatments might induce remission of indolent lymphoma when SVR is achieved even without chemotherapy, emphasizing the role of HCV in lymphomagenesis in this context. However, studies are needed to provide prospective evidence of a causal relationship between chronic HCV infection and other extrahepatic cancers and to determine whether the risk of extrahepatic cancers is reduced with SVR. In this Review, we report on recent studies analysing the risk of extrahepatic cancers associated with chronic HCV infection. Although there is no doubt regarding the direct and indirect causality between HCV and NHL, an increased risk of other cancers is less clear, with the exception of cholangiocarcinoma.

Clinicopathological features of primary splenic follicular lymphoma

Follicular lymphoma (FL) is a low-grade lymphoma that is usually characterized by generalized lymphadenopathy. Extranodal invasion by FL generally involves the bone marrow, skin, and duodenum; splenic infiltration often occurs in the advanced stages. However, primary splenic FL is very rare. Hence, few studies have been performed on splenic FL, and its clinicopathological features have not been established. This study aimed to investigate the clinicopathological features of primary splenic FL, as compared to nodal FL. We analyzed 17 patients diagnosed with primary splenic FL and 153 control patients with systemic FL. Hepatitis C virus (HCV)-positive status was significantly more common in patients with splenic FL than in the control patients (p = 0.02). Ann Arbor stage III or IV (p = 0.0003) and high-risk FLIPI (Follicular Lymphoma International Prognostic Index) (p = 0.03) were significantly less common in patients with splenic FL than in the control patients; however, the overall and progression-free survival curves were not significantly different between the groups. Among the 17 patients with splenic FL, the progression-free survival was significantly worse in patients who underwent splenectomy without receiving postoperative chemotherapy than in those who did (p = 0.03). These results suggest that primary splenic FL should be considered different from systemic FL; accordingly, its management should also be conducted differently.

In Situ Hepatitis C NS3 Protein Detection Is Associated with High Grade Features in Hepatitis C-Associated B-Cell Non-Hodgkin Lymphomas

Hepatitis C Virus (HCV) infection is associated with the B-cell non-Hodgkin lymphomas (NHL), preferentially marginal zone lymphomas (MZL) and diffuse large B-cell lymphomas (DLBCL). While chronic antigenic stimulation is a main determinant of lymphomagenesis in marginal zone lymphomas (MZL), a putative role of HCV infection of B-cells is supported by in vitro studies. We performed a pathological study within the "ANRS HC-13 LymphoC" observational study focusing on in situ expression of the oncogenic HCV non structural 3 (NS3) protein. Lympho-C study enrolled 116 HCV-positive patients with B-NHL of which 86 histological samples were collected for centralized review. Main histological subtypes were DLBCL (36%) and MZL (34%). Almost half of DLBCL (12/26) were transformed from underlying small B-cell lymphomas. NS3 immunostaining was found positive in 17 of 37 tested samples (46%). There was a striking association between NS3 detection and presence of high grade lymphoma features: 12 out of 14 DLBCL were NS3+ compared to only 4 out of 14 MZL (p = 0.006). Moreover, 2 among the 4 NS3+ MZL were enriched in large cells. Remarkably, this study supports a new mechanism of transformation with a direct oncogenic role of HCV proteins in the occurrence of high-grade B lymphomas.

Bcl6 Sets a Threshold for Antiviral Signaling by Restraining IRF7 Transcriptional Program

The coordination of restraining and priming of antiviral signaling constitute a fundamental aspect of immunological functions. However, we currently know little about the molecular events that can translate the pathogenic cues into the appropriate code for antiviral defense. Our present study reports a specific role of B cell lymphoma (Bcl)6 as a checkpoint in the initiation of the host response to cytosolic RNA viruses. Remarkably, Bcl6 specifically binds to the interferon-regulatory factor (IRF)7 loci and restrains its transcription, thereby functioning as a negative regulator for interferon (IFN)-β production and antiviral responses. The signal-controlled turnover of the Bcl6, most likely mediated by microRNA-127, coordinates the antiviral response and inflammatory sequelae. Accordingly, de-repression of Bcl6 resulted in a phenotypic conversion of macrophages into highly potent IFN-producing cells and rendered mice more resistant to pathogenic RNA virus infection. The failure to remove the Bcl6 regulator, however, impedes the antiviral signaling and exaggerates viral pneumonia in mice. We thus reveal a novel key molecular checkpoint to orchestrate antiviral innate immunity.

Characteristics of primary splenic diffuse large B-cell lymphoma and role of splenectomy in improving survival

BACKGROUND

Primary splenic diffuse large B-cell lymphoma (PS-DLBCL), an uncommon type of non-Hodgkin lymphoma, has been investigated only in small patient series before the rituximab era. The therapeutic role of splenectomy in addition to immunochemotherapy is unknown.

METHODS

The databases of 7 medical centers in Israel were searched for patients diagnosed with PS-DLBCL in 1982-2013, and clinical, treatment, and outcome data were collected for 87 patients. The mean patient age was 59.6 years; 57.5% were male.

RESULTS

Patients presented with abdominal pain (81%), B symptoms (59%), splenomegaly (84%), splenic masses (97%), and high lactate dehydrogenase (LDH) levels (84%); 61% had stage I or II disease. The diagnosis was made with core-needle biopsy in 46 patients and with diagnostic splenectomy in 39 patients. Eighty patients (92%) were treated with cyclophosphamide, doxorubicin, vincristine, and prednisone; 68 (78%) received rituximab. A complete response was achieved in 67 patients (77%), and a partial response was achieved in 8 (9%). At 5 years, the overall survival (OS) rate was 77%, and the progression-free survival (PFS) rate was 67%. When patients were stratified by splenectomy at diagnosis, the OS rates were 91% for splenectomized patients and 68% for nonsplenectomized patients (P = .08), and the PFS rates were 85% and 55%, respectively (P = .02). The respective values for the subgroup with early-stage disease were 96% and 63% for OS (P = .009) and 90% and 51% for PFS (P = .01). In a multivariate analysis, a low Eastern Cooperative Oncology Group performance status and splenectomy independently predicted better PFS (P < .03).

CONCLUSIONS

Patients with PS-DLBCL usually present with abdominal pain, high LDH levels, and a splenic mass. This study shows for the first time that splenectomy at diagnosis improves survival, specifically in patients with early-stage disease.

Hepatitis C virus and diffuse large B-cell lymphoma: Pathogenesis, behavior and treatment

A significant association between hepatitis C virus (HCV) infection and B-cell lymphoma has been reported by epidemiological studies, most of them describing a strong relationship between indolent lymphomas and HCV. Furthermore, the curative potential of antiviral therapy on HCV related indolent lymphomas supports a specific role for the virus in lymphomagenesis. These observations are reinforced by numerous laboratory experiments that led to several hypothetical models of B-cell transformation by HCV. Diffuse large B-cell lymphoma (DLBCL), the most common lymphoma subtype in the western countries, has been associated to HCV infection despite its aggressive nature. This association seems particularly prominent in some geographical areas. Clinical presentation of HCV-associated DLBCL has consistently been reported to differ from the HCV-negative counterpart. Nevertheless, histopathology, tolerance to standard-of-care chemo-immunotherapy (R-CHOP or CHOP-like regimens) and final outcome of HCV-positive DLBCL patients is still matter of debate. Addition of rituximab has been described to enhance viral replication but the probability of severe hepatic complications remains low, with some exceptions (i.e., hepatitis B virus or immune immunodeficiency virus co-infected patients, presence of grade > 2 transaminases elevation, cirrhosis or hepatocarcinoma). HCV viral load in this setting is not necessarily directly associated with liver damage. Overall, treatment of HCV associated DLBCL should be performed in an interdisciplinary approach with hepatologists and hematologists with close monitoring of liver function. Available reports reveal that the final outcome of HCV-positive DLBCL that receive standard immunochemotherapy is not inferior to their HCV-negative counterpart. This review summarizes data on epidemiology, pathogenesis and therapeutic approach on HCV-associated DLBCL. Several issues that are matter of debate like clinical management of patients with transaminase elevation, criteria for discontinuing or starting immuno-chemotherapy, as well as the exact role of monoclonal antibodies will be analyzed.

Unusual Course of Splenic Marginal Zone Lymphoma

A 53-year-old woman was diagnosed with splenic marginal zone lymphoma by pathological examination on left submandibular lymph node and bone marrow biopsies and markedly enlarged spleen. Four cycles of Rituximab chemotherapy were given. Seven months after finishing Rituximab chemotherapy, she developed left upper extremity swelling without evidence of deep venous thrombosis. Repeat PET/CT scan demonstrated multiple left axillary lymph nodes extending to left retroclavicular region and a new lymph node posterior to the left scapula. Biopsy of the lymph node demonstrated marginal zone lymhoma pattern with increased numbers of large cells, but not outright diffuse large B-cell lymphoma. Despite resuming rituximab, patient had persistent leukocytosis and severe anemia. Restaging PET/CT showed 3 new left anterior cervical lymph nodes and 1 new right axillary lymph node. Spleen has further enlarged. R-CHOP chemotherapy was started, which improved leukocytosis.After 4 cycles of R-CHOP, PET/CT showed new metabolic activity within right inguinal and abdominal lymph nodes. Patient was given one cycle of Bendamustine. She developed a possible “hematoma” in right medial elbow. However, MRI study revealed a subcutaneous deposit of the lymphoma. Patient needs consistently blood transfusion and she deteriorated quickly. Our patient had an aggressive course of splenic marginal zone lymphoma, not responding to four trials of chemotherapy although SMZL is well-known to be an indolent low grade lymphoma. This case report emphasizes the importance to individualize the treatment in SMZL patients and repeat bone marrow biopsy if the disease recurs.

Early-stage splenic diffuse large B-cell lymphoma is highly associated with hepatitis C virus infection

Splenic marginal zone lymphoma (SMZL) and splenic diffuse large B-cell lymphoma (DLBCL) are the most common types of lymphomas involving the spleen. Geographic variation in hepatitis C virus (HCV) seroprevalence is characteristic of splenic lymphomas. In Italy, HCV seroprevalence was higher in patients with SMZL and splenic DLBCL than in patients with all types of lymphoma. In Japan, HCV seroprevalence was higher in patients with splenic DLBCL than in patients with all types of lymphoma; however, HCV seroprevalence in patients with SMZL was similar to that in patients with all types of lymphoma. In this study, clinicopathological data of 74 splenic lymphoma cases between 1988 and 2011 collected from the Department of Pathology at National Taiwan University Hospital were analyzed. Serology for HCV infection was available for 41 cases. Splenic DLBCL and SMZL accounted for 36% (n = 27) and 42% (n = 31) of splenic lymphomas, respectively. Microscopically, most cases of DLBCL (26/27) presented with circumscribed tumor and most cases of SMZL (28/31) presented with white pulp expansion. HCV seroprevalence in patients with DLBCL and SMZL was 44% and 10%, respectively (7/16 vs. 2/20, p = 0.020). The pattern identified in this study is closer to that in Japan than in Italy. HCV seroprevalence in patients with early-stage (I/II) and late-stage (III/IV) DLBCL was 100% and 10%, respectively (6/6 vs. 1/10, p < 0.001). Early-stage DLBCL is clinically considered a form of primary splenic lymphoma rather than a systemic lymphoma with splenic involvement. High HCV seroprevalence in patients with early-stage DLBCL suggests a role of HCV in the pathogenesis of primary DLBCL.

Etiological factors in primary hepatic B-cell lymphoma

Sixty-four cases of malignant lymphoma involving the liver were examined. Of these, 20 cases were histologically confirmed to be primary hepatic B-cell lymphoma. Twelve of these 20 cases were diffuse large B-cell lymphoma (DLBCL) and eight cases were mucosa-associated lymphoid tissue (MALT) lymphoma. Of the 12 cases of DLBCL, six were immunohistologically positive for CD10 and/or Bcl6 (indicating a germinal center phenotype), six were positive for Bcl2, and five were positive for CD25. Eight of the 12 DLBCL cases (66.7%) and two of the eight MALT lymphoma cases (25%) had serum anti-hepatitis C virus (HCV) antibodies and HCV RNA. The incidence of HCV infection was significantly higher in the hepatic DLBCL cases than in systemic intravascular large B-cell cases with liver involvement (one of 11 cases, 9.1%) and T/NK-cell lymphoma cases (one of 19 cases, 5.3%) (p < 0.01 for both). Two hepatic DLBCL cases (16.7%) had rheumatoid arthritis treated with methotrexate, and four MALT lymphoma cases (50%) had Sjögren’s syndrome, primary biliary cirrhosis, or autoimmune hepatitis; one case in each of these two groups was complicated by chronic HCV-seropositive hepatitis. Although primary hepatic lymphoma is rare, persistent inflammatory processes associated with HCV infection or autoimmune disease may play independent roles in the lymphomagenesis of hepatic B cells.

How I diagnose and treat splenic lymphomas

The incidental finding of an isolated splenomegaly during clinical assessment of patients evaluated for unrelated causes has become increasingly frequent because of the widespread use of imaging. Therefore, the challenging approach to the differential diagnosis of spleen disorders has emerged as a rather common issue of clinical practice. A true diagnostic dilemma hides in distinguishing pathologic conditions primarily involving the spleen from those in which splenomegaly presents as an epiphenomenon of hepatic or systemic diseases. Among the causes of isolated splenomegaly, lymphoid malignancies account for a relevant, yet probably underestimated, number of cases. Splenic lymphomas constitute a wide and heterogeneous array of diseases, whose clinical behavior spans from indolent to highly aggressive. Such a clinical heterogeneity is paralleled by the high degree of biologic variation in the lymphoid populations from which they originate. Nevertheless, the presenting clinical, laboratory, and pathologic features of these diseases often display significant overlaps. In this manuscript, we present our approach to the diagnosis and treatment of these rare lymphomas, whose complexity has been so far determined by the lack of prospectively validated prognostic systems, treatment strategies, and response criteria.

Bone marrow involvement by hodgkin and non-hodgkin lymphomas

Bone marrow evaluation plays a critical role in staging and predicting prognosis in patients with Hodgkin lymphoma or non-Hodgkin lymphoma. Bone marrow can be the initial site of detection of lymphoma in patients with unexplained symptoms or cytopenias. A comprehensive evaluation of bone marrow includes complete blood counts, blood morphology, bone marrow aspirate, and generous core biopsy sections. Specialized testing should be used in a logical fashion on a case by case basis.

B-cell clonality in the liver of hepatitis C virus-infected patients

AIM

The association of hepatitis C virus (HCV) infection with type II mixed cryoglobulinemia is well established, but the role of HCV in B-cell lymphoma remains controversial. In patients with HCV infection, B-cell clonal expansions have been detected in peripheral blood and bone marrow, and a high prevalence of B-cell non-Hodgkin's lymphomas has been documented. Liver biopsies in chronic HCV infection frequently show portal lymphoid infiltrates with features of B follicles, whose clonality has not yet been investigated. The object of this study was to determine the frequency of liver-infiltrating monoclonal B-cells in 40 patients with HCV infection.

METHODS

Eight hundred and forty-eight patients were studied prospectively, including 40 HCV-positive patients and 808 patients with chronic hepatitis B virus (HBV) infection. Immunohistochemical study for B- and T-cell markers was performed on the paraffin-embedded liver tissue sections. The clonality of lymphoid B-cells was tested using a polymerase chain reaction (PCR) approach designed to identify immunoglobulin heavy chain gene (IgH) rearrangements.

RESULTS

Liver-infiltrating monoclonal B-cells were detected in the liver for 4 (10%) of 40 HCV-positive patients but were present in only 3 (0.37%) of 808 liver biopsy specimens with chronic HBV infection. Chi-square testing showed that the monoclonal B-cells infiltration in the liver was more frequent in the HCV-infected patients (P = 0.000). A clonal IgH rearrangement was detected in 5 (71.4%) of 7 liver biopsy specimens with monoclonal B-cells infiltration. In 2 of 5 patients with both a clonal B-cell expansion and monoclonal B-cells infiltration in the liver, a definite B-cell malignancy was finally diagnosed.

CONCLUSION

Liver-infiltrating monoclonal B-cells are detected in the liver of patients with chronic HCV and HBV infection. A high percentage of patients with monoclonal B-cells infiltration and B-cell clonality in the liver were finally diagnosed as having a definite B-cell malignancy.

Laparoscopic Treatment of Simultaneous Splenic Lymphangioma and Non-Hodgkin's Lymphoma: Report of a Case

We report, to the best of our knowledge, the first case of simultaneous splenic lymphangioma and non-Hodgkin's B-cell lymphoma with liver and bone marrow involvement arising in a 69-year-old woman suffering from chronic hepatitis C infection treated with laparoscopic splenectomy followed by polychemotherapy. After 22 months from surgical treatment, the patient is alive without signs of residual disease. According to our experience, laparoscopic splenectomy followed by polychemotherapy seems to be an effective treatment for simultaneous splenic lymphangioma and non-Hodgkin's B-cell lymphoma.

HCV non-structural protein 3 and HCV RNA genome in non-Hodgkin lymphoma and transition of the serum HCV RNA level: a retrospective analysis in one institution

There have been various reports on the association of hepatitis C virus (HCV) infection with B lymphocyte proliferative disorders, such as non-Hodgkin lymphoma (NHL). We experienced a case (Case 1) of anti-HCV antibody (HCV-Ab)-positive NHL in which HCV nonstructural protein 3 (NS3) expression was observed in lymphoma tissue at the time of recurrence and in which the serum HCV RNA level exhibited a transient increase prior to recurrence. We investigated the HCV RNA genome in lymphoma tissue in Case 1, and it could be detected at recurrence. We also investigated HCV NS3 protein expression in lymphoma tissue and changes in serum HCV RNA level during the clinical course in four other cases of HCV-Ab-positive NHL treated in our hospital. We examined lymphoma tissues for HCV NS3 protein expression in four of the five cases, but it was not identified except for in Case 1 at recurrence. In three cases with no recurrence, serum HCV RNA levels showed a tendency to decrease after completion of chemotherapy and became stable thereafter. Further studies are necessary to clarify the association between serum HCV RNA and the onset and exacerbation of NHL.

Lymphoma microenvironment: culprit or innocent?

Studies are revealing that lymphoid neoplasms are characterized by well-defined chromosome translocations and by the accumulation of subsequent molecular alterations involving mainly the cell cycle and/or apoptotic pathways. However, survival of B and T tumor cells is also dependent on the interactions with the accompanying cells that comprise the lymphoma microenvironment. Although non-tumor cells can contribute both positive and negative signals to the lymphoma cells, in this review we present compelling evidence of the essential influence of the tumor microenvironment on the initiation and progression of specific lymphoma types, highlighting some new therapeutic approaches that target the lymphoma microenvironment.

Malignant lymphoma of spleen presenting as acute pancreatitis: A case report

This is a case report of a patient who presented with acute pancreatitis without the common causes. A pancreatic biopsy revealed large B cell lymphoma. Spleen lymphoma with pancreatic involvement inducing acute pancreatitis, which is a rare disorder, was diagnosed. Here we also review the few similar cases reported in the literature.

Altered expression of the tetraspanin CD81 on B and T lymphocytes during HIV-1 infection

CD81 is a member of the tetraspan superfamily and plays a role in immune responses and in hepatitis C virus (HCV) pathogenesis. We analysed CD81 cell surface and mRNA expression in different lymphocytic subpopulations in human immunodeficiency virus (HIV)-1, HCV and dually infected subjects. CD81 cell surface expression was evaluated with fluorescence activated cell sorter (FACS) analysis; mRNA quantification was performed with semiquantitative polymerase chain reaction (PCR). CD81 cell surface expression on CD4(+) T lymphocytes was significantly different by analysis of variance (anova) test (P < 0.001), with reduced expression in HIV-1(+) patients. In B lymphocytes, higher cell surface expression was present in HIV-1, in HCV and in dually infected subjects compared to healthy controls. CD81 expression on B lymphocytes showed a positive correlation with plasma HIV-RNA. CD81 mRNA levels in B lymphocytes were significantly higher in HIV-1(+) patients compared to healthy controls. The potential consequence of the down-regulation of CD81 in CD4(+) cells during HIV-1 infection in conjunction with diverted CD28, CD4 and CD3 expression is the disruption of T cell function. Increased CD81 expression on B lymphocytes might explain the higher prevalence of lymphoproliferative disorders in HIV-1 and HCV infection. Up-regulation of CD81 mRNA on CD4(+) T cells indicates that down-regulation of CD81 occurs at the post-transcriptional/translational level.

The emerging concept of antigen-driven lymphomas: epidemiology and treatment implications

PURPOSE OF REVIEW

Dramatic increases in the incidence of lymphomas worldwide have stimulated considerable efforts to identify factors that contribute to the etiology of this heterogeneous group of malignancies. The treatment and, ultimately, the prevention of lymphoma depend on our understanding of the complex interaction of exogenous agents with the molecular milieu which initiates and sustains a lymphoid malignancy. This review discusses the current evidence for the role of foreign or self antigens in the initiation of lymphomagenesis.

RECENT FINDINGS

Recent data have demonstrated an increased risk of lymphoma among individuals with chronic inflammatory conditions, persistent infections or immunodeficient states. Common to these clinical conditions is antigenic stimulation leading to an inflammatory cascade of cellular and cytokine reactions that may tax the host immune response, provoke tissue injury and eventually result in lymphoid neoplasia.

SUMMARY

Efforts to detect and suppress chronic, antigen-driven inflammation have suggested that neoplastic progression may often be interrupted and controlled. Elucidation of the etiologic mechanisms critical to the survival of these malignancies would provide promising alternatives for the prevention and treatment of some lymphomas.

Analysis of in vitro replicated human hepatitis C virus (HCV) for the determination of genotypes and quasispecies

Isolation and self-replication of infectious HCV has been a difficult task. However, this is needed for the purposes of developing rational drugs and for the analysis of the natural virus. Our recent report of an in vitro system for the isolation of human HCV from infected patients and their replication in tissue culture addresses this challenge. At California Institute of Molecular Medicine several isolates of HCV, called CIMM-HCV, were grown for over three years in cell culture. This is a report of the analysis of CIMM-HCV isolates for subtypes and quasispecies using a 269 bp segment of the 5'UTR. HCV RNA from three patients and eleven CIMM-HCV were analyzed for this purpose. All isolates were essentially identical. Isolates of HCV from one patient were serially transmitted into fresh cells up to eight times and the progeny viruses from each transmission were compared to each other and also to the primary isolates from the patient's serum. Some isolates were also transmitted to different cell types, while others were cultured continuously without retransmission for over three years. We noted minor sequence changes when HCV was cultured for extended periods of time. HCV in T-cells and non-committed lymphoid cells showed a few differences when compared to isolates obtained from immortalized B-cells. These viruses maintained close similarity despite repeated transmissions and passage of time. There were no subtypes or quasispecies noted in CIMM-HCV.

Nodal and splenic marginal zone B cell lymphomas

Splenic marginal zone lymphoma (SMZL) and nodal marginal zone lymphoma (NMZL) are newly defined, separate clinicopathological entities. Both are rare lymphoma types, with low reproducibility in the diagnosis, although a conjunction of molecular and clinical studies seems to be now facilitating a more accurate diagnosis and understanding of the neoplastic process. SMZL is a disease involving the spleen, bone marrow and peripheral blood since the initial manifestations of the disease. The diagnosis has been until very recently based on the pathological study of the spleen with the conjunction of the clinical features, although the integration of the morphology in bone marrow and peripheral blood with the immunophenotype and molecular characteristics of the tumour makes a more accurate diagnosis now possible. The most frequent molecular alteration found in SMZL is allelic loss at the 7q chromosomal region. SMZL is an indolent lymphoma, although there is small subset of patients in which it follows an aggressive course. Molecular studies of SMZL are starting to reveal new diagnostic and prognostic markers, and to identify new potentially useful therapeutic targets. Nodal marginal zone lymphoma is a B-cell neoplasm originated in the lymph node, whose histology resembles the nodal infiltration by MALT- or Splenic-type marginal zone lymphoma, in the absence of clinical evidence of extranodal or spleen disease. The lack of characteristic phenotypic or molecular diagnostic findings is still hampering the reproducibility of this diagnosis. Here we review the main morphological and immunophenotypical markers, discussing the differential with other overlapping entities, singularly follicular lymphoma. Specific therapeutic protocols and prognostic factors are required to more precisely define this tumour.