Response to antiviral treatment in hepatitis C virus-associated marginal zone lymphomas

Indolent B-cell lymphomas associated with HCV infection: clinical and virological features and role of antiviral therapy

The association between hepatitis C virus (HCV) infection and B-cell non-Hodgkin's lymphomas (NHL) has been demonstrated by epidemiological studies, in particular in highly endemic geographical areas such as Italy, Japan, and southern parts of United States. In these countries, together with diffuse large B-cell lymphomas, marginal zone lymphomas are the histotypes most frequently associated with HCV infection; in Italy around 20–30% cases of marginal zone lymphomas are HCV positive. Recently, antiviral treatment with interferon with or without ribavirin has been proved to be effective in the treatment of HCV-positive patients affected by indolent lymphoma, prevalently of marginal zone origin. An increasing number of experiences confirmed the validity of this approach in marginal zone lymphomas and in other indolent NHL subtypes like lymphoplasmacytic lymphoma. Across different studies, overall response rate was approximately 75%. Hematological responses resulted significantly associated with the eradication of the virus. This is the strongest evidence of a causative link between HCV and lymphomas. The aim of this paper is to illustrate the relationship between HCV infection and different subtypes of indolent B-cell lymphomas and to systematically summarize the data from the therapeutic studies that reported the use of antiviral treatment as hematological therapy in patients with HCV-associated indolent lymphomas.

HCV and lymphoproliferation

Hepatitis C virus (HCV) infection is a serious public health problem because of its worldwide diffusion and sequelae. It is not only a hepatotropic but also a lymphotropic agent and is responsible not only for liver injury--potentially evolving to cirrhosis and hepatocellular carcinoma--but also for a series of sometimes severely disabling extrahepatic diseases and, in particular, B-cell lymphoproliferative disorders. These latter range from benign, but prelymphomatous conditions, like mixed cryoglobulinemia, to frank lymphomas. Analogously with Helicobacter pylori related lymphomagenesis, the study of the effects of viral eradication confirmed the etiopathogenetic role of HCV and showed it is an ideal model for better understanding of the molecular mechanisms involved. Concerning these latter, several hypotheses have been proposed over the past two decades which are not mutually exclusive. These hypotheses have variously emphasized the important role played by sustained stimulation of the immune system by HCV, infection of the lymphatic cells, viral proteins, chromosomal aberrations, cytokines, or microRNA molecules. In this paper we describe the main hypotheses that have been proposed with the corresponding principal supporting data.

Hepatitis C and non-Hodgkin lymphoma: the clinical perspective

Hepatitis C virus (HCV) is a commonly transmitted infection that has both hepatic and extrahepatic repercussions. These range from the inflammatory to the oncologic with an undisputed link to hepatitis, liver cirrhosis, and hepatocellular carcinoma. Its role in the development of B cell non-Hodgkin lymphoma (B-NHL) is becoming better understood, leading to opportunities for research, therapy, and even prevention. Research in the field has progressed significantly over the last decade, with the number of patients diagnosed with HCV and B-NHL rising incrementally. It is therefore becoming crucial to fully understand the pathobiologic link of HCV in B cell lymphomagenesis and its optimal management in the oncologic setting.

Hepatitis C virus infection and lymphoma

Apart from its well known role as an etiological agent for non-A and non-B viral hepatitis, there is growing evidence that hepatitis C virus is associated to B-cell non-Hodgkin lymphoma. The association between HCV and lymphoproliferative disorders has been recently postulated based on epidemiological data, biological studies and clinical observations. Although various subtypes of lymphomas appear to be associated to HCV, diffuse large B-cell lymphoma, small lymphocytic lymphoma/chronic lymphocytic leukemia and marginal zone lymphoma appeared to be particularly represented among HCV-positive patients. The causative role of HCV in those disorders has been further supported by the response to antiviral therapy. Despite a better understanding of pathophysiological processes at stake leading from HCV infection to overt lymphoma, many issues still need to be further elucidated. Although HCV has been demonstrated to directly infect peripheral blood mononuclear cells both in vitro and, in some cases, in vivo, a strong body of evidence rather supports the hypothesis of an indirect transformation mechanism by which sustained antigenic stimulation leads from oligoclonal to monoclonal expansion and sometimes to lymphoma, probably through secondary oncogenic events. Here, we review epidemiological and biological studies, as well as clinical data on antiviral therapy, linking HCV-infection to B-cell non-Hodgkin lymphoma.

The role of toll-like receptors in chronic B-cell malignancies

Toll-like receptors (TLR) are key players in host defence from infection. They recognize a specific set of molecular patterns of microbial origin, immediately trigger an innate immune response, and bridge innate and adaptive immunity. TLR have also been shown to play a role in tumor development. In this context, chronic B-cell malignancies are an interesting example as clonal B lymphocytes remain responsive to and dependent on stimuli originating from the microenvironment which then become crucial for maintaining and propagating the disease. Emerging evidences suggest that, among other microenvironmental elements, TLR ligands may play a role in the pathogenesis of chronic B-cell lymphoid malignancies. Conceivably, their manipulation may find a place in specific settings of treatment of these tumors.

Hepatitis C and lymphoproliferative disorders: from mixed cryoglobulinemia to non-Hodgkin's lymphoma

BACKGROUND & AIMS

Hepatitis C virus is associated with both mixed cryoglobulinemia and non-Hodgkin's lymphoma, particularly B-cell non-Hodgkin's Lymphoma. Although there are geographic discrepancies in the incidence and prevalence of hepatitis C virus-related lymphomas, large epidemiologic studies and meta-analyses confirm this relationship in both patients with and without mixed cryoglobulinemia. Other factors such as gene translocation, somatic hypermutation and direct infection may also play a role in the malignant transformation of B-cells.

METHODS

Recent advances in our understanding between the complex relationship between hepatitis C virus and its interactions with cell proteins on B-cell surface membranes has led to proposed mechanisms on how hepatitis C virus leads to chronic antigenic stimulation resulting in lymphoproliferation.

RESULTS

Hepatitis C virus is more weakly associated with T-cell lymphomas, Waldenstrom's macroglobulinemia and other monoclonal gammopathies. Remission of mixed cryoglobulinemia is strongly associated with reduction of hepatitis C virus viral load and recurrence of disease corresponds with viral relapse. Similarly, some studies have shown complete remissions of low grade lymphomas with sustained viral response after antiviral therapy for hepatitis C virus.

CONCLUSIONS

Further studies are needed to more clearly understand the pathogenesis and management of hepatitis C virus-related lymphoproliferative disorders.

Extrahepatic manifestations of hepatitis C virus infection

Hepatitis C virus may cause hepatic and extrahepatic diseases. Extrahepatic manifestations range from disorders for which a significant association with viral infection is supported by epidemiologic and pathogenetic data, to anecdotal observations without clear proof of causality. This article describes the diagnosis and treatment of these diseases.

Treatment of hepatitis C-associated mixed cryoglobulinemia vasculitis

PURPOSE OF REVIEW

Hepatitis C virus infection is the main cause of mixed cryoglobulinemia vasculitis. The disease expression of mixed cryoglobulinemia vasculitis is variable, ranging from mild clinical symptoms (purpura, arthralgia) to fulminant life-threatening complications (glomerulonephritis, widespread vasculitis). Treatment of hepatitis C virus-mixed cryoglobulinemia vasculitis may target either the viral trigger (hepatitis C virus) or the downstream B-cell arm of autoimmunity. This review focuses on recent advances in our understanding of the treatment of hepatitis C virus-mixed cryoglobulinemia vasculitis.

RECENT FINDINGS

Aggressive antiviral therapy with Peg-IFNalpha and ribavirin should be considered as induction therapy for hepatitis C virus-mixed cryoglobulinemia vasculitis with mild to moderate disease severity and activity. In patients presenting with severe disease, an induction phase of immunosuppression is often necessary while awaiting the generally slow response to antiviral treatments. Combination therapy with rituximab and Peg-IFNalpha plus ribavirin appears logical as it may target both the viral trigger (hepatitis C virus) and cryoglobulin-producing B-cells.

SUMMARY

Antiviral therapy and rituximab are the main therapeutic options in hepatitis C virus-mixed cryoglobulinemia vasculitis. Further studies are needed to better define the therapeutic strategy.

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.

Clonal expansion of immunoglobulin M+CD27+ B cells in HCV-associated mixed cryoglobulinemia

Hepatitis C virus (HCV) is associated with B-cell lymphoproliferative disorders such as mixed cryoglobulinemia (MC) and B-cell non-Hodgkin lymphoma (B-NHL). The pathogenesis of these disorders remains unclear, and it has been proposed that HCV drives the pro-liferation of B cells. Here we demonstrate that certain HCV(+)MC(+) subjects have clonal expansions of immunoglobulin M (IgM)(+)kappa(+)IgD(low/-)CD21(low)CD27(+) B cells. Using RT-PCR to amplify Ig from these singly sorted cells, we show that these predominantly rheumatoid factor-encoding V(H)1-69/J(H)4 and V(kappa)3-20 gene segment-restricted cells have low to moderate levels of somatic hypermutations. Ig sequence analysis suggests that antigen selection drives the generation of mutated clones. These findings lend further support to the notion that specific antigenic stimulation leads to B-cell proliferation in HCV MC and that chronic B-cell stimulation may set the stage for malignant transformation and the development of B-NHL. The finding that these hypermutated, marginal zone-like IgM(+)CD27(+) B cells are clonally expanded in certain subjects with MC offers insight into mechanisms of HCV-associated MC and B-cell malignancy. This study was registered at www.clinicaltrials.gov as NCT00219999.

Splenic marginal zone lymphoma proposals for a revision of diagnostic, staging and therapeutic criteria

Since the initial description of splenic marginal zone lymphoma (SMZL) in 1992, an increasing number of publications have dealt with multiple aspects of SMZL diagnosis, molecular pathogenesis and treatment. This process has identified multiple inconsistencies in the diagnostic criteria and lack of clear guidelines for the staging and treatment. The authors of this review have held several meetings and exchanged series of cases with the objective of agreeing on the main diagnostic, staging and therapeutic guidelines for patients with this condition. Specific working groups were created for diagnostic criteria, immunophenotype, staging and treatment. As results of this work, guidelines are proposed for diagnosis, differential diagnosis, staging, prognostic factors, treatment and response criteria. The guidelines proposed here are intended to contribute to the standardization of the diagnosis and treatment of these patients, and should facilitate the future development of clinical trials that could define more precisely predictive markers for histological progression or lack of response, and evaluate new drugs or treatments.

Splenic marginal zone lymphoma with and without villous lymphocytes

Splenic marginal zone lymphoma with or without villous lymphocytes (SLVL/SMZL) is a low grade B-cell lymphoma that affects patients in the sixth decade and has a median survival greater than 10 years. A substantial proportion of patients die from causes unrelated to the disease. Close to a third of the patients do not require intervention and a policy of watch and see is reasonable and recommended. There are several therapeutic options that have proved effective in these patients. Due to the natural history of the lymphoma, the main goal of all these treatments is to achieve control of the disease rather than its eradication. Retrospective designs of all documented studies, the lack of uniform response criteria and the heterogeneity in the patient's features makes interpretation of the data difficult. Splenectomy remains one of the first line options in patients fit for surgery. Amongst chemotherapy, purine analogues, in particular fludarabine in combination or not with Rituximab and Rituximab alone have a greater efficacy than alkylating agents in terms of achieving better quality of response and longer progression free survival; therefore these agents are recommended particularly in patients who are not candidates for surgery or relapse after splenectomy. In the small proportion of patients with concomitant hepatitis C virus (HCV) infection, Interferon-alpha, ribavirin or a combination of both has demonstrated a significant activity with responses correlating with clearance of HCV RNA in the blood; therefore, these agents should be considered in the therapeutic scenario as a first line in these small cohort of patients. Patients that transform to high-grade lymphoma and the minority that have TP53 abnormalities should be treated with other schedules. Prospective randomized trials would be desirable to ascertain the independent prognostic factors and the biological features that predict disease progression and drug resistance to device the optimal management and treatment for SLVL/SMZL.

Cryoglobulinemia

Cryoglobulinemia refers to the presence in serum of immunoglobulins that precipitate at a cold temperature. Type I cryoglobulins are single monoclonal immunoglobulins usually associated with haematological disorders. Types II and III are mixed cryoglobulins, composed of monoclonal or polyclonal IgM respectively, having rheumatoid factor activity that bind to polyclonal immunoglobulins. Mixed cryoglobulinemia (MC) syndrome is a consequence of immune-complex mediated vasculitis and is characterized by a typical clinical triad: purpura, weakness, arthralgias; many organs particularly kidney and peripheral nervous system may be involved. MC may be associated with infectious and systemic disorders and since 1990 studies have demonstrated that hepatitis C virus (HCV) may be considered the principal trigger of the disease. The relation between MC and HCV infection shows new insights in the interpretation of the link between viral infection, autoimmune phenomena and lymphoproliferative disorders evolution. In fact, the virus chronically stimulates B-cell polyclonal proliferation from which a monoclonal population may emerge. In symptomatic patients with HCV related MC therapeutic strategy should include an attempt at viral eradication. Antiviral therapy may also be effective in determining the regression of B-cell lymphoproliferative disorder. Rituximab could represent a safe and effective alternative to standard immunosuppression and exerts selective B-cell control.

Hepatitis C virus-related lymphoproliferative disorders: An overview

Hepatitis C virus (HCV) is a global health problem affecting 3% of the world's population (about 180 million) and a cause of both hepatic and extrahepatic diseases. B-cell lymphoproliferative disorders, whose prototype is mixed cryoglobulinemia, represent the most closely related as well as the most investigated HCV-related extrahepatic disorder. The association between extrahepatic (lymphoma) as well as hepatic malignancies (hepatocellular carcinoma) has justified the inclusion of HCV among human cancer viruses. HCV-associated manifestations also include porphyria cutanea tarda, lichen planus, nephropathies, thyreopathies, sicca syndrome, idiopathic pulmonary fibrosis, diabetes, chronic polyarthritis, sexual dysfunctions, cardiopathy/atherosclerosis, and psychopathological disorders. A pathogenetic link between HCV virus and some lymphoproliferative disorders was confirmed by their responsiveness to antiviral therapy, which is now considered the first choice treatment. The aim of the present paper is to provide an overview of extrahepatic manifestations of HCV infection with particular attention to B-cell lymphoproliferative disorders. Available pathogenetic hypotheses and suggestions about the most appropriate, currently available, therapeutic approaches will also be discussed.

Characterization of B cell lymphoma in patients with Sjögren's syndrome and hepatitis C virus infection

OBJECTIVE

To characterize the clinical and immunologic patterns of expression, response to therapy, and outcome of patients with Sjögren's syndrome (SS) and associated hepatitis C virus (HCV) infection who developed B cell lymphoma.

METHODS

Various international reference centers constituted a multicenter study group with the purpose of creating a registry of patients with SS-HCV who developed B cell lymphoma. A protocol form was used to record the main characteristics of SS, chronic HCV infection, and B cell lymphoma.

RESULTS

Twenty-five patients with SS-HCV with B cell lymphoma were included in the registry. There were 22 (88%) women and 3 (12%) men (mean age 55, 58, and 61 years at SS, HCV infection, and lymphoma diagnosis, respectively). The main extraglandular SS manifestations were cutaneous vasculitis in 15 (60%) patients and peripheral neuropathy in 12 (48%); the main immunologic features were positive rheumatoid factor (RF) in 24 (96%) and type II cryoglobulins in 20 (80%). The main histologic subtypes were mucosa-associated lymphoid tissue (MALT) lymphoma in 11 (44%) patients, diffuse large B cell lymphoma in 6 (24%), and follicular center cell lymphoma in 6 (24%). Fifteen (60%) patients had an extranodal primary location, most frequently in the parotid gland (5 patients), liver (4 patients), and stomach (4 patients). Twelve (52%) of 23 patients died after a median followup from the time of lymphoma diagnosis of 4 years, with lymphoma progression being the most frequent cause of death. Survival differed significantly between the main types of B cell lymphoma.

CONCLUSION

Patients with SS-HCV and B cell lymphoma are clinically characterized by a high frequency of parotid enlargement and vasculitis, an immunologic pattern overwhelmingly dominated by the presence of RF and mixed type II cryoglobulins, a predominance of MALT lymphomas, and an elevated frequency of primary extranodal involvement in organs in which HCV replicates (exocrine glands, liver, and stomach).

Extrahepatic manifestations of Hepatitis C Virus infection: a general overview and guidelines for a clinical approach

Hepatitis C Virus is associated with a wide series of extrahepatic manifestations. Based on available data the link between the virus and some of these extrahepatic diseases is only suggested and needs further confirmation. Hepatitis C Virus-related lymphoproliferative disorders, whose prototype is mixed cryoglobulinaemia, represent the most closely related extrahepatic manifestations of Hepatitis C Virus. Other Hepatitis C Virus-associated disorders include nephropathies, thyreopathies, sicca syndrome, idiopathic pulmonary fibrosis, porphyria cutanea tarda, lichen planus, diabetes, chronic polyarthritis, cardiopathy and atherosclerosis. A pathogenetic link between Hepatitis C Virus and some extrahepatic manifestations was confirmed by their responsiveness to antiviral therapy, which is now deemed the first therapeutic option to consider. By contrast, there are diseases where treatment with interferon was ineffective or dangerous. The aim of the present paper is to outline the most recent evidence concerning extrahepatic disorders that are possibly associated with Hepatitis C Virus infection. Special emphasis will be given to discussion of the most appropriate clinical approaches to be adopted in order to diagnose, treat (possibly prevent) and follow-up extrahepathic diseases in patients with Hepatitis C Virus infection.

HCV-NS3 and IgG-Fc crossreactive IgM in patients with type II mixed cryoglobulinemia and B-cell clonal proliferations

We demonstrate that in three cases of MC (two with immunocytoma), the IgM-RF+ component of their cryoprecipitated represents the circulating counterpart of the B-cell receptor (BCR) of the monoclonal overexpanded B-cell population. These IgMs were isolated and used to demonstrate a crossreactivity against both hepatitis C virus (HCV) NS3 antigen and the Fc portion of IgG. Epitopes were identified in a fraction of exemplary samples by using epitope excision approach (NS(31250-1334) and IgG Fc(345-355)). The same phenomenon of crossreactivity has been shown to occur in vivo after immunization of a mouse with the NS3(1251-1270) peptide. To verify if the same reaction was also present in MC samples characterized by an oligo/polyclonal B-cell proliferation, IgM crossreactivity was tested in 14 additional samples. Five out of the 14 were reactive against HCV NS3 and 11 out of 14 were reactive against IgG-Fc peptide. The data support the role of HCV NS3 antigen in a subset of patients with MC, whereas the high frequency of the IgG-Fc epitope suggests that these B cells originate from precursors strongly selected for auto-IgG specificity. We suggest that engagement of specific BCRs by NS3 (or NS3-immunocomplex) antigen could explain the prevalence of IgM cryoglobulins in these patients.

Prevalence of HCV infection in nongastric marginal zone B-cell lymphoma of MALT

BACKGROUND

Hepatitis C virus (HCV) infection is frequently associated with B-cell non-Hodgkin's lymphomas. We investigated the prevalence of HCV infection in nongastric marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) in order to define the relationship between the viral infection and the presenting features, treatment, and outcome.

METHODS

We retrospectively studied 172 patients with a histological diagnosis of marginal zone B-cell lymphoma of MALT, except for stomach, and with available HCV serology, among a series of 208 patients.

RESULTS

HCV infection was documented in 60 patients (35%). Most HCV-positive patients (97%) showed a single MALT organ involvement. HCV-positive patients showed a more frequent involvement of skin (35%), salivary glands (25%), and orbit (15%). The majority of stage IV HCV-positive patients (71%) had a single MALT site with bone marrow involvement. The overall response rate was similar in HCV-positive (93%) and HCV-negative patients (87%). Overall survival (OS) and event-free survival (EFS) did not differ according to HCV infection. In multivariate analysis, advanced disease (stage III-IV) was associated with a poorer OS (P = 0.0001), irrespective of HCV serostatus.

CONCLUSIONS

This study shows that nongastric marginal zone lymphomas are characterized by a high prevalence of HCV infection. Patients with involvement of a single MALT site have the highest prevalence of HCV. HCV-positive nongastric lymphomas of MALT show an indolent course similar to HCV-negative patients and seem an ideal target for exploiting the antilymphoma activity of antiviral treatments.

TCRgammadelta+ large granular lymphocyte leukemias reflect the spectrum of normal antigen-selected TCRgammadelta+ T-cells

T-cell large granular lymphocytes (LGL) proliferations range from reactive expansions of activated T cells to T-cell leukemias and show variable clinical presentation and disease course. The vast majority of T-LGL proliferations express TCRalphabeta. Much less is known about the characteristics and pathogenesis of TCRgammadelta+ cases. We evaluated 44 patients with clonal TCRgammadelta+ T-LGL proliferations with respect to clinical data, immunophenotype and TCR gene rearrangement pattern. TCRgammadelta+ T-LGL leukemia patients had similar clinical presentations as TCRalphabeta+ T-LGL leukemia patients. Their course was indolent and 61% of patients were symptomatic. The most common clinical manifestations were chronic cytopenias - neutropenia (48%), anemia (23%), thrombocytopenia (9%), pancytopenia (2%) - and to a lesser extent splenomegaly (18%). Also multiple associated autoimmune (34%) and hematological (14%) disorders were found. Leukemic LGLs were predominantly positive for CD2, CD5, CD7, CD8, and CD57, whereas variable expression was seen for CD16, CD56, CD11b, and CD11c. The Vgamma9/Vdelta2 immunophenotype was found in 48% of cases and 43% of cases was positive for Vdelta1, reflecting the TCR-spectrum of normal TCRgammadelta+ T-cells in adult PB. Identification of the well-defined post-thymic Vdelta2-Jdelta1 selection determinant in all evaluable Vgamma9+/Vdelta2+ patients, is suggestive of common (super)antigen involvement in the pathogenesis of these TCRgammadelta+ T-LGL leukemia patients.

Viruses and lymphoma

The aetiology of lymphomas is poorly understood and the striking increase in its incidence rate in developed societies remains unexplained. The concept of lymphoma as a virally-induced malignancy is not surprising since viruses are implicated in approximately 15% of all cancers. However, lymphoma represents a complex multistep process and, although viral associations have been identified, integration of the available epidemiological and scientific data poses substantial questions. The study of oncogenic viruses has and will continue to yield major insights into the pathogenesis of lymphoma. Further research is likely to uncover new lymphoma associations between both known and as yet unidentified viruses, may provide cellular and pharmacological targeted antiviral therapy strategies for the treatment of malignant lymphoma, and ultimately may generate the most promising avenue for lymphoma prevention.

State-of-the-art therapeutics: marginal-zone lymphoma

Marginal-zone lymphomas comprise the mucosa-associated lymphoid tissue (MALT) type (extranodal marginal-zone lymphoma [EMZL]), the nodal marginal zone B-cell lymphoma (NMZL) and the splenic MZL (SMZL). EMZL is relatively common, whereas the remaining two entities are relatively rare disorders. EMZL, especially in its gastric localization, is the most studied MZL, and there are many data both on the underlying genetic lesions and on the role of infectious agents. These data have determined unique approach among all other lymphoma subtypes: the possibility of treating a subset of patients with antibiotics alone as first line of treatment. Indeed, there is compelling evidence that histologic regressions can be achieved in most gastric MALT lymphomas by eradicating Helicobacter pylori infection. However, molecular follow-up studies showed the persistence of the malignant clone in half of the cases in histologic remission after antibiotic treatment and transient, either histologic or molecular, relapses have been reported, too. Hence, a careful long-term follow-up is mandatory after antibiotic treatment. Radiotherapy, chemotherapy, anti-CD20 monoclonal antibodies are effective alternative therapies. The precise role of surgical resection should be redefined in view of the encouraging results of conservative approaches. Differently from EMZL, both SMLZ and NMZL often present with disseminated disease at diagnosis. The therapeutic approach comprises splenectomy, for SMZL, and chemotherapy, but with no consensus about the best treatment. This review addresses the current knowledge on the clinical features and therapeutic approaches for the individual MZLs.

Cryoglobulinemia

Mixed cryoglobulinemia (MC) type II is a disorder characterized by circulating cold-precipitable immune complexes composed of polyclonal immunoglobulin IgG and monoclonal IgM rheumatoid factor (RF). The systemic vasculitis which characterizes the disease is caused by the deposition of immune complexes on the walls of small vessels, and by the subsequent activation of the complement cascade. MC may be asymptomatic or lead to clinical manifestations characterized by a typical triad--purpura, arthralgia, and weakness--and in some cases by a more serious vasculitis with neurologic and renal involvement. In the vast majority (more than 90%) of patients, MC is associated with hepatitis C virus (HCV) infection, which is considered the triggering factor of the disease. The association between cryoglobulinemia and HCV infection, and the possible evolution to B-cell lymphomas usually after long-term follow-up, suggest the role of HCV infection both in the pathogenesis of MC and in lymphomagenesis. In fact, the virus chronically stimulates the polyclonal proliferation of B cells from which a monoclonal population may emerge. This paper also reviews the treatment strategies for MC syndrome, emphasizing the issue of the eradication of HCV, and the clinical and biological activity of rituximab for selective B-cell control.