Eradication of Borrelia burgdorferi infection in primary marginal zone B-cell lymphoma of the skin

The Genetic Landscape of Primary Breast Marginal Zone Lymphoma Identifies a Mutational-driven Disease With Similarities to Ocular Adnexal Lymphoma

Extranodal marginal zone lymphomas (eMZL) can occur in any organ and site of the body. Recent research has shown that they differ from organ to organ in terms of their mutational profile. In this study, we investigated a cohort of primary breast marginal zone lymphomas (PBMZL) to get a better insight into their morphologic and molecular profile. A cohort of 15 cases (14 female and 1 male) was characterized by immunohistochemistry (IHC) for 19 markers, fluorescence in situ hybridization (FISH), and high throughput sequencing (HTS) using a lymphoma panel comprising 172 genes. In addition, PCR for the specific detection of Borrelia spp. and metagenomics whole genome sequencing were performed for infectious agent profiling. Follicular colonization was observed in most cases, while lymphoepithelial lesions, though seen in many cases, were not striking. All 15 cases were negative for CD5, CD11c, and CD21 and positive for BCL2 and pan B-cell markers. There were no cases with BCL2 , BCL10 , IRF4 , MALT1 , or MYC translocation; only 1 had a BCL6 rearrangement. HTS highlighted TNFAIP3 (n=4), KMT2D (n=2), and SPEN (n=2) as the most frequently mutated genes. There were no Borrelia spp. , and no other pathogens detected in our cohort. One patient had a clinical history of erythema chronicum migrans affecting the same breast. PBMZL is a mutation-driven disease rather than fusion-driven. It exhibits mutations in genes encoding components affecting the NF-κB pathway, chromatin modifier-encoding genes, and NOTCH pathway-related genes. Its mutational profile shares similarities with ocular adnexal and nodal MZL.

Cutaneous B-Cell Lymphomas

Primary cutaneous B-cell lymphomas represent a type of non-Hodgkin's lymphoma of the skin without evidence of extracutaneous involvement at the time of diagnosis. According to the 2018 World Health Organization-the European Organization for Research and Treatment of Cancer classification, primary cutaneous B-cell lymphomas include primary cutaneous marginal zone lymphoma, primary cutaneous follicle center lymphoma, primary cutaneous diffuse large B-cell lymphoma, leg type, intravascular large B-cell lymphoma, and Epstein-Barr virus+ mucocutaneous ulcer (provisional). Herein, we provide a comprehensive review of the updated literature on these entities, including clinical presentation, histopathology, immunophenotype, molecular genetics, prognosis, and treatment.

Primary central nervous system marginal zone lymphoma

Marginal zone lymphoma (MZL) is the most common indolent lymphoma primarily arising in the central nervous system (CNS). To date, 207 cases of primary CNS MZL (PCNSMZL) were published, mostly as single case reports or small case series. It most commonly presents as extra-axial dural-based masses, more frequently in middle-aged women, displaying an insidious onset, with a long history of symptoms preceding the diagnosis. PCNSMZL can be radiographically mistaken for meningioma. PCNSMZL consists of CD20+ , CD3- small B lymphocytes with varying degrees of plasmacytic differentiation and low proliferation index. Trisomy 3, but not MALT1 or IgH translocation, is a common genetic abnormality. Other recurrent genetic abnormalities involve TNFAIP3 and NOTCH2. Ethiopathogenesis was poorly investigated. Due to its rarity, standard of care remains to be defined; it exhibits an excellent prognosis after varied treatments, such as surgery, radiotherapy, chemotherapy or their combinations. Nevertheless, each treatment should be considered after an accurate analysis of overtreatment risk. Short follow-up is a major limitation in reported PCNSMZL cases, which restrains our knowledge on long-term results and iatrogenic sequels. This review was focussed on presentation, differential diagnoses, pathological findings, treatment options and clinical outcomes of PCNSMZL; recommendations for best clinical practice are provided.

Management of Marginal Zone Lymphoma: A Canadian Perspective

Marginal zone lymphomas (MZL) are a rare, heterogenous group of lymphomas, accounting for 5-17% of indolent non-Hodgkin lymphomas in the western world. They can be further divided into three subtypes: extranodal MZL, splenic MZL, and nodal MZL. These subtypes differ in clinical presentation and behavior, which influences how they are managed. There is currently no standard of care for the treatment of MZL, owing to the difficulty in conducting phase 3 randomized trials in MZL, and the fact that there are limited data on the efficacy of therapy in individual subtypes. Treatment practices are thus largely borrowed from other indolent lymphomas and are based on patient and disease characteristics, as well as access to therapy. This review summarizes the Canadian treatment landscape for MZL and how these therapies may be sequenced in practice.

Bacterial infection-driven lymphomagenesis

PURPOSE OF REVIEW

The first convincing evidence for a causal relationship between bacterial infection and lymphomagenesis came from the link between gastric lymphoma and chronic Helicobacter pylori gastritis. This review will summarize the current epidemiological, clinical, and biological evidence of a causative role of bacteria in the development of malignant lymphomas, particularly, the extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type.

RECENT FINDINGS

Other microorganisms have been associated with specific extranodal lymphoma sites with variable and not always definitive, evidence, including Chlamydia psittaci , Borrelia burgdorferi , Campylobacter jejuni and, most recently, Coxiella Burnetii . According to most plausible models, lymphoma growth is a consequence of continuous antigenic stimulation induced by chronic infection. However, some evidence of a direct oncogenic role of H. pylori has been provided, too.

SUMMARY

Lymphomas are not the result of a single cause but multifactorial diseases, influenced by a variety of genetic and environmental elements. Hence, ascertaining the specific contribution of bacterial infections is not always easy. Nevertheless, the eradication of the associated chronic infection may result in sustained lymphoma regression. Moreover, the association between infections and lymphoma may offer opportunities for reducing lymphoma incidence by preventing the predisposing infections or treating them early.

Management of Extranodal Marginal Zone Lymphoma: Present and Upcoming Perspectives

Simple Summary

Extranodal marginal zone lymphoma distinguishes itself from other indolent lymphomas due to its unique pathophysiology and natural history. This is reflected in its management, where next to traditional treatment strategies such as observation, radiotherapy or chemotherapy, eradication of the causal agent and even surgery represent important aspects of therapy. This review focuses on the particular aspects of this indolent lymphoma that affect management and summarizes the current evidence and different guidelines.

Abstract

Extranodal marginal zone lymphoma (EMZL) encompasses a subgroup of non-Hodgkin lymphomas that often present with localized involvement and may manifest in a diversity of organs and tissues. EMZL pathogenesis is in some cases linked to chronic inflammation/infection, which may impose additional diagnostic and clinical challenges. The most studied and established connection is the presence of Helicobacter pylori in gastric EMZL. Due to its heterogeneity of presentation and intricate pathological features, treatment can be complex, and staging systems are decisive for the choice of therapy. Nevertheless, there is no consensus regarding the most suitable staging system, and recommendations vary among different countries. As a rule of thumb, in limited stages, a local therapy with surgery or radiation is the preferred option, and it is potentially curative. Of note, eradicating the causal agent may be an important step of treatment, especially in gastric EMZL, in which Helicobacter pylori eradication remains the first-line therapy for the majority of patients. In patients with more advanced stages, watch-and-wait is a valuable option, especially amongst those without clear indications for systemic therapy, and it may be carried on for several years. If watch-and-wait is not an option, systemic therapy may be needed. Even though several agents have been tested as monotherapy or in combination in recent years, there is no consensus regarding the first-line therapy, and decisions can vary depending on individual factors, such as age, clinical performance and stage. This review aims to discuss the several aspects of EMZL, including genetic milieu, pathogenesis and staging systems, that may influence the choice of therapy. In addition, we present a summary of evidence of several systemic therapies, compare different recommendations worldwide and discuss future perspectives and novelties in its therapy.

Cutaneous Reactive B-cell Lymphoid Proliferations

Cutaneous lymphoid hyperplasia (CLH), also known as cutaneous pseudolymphoma, is a spectrum of benign conditions characterized by reactive B- and T-cell cutaneous lymphocytic infiltrates. B-cell lymphoid proliferations are a heterogenous group of non-neoplastic cutaneous diseases that must be histopathologically distinguished from cutaneous B-cell lymphomas. These proliferations can be observed as reactive phenomena to infections, medications, allergens, neoplasms, and more. Further, there are many inflammatory conditions that present with reactive B-cell infiltrates, including actinic prurigo, Zoon balanitis, Rosai-Dorfman, and cutaneous plasmacytosis. This review summarizes multiple cutaneous B-cell lymphoid proliferations within the major categories of reactive and disease-associated CLH. Further we discuss major discriminating features of atypical CLH and malignancy. Understanding the specific patterns of B-cell CLH is essential for the proper diagnosis and treatment of patients presenting with such lesions.

Marginal Zone B-Cell Populations and Their Regulatory Potential in the Context of HIV and Other Chronic Inflammatory Conditions

Inflammation in the context of Human Immunodeficiency Virus (HIV) establishes early and persists beyond antiretroviral therapy (ART). As such, we have shown excess B-cell activating factor (BAFF) in the blood of HIV-infected progressors, as soon as in the acute phase, and despite successful ART. Excess BAFF was associated with deregulation of the B-cell compartment; notably, with increased frequencies of a population sharing features of both transitional immature (TI) and marginal zone (MZ) B-cells, we termed Marginal Zone precursor-like (MZp). We have reported similar observations with HIV-transgenic mice, Simian Immunodeficiency Virus (SIV)-infected macaques, and more recently, with HIV-infected Beninese commercial sex workers, which suggests that excess BAFF and increased frequencies of MZp B-cells are reliable markers of inflammation in the context of HIV. Importantly, we have recently shown that in healthy individuals, MZps present an important regulatory B-cell (Breg) profile and function. Herein, we wish to review our current knowledge on MZ B-cell populations, especially their Breg status, and that of other B-cell populations sharing similar features. BAFF and its analog A Proliferation-Inducing Ligand (APRIL) are important in shaping the MZ B-cell pool; moreover, the impact that excess BAFF—encountered in the context of HIV and several chronic inflammatory conditions—may exert on MZ B-cell populations, Breg and antibody producing capacities is a threat to the self-integrity of their antibody responses and immune surveillance functions. As such, deregulations of MZ B-cell populations contribute to autoimmune manifestations and the development of MZ lymphomas (MZLs) in the context of HIV and other inflammatory diseases. Therefore, further comprehending the mechanisms regulating MZ B-cell populations and their functions could be beneficial to innovative therapeutic avenues that could be deployed to restore MZ B-cell immune competence in the context of chronic inflammation involving excess BAFF.

Current Status of the Spectrum and Therapeutics of Helicobacter pylori-Negative Mucosa-Associated Lymphoid Tissue Lymphoma

Simple Summary

The prevalence of Helicobacter pylori (HP)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma has increased over the last two decades, whereas that of HP-positive gastric MALT lymphoma has decreased. Although the role of first-line antibiotics in the treatment of HP-negative gastric MALT lymphomas remains ambiguous, several case series have reported that a first-line HP eradication therapy (HPE)-like regimen could result in complete remission in a proportion of patients with localized HP-negative gastric MALT lymphoma. Previous sporadic reports have indicated that certain patients with extragastric MALT lymphoma can respond to first-line antibiotic treatment as well. These findings suggest that, in contrast to antibiotic-unresponsive tumors, antibiotic-responsive tumors may be recognized within the spectrum of HP-negative MALT lymphoma. In addition to conventional chemotherapy and immunochemotherapy, macrolide antibiotics and immunomodulatory drugs have been previously used and demonstrated to be efficacious. This article provides the spectrum and therapeutics for HP-negative MALT lymphoma.

Abstract

Helicobacter pylori (HP)-unrelated mucosa-associated lymphoid tissue (MALT) lymphoma includes the majority of extragastric MALT lymphomas and a small proportion of gastric MALT lymphomas. Although the role of first-line antibiotics in treating HP-negative gastric MALT lymphomas remains controversial, HP eradication therapy (HPE)-like regimens may result in approximately 20–30% complete remission (CR) for patients with localized HP-negative gastric MALT lymphoma. In these patients, H. heilmannii, H. bizzozeronii, and H. suis were detected in sporadic gastric biopsy specimens. Extragastric MALT lymphoma is conventionally treated with radiotherapy for localized disease and systemic chemotherapy for advanced and metastatic diseases. However, a proportion of extragastric MALT lymphomas, such as ocular adnexal lesions and small intestinal lesions, were reported to be controlled by antibiotics for Chlamydophila psittaci and Campylobacter jejuni, respectively. Some extragastric MALT lymphomas may even respond to first-line HPE. These findings suggest that some antibiotic-responsive tumors may exist in the family of HP-negative MALT lymphomas. Two mechanisms underlying the antibiotic responsiveness of HP-negative MALT lymphoma have been proposed. First, an HPE-like regimen may eradicate the antigens of unknown bacteria. Second, clarithromycin (the main component of HPE) may have direct or indirect antineoplastic effects, thus contributing to the CR of these tumors. For antibiotic-unresponsive HP-negative MALT lymphoma, high-dose macrolides and immunomodulatory drugs, such as thalidomide and lenalidomide, have reported sporadic success. Further investigation of new treatment regimens is warranted.

No evidence of Borrelia in Cutaneous Infiltrates of B-cell lymphomas with a highly sensitive, semi-nested real time Polymerase chain reaction (PCR) targeting the 5S-23S intergenic spacer region (IGS)

BACKROUND

The role of Borrelia in the development of skin lymphomas has been under discussion for decades. A similar association has been shown for Helicobacter pylori and gastric lymphomas (MALT type). Nevertheless, few molecular studies investigated Borrelia in skin lymphomas and the results are controversial.

METHODS

We analysed 46 formalin-fixed, paraffin-embedded skin specimens of clincopathologically confirmed B-cell lymphomas (15 marginal zone lymphomas; 20 follicular lymphomas; 3 diffuse large B-cell lymphomas; 8 secondary cutaneous infiltrates) taken from 36 patients from Northern Germany, an endemic area for Borrelia. Fifteen pseudolymphomatous lesions of cutaneous Borreliosis served as control. Both groups were examined with a real time (rt) PCR and a semi-nested PCR targeting the 5S-23S intergenic spacer region (IGS). A multiplex PCR was used to investigate B-cell clonality in all lymphomatous infiltrates (Biomed Primers).

RESULTS

With both assays no B. burgdorferi-specific DNA was identified in any of the B-cell lymphomas, while all 15 Borreliosis specimens gave a positive PCR result in the semi-nested PCR protocol, 12 were also positive in the rt PCR (p<.01). All B-cell lymphomas showed monoclonal IgH-Rearrangement. Analysis of cutaneous B-cell lymphomas from available studies including ours (n=334) reveals an Odds ratio < 1.

CONCLUSION

While some previous studies suggested an association between B. burgdorferi and the development of cutaneous B-cell lymphomas in endemic areas, we were unable to confirm this in our patients, despite a highly sensitive Borrelia PCR assay. Our results including meta-analysis of previous studies question the need for antibiotic therapy in patients with cutaneous B-cell lymphomas.

CUTANEOUS B-CELL LYMPHOMAS: UPDATE ON DIAGNOSIS, RISK-STRATIFICATION, AND MANAGEMENT

PCBCLs are a group of Non-Hodgkin's B-cell lymphomas originating in and usually confined to the skin, representing approximately one fourth of primary cutaneous lymphomas (PCL). Their current classification system has been the result of the joint World Health Organization (WHO) - European Organization for Research and Treatment of Cancer (EORTC) consensus in 2018. To date, several types of PCBCLs have been described in the scientific literature, with different clinical presentation and prognosis. Primary cutaneous follicle-center lymphoma (PCFCL) and primary cutaneous marginal zone lymphoma (PCMZL) are the most common forms, with a typical indolent course. On the contrary, primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL, LT) is less common, yet more aggressive, with a reported 5-year overall survival of approximatively 50%. In this review, we outline the PCBCLs defining diagnostic criteria, report the features of the less common subtypes and summarize the noteworthy therapeutical options currently available in this field.

Primary Cutaneous Lymphomas in Thailand: A 10-Year Retrospective Study

Background

Primary cutaneous lymphomas (PCLs) refer to cutaneous lymphomas that primarily develop in the skin with no evidence of extracutaneous disease at the time of diagnosis. The epidemiological and clinical data of PCLs in Thailand are lacking.

Objectives

To evaluate the frequency, demographic data, and clinical characteristics of different subtypes of PCLs in a tertiary care university hospital.

Methods

In total, 137 patients with PCLs diagnosed in our hospital in 2008–2017 were retrospectively reviewed.

Results

Of the 137 patients, 57 (41.6%) were male and 80 (58.4%) were female (M : F = 1 : 1.4). The median age at diagnosis was 40 years. Most patients (134, 97.8%) had cutaneous T-cell lymphomas (CTCLs). Three patients (2.2%) had cutaneous B-cell lymphomas (CBCLs). The most common subtype was mycosis fungoides (MF) (67.9%), followed by subcutaneous panniculitis-like T-cell lymphoma (SPTCL) (21.2%), primary cutaneous anaplastic large cell lymphoma (pcALCL) (3.6%), lymphomatoid papulosis (LyP) (1.5%), primary cutaneous gamma/delta T-cell lymphoma (pcGDTCL) (1.5%), Sézary syndrome (SS) (0.7%), extranodal NK/T-cell lymphoma, nasal type (ENKTCL-NT) (0.7%), primary cutaneous peripheral T-cell lymphoma, not otherwise specified (pcPTCL-NOS) (0.7%), primary cutaneous diffuse large B-cell lymphoma, leg type (pcDLBCL-LT) (1.5%), and primary cutaneous follicle center lymphoma (pcFCL) (0.7%). Most patients with MF presented with early-stage disease (84.0%), with hypopigmented MF the most common variant (42.6%).

Conclusions

Compared to earlier Caucasian and Asian studies, the present study revealed a higher proportion of CTCL patients with a younger age at onset and a female predominance. MF was the most common CTCL subtype, followed by SPTCL. More than 80% of MF patients were diagnosed at an early stage.

Role of Specific B-Cell Receptor Antigens in Lymphomagenesis

The B-cell receptor (BCR) signaling pathway is a crucial pathway of B cells, both for their survival and for antigen-mediated activation, proliferation and differentiation. Its activation is also critical for the genesis of many lymphoma types. BCR-mediated lymphoma proliferation may be caused by activating BCR-pathway mutations and/or by active or tonic stimulation of the BCR. BCRs of lymphomas have frequently been described as polyreactive. In this review, the role of specific target antigens of the BCRs of lymphomas is highlighted. These antigens have been found to be restricted to specific lymphoma entities. The antigens can be of infectious origin, such as H. pylori in gastric MALT lymphoma or RpoC of M. catarrhalis in nodular lymphocyte predominant Hodgkin lymphoma, or they are autoantigens. Examples of such autoantigens are the BCR itself in chronic lymphocytic leukemia, LRPAP1 in mantle cell lymphoma, hyper-N-glycosylated SAMD14/neurabin-I in primary central nervous system lymphoma, hypo-phosphorylated ARS2 in diffuse large B-cell lymphoma, and hyper-phosphorylated SLP2, sumoylated HSP90 or saposin C in plasma cell dyscrasia. Notably, atypical posttranslational modifications are often responsible for the immunogenicity of many autoantigens. Possible therapeutic approaches evolving from these specific antigens are discussed.

Borrelia burgdorferi in primary cutaneous lymphomas: a systematic review and meta-analysis

BACKGROUND

The association between Borrelia burgdorferi and primary cutaneous lymphoma is still unclear. This systematic review and meta-analysis aims to define the association of Borrelia burgdorferi with primary cutaneous lymphoma and its different entities.

METHODS

Electronic databases were searched for all studies that assessed the presence of Borrelia burgdorferi DNA in specimens of primary cutaneous lymphoma. The association between Borrelia and primary cutaneous lymphomas was assessed with an odds ratio (significant p < 0.05); cutaneous specimens with no lymphoproliferative disorders were used as controls. A secondary analysis was performed to assess the prevalence of Borrelia infection in different lymphoma entities.

RESULTS

Ten studies with 506 primary cutaneous lymphomas and 201 controls were included. The prevalence of Borrelia DNA positivity was highly heterogeneous among studies from different regions. Borrelia DNA positivity was significantly associated with primary cutaneous lymphomas (odds ratio = 10.88; p < 0.00001). The prevalence of Borrelia DNA positivity was similar among different entities (marginal zone: 7.3 %; follicular: 8.1 %; diffuse large B-cell: 7.5 %; mycosis fungoides: 8 %).

CONCLUSIONS

Borrelia burgdorferi is significantly associated with primary cutaneous lymphomas, with no differences among the several lymphoma entities (both B-cell and T-cell), but with strong geographical differences. Molecular testing for Borrelia would be justified in patients with primary cutaneous lymphoma from endemic areas.

How I Diagnose Primary Cutaneous Marginal Zone Lymphoma

OBJECTIVES

Primary cutaneous marginal zone lymphoma (PCMZL) is 1 of the 3 major subtypes of primary cutaneous B-cell lymphoma. The diagnosis of PCMZL may be challenging, as the differential diagnosis includes benign cutaneous lymphoproliferations as well as other primary or secondary cutaneous B-cell or T-cell lymphomas. This review describes our approach to the diagnosis of PCMZL.

METHODS

Two cases are presented that illustrate how we diagnose each of the 2 subtypes of PCMZL. The clinicopathologic features of PCMZL and the ways in which these cases can be distinguished from both benign and other neoplastic entities are emphasized.

RESULTS

A definitive diagnosis of PCMZL requires the incorporation of histologic and immunophenotypic features, molecular genetic studies in some cases, and just as importantly, clinical findings. Emerging data suggest that the heavy chain class-switched cases may be more like a clonal chronic lymphoproliferative disorder.

CONCLUSIONS

The 2 subtypes of PCMZL create different diagnostic challenges and require the use of a multiparameter approach. Although very indolent, it is important to distinguish PCMZLs from reactive proliferations, because they frequently recur and may require antineoplastic therapies. It is also critical to distinguish PCMZLs from other B- or T-cell lymphomas so that patients are properly evaluated and not overtreated.

A Practical Approach to the Diagnosis of Lyme Borreliosis: From Clinical Heterogeneity to Laboratory Methods

Clinical evaluation of Lyme Borreliosis (LB) is the starting point for its diagnosis. The patient's medical history and clinical symptoms are fundamental for disease recognition. The heterogeneity in clinical manifestations of LB can be related to different causes, including the different strains of Borrelia, possible co-infection with other tick transmitted pathogens, and its interactions with the human host. This review aims at describing the heterogeneous symptoms of Lyme Borreliosis, as well as offering a practical approach for recognition of the disease, both in terms of clinical features and diagnostic/research tools.

Bacterial infection and non-Hodgkin's lymphoma

One quarter of all cancers are linked to infectious diseases. The link between viral infection and cancer has been widely studied, but few reports have focused on the carcinogenic role of bacterial infection. Nonetheless, Helicobacter pylori, Chlamydia psittaci, Coxiella burnetii, Borrelia burgdorferi and Campylobacter jejuni are bacteria that can be associated with non-Hodgkin's lymphoma (NHL), the most common haematologic malignancy. Here, we review the evidence in favour of a link between these bacterial infections and NHL. Sero-epidemiological observation makes it possible to identify a link between H. pylori, C. burnetii, B. burgdorferi infection and NHL. Helicobacter pylori, Chlamydia psittaci, Coxiella burnetii, Borrelia burgdorferi and Campylobacter jejuni could be identified in NHL tissue samples at the site of chronic inflammation, where B and T lymphocytes are attracted to participate in follicle formation. Lymphoma remissions have been observed under antimicrobial therapies supporting the carcinogenic contribution of bacteria. If the theory of causality is characterized by the lack of universal criteria for establishing a causal link between two diseases, infection and lymphoma, epidemiological, clinical, and histological evidences reported here, should lead clinicians to pay attention to these infectious agents, to detect early lymphoma transformation.

Dural Marginal Zone Lymphoma in a Patient With a Hepatitis C Virus Infection

Primary dural marginal zone lymphomas (MZLs) are exceptionally rare, with fewer than 100 cases reported to date. While the association between hepatitis C virus (HCV) infection and lymphoma is well established, it is unclear if this association extends to all anatomic sites. Here we report a case of dural MZL in a 61-year-old woman with an HCV infection. To our knowledge, this is the first report of a dural MZL associated with an HCV infection in an immunocompetent patient and was successfully treated with radiotherapy and rituximab. As such, future cases of primary MZL found in the dura should prompt consideration of co-infection with microbials such as HCV and upfront treatment with anti-virals should be considered.

MALT Lymphoma as a Model of Chronic Inflammation-Induced Gastric Tumor Development

Mucosa-associated lymphoid tissue (MALT) lymphoma, or extranodal marginal zone lymphoma of MALT, is an indolent B-cell non-Hodgkin lymphoma linked with preexisting chronic inflammation. The stomach is the most commonly affected organ and the MALT lymphoma pathogenesis is clearly associated with Helicobacter pylori gastroduodenitis. Inflammation induces the lymphoid infiltrates in extranodal sites, where the lymphoma then subsequently develops. Genetic aberrations arise through the release of reactive oxygen species (ROS), H. pylori-induced endonucleases, and other effects. The involvement of nuclear factor kappa B (NF-κB) pathway activation, a critical regulator of pro-inflammatory responses, further highlights the role of inflammation in gastric MALT lymphoma. The NF-κB pathway regulates key elements of normal lymphocyte function, including the transcription of proliferation-promoting and anti-apoptotic genes. Aberrant constitutive activation of NF-κB signaling can lead to autoimmunity and malignancy. NF-κB pathway activation can happen through both the canonical and non-canonical pathways and can be caused by multiple genetic aberrations such as t(11;18)(q12;q21), t(1;14)(p22;q32), and t(14;18)(q32;q21) translocations, chronic inflammation and even directly by H. pylori-associated mechanisms. Gastric MALT lymphoma is considered one of the best models of how inflammation initiates genetic events that lead to oncogenesis, determines tumor biology, dictates clinical behavior and leads to viable therapeutic targets. The purpose of this review is to present gastric MALT lymphoma as an outstanding example of the close pathogenetic link between chronic inflammation and tumor development and to describe how this information can be integrated into daily clinical practice.

Kutane Lymphome

Kutane Lymphome (cutaneous lymphomas: CL) umfassen die Gruppe der kutanen T-Zell-Lymphome (cutaneous T-cell lymphomas: CTCL), kutanen B-Zell-Lymphome (cutaneous B-cell lymphomas: CBCL) und die sog. hämatodermischen Neoplasien (HN). CL gehören zur Gruppe der Non-Hodgkin-Lymphome (NHL) und stellen in der Subgruppe der extranodalen NHL die zweithäufigste Gruppe hinter den gastrointestinalen Lymphomen dar (Jaffe et al. 2009). Man unterscheidet zwischen primären und sekundären CL. Primäre CL haben ihren Ursprung in der Haut und bleiben in der Regel darauf auch längere Zeit beschränkt, während sekundäre CL kutane Manifestationen von primär nodalen oder extranodalen Lymphomen darstellen (Willemze 2005). Die primären CL unterscheiden sich hinsichtlich klinischem Verlauf, Therapieoptionen und Prognose erheblich von nodalen und extrakutanen Lymphomen. So zeigen z. B. die primär kutanen CD30+-T-Zell-Lymphome einen gutartigen Verlauf, wogegen die nodalen Varianten als aggressiv eingestuft werden. Da die CL zumeist weniger aggressiv sind, werden sie auch weniger aggressiv behandelt.

Recent advances in understanding the biology of marginal zone lymphoma

There are three different marginal zone lymphomas (MZLs): the extranodal MZL of mucosa-associated lymphoid tissue (MALT) type (MALT lymphoma), the splenic MZL, and the nodal MZL. The three MZLs share common lesions and deregulated pathways but also present specific alterations that can be used for their differential diagnosis. Although trisomies of chromosomes 3 and 18, deletions at 6q23, deregulation of nuclear factor kappa B, and chromatin remodeling genes are frequent events in all of them, the three MZLs differ in the presence of recurrent translocations, mutations affecting the NOTCH pathway, and the transcription factor Kruppel like factor 2 ( KLF2) or the receptor-type protein tyrosine phosphatase delta ( PTPRD). Since a better understanding of the molecular events underlying each subtype may have practical relevance, this review summarizes the most recent and main advances in our understanding of the genetics and biology of MZLs.

Overview on the management of non-gastric MALT lymphomas

Extranodal marginal zone B-cell lymphomas (EMZLs) of the mucosa-associated lymphoid tissue (MALT) are indolent lymphomas which can present at any extranodal site. The most frequent localizations (other than stomach) are ocular adnexa, salivary gland, skin, lung and thyroid. Chronic inflammation and antigenic stimulation are a potential risk for the development of MALT lymphomas. While Helicobacter Pylori (HP) is known to be associated with gastric MALT lymphoma and antibiotic therapy is effective in the setting of HP-positive, other microorganisms (such as Chlamydophila Psittaci, Campylobacter Jejiuni, Borrelia Burgdoferi) have been implicated in the pathogenesis of non-gastric MALT lymphomas. However, antibiotic therapy has not been extensively investigated for the non-gastric type, except for ocular adnexal MALT lymphoma, which could benefit from an upfront treatment with doxycycline. Surgery, radiotherapy, Rituximab alone or in combination with chemotherapy and "chemo-free" approaches, including lenalidomide, have shown efficacy in the treatment of non-gastric MALT lymphomas.

Mucosa-associated lymphoid tissue (MALT) variant of primary rectal lymphoma: a review of the English literature

PURPOSE

Primary rectal lymphoma (PRL) is the third most common cause of rectal cancer following adenocarcinoma (90-95 %) and carcinoid (5 %). The most common variant of PRL is the mucosa-associated lymphoid tissue (MALT) type. To date, no study has been able to recommend an optimal treatment algorithm for this rare disease. The aim of our study was to review the English literature on primary rectal MALT lymphoma.

METHODS

A review of the English literature was conducted to identify articles describing the MALT variant of PRL.

RESULTS

Fifty-one cases were identified. A complete response was achieved in 12 of 19 cases treated with Helicobacter pylori eradication therapy, 5 of 6 with radiation, 2 of 4 cases with chemotherapy, 2 of 4 with endoscopic resection, 6 of 8 cases with surgical resection, and all 8 with combination therapies. Cases failing initial therapies were responsive to various second-line treatments. Two cases spontaneously regressed with observation alone.

CONCLUSION

Complete regression of primary rectal MALT lymphoma was achieved using various therapeutic strategies, although the numbers of different treatment modalities are too small to draw definitive conclusions.

TCD4pos lymphocytosis in rheumatoid and psoriatic arthritis patients following TNFα blocking agents

Background

Lymphocyte expansion and true lymphocytosis are commonly observed in the everyday clinical practice. The meaning of such phenomenon is often poorly understood so that discrimination between benign and malignant lymphocytosis remains difficult to establish. This is mainly true when lymphocytosis rises in patients affected by immune-mediated chronic inflammatory diseases under immunosuppressive treatment, conditions potentially associated with lymphomagenesis. In this brief report the development of mild T CD4^pos lymphocytosis in a group of patients with chronic arthritis under anti-TNF-α treatment is described.

Methods

Two hundred eight rheumatoid arthritis (RA) and psoriatic arthritis (PsA) patients have been evaluated longitudinally for at least 1-year before and 2-years after anti-TNF-α therapy introduction for the possible appearance of a lymphocyte expansion. In patients who developed lymphocyte expansion, T, B and NK cells were analysed.

Results

Twenty-five out of 208 (12%) subjects developed a mild T CD4^pos lymphocytosis, during anti-TNF-α therapy, which reverted after its interruption. Higher lymphocyte count, more frequent use of steroids and shorter disease duration, before biological therapy start, have emerged as risk factors for lymphocytosis development.

Conclusions

This is the first longitudinal cohort study evaluating the onset of lymphocytosis in RA and PsA patients under anti-TNF-α treatment and its possible clinical relevance. A mild T CD4^pos lymphocytosis has been observed in 12% of RA and PsA patients probably related to anti-TNF-α treatment as previously reported by anecdotal cases. Patients with higher baseline lymphocyte count, use of steroids and shorter disease duration before the introduction of biologic therapy, seem to be prone to develop this laboratory reversible abnormality.

Cutaneous marginal zone lymphomas

Primary cutaneous marginal zone lymphoma (CMZL) is one of the major primary B-cell lymphomas of skin. Two types are recognized: a more common class-chain switched CMZL, and a much less common IgM+ CMZL. The extremely indolent course, together with other features distinct from most other MALT lymphomas, has led some to question whether at least the class-switched cases should be considered an overt lymphoma.

Antiviral therapy of hepatitis C as curative treatment of indolent B-cell lymphoma

The association of hepatitis C virus (HCV) and B-cell non-Hodgkin lymphomas (NHL) has been highlighted by several epidemiological and biological insights; however the most convincing evidence is represented by interventional studies demonstrating the capability of antiviral treatment (AT) with interferon (IFN) with or without ribavirin to induce the regression of indolent lymphomas, especially of marginal-zone origin. In the largest published retrospective study (100 patients) the overall response rate (ORR) after first-line IFN-based AT was 77% (44% complete responses) and responses were sustainable (median duration of response 33 mo). These results were confirmed by a recent meta-analysis on 254 patients, demonstrating an ORR of 73%. Moreover this analysis confirmed the highly significant correlation between the achievement of viral eradication sustained virological response (SVR) and hematological responses. Two large prospective studies demonstrated that AT is associated with improved survival and argue in favor of current guidelines’ recommendation of AT as preferential first-line option in asymptomatic patients with HCV-associated indolent NHL. The recently approved direct-acting antiviral agents (DAAs) revolutionized the treatment of HCV infection, leading to SVR approaching 100% in all genotypes. Very preliminary data of IFN-free DAAs therapy in indolent HCV-positive NHL seem to confirm their activity in inducing lymphoma regression.

MALT lymphoma: A paradigm of NF-κB dysregulation

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) invariably arises from a background of chronic microbial infection and/or autoimmune disorder at diverse mucosal sites. The prolonged chronic infection and/or autoimmunity generate active immune and inflammatory responses that provide a setting for evolution and development of autoreactive B-cells, their expansion and eventual malignant transformation following acquisition of genetic changes. The immune responses also play a critical role in sustaining the growth and survival of the transformed cells as shown by complete regression of a high proportion of MALT lymphoma of the stomach, ocular adnexa and skin following anti-microbial treatment. B-cell receptor engagement by auto-antigen as well as T-cell help including both cognate interaction and bystander help via soluble ligands such as CD40L and BAFF are thought to underpin the immunological drive in the lymphoma development through activation of the canonical and non-canonical NF-κB pathway respectively. Similarly, the three MALT lymphoma associated chromosome translocations, namely t(1;14)(p22;q32)/BCL10-IGH, t(14;18)(q32;q21)/IGH-MALT1,and t(11;18)(q21;q21)/BIRC3 (API2)-MALT1, are also capable of activating both canonical and non-canonical NF-κB pathways. Furthermore, TNFAIP3 (A20) inactivation by deletion and/or mutation abolishes the auto-negative feedback to several signalling including BCR and TLR, which connect to the canonical NF-κB activation pathway. Thus, there is a considerable overlap in the molecular pathways dysregulated by immunological drive and somatic genetic changes, strongly arguing for their oncogenic cooperation in the development of MALT lymphoma.

Splenic marginal zone lymphoma: from genetics to management

Splenic marginal zone lymphoma (SMZL) is a rare B-cell malignancy involving the spleen, bone marrow, and frequently the blood. SMZL lymphomagenesis involves antigen and/or superantigen stimulation and molecular deregulation of genes (NOTCH2 and KLF2) involved in the physiological differentiation of spleen marginal zone B cells. Diagnosis requires either spleen histology or, alternatively, the documentation of a typical cell morphology and immunophenotype on blood cells coupled with the detection of intrasinusoidal infiltration by CD20+ cells in the bone marrow. Among B-cell tumors, deletion of 7q and NOTCH2 mutations are almost specific lesions of SMZL, thus representing promising diagnostic biomarkers of this lymphoma. Although the majority of SMZLs show an indolent course with a median survival of approximately 10 years, nearly 30% of patients experience a poor outcome. No randomized trials are reported for SMZL, and few prospective trials are available. A watch-and-wait approach is advisable for asymptomatic patients. Treatment options for symptomatic patients ranges from splenectomy to rituximab alone or combined with chemotherapy. In some geographic areas, a subset of patients with SMZL associates with hepatitis C virus infection, prompting virus eradication as an effective lymphoma treatment. It would be worthwhile to explore deregulated cellular programs of SMZL as therapeutic targets in the future; improved clinical and biological prognostication will be essential for identifying patients who may benefit from novel approaches.

The spectrum of MALT lymphoma at different sites: biological and therapeutic relevance

Extranodal marginal zone (MZ) B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The best evidence of an etiopathogenetic link is provided by the association between Helicobacter pylori–positive gastritis and gastric MALT lymphoma. Indeed, successful eradication of this microorganism with antibiotics can be followed by gastric MALT lymphoma regression in most cases. Other microbial agents have been implicated in the pathogenesis of MZ lymphoma arising at different sites. Apart from gastric MALT lymphoma, antibiotic therapies have been adequately tested only in ocular adnexal MALT lymphomas where upfront doxycycline may be a reasonable and effective initial treatment of patients with Chlamydophila psittaci–positive lymphoma before considering more aggressive strategies. In all other instances, antibiotic treatment of nongastric lymphomas remains investigational. Indeed, there is no clear consensus for the treatment of patients with gastric MALT lymphoma requiring further treatment beyond H pylori eradication or with extensive disease. Both radiotherapy and systemic treatments with chemotherapy and anti-CD20 antibodies are efficacious and thus the experience of individual centers and each patient’s preferences in terms of adverse effects are important parameters in the decision process.

The role of infectious agents, antibiotics, and antiviral therapy in the treatment of extranodal marginal zone lymphoma and other low-grade lymphomas

OPINION STATEMENT

There is strong evidence to corroborate the association with Helicobacter pylori (Hp) to gastric extranodal marginal zone lymphoma (ENMZL) and hepatitis C virus (HCV) to splenic/nodal marginal zone lymphoma. Koch's postulates generally hold for these two associations and eradication of the infectious agent is well supported. Hp eradication (HPE) is recommended as front-line therapy for early stage gastric ENMZL regardless of Hp status. Complete response (CR) rate for Hp-negative patients is not as high as for Hp-positive patients; however, the benign nature of HPE and high rates of salvage allow this strategy to be safe while sparing some Hp-negative patients from systemic therapy or radiation. Similarly for HCV-seropositive patients, treatment with antivirals should be strongly considered as first-line for those who do not require immediate cytoreductive therapy or at some point even after completing chemoimmunotherapy. The controversy regarding the role for antibiotics is greatest for primary ocular adnexal lymphoma (POAL). Considering the low incidence of Chlamydia psittaci (Cp) infection with OAL and the challenges to reliably identifying Cp, we typically do not consider doxycycline in POAL treatment. Involved-field radiotherapy (IFRT) remains the treatment of choice for most with unilateral POAL. However, if reliable detection of Cp is available and Cp is identified, patients with unilateral low tumor stage POAL who do not require immediate radiotherapy could be considered for doxycycline as front-line treatment. Other infectious associations to indolent lymphomas have been made, including Borrelia borgdorferi (Bb) in cutaneous lymphoma and Campylobacter in immunoproliferative small intestinal disease (IPSID), but these associations are not as strong and primary treatment targeting the infectious agents is not recommended.

Emerging role of infectious etiologies in the pathogenesis of marginal zone B-cell lymphomas

Extranodal marginal zone B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The most frequently affected organ is the stomach, where MALT lymphoma is incontrovertibly associated with a chronic gastritis induced by a microbial pathogen, Helicobacter pylori. Gastric MALT lymphoma therefore represents a paradigm for evaluating inflammation-associated lymphomagenesis, which may lead to a deeper understanding of a possible etiologic association between other microorganisms and nongastric marginal zone lymphomas. Besides infectious etiology, chronic inflammation caused by autoimmune diseases, such as Sjögren syndrome or Hashimoto thyroiditis, can also carry a significant risk factor for the development of marginal zone lymphoma. In addition to the continuous antigenic drive, additional oncogenic events play a relevant role in lymphoma growth and progression to the point at which the lymphoproliferative process may eventually become independent of antigenic stimulation. Recent studies on MALT lymphomas have in fact demonstrated genetic alterations affecting the NF-κB) pathway, a major signaling pathway involved in many cancers. This review aims to present marginal zone lymphoma as an example of the close pathogenetic link between chronic inflammation and tumor development, with particular attention to the role of infectious agents and the integration of these observations into everyday clinical practice. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."

A retrospective international study on primary extranodal marginal zone lymphoma of the lung (BALT lymphoma) on behalf of International Extranodal Lymphoma Study Group (IELSG)

Primary lymphoma of the lung is a rare entity. Clinical features, optimal treatment, role of surgery and outcomes are not well defined, and the follow-up is variable in published data. Clinical data of 205 patients who were confirmed to have bronchus mucosa-associated lymphoid tissue lymphoma from December 1986 to December 2011 in 17 different centres worldwide were evaluated. Fifty-five per cent of the patients were female. The median age at diagnosis was 62 (range 28-88) years. Only 9% had a history of exposure to toxic substances, while about 45% of the patients had a history of smoking. Ten per cent of the patients had autoimmune disease at presentation, and 19% patients had a reported preexisting lung disease. Treatment modalities included surgery alone in 63 patients (30%), radiotherapy in 3 (2%), antibiotics in 1 (1%) and systemic treatment in 128 (62%). Patients receiving a local approach, mainly surgical resection, experienced significantly improved progression-free survival (p = 0.003) versus those receiving a systemic treatment. There were no other significant differences among treatment modalities. The survival data confirm the indolent nature of the disease. Local therapy (surgery or radiotherapy) results in long-term disease-free survival for patients with localized disease. Systemic treatment, including alkylating-containing regimens, can be reserved to patients in relapse after incomplete surgical excision or for patients with advanced disease. Copyright © 2015 John Wiley & Sons, Ltd.

Best practices in diagnostic immunohistochemistry: workup of cutaneous lymphoid lesions in the diagnosis of primary cutaneous lymphoma

CONTEXT

Primary cutaneous lymphoma is a common extranodal non-Hodgkin lymphoma. These lesions share common features with their nodal counterparts, but also have differences in morphology, unique clinical presentations, and immunohistochemical features.

OBJECTIVE

To review the 2008 World Health Organization (WHO) and 2005 consensus WHO-EORTC (European Organisation for Research and Treatment of Cancer) classifications, and address the immunohistochemical findings in the most common primary cutaneous T- and B-cell lymphomas. Since clonality testing is commonly used as an ancillary test in the evaluation of cutaneous lymphoma, a brief section in the use and pitfalls of clonality testing is included.

DATA SOURCES

The WHO and EORTC classification publications and the relevant recent literature were used to compile appropriate and practical guidelines in this review.

CONCLUSIONS

The practice of dermatopathology and hematopathology varies widely. Thus, while this review provides an overview and guideline for the workup of lymphoid lesions of the skin, the practitioner should understand the importance of clinical correlation as well as appropriate utility of available resources (such as clonality testing) in arriving at a diagnosis in cutaneous lymphoid lesions.

Management of the marginal zone lymphomas

Marginal zone lymphomas (MZL) represent around 8 % of all non-Hodgkin lymphomas. During the last decades a number of studies have addressed the mechanisms underlying the disease development. Extranodal MZL lymphoma usually arises in mucosal sites where lymphocytes are not normally present from a background of either autoimmune processes, such as Hashimoto thyroiditis or Sjögren syndrome or chronic infectious conditions. In the context of a persistent antigenic stimulation, successive genetic abnormalities can progressively hit a B-cell clone among the reactive B-cells of the chronic inflammatory tissue and give rise to a MALT lymphoma. The best evidence of an etiopathogenetic link is available for the association between Helicobacter pylori-positive gastritis and gastric MALT lymphoma. Indeed, a successful eradication of this micro-organism with antibiotics can be followed by gastric MALT lymphoma regression in more than 2/3 of cases. Other microbial agents have been implicated in the pathogenesis of MZL arising in the skin (Borrelia burgdorferi), in the ocular adnexa (Chlamydophila psittaci), and in the small intestine (Campylobacter jejuni). The prevalence of hepatitis C virus (HCV) has also been reported higher in MZL patients (particularly of the splenic type) than in the control population, suggesting a possible causative role of the virus. In non-gastric MALT lymphoma and in splenic MZL the role of the antimicrobial therapy is, however, less clear. This review summarizes the recent advances in Marginal Zone Lymphomas, addressing the critical points in their diagnosis, staging and clinical management.

Epidemiology and etiology of non-hodgkin lymphoma

Non-Hodgkin lymphoma (NHL) consists of many histologically and biologically distinct lymphoid malignancies with poorly understood, but possibly distinct, etiologies. The patterns of incidence and time trend vary not only by age, sex, and race/ethnicity in the USA, but also show significant geographic differences, suggesting the potential role of infectious agents, environmental factors, and lifestyle factors in addition to host genetic status in the development of NHL. Important pathogenetic mechanisms include immune modulation and chronic antigen stimulation. Epidemiologic studies in the past two decades have provided intriguing new insights on the possible causes of lymphoma and support the idea that there is some mechanistic commonality of lymphomagenesis, but significant etiologic heterogeneity clearly exists. This review presents a summary of the current understanding of the descriptive epidemiology and etiology of NHL and suggests areas of focus for future epidemiologic research.

[Two cases of proliferation of monoclonal and monotypic lymphocytes and plasma cells corresponding to acrodermatitis chronica atrophicans]

BACKGROUND

While a dermal proliferation of monotypic monoclonal lymphocytes and plasma cells suggests above all cutaneous marginal zone lymphoma (CMZL) or plasmacytoma, it may also correspond to a Borrelia infection of which the clinic picture is evocative, as demonstrated in the cases presented herein.

PATIENTS AND METHODS

The files of two patients were submitted for discussion at the regional multidisciplinary staff meeting on cutaneous lymphomas after review of the skin biopsies led to a diagnosis of plasmacytoma and CMZL on the basis of infiltrate containing abundant plasma cells. The infiltrates of both patients showed a kappa monotypic light chain and cutaneous B-cell clones were detected. However, the clinical features, with monomelic maculopapular rash, were evocative primarily of Borrelia infection. Diagnosis was confirmed by positive serology and clinical cure was achieved after 3 weeks of oral tetracycline, without relapse.

COMMENTS

A link between Borrelia infection and cutaneous lymphomas has long been thought to exist. Further, it is recommended that antibiotics be considered in CMZL before undertaking systemic therapy. The classic histological appearance of the tertiary phase of early-stage Lyme's disease shows perivascular and periadnexal infiltrate comprising lymphocytes and plasma cells. At the later stages, epidermal atrophy occurs with thinning of the dermis. The monoclonal and monotypic nature of skin proliferation points above all to CMZL or plasmacytoma. However, clinicopathological correlation is an essential step before such a diagnosis may be made. In the event of monomelic erythema, as in our patients, it is important to screen for Borrelia infection, which responds well to appropriate treatment.

[A case of Lyme neuroborreliosis coexistent with T-cell lymphoma]

An 80-year-old Japanese man developed sensory disturbance of his extremities. One week after the onset of sensory disturbance, he also developed bilateral facial nerve palsy, weakness of the extremities, vesicorectal disturbance, general fatigue, and syndrome of inappropriate antidiuretic hormone secretion (SIADH). His symptoms worsened gradually. Despite the absence of apparent tick bite and characteristic skin lesions, we suspected Lyme neuroborreliosis (LNB) because of pleocytosis and elevated protein levels in the cerebrospinal fluid (CSF), in addition to the aforementioned symptoms. After combined administration of antibiotics and steroids, his symptoms improved rapidly. CSF showed highly elevated levels of the chemokine CXCL-13 and his serum was positive for IgM against Borrelia afzelii. Therefore, we diagnosed him as having LNB. He developed an exacerbation of SIADH and generalized fatigue during the course of LNB. His condition deteriorated despite further administration of antibiotics and steroids. Bone marrow aspiration revealed the presence of medium- to large-sized atypical lymphoma cells and lymphoma cells positive for CD8 but negative for CD45. Therefore, we diagnosed T-cell lymphoma. In recent years, an association between Borrelial infection and lymphoma development has been suspected. Borrelia afzelii infection may have been involved in the development of T-cell lymphoma in this case.

Kutane Lymphome

Kutane Lymphome (cutaneous lymphomas: CL) umfassen die Gruppe der kutanen T-Zell-Lymphome (cutaneous T-cell lymphomas: CTCL), kutanen B-Zell-Lymphome (cutaneous B-cell lymphomas: CBCL) und die sog. hämatodermischen Neoplasien (HN). CL gehören zur Gruppe der Non-Hodgkin-Lymphome (NHL) und stellen in der Subgruppe der extranodalen NHL die zweithäufigste Gruppe hinter den gastrointestinalen Lymphomen dar (Jaffe et al. 2009). Man unterscheidet zwischen primären und sekundären CL. Primäre CL haben ihren Ursprung in der Haut und bleiben in der Regel darauf auch längere Zeit beschränkt, während sekundäre LymphomekutaneCL kutane Manifestationen von primär nodalen oder extranodalen Lymphomen darstellen (Willemze 2005). Die primären CL unterscheiden sich hinsichtlich klinischem Verlauf, Therapieoptionen und Prognose erheblich von nodalen und extrakutanen Lymphomen. So zeigen z. B. die primär kutanen CD30⁺ Lymphome einen gutartigen Verlauf, wogegen die nodalen Varianten als aggressiv eingestuft werden. Da die CL zumeist weniger aggressiv sind, werden sie weniger aggressiv behandelt.

Marginal zone lymphomas and infectious agents

A link with infectious agents, bacteria and viruses in particular, has been reported for many lymphoma entities. Marginal zone lymphomas (extranodal, nodal and splenic forms) are frequently associated with chronic infections, with important clinical, molecular, biological, and therapeutic implications. The well-known correlation between Helicobacter pylori and gastric MALT-lymphoma, the recently reported links between Chlamydophila psittaci and ocular adnexal MALT-lymphoma and Borrelia burgdorferi and cutaneous MALT lymphoma constitute the best studied examples of lymphomagenic activity of bacteria, while the hepatitis C virus represents the most extensively investigated virus associated with marginal zone lymphomas. Biological and clinical features, therapeutic implications and future perspectives of these lymphoma-microbial associations are discussed in this review.

Molecular and genomic aberrations in Chlamydophila psittaci negative ocular adnexal marginal zone lymphomas

The etiology and pathogenesis of ocular adnexal extranodal marginal zone lymphoma (OAEMZL) are still unknown and the association with Chlamydophila psittaci (C. psittaci) has been shown in only some geographic regions. Herein, we comprehensively examined the frequency of chromosomal translocations as well as CARD11, MYD88 (L265P), and A20 mutations/deletions in 45 C. psittaci negative OAEMZLs. t(14;18)(q32;q21) IGH-MALT1 and t(11;18)(q21;q21) API2-MALT1 were not detected in any of the analyzed tumors while three tumors harbored IGH translocations to an unidentified partner. CARD11 mutations were not found in all analyzed tumors, while the MYD88 L265P mutation was detected in three (6.7%) tumors. A20 mutations and deletions were each detected in seven (15.6%) and six (13.3%) tumors, respectively. Therefore, the observed genetic aberrations could account for the activation of the nuclear factor (NF)-kB signaling pathway in only a minority of the cases. Further studies are needed to identify the molecular mechanisms underlying the pathogenesis of OAEMZL.

Antibiotic therapy in nongastrointestinal MALT lymphoma: a review of the literature

Although antibiotic therapy has been established as the standard of care in patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma, much less is known about the value of antibiotic therapy in nongastrointestinal (non-GI) MALT lymphomas. A computerized search (Medline) accompanied by a manual search to identify clinical reports on the topic of antibacterial therapy in patients with non-GI MALT lymphomas was performed. The majority of data were available for MALT lymphoma of the ocular adnexa (OAML) including a total of 131 patients in 4 retrospective studies, 3 prospective series (including 81 patients), and 1 case report. Treatment was exclusively targeting Chlamydophila psittaci (CP), using doxycycline in all but 2 studies. The median follow-up for these studies was 25 months, and both CP-positive as well as CP-negative patients responded. Complete remission was achieved in 23 patients (18%), 36 (27%) had a partial remission, 55 (42%) had stable disease, and 8 patients (6%) had progressive disease accounting for an overall response rate of 45%. In the largest study, a better response was suggested in CP-positive patients. By contrast, only scattered reports could be found for other non-GI localizations, allowing no conclusion about the benefit of antibiotic therapy and probably resulting in a publication bias toward positive cases. Based on these results, antibiotic therapy using doxycycline appears to be a reasonable first-line therapy for patients with OAML. Antibiotics, however, remain experimental for the time being in patients with other non-GI MALT lymphomas. Further preclinical studies as well as large-scale therapeutic trials are warranted to define the role of antibiotic therapy in such patients.