Characterization of prelymphomatous stages of B cell lymphoproliferation in Sjögren's syndrome

Identification of transitional type II B cells in the salivary glands of patients with Sjögren's syndrome

OBJECTIVE

To identify B cell subpopulations participating in the lymphocyte infiltrate of salivary glands from patients with primary Sjögren's syndrome. A special emphasis was placed on those B lymphocytes included in the ectopic germinal centers (GCs).

METHODS

The presence of B cells in salivary glands and their polyclonality were ascertained by phenotyping and reverse transcription-polymerase chain reaction in salivary gland samples from 18 patients. Their phenotype was thoroughly analyzed using a number of double-staining combinations. The results obtained in tissue sections were confirmed by fluorescence-activated cell sorting analysis of B cells eluted from salivary glands, and these findings were compared with those in tonsils.

RESULTS

Memory-type B cells were defined as CD20+, CD27+ and were seen in all specimens, whereas GCs were found in only 7 specimens. Furthermore, B cells found in these GCs lacked certain characteristics of centroblasts and centrocytes. Instead, they fulfilled the criteria for transitional type II (TII) B cells and resembled marginal-zone B cells. BAFF (the assistance of which is required for proper transformation of transitional TI B cells into transitional TII B cells) accumulated adjacent to transitional and marginal-zone-like B lymphocytes. Further evidence for the involvement of BAFF came from the expression of its receptors on infiltrating B cells.

CONCLUSION

These transitional TII and marginal-zone-like B cells are probably instrumental in the local production of autoantibodies and possibly influential in the ensuing destruction of epithelial cells.

Role of complement and B lymphocytes in Sjögren's syndrome-like autoimmune exocrinopathy of NOD.B10-H2b mice

Sjögren's syndrome (SjS) is a human autoimmune disease characterized by the loss of exocrine function as a result of a chronic immune attack directed primarily against the salivary and lacrimal glands leading to xerostomia (dry mouth) and xerophthalmia (dry eyes). NOD.B10-H2b mice manifest many features of SjS, exhibiting exocrine gland dysfunction concomitant with leukocyte infiltration of the salivary and lacrimal glands. Recent studies have shown that both SjS patients and NOD.B10-H2b mice exhibit increased B lymphocyte survival, B cell hyper-reactivity and hyper-gammaglobulinemia with high production of autoantibodies. To study the possible influence of complement on the development and expression of SjS-like disease of the NOD.B10-H2b, we have utilized a prophylactic treatment with CVF known to interfere with the action of complement C3 factor. NOD.B10-H2b mice, injected with CVF starting at 10 weeks of age, a time when leukocyte infiltration is expected to begin, failed to develop salivary dysfunction out to 24 weeks of age, a time when reduced salivary flow rates are known to occur in non-treated animals. Concomitant with retention of salivary exocrine function, CVF-treated mice showed reduced levels of leukocytic infiltration, reduction of anti-nuclear autoantibodies and major alterations in the B lymphocyte profiles while maintaining general pathophysiological measures of disease. These data suggest that C3 plays a significant role in development and onset of SjS-like disease, yet additional studies need to be carried out to identify the precise mode of action.

Lymphoproliferative disorders in Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic organ-specific autoimmune disease characterized by lymphocytic infiltration into the salivary and lacrimal glands. About half of primary SS patients develop systemic disorders. Primary SS can be divided into three stages according to the extent of organ damage and the course of the disease. In stage I, (approx. 45% of cases), patients have only sicca syndrome and do not experience any systemic involvement, even after 10 years. In stage II (approx. 50% of cases), patients experience lymphocytic organ damage, which may involve the pulmonary, renal, hepatic, hematologic, and/or dermatologic systems, among others. Finally, in stage III (approx. 5% of cases), patients develop malignant lymphomas. Lymphomas in salivary glands are thought to arise from lymphoepithelial lesions in which there are close interactions among epithelial cells, T cells, and B cells. The B cells in the lesions become activated through the interaction between CD40L and CD40. The progression from polyclonal lymphoproliferation to monoclonal lymphoproliferation, to mucosa-associated lymphoid tissue (MALT) lymphoma, and finally to high-grade malignant lymphoma is regarded as a multi-step process. Antigenic activation of B cells, together with oncogenic events, including p53 inactivation and bcl-2 activation, may play important roles in B cell monoclonal proliferation and malignant transformation. The rheumatoid factor clone is regarded as a candidate B cell clone that undergoes transformation.

Rheumatoid arthritis and malignant lymphomas

PURPOSE OF REVIEW

The reason for the increased lymphoma risk in patients with rheumatoid arthritis (RA) has remained unclear. Reports of lymphomas in patients treated with TNF-blockers have brought renewed interest in this issue. This review summarizes data on possible associations between RA and lymphomas, including different treatments and RA disease related risk factors.

RECENT FINDINGS

Some recent studies reported increased lymphoma risks linked to RA disease activity. The hypothesis that disease-modifying drugs, and in particular methotrexate, would increase the lymphoma risk receives little support. Observation times for the TNF-blocking therapies are still short, but so far no clear increased risk for lymphoma has been observed. Presence of Epstein-Barr virus, as analyzed with EBER in situ hybridization, appears to be uncommon in RA related lymphomas. Hypothetically, an increased proliferative drive caused by self or non-self antigens may play a role in lymphoma development in RA patients, but this has to be further studied.

SUMMARY

Rheumatologists need to be aware of the increased lymphoma risk in their RA patients. The reason for the increased lymphoma risk in RA patients is still unclear, but available studies rather support the hypothesis of a link between RA disease severity and the risk of lymphoma than increased risks associated with specific treatment regimens. To facilitate the future evaluation of lymphoma risks in connection with treatment, we suggest that patients treated with new drugs should be subject to structured surveillance. Collected information should include data about RA disease activity and severity.

Clonality analysis of alveolar B lymphocytes contributes to the diagnostic strategy in clinical suspicion of pulmonary lymphoma

The diagnostic procedure of chronic pulmonary opacities may envisage the search for non-Hodgkin lymphoma (NHL). Previous retrospective studies have shown that clonality analysis of bronchoalveolar B lymphocytes could reflect the clonality of pulmonary lymphocytes. Our objective was to define the diagnostic usefulness of bronchoalveolar lavage (BAL) B-lymphocyte clonality analysis in the setting of a clinical suspicion of both primary and secondary pulmonary lymphoma. A prospective BAL fluid B-cell clonality analysis was performed by polymerase chain reaction (PCR) in 106 consecutive patients presenting with a clinical suspicion of pulmonary NHL. Diagnosis was pulmonary B-cell lymphoma for 22 patients (13 primary and 9 secondary). When compared, pulmonary biopsy and BAL fluid have clonal identity. The detection of a strong B-cell clonal population in BAL fluid was associated with the diagnosis of pulmonary NHL (P <.0001), with a 97% specificity and a 95% negative predictive value. Thus, the absence of a dominant B-cell clone detection in BAL fluid could help to dismiss invasive investigations of pulmonary lesions. The detection of a dominant B-cell clone would lead to the performance of a pulmonary biopsy to get histologic diagnosis in primary pulmonary lymphoma and, by contrast, would avoid the need for biopsy in the setting of a secondary pulmonary lymphoma.

Analysis of B-cell clonality in the hepatic tissue of patients with Sjögren's syndrome

OBJECTIVE

We investigated the incidence of B-cell clonality in the minor salivary gland and liver (extra-glandular lesion) of patients with Sjögren's syndrome (SS). We also compared B-cell clonality in the minor salivary gland and liver in the same individuals, and compared its incidence among patients with various liver diseases, such as primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH).

METHODS

A minor salivary gland biopsy was performed on 35 patients with SS (30 patients with primary SS, and five patients with secondary SS). A liver biopsy was performed on nine patients with SS associated with bile duct lesions, two patients with PBC, one patient with AIH, one patient with drug-induced liver dysfunction, and three patients with viral hepatitis. DNA was extracted from each tissue sample and then subjected to Polymerase Chain Reaction (PCR). B-cell clonality was analysed by assessing the rearrangement of the immunoglobulin heavy chain (IgH) gene by PCR.

RESULTS

B-cell clonality was confirmed in the minor salivary gland biopsy sample in 23 of the 35 patients (65.7%), and in the liver biopsy sample (non-exocrine organ involvement) in seven of the nine patients (77.8%). The presence or absence of B-cell clonality was investigated in both the minor salivary gland and liver in seven patients, but B-cell clonality was confirmed in both tissues in only one patient, and the pattern of clonality in the minor salivary gland differed from that in the liver. B-cell clonality was detected in the liver of the PBC and AIH patients.

CONCLUSION

B-cell clonality is a phenomenon that is observed frequently in SS lesions in the salivary glands and liver. The appearance of B-cell clonality was shown to be attributable to antigen-driven clonal expansion.

Extrasalivary lymphoma development in Sjögren's syndrome: clonal evolution from parotid gland lymphoproliferation and role of local triggering

OBJECTIVE

To characterize Sjögren's syndrome (SS)-related B cell lymphoproliferation at the premalignant stage and during the evolution to B cell lymphoma, and to better understand the pathobiologic mechanisms associated with clonal expansion and the possible influence of different microenvironments on neoplastic transformation.

METHODS

We analyzed sequential parotid and lung biopsy specimens that were obtained from a single patient with SS at multiple time points over a 7-year period. Polymerase chain reaction DNA amplification, cloning, and sequencing of the immunoglobulin heavy chain variable region showed clonality, somatic mutations, intraclonal heterogeneity, and genealogic relationships of the B cell clones in the different biopsy specimens.

RESULTS

The evolution of a nonmalignant B cell clone that was present in the parotid gland and evolved into a B cell lymphoma was documented. During such a process, one subclone was selected that accumulated somatic mutations in a pattern consistent with the preservation of antigen receptor functionality, possibly attributable to continued hypermutation and selection. Intraclonal diversity indicated the presence of local triggers in both the parotid and lung microenvironments.

CONCLUSION

Molecular followup of B cell lymphoproliferation in SS, from nonmalignant stage to overt B cell lymphoma, indicated a role for B cell receptor engagement in clonal survival. The outgrowth of one subclone, with malignant transformation in the lung, a target organ different from the initial site of the lymphoproliferative process (the parotid gland), indicates that resident stimuli in different microenvironments may locally sustain ongoing lymphoproliferation and B cell transformation.

Lymphoproliferation in autoimmunity and Sjögren’s syndrome

Sjögren's syndrome is a chronic inflammatory process involving primarily the exocrine glands. Its association with lymphoma is well documented. A low-grade marginal-zone lymphoma related to mucosa-associated lymphoid tissue is the most common lymphoid neoplasia in Sjögren's syndrome. Among all autoimmune diseases, Sjögren's syndrome is the best tool to clarify the multiple components of autoimmunity and lymphomatogenesis. Herewith, the authors review the literature and discuss the molecular, clinical, histopathologic, and therapeutic aspects of these tumors in Sjögren's syndrome.

[Diagnosis of the Mikulicz-Sjogren syndrome using biopsy of the minor salivary glands]

BACKGROUND

Sjögren's syndrome (SS) represents autoimmune disease characterized by chronic inflammation, destruction and insufficiency of exocrine glands, particularly salivary and lacrimal glands, accompanied by dryness of mouths and eyes. Diagnostic work-up involves clinical laboratory tests, radiography, scintigraphy and bioptic histopathological examination. Examination of small salivary glands in the biopsy of the lower lip represents a "golden standard" of diagnosis of SS, concerning the fact that the growth and the disfunction of salivary and lacrimal glands occurs in different pathologic states.

METHODS

Resected specimens of the lower lip were obtained from 47 patients with clinical diagnosis of SS. After standard histopathological treatment, slices were hematoxylin and eosin stained. Immunohistochemistry against smooth muscle actin was performed using LSAB+ method (AHSMA-M7558, DAKO 1:50). On the basis of generally accepted histopathological diagnostic criteria the results were categorized as: findings suspicious for SS; findings compatible with the diagnosis of SS (mild, moderate and high degree of inflammation); nonspecific inflammatory reaction and nonrepresentative biopsy samples.

RESULTS

Diagnosis of SS was confirmed in 32% of cases. In 2% of cases findings were suspected for SS, in 36% of cases findings were compatible with the diagnosis of nonspecific inflammation, and in 30% of cases material was not representative.

CONCLUSIONS

By the biopsy of salivary glands of the lower lip the diagnosis of SS was confirmed in 50-60% of cases. Upon the precise diagnostic criteria it was also possible to determine the intensity of inflammation and tissue destruction in SS and identify other pathological conditions, which justified the biopsy. Surgical technique had to be adequate in order to obtain representative number of small salivary glands. In the presented material 30% of specimens were nonrepresentative which was very high percentage compared with literature data. This was most probably the reason why the diagnosis of SS was confirmed in only 32% of cases, i.e., in every third patient.

Efficacy of selective B cell blockade in the treatment of rheumatoid arthritis: evidence for a pathogenetic role of B cells

OBJECTIVE

The pathogenetic role of B cells in rheumatoid arthritis (RA) is under debate, but it is currently believed to be marginal. The availability of selective anti-B cell treatment provides a unique opportunity to clarify this issue. This study was undertaken to investigate the effects of B cell blockade in the treatment of refractory RA, and to evaluate the implications with regard to the role of B cells in the disease.

METHODS

Five female patients with active, evolving erosive RA were treated with rituximab, an anti-CD20 chimeric monoclonal antibody. All 5 patients had been nonresponders to combination therapy with methotrexate plus cyclosporin A. Two of the 5 had also failed to respond to anti-tumor necrosis factor alpha therapy. All of these treatments were discontinued 1 month before institution of anti-CD20 therapy.

RESULTS

Marked clinical improvement was observed in 2 patients (American College of Rheumatology 70% response [ACR70] and ACR50, respectively), starting at the end of the second month after institution of anti-CD20 therapy (month 2) and lasting until month 10 in 1 patient (articular relapse) and month 12 in the other (last followup). ACR20 response was observed in 2 additional patients, lasting until month 5 and month 7, respectively (articular relapse in both). Decrease or normalization of serum C-reactive protein and rheumatoid factor levels were observed in these patients. In contrast, patient 3 had no response to the treatment. RA synovitis and evolving erosive damage were decreased in patients exhibiting a major response, as demonstrated by imaging studies.

CONCLUSION

Our finding of the clinical efficacy of selective B cell blockade indicates that B cells play a critical role in rheumatoid synovitis, at least in a subset of patients. Qualitative or quantitative differences in B cell commitment in RA pathobiology might have a function in the different responses observed.

Abnormalities of B cell phenotype, immunoglobulin gene expression and the emergence of autoimmunity in Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune disorder characterized by specific pathologic features and the production of typical autoantibodies. In addition, characteristic changes in the distribution of peripheral B cell subsets and differences in use of immunoglobulin variable-region genes are also features of pSS. Comparison of B cells from the blood and parotid gland of patients with pSS with those of normal donors suggests that there is a depletion of memory B cells from the peripheral blood and an accumulation or retention of these antigen-experienced B cells in the parotids. Because disordered selection leads to considerable differences in the B cell repertoire in these patients, the delineation of its nature should provide important further clues to the pathogenesis of this autoimmune inflammatory disorder.

Lymphomas complicating Sjögren's syndrome and hepatitis C virus infection may share a common pathogenesis: chronic stimulation of rheumatoid factor B cells

BACKGROUND

The occurrence of B cell non-Hodgkin's lymphoma is a complication of Sjögren's syndrome (SS) and, at least in some countries, of chronic hepatitis C virus (HCV) infection. Lymphomas occurring in both diseases share a number of characteristics: predominance of low grade, marginal zone histological type, frequency of mucosal localisation, possible transformation into a large B cell lymphoma, association with asymptomatic low level cryoglobulinaemia, absence of virus within lymphoma cells, but localisation of lymphomas in organs where the chronic viral infection is active in patients with HCV and where the autoimmune disease is active in patients with SS.

HYPOTHESIS

It is proposed that in both diseases the first event of lymphomagenesis is the chronic stimulation at the site of the disease of polyclonal B cells secreting rheumatoid factor (RF). Then, that these RF B cells may become monoclonal and disseminate in other organs. The monoclonal secreted RF complexed with polyclonal IgG may cryoprecipitate. The following step would be a chromosomal abnormality (for example, trisomy 3 or bcl-2 translocation) which would confer to these cells a low grade B cell lymphoma comportment. A last event (for example, a mutation of p53) might transform this low grade B cell lymphoma into a high grade, large B cell lymphoma. The non-random utilisation of VH and VL by SS associated lymphoma B cells and the recent demonstration that these lymphoma B cells may display RF activity support the hypothesis that these lymphomas grow through an autoantigen driven process.

CONCLUSION

The best preventive treatment of lymphoproliferations occurring in SS probably consists in decreasing the hyperactivation of autoreactive B cells when it is present, allowing the use of immunosuppressive drugs such as methotrexate or even tumour necrosis factor alpha antagonists, which in theory could favour other types of lymphoproliferation.

The cryoglobulins: an overview

Cryoglobulins are cold-precipitable immunoglobulins associated with a number of infectious, autoimmune and neoplastic disorders. Their appearance along with rheumatoid factor (RF) can be considered a normal event in the clearance of immune complexes and rarely produces any symptoms. The association between hepatitis C virus (HCV) and mixed cryoglobulinemia (MC) has been rendered evident since the recognition of serological markers of HCV infection. There is thus every reason to suppose that direct or indirect involvement of B cells on the part of the HCV results in their persistent stimulation, clonal expansion and release of molecules with RF activity. The formation of RF/IgG immune complexes is the key pathogenetic mechanism. The close correlation between HCV infection and MC also throws new light on the interpretation of autoimmune phenomena in the course of viral infection and on the close link between autoimmune diseases and lymphoproliferative disorders. The higher risk of non-Hodgkin's lymphoma (NHL) displayed by HCV positive subjects, especially in the Mediterranean basin, suggests that the HCV's chronic lymphoproliferative drive may progress towards frank lymphoid neoplasia. The presence of MC does not represent an in situ or 'occult' NHL, because recent evidences indicate that none of the clones interpreted as predominant displays the molecular features of a true neoplastic process. The cryoglobulinemic syndrome is probably the consequence of pathogenic noxae that act upon the immune system of a host in which regulation of the peripheral T cell response appears to be in some way altered.

Preliminary classification of nonmalignant B cell proliferation in Sjögren's syndrome: perspectives on pathobiology and treatment based on an integrated clinico-pathologic and molecular study approach

A classification of nonmalignant lymphoproliferation in Sjögren's syndrome is presented, based on the results of international meetings regarding Sjögren's syndrome-associated lymphomagenesis and on our results of a clinico-pathologic and molecular study and long-term follow-up in well-characterized patients. Sjögren's syndrome pathobiology has similarities to hepatitis C virus-related B-cell lymphoproliferation. Antigen stimulation with the preferential expansion of rheumatoid factor-positive clones and specific immunoglobulin gene expression and recombination represent key biologic events in lymphoproliferation. This classification is based on the coupling of molecular and histological studies and may result in more selective treatment approaches.

Will the “new biology” Affect the Future of Histopathology?

The technologies used in histopathology are changing as a consequence of the current revolutionary progress in several areas of biology. It is likely that general cancer management will improve because of the impact of molecular techniques and immunohistochemistry on tumor diagnosis and classification and on the determination of prognosis and response to therapy. Moreover, as therapies are starting to be modelled after the distinctive molecular characteristics of a specific tumor, the availability of molecular tests to all patients will become a matter of great importance.

Pathological features of lymphoid proliferations of the salivary glands: lymphoepithelial sialadenitis versus low-grade B-cell lymphoma of the malt type

Lymphoid proliferations of the salivary glands can be either reactive or neoplastic. Reactive lesions include the lymphoepithelial sialadenitis (LESA; also known as myoepithelial sialadenitis [MESA]) of Sjogren's syndrome. Lymphomas of the salivary glands are predominantly B-cell type and include extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) type. The spectrum of histopathologic features of LESA/MESA includes 1) "fully benign lymphoid infiltrate," with or without an associated lymphoid follicular structure, without immunoglobulin (Ig) light chain restriction in B-cells, and without any features of aggressive behavior, and 2) "lymphoproliferative lesions," with or without areas of Ig light chain restriction in B-cells, with the usual presence of centrocyte-like cells. A more or less pronounced lymphoepithelial aggressiveness may be present without definite evidence of malignancy. B-cell clones are detected in over 50% of cases of LESA/MESA by molecular genetic methods, but this does not correlate with morphological or clinical evidence of overt lymphoma. On the other hand, "marginal zone B-cell lymphoma of the MALT type" of the salivary glands produces a dense lymphoid infiltrate diffusely involving the gland, with obliteration of acini. The centrocyte-like cells form broad "halos" around the epithelial cell nests and broad strands between lymphoepithelial lesions, often linking together several lymphoepithelial lesions. Further, lymphoma cells express monotypic surface Ig, and in the majority of the cases, the plasma cells are also monoclonal. In conclusion, the diagnosis of LESA/MESA versus marginal zone B-cell lymphoma of the MALT type still relies on the evaluation of morphological features. It seems that molecular genetic analysis has little or no practical role in the clinical diagnosis of salivary gland lymphoma in a setting of LESA/MESA and Sjögren's syndrome.

Pre-malignant and malignant lymphoproliferations in an HCV-infected type II mixed cryoglobulinemic patient are sequential phases of an antigen-driven pathological process

Type II mixed cryoglobulinemia (MC) is a systemic vasculitis characterized by the presence in the serum of a monoclonal cryoprecipitable IgM with rheumatoid factor (RF) activity. Hepatitis C virus (HCV) has been recognized as its major etiologic factor. Because MC frequently evolves into overt B-cell non-Hodgkin's lymphoma (NHL), chronic HCV infection is hypothesized to lead to both benign and malignant lymphoproliferative disease. In this study, we investigated mutations in the V(H) and V(K) genes of the B-cell clone originating the overt B-cell lymphoma in a subject with MC. Mutational patterns were analyzed longitudinally in two bone marrow biopsies obtained at the stage of MC, as well as in multiple involved tissues (bone marrow, liver, and peripheral blood cells) at the stage of overt NHL. Hybridization of variable-diversity-joining (VDJ) PCR products with a probe specific for the neoplastic clone indicated that the lymphoma originated from one of the clones over-stimulated during MC. This clone producing an IgM highly homologous to a protein with RF specificity may explain the MC syndrome in the patient. Moreover, the presence of an IgH ongoing mutation process and the expression of an Ig antigen receptor significantly homologous to an anti-HCV protein support the hypothesis that the MC syndrome and the subsequent evolution to NHL are antigen-driven lymphoproliferative processes possibly sustained by HCV. Furthermore, the marked reduction in intra-clonal diversity in the last bone marrow biopsy obtained at the stage of overt NHL points out a minor dependence of the cells on the antigen-driven mechanism, although an intrinsic propensity of the neoplastic cell to undergo replacement mutations cannot be excluded.

Gastric mucosa as an additional extrahepatic localization of hepatitis C virus: viral detection in gastric low-grade lymphoma associated with autoimmune disease and in chronic gastritis

The hepatitis C virus (HCV) has been linked to B-cell lymphoproliferation and autoimmunity, and has been localized in several tissues. The clinical observation of an HCV-infected patient with Sjögren's syndrome (SS) and Helicobacter pylori (HP) positive gastric low-grade B-cell non-Hodgkin's lymphoma (NHL), which did not regress after HP eradication, led us to investigate the possible localization of HVC in the gastric microenvironment. HCV genome and antigens were searched in gastric biopsy specimens from the previously mentioned case, as well as from 9 additional HCV-infected patients (8 with chronic gastritis and 1 with gastric low-grade B-cell NHL). HCV-specific polymerase chain reaction (PCR) and immunohistochemistry procedures were used. The gastric B-cell NHL from the patient with SS was characterized by molecular analyses of B-cell clonality. HCV RNA was detected in both the gastric low-grade B-cell NHL and in 3 out of 6 gastric samples from the remaining cases. HCV antigens were detected in the residual glandular cells within the gastric B-cell NHL lesions, in glandular cells from 2 of the 3 additional gastric lesions that were HCV positive by PCR, and in 1 additional chronic gastritis sample in which HCV-RNA studies could not be performed. By molecular analyses, of immunoglobulin genes, the B-cell NHL from the patient with SS was confirmed to be a primary gastric lymphoma, subjected to ongoing antigenic stimulation and showing a significant similarity with rheumatoid factor (RF) and anti-HCV- antibody sequences. Our results show that HCV can localize in the gastric mucosa.

Oligoclonal non-neoplastic B cell expansion is the key feature of type II mixed cryoglobulinemia: clinical and molecular findings do not support a bone marrow pathologic diagnosis of indolent B cell lymphoma

OBJECTIVE

Type II mixed cryoglobulinemia (type II MC) is often characterized by features of indolent B cell lymphoma (IBCL) found on pathologic examination of bone marrow, whereas the clinical evidence does not indicate a neoplastic disorder. To better address the issue of indolent malignant versus nonmalignant bone marrow lymphoproliferation underlying type II MC, molecular analyses of B cell clonality were performed in the present study, in conjunction with clinical and pathologic characterization.

METHODS

Polymerase chain reaction DNA amplification of immunoglobulin heavy chain genes was performed in bone marrow biopsy specimens obtained from 15 selected patients with type II MC, all infected with hepatitis C virus. Five of them had also developed overt B cell lymphoma (OBCL) during followup. Bone marrow features were consistent with IBCL in 9 of the 15 patients (group 1) and with reactive lymphoplasmacytosis in 6 of the 15 (group 2).

RESULTS

An oligoclonal B cell expansion was detected in 6 of 9 baseline bone marrow lesions from group 1 patients (biclonal or monoclonal expansion in the remaining 3 cases), and in 6 of 6 from group 2 patients. OBCL was always monoclonal. Selected lesions were analyzed by clonospecific hybridization and by cloning and sequence analysis in patients who had developed OBCL at followup. In 4 of 5 cases, OBCL did not originate from the dominant B cell clones that were overexpanded in the putative neoplastic baseline bone marrow lesions. OBCL clones showed significant homology with rheumatoid factor database sequences.

CONCLUSION

Based on the present results, as well as on evidence from previous studies of liver lesions, oligoclonal non-neoplastic B cell proliferation in the course of chronic infection-related inflammation appears to be the key feature of type II MC. Of note, molecular evidence from target tissues supports the clinical findings both at the time of type II MC diagnosis and in cases of OBCL complication. Bone marrow pathologic findings resembling those of IBCL should thus be considered in the light of clinical and molecular evidence.

Lymphomas in patients with Sjögren's syndrome: review of the literature and physiopathologic hypothesis

The occurrence of non Hodgkin's lymphoma (NHL) is the most serious complication of Sjögren's syndrome (SS). Taking the opportunity to study 16 patients with lymphoma and an underlying SS, we performed a review of literature concerning SS and lymphoma and made an hypothesis on the physiopathology of lymphoproliferation in patients with SS. Lymphomas occurring in patients with SS are in most cases low grade marginal zone lymphomas (MZL). They arise frequently in mucosal extranodal sites, not only in the salivary glands but also the stomach and the lung. These lymphomas are not associated with viruses including hepatitis C virus (HCV), Epstein-Barr virus, human herpes virus 8 or human T lymphotropic virus-I, known to be present in other types of lymphomas. Some of the translocations or mutations of oncogenes or anti-oncogenes described in other lymphomas are also detected in SS-associated lymphomas. Lymphomas complicating SS share a number of characteristics with lymphomas complicating HCV infection. We make the assumption that, in both diseases, the first event of lymphomagenesis is the chronic stimulation, on the site of the disease, of polyclonal B-cells secreting rheumatoid factor (RF). Then, these RF B-cells may become monoclonal and disseminate in other organs. The monoclonal secreted RF complexed with polyclonal IgG may cryoprecipitate. The following step would be a chromosomal abnormality (e.g. trisomy 3) which would confer to these cells a low grade B-cell lymphoma compartment. A last event (e.g. mutation of p53) could transform this low grade B-cell lymphoma into a high grade large B-cell lymphoma. If this hypothesis was correct, most of B-cell lymphomas associated with SS should have a surface immunoglobulin with RF activity and should grow through an auto-antigen driven process.

Pulmonary manifestations of Sjögren's syndrome

Sjögren's syndrome is one of the most common systemic rheumatic diseases. Pulmonary disease is prevalent in Sjögren's syndrome; respiratory manifestations include chronic cough, obstructive airways disease, pulmonary lymphoma, and interstitial lung disease that may progress to severe pulmonary fibrosis.

[Gougerot-Sjögren syndrome and malignant lymphoproliferative syndromes]

INTRODUCTION

This review is aimed at defining the frequency, anatomical and clinical presentation, pathogenesis, predictive factors and treatment of malignant lymphoproliferative diseases occurring in the course of Sjögren's syndrome.

CURRENT KNOWLEDGE AND KEY POINTS

The frequency of non-Hodgkin's lymphoma (NHL) is estimated to be about 7%. Other malignant lymphoproliferative diseases (Waldenstrom's macroglobulinemia, multiple myeloma, Hodgkin's disease) are rarely observed. NHL is most frequently extranodal (affecting the salivary glands, stomach, lung, etc) in low grade malignancy (MALT lymphoma [mucosa associated lymphoid tissue]). The pathogenesis of NHL in Sjögren's syndrome is a multi-step process, including B cell monoclonal proliferation, oncogenic and/or infectious agents, and/or cytokines. Various predictive factors such as persistent enlargment of parotid glands, adenopathy, splenomegaly, mixed cryoglobulinemia, monoclonal gammopathy, suggest potential lymphoma evolution. The treatment of Sjögren's syndrome-associated NHL depends on the type of lymphoma. Moreover, in patients with low-grade lymphoma therapeutical strategies varies according to the stage and evolution of the disease.

FUTURE PROSPECTS AND PROJECTS

Future prospective longitudinal studies should permit to define the best criteria for malignant transformation and to improve therapeutical strategies.

Clonal Analysis of Intrahepatic B Cells from HCV-Infected Patients With and Without Mixed Cryoglobulinemia

Clonal rearrangements of Ig heavy chain (IgH) genes and hepatitis C virus (HCV) genomic sequences were assayed on intrahepatic B lymphocytes isolated from HCV chronically infected patients with and without type II mixed cryoglobulinemia (MC). Liver tissue samples from eight patients with and nine without MC were subjected to routine histologic studies, immunophenotyping, and genotypic analysis including IgH V-D-J region gene rearrangements by PCR. RT-PCR, signal amplification by branched DNA assay, and in situ hybridization technique were used to detect and quantitate HCV RNA genomic sequences in selected B cells purified from each tissue sample. Although HCV infection of intrahepatic B cells was shown in all patients both with and without MC, frank B cell monoclonal and oligoclonal patterns were found in only three and four patients with MC, respectively. No monoclonal profile was seen in the noncryoglobulinemic patients, whereas an oligoclonal profile was demonstrated in four of them. No clonalities were shown in HCV-unrelated patients matched for age and severity of liver disease. No obvious difference in HCV genotype distribution was found in relation to the clonal expansion profile. Noncryoglobulinemic patients showing clonal expansion in liver tissue had higher titers of serum rheumatoid factor (RF). Spontaneous production of RF was shown in cell cultures of intrahepatic B cells, suggesting their persistent stimulation in vivo. These data indicate that HCV infection of B cells and B cell clonal expansions occur in the liver microenvironment and preferentially involve RF-producing cells.

Gastric B-cell clonal expansion and Helicobacter pylori infection in patients with autoimmune diseases and with dyspepsia. A follow-up study

BACKGROUND

It is not clear whether gastric B-cell clonal expansion, a possible precursor of mucosa-associated lymphatic tissue (MALT) lymphoma, is exclusively linked to Helicobacter pylori infection and virulence.

METHODS

In this study we followed up, for up to 33 months, 16 VDJ polymerase chain reaction-positive patients (4 with dyspepsia, 9 with Sjögren's syndrome, and 3 with other autoimmune diseases). Of these, 12 were H. pylori-positive. In addition, in H. pylori-positive patients we tested whether the serum anti-cag-A (a potential marker of virulence) was preferentially associated with B-cell clonality.

RESULTS

In all but one patient clonality appeared temporally unrelated to H. pylori infection. The prevalence of anti-cagA was not higher in H. pylori/VDJ-positive patients than in controls.

CONCLUSIONS

These data indicate that, in addition to H. pylori, gastric B-cell clonality may be sustained by other agents/mechanisms. Anti-cag-A does not appear to be involved in the pathogenesis of clonality.

Characterization of Overt B-Cell Lymphomas in Patients With Hepatitis C Virus Infection

A pathogenetic role of the hepatitis C virus (HCV) has been hypothesized for a subset of B-cell non-Hodgkin's lymphomas (NHLs). However, the preliminary characterization of B-cell NHLs in HCV-infected individuals has been poorly addressed. In the present study, we report detailed information on 35 consecutive patients with overt B-cell NHL of recent onset and HCV infection; all patients referred to a single oncological center in Northeast Italy. Histopathologic evaluation was performed by a single reference hemopathologist, and the link with the two relevant autoimmune diseases predisposing to B-cell NHL and in which HCV has been implied, ie, “essential” mixed cryoglobulinemia (EMC) and Sjögren's syndrome, was investigated. Control groups included 122 consecutive HCV-negative patients with B-cell NHL and 464 consecutive histopathologic cases of B-cell NHL referred to the same center, as well as 127 consecutive patients with HCV infection and without lymphoma referred to a different center in the same geographical area. B-cell NHLs in HCV-infected patients frequently presented at onset (1) an extranodal localization with peculiar target organs of HCV infection (ie, the liver and major salivary glands) being significantly overrepresented; (2) a diffuse large cell histotype without any prior history of low-grade B-cell malignancy or bone marrow involvement; and (3) a weak association with a full-blown predisposing autoimmune disease, although serum autoimmune features were common and cryoglobulins were always present. Therefore, the HCV-related B-cell NHLs in this oncological series presented distinctive features compared with B-cell NHLs in HCV-negative patients, and they differed from bone marrow low-grade NHLs frequently diagnosed in HCV-positive patients with EMC. Such novel information may be relevant for future research aimed at clarifying the possible link between HCV infection, autoimmunity, nonmalignant B-cell lymphoproliferation, and overt B-cell malignancy.

Characterization of Overt B-Cell Lymphomas in Patients With Hepatitis C Virus Infection

A pathogenetic role of the hepatitis C virus (HCV) has been hypothesized for a subset of B-cell non-Hodgkin's lymphomas (NHLs). However, the preliminary characterization of B-cell NHLs in HCV-infected individuals has been poorly addressed. In the present study, we report detailed information on 35 consecutive patients with overt B-cell NHL of recent onset and HCV infection; all patients referred to a single oncological center in Northeast Italy. Histopathologic evaluation was performed by a single reference hemopathologist, and the link with the two relevant autoimmune diseases predisposing to B-cell NHL and in which HCV has been implied, ie, “essential” mixed cryoglobulinemia (EMC) and Sjögren's syndrome, was investigated. Control groups included 122 consecutive HCV-negative patients with B-cell NHL and 464 consecutive histopathologic cases of B-cell NHL referred to the same center, as well as 127 consecutive patients with HCV infection and without lymphoma referred to a different center in the same geographical area. B-cell NHLs in HCV-infected patients frequently presented at onset (1) an extranodal localization with peculiar target organs of HCV infection (ie, the liver and major salivary glands) being significantly overrepresented; (2) a diffuse large cell histotype without any prior history of low-grade B-cell malignancy or bone marrow involvement; and (3) a weak association with a full-blown predisposing autoimmune disease, although serum autoimmune features were common and cryoglobulins were always present. Therefore, the HCV-related B-cell NHLs in this oncological series presented distinctive features compared with B-cell NHLs in HCV-negative patients, and they differed from bone marrow low-grade NHLs frequently diagnosed in HCV-positive patients with EMC. Such novel information may be relevant for future research aimed at clarifying the possible link between HCV infection, autoimmunity, nonmalignant B-cell lymphoproliferation, and overt B-cell malignancy.