Shortened and intensified MJMA: an effective salvage therapy for relapsed and refractory lymphomas and a strong mobilizer of PBSCs.

There is great interest in chemotherapies for relapsed or refractory lymphomas that are both directly effective against the lymphoma and able to mobilize PBSCs for rescue after high-dose chemotherapy (HDC). Twenty-eight patients with relapsed or refractory lymphomas were treated with a shortened, intensified MJMA regimen (mitoxantrone 10 mg/m(2) i.v. day 1, carboplatin 200 mg/m(2) i.v. days 1-2, methylprednisolone 500 mg/m(2) i.v. days 1-3, cytarabine 2000 mg/m(2) i.v. day 3) for six cycles every 21 days. A median of five cycles/patient was administered. Nineteen patients had complete responses, seven partial responses and two no responses. The only remarkable toxicity was hematological. In 18 patients who were candidates for HDC, a mean of 10.45 x 10(6) CD34/kg of patients' body weight was collected (range: 3.70-24.88 x 10(6)/kg). Eleven patients underwent transplantation, which converted two of four partial responses into complete responses. The median follow-up was 49 months. Survival parameters were not related to relapsed/refractory status or to the time from the last chemotherapy, but were related only weakly to the number of prior chemotherapies. Outpatient MJMA is a feasible and very effective salvage chemotherapy per se. The complete response rate is high and it is a powerful PBSC mobilizer.

Complete long-term response to radiotherapy of gastric early-stage marginal zone lymphoma resistant to both anti-Helicobacter pylori antibiotics and chemotherapy.

BACKGROUND: The optimal approach to patients with gastric lymphoma of extranodal mucosa-associated lymphoid tissue (MALT) that resist to anti-Helicobacter pylori (HP) eradication therapy is still to be defined. PATIENTS AND METHODS: From January 1997 to December 2004, we observed 24 patients affected with newly diagnosed early-stage and HP-positive gastric lymphoma of the MALT type. Five of them resisted to oral anti-HP antibiotic regimens and to subsequent one (two patients) or two (three patients) chemotherapy regimens. Age ranged between 51 and 77 years (median 70); three were females. Translocation (11;18) was ascertained in one subject. They were admitted to local radiation therapy with a total dose of 30 Gy. RESULTS: All such resistant patients achieved complete remission after radiotherapy. No relapses were observed after 21, 45, 48, 52, and 67 months of uninterrupted follow-up. Early toxicity was very low and consisted of mild nausea. Late toxicity or secondary malignancy was not recorded so far. CONCLUSIONS: Radiotherapy proved to be effective and safe for early-stage HP-positive gastric extranodal lymphoma of MALT type that is resistant to anti-HP eradication antibiotics and to following chemotherapy. Radiotherapy might be suggested as principal salvage therapy after resistance to HP eradication, instead of chemotherapy.

A modified high-dose dexamethasone regimen for primary systemic (AL) amyloidosis.

High-dose dexamethasone (HD-Dex) has been reported to benefit AL amyloidosis patients with varying response rates. Our preliminary experience with the usual HD-Dex schedule indicated that the induction phase was rather toxic in AL patients. We therefore adopted a milder schedule consisting of dexamethasone 40 mg on d 1-4 q21 d for up to eight cycles. Overall 8 out of 23 (35%) treated patients responded to treatment in a median time of 4 months (range 2-6 months) without significant toxicity. This regimen may be considered front-line therapy when autologous stem cell transplantation is not feasible and when a rapid response is particularly important.

Translocation T(4;14)(p16.3;q32) is a recurrent genetic lesion in primary amyloidosis.

Primary amyloidosis is a fatal disorder characterized by low numbers of clonal plasma cells in the bone marrow and the systemic deposition of light chain fragments in the form of amyloid. The molecular pathobiology of amyloidosis is primarily unknown. Recently, a novel karyotypically undetectable t(4;14)(p16.3;q32) translocation has been identified in approximately 20% of multiple myeloma patients. The translocation leads to the apparent deregulation of two genes located on 4p16.3, the fibroblast growth-factor receptor 3 (FGFR3), and the putative transcription factor multiple myeloma SET domain (MMSET), and to the generation of IGH/MMSET hybrid transcripts. In this study, we investigated the presence of the t(4;14) translocation in 42 AL patients using a reverse transcriptase-polymerase chain reaction assay for the detection of IGH/MMSET transcripts. Chimeric transcripts were found in six patients (14%) and were consistent with a 4p16.3 breakpoint involving intron 3 and juxtaposing IGH regions to exon 4. In three of these cases, hybrid transcripts juxtaposing IGH regions to exon 5 were also observed and were probably the result of an alternative splicing skipping exon 4. Because all of the fusion transcripts (six of six) excluded exon 3, the first translated MMSET exon, only putative 5' truncated MMSET proteins could be generated. In conclusion, our results demonstrate that the t(4;14)(p16.3;q32) translocation is a recurrent genetic lesion in primary amyloidosis.

Biological features of the clone involved in primary amyloidosis (AL).

Primary light chain-associated amyloidosis (AL) is a plasma cell dyscrasia that causes morbidity via systemic tissue deposition of monoclonal light chains in the form of fibrils (amyloid). It is the most common form of systemic amyloidosis in Western countries and is rapidly fatal. Knowledge of the pathobiology of the underlying B cell clone is of primary importance for the design and optimization of therapeutic strategies.

Protein aggregation.

Protein aggregation occurs in vivo as a result of improper folding or misfolding. Diverse diseases arise from protein misfolding and are now grouped under the term "protein conformational diseases", including most of the neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, the prion encephalopathies and Huntington's disease, as well as cystic fibrosis, sickle cell anemia and other less common conditions. The hallmark event in these diseases is a change in the secondary and/or tertiary structure of a normal, functional protein, leading to the formation of protein aggregates with various supramolecular organizations. In most cases the aggregates are organized in structurally well-defined fibrils forming amyloid deposits. The crucial feature of the amyloidogenic proteins is their structural instability induced either by mutations, post-translational modifications, or local conditions, such as pH, temperature, and co-solutes. The conformational change may promote the disease either by gain of a toxic activity or by the lack of biological function of the natively folded protein. As different molecular mechanisms are involved in the formation of the various forms of protein aggregates, the laboratory diagnostic approach remains frequently elusive.

Detection of t(4;14)(p16.3;q32) chromosomal translocation in multiple myeloma by reverse transcription-polymerase chain reaction analysis of IGH-MMSET fusion transcripts.

We and others have recently identified a novel recurring t(4;14)(p16.3; q32) translocation in multiple myeloma (MM) that leads to an apparent deregulation of the FGFR3 and WHSC1/MMSET genes. Because the presence of IGH-MMSET hybrid transcripts has been found in MM cell lines with t(4;14), they may represent a specific tumor-associated marker in MM. In this study, we developed a reverse transcription-PCR (RTPCR) assay for detecting chimeric transcripts from all of the 4p16.3 breakpoints identified thus far, and we used it to investigate a representative panel of 53 MM patients and 16 patients with monoclonal gammopathy of uncertain significance; in addition, t(4;14) was investigated in all of the MM patients by means of two-color fluorescence in situ hybridization. IGH-MMSET transcripts were found in 11 of the 53 (20%) MM cases and 1 of 16 (6%) cases of monoclonal gammopathy of uncertain significance. There was complete concordance between the RT-PCR and fluorescence in situ hybridization analyses of the MM cases. The results of this study indicate that RT-PCR is a sensitive and reliable method of detecting t(4;14) and suggest that it may be useful for monitoring the disease in a significant proportion of patients.

Abnormalities in thrombin-antithrombin pathway in AL amyloidosis.

Various pathogenic factors have been proposed to explain the abnormal hemostasis observed in AL amyloidosis. Since imbalance between clotting factors and inhibitors could play a pathogenic role in both hemorrhagic and thrombotic manifestations, we investigated the thrombin-antithrombin pathway in 35 patients with AL amyloidosis. Ten patients suffered from bleeding while 3 patients experienced deep venous thrombosis. Thrombin time was prolonged in 29 subjects, the mean values of antithrombin III activity (ATIII Act) were significantly lower than those of antithrombin III antigen (ATIII Ag) with loss of relationship between these two different techniques of ATIII detection, normally observed in healthy controls. In 19 patients increased levels of thrombin-antithrombin (TAT) complexes were present. Crossed immunoelectrophoresis of ATIII, performed in presence of heparin, evidenced ATIII forms with reduced binding capacity to heparin and TAT complexes of various electrophoretic mobilities. In conclusion, the impairment of the thrombin-antithrombin pathway, in association with the low ATIII biological activity, might play a pathogenic role in the hypercoagulable state reported in AL amyloidosis, despite the higher frequency of bleeding manifestations.

The degrees of plasma cell clonality and marrow infiltration adversely influence the prognosis of AL amyloidosis patients.

BACKGROUND AND OBJECTIVE: Primary amyloidosis is a lethal form of plasma cell (PC) dyscrasia characterized by deposits of monoclonal immunoglobulin light chains that cause organ dysfunction. In contrast to multiple myeloma, the amyloid clone is typically indolent and of small size, and marrow PC clonality is not always apparent. This is generally investigated by analyzing the light chain isotype ratio in bone marrow PC. We investigated whether the degree of PC infiltration (PC%) and clonality (PC isotype ratio) affected survival in 56 consecutive patients with primary amyloidosis. DESIGN AND METHODS: PC% was determined by morphologic examination. Immunofluorescence microscopy was used to determine the PC light chain isotype ratio. Statistical analysis was carried out using Cox regression models. RESULTS: The degrees of PC clonality and infiltration were inversely correlated with survival (PC isotype ratio, p = 0.001; PC%, p = 0.008). The two variables were weakly correlated (p = 0.02; r = 0.3). Bone marrow PC isotype ratio demonstrated a powerful independent prognostic value at multivariate analysis when analyzed together with congestive heart failure (the major known negative prognostic factor) and PC%. k/l ratio cut-off values of 0.2 (l patients, p = 0.022) and 16 (k patients, p = 0.03) discriminated two groups with a similar number of patients and significantly different survivals. INTERPRETATION AND CONCLUSIONS: PC clonality and marrow infiltration are important parameters that influence prognosis, presumably because they reflect the amount of pathogenic light chain synthesis.

Cells with clonal light chains are present in peripheral blood at diagnosis and in apheretic stem cell harvests of primary amyloidosis.

In primary systemic amyloidosis, small numbers of bone marrow plasma cells secrete monoclonal light chains that form extracellular fibrils (amyloid) in various organs. Evidence limited to a few cases suggests that rare clonal elements can also be found in the peripheral blood (PB), and this may be relevant in PB stem cell autotransplantation. Since up to 40% of amyloid clones do not synthesize heavy chains, in order to detect tumor cells with high specificity and sensitivity we developed a seminested allele-specific oligonucleotide polymerase chain reaction for tumor light chains. Clone-related sequences were detected in DNA and/or cDNA from the PB cells of eight of 10 patients at diagnosis and from apheretic collections of three of four cases undergoing PB progenitor autotransplantation. Since there are experimental data suggesting that circulating tumor cells may be involved in the growth of the amyloidogenic clone and may be chemoresistant, these findings are relevant to the use of leukapheresis purging strategies for PB progenitor autotransplantation in amyloidosis.

Evidence that amyloidogenic light chains undergo antigen-driven selection.

AL amyloidosis is characterized by fibrillar tissue deposits (amyloid) composed of monoclonal light chains secreted by small numbers of indolent bone marrow plasma cells whose ontogenesis is unknown. To address this issue and to provide insights into the processes that accompanied pathogenic light chain formation, we isolated the complete variable (V) regions of 14 light (VL) and 3 heavy (VH) chains secreted by amyloid clones at diagnosis (10 Bence Jones and 4 with complete Igs, 9 lambda and 5 kappa) by using an inverse polymerase chain reaction-based approach free of primer-induced biases. Amyloid V regions were found to be highly mutated compared with the closest germline genes in the databases or those isolated from the patients' DNA, and mutations were not associated with intraclonal diversification. Apparently high usage of the lambdaIII family germline gene V lambdaIII.1 was observed (4 of 9 lambda light chains). Analysis of the nature and distribution of somatic mutations in amyloid V regions showed that there was statistical evidence of antigen selection in 8 of 14 clones (7 in VL and 1 in VH). These results indicate that a substantial proportion of the amyloid clones developed from B cells selected for improved antigen binding properties and that pathogenic light chains show evidence of this selection.

Clonality and specificity of cryoglobulins associated with HCV: pathophysiological implications.

BACKGROUND/AIMS: Hepatitis C virus (HCV) infection plays a central role in the pathogenesis of mixed cryoglobulinemia through molecular mechanisms which remain to be elucidated. The aim of this study was to investigate the role of antibody responses to HCV in the pathogenesis of cryoglobulinemia through characterization of the anti-HCV specificity and immunochemical characteristics of the immunoglobulins involved in cryoprecipitation. METHODS: Sera from 50 consecutive patients with chronic HCV infection (RNA positive) were screened for the presence of cryoglobulins. The two major components of cryoprecipitates, IgM rheumatoid factors and IgG, were separated by high performance liquid chromatography and analyzed for immunochemical composition by immunoblotting and antibody specificity by ELISA and immunoblotting using recombinant HCV proteins and synthetic peptides as antigens. RESULTS: Cryoprecipitates were observed in 27 patients and characterized by immunofixation: 13 (48%) were classified as type II and 14 (52%) as type III. Monoclonal immunoglobulins were detected by immunoblotting in 20 cryoprecipitates: IgM in 14 samples and IgG in 14, with a clear preponderance of IgG3 (12/14). Specificity studies on sera and purified IgM and IgG fractions from cryoprecipitates revealed enrichment in cryoglobulins, predominantly polyclonal IgG1, reactive with the HCV structural proteins, whereas specificities for nonstructural viral proteins were relatively less represented compared to whole serum. No restricted pattern of fine specificity was observed. IgG3 subclass was apparently not involved in HCV nucleoprotein binding. CONCLUSIONS: Our findings do not support a direct link between monoclonal cryoglobulins and immune response to HCV According to the proposed pathogenetic model, HCV infection can induce the formation of cryoprecipitable rheumatoid factors, sustain their production, and eventually lead to monoclonal B-cell expansion through several cooperative mechanisms.

Membrane CD22 defines circulating myeloma-related cells as mature or later B cells.

Circulating clonally related earlier cells are present in multiple myeloma (MM) and may be involved in the dissemination of this disease, its recurrence, and chemoresistance. The nature, stage of differentiation, and size of this cell population remain uncertain. Unlike other B-cell markers, CD22 membrane expression is limited to the late differentiation stages comprised between mature B cells (CD22+) and plasma cells (PC; CD22-) and may thus be useful in delimiting the maturational state of circulating early myeloma cells. Peripheral blood clone-related cells were detected by anti-idiotypic (Id) monoclonal antibodies and found to express CD22 (92% to 95%), monotypic light and heavy chain (100%), and CD38 (45%), whereas bone marrow PC were CD22-negative. CD22 expression was also documented on functional myeloma PC precursors, defined as peripheral blood cells capable of in vitro cytokine-driven monotypic PC differentiation, because up to approximately 70% inhibition of this process was obtained in 10 myeloma patients through the use of biospecific antibodies (BsAb) that deliver the plant toxin saporin to CD22+ cells. As further evidence of CD22 on circulating abnormal cells, it was found that in the only patient analyzed for DNA content, a portion of the peripheral blood CD22+ cells killed were hyperdiploid. Collectively, these findings indicate that most peripheral blood myeloma PC precursors are mature or later B cells presenting membrane CD22. The pattern of CD22 expression suggests the existence in MM of a differentiation process analogous to the normal antigenic response, in which CD22+ B cells migrate to the bone marrow and lose CD22 with PC differentiation. In addition, the sensitivity of myeloma PC precursors to the cytotoxic effects of the anti-CD22 BsAb and the possibility of interfering with their differentiation have potential therapeutic relevance.