Activity of aldehyde dehydrogenase in B-cell and plasma cell subsets of monoclonal gammopathy patients and healthy donors.

BACKGROUND: Aldehyde dehydrogenase (ALDH) is highly active in physiological stem cells as well as in tumor-initiating cells of some malignancies including multiple myeloma (MM). Finding higher activity of ALDH in some cell subsets in monoclonal gammopathies (MG) could identify potential source of myeloma-initiating cells (MICs). METHODS: Bone marrow of 12 MM, 9 monoclonal gammopathy of undetermined significance (MGUS), and 10 healthy donors (HD) were analyzed by flow cytometry. ALDH activity of B-cells and plasma cells (PC) was analyzed using Aldefluor. RESULTS: Similar changes of ALDH activity were found during B-cell development in HD and MG. Decreasing of ALDH activity from immature to naïve B-cells was found. In postgerminal stages, the activity started to increase, and in PCs, the ALDH activity was the same as in immature B-cells. Increased ALDH activity of all PC subsets compared to naïve B-cells was found in MM as well as in HD, while in MGUS, only CD19- PCs have higher ALDH activity. In HD, ALDH activity was higher in CD19+ PCs compared with MG. CONCLUSIONS: Our results indicate that changes of ALDH activity are the natural phenomenon in B-cell development; thus, high ALDH activity as a single marker is not appropriate for MICs identification.

C-src enriched serum microvesicles are generated in malignant plasma cell dyscrasia.

Plasma cell dyscrasias are immunosecretory disorders that can lead to hematological malignancies such as Multiple Myeloma (MM). MM accounts for 15% of all hematologic cancers, and those diagnosed with MM typically become severely ill and have a low life expectancy. Monoclonal immunoglobulin Free Light Chains (FLC) are present in the serum and urine of many patients with plasma cell diseases. The biological differences between monoclonal FLCs, produced under malignant or benign dyscrasias, has not yet been characterized. In the present study, we show that endothelial and heart muscle cell lines internalize kappa and lambda FLCs. After internalization, FLCs are rerouted in the extracellular space via microvesicles and exosomes that can be re-internalized in contiguous cells. Only FLCs secreted from malignant B Lymphocytes were carried in Hsp70, annexin V, and c-src positive vesicles. In both MM and AL Amyloidosis patients we observed an increase in microvesicle and exosome production. Isolated serum vesicles from MM, AL Amyloidosis and monoclonal gammopathy of undetermined significance (MGUS) patients contained FLCs. Furthermore MM and AL amyloidosis vesicles were strongly positive for Hsp70, annexin V, and c-src compared to MGUS and control patients. These are the first data implying that FLCs reroute via microvesicles in the blood stream, and also suggest a potential novel mechanism of c-src activation in plasma cell dyscrasia.

The prolyl-hydroxylase EGLN3 and not EGLN1 is inactivated by methylation in plasma cell neoplasia.

EGLN1 and EGLN3 are members of the egg-laying-defective 9 (EglN) prolyl-hydroxylases which during normoxia catalyse hydroxylation of the hypoxia-inducible factor (HIF)-1alpha, thereby promoting its ubiquitination by a complex containing the von Hippel-Lindau (VHL) tumour suppressor. EGLN3 also has pro-apoptotic activity in some cell types. Analyses of a well-characterised series of cases of plasma cell dyscrasias, including multiple myeloma (MM), Waldenström's macroglobulinaemia (WM) and monoclonal gammopathy of undetermined significance (MGUS) surprisingly demonstrated that the CpG island of EGLN3, and not EGLN1, is frequently methylated in these disorders. Multiple myeloma patients with a methylated EGLN3 promoter showed trends towards an increased risk of death, bone lytic lesions, anaemia, advanced stage of disease and the presence of extramedullary disease. Those individuals with methylation in the EGLN3 CpG island also had significantly lower albumin levels. These data suggest that the prolyl-hydroxylases may be a novel class of potential tumour suppressors in plasma cell neoplasia that warrant further investigation with regard to their potential utility as biomarkers. Moreover, we observed that EGLN3 is also methylated at high frequency in B-cell lymphoma subtypes, implying that loss of EGLN3 is an important epigenetic event not only in plasma cell neoplasias but also in B-cell neoplasias.

hMLH1 and MGMT inactivation as a mechanism of tumorigenesis in monoclonal gammopathies.

Monoclonal gammopathies are a group of disorders characterized by clonal proliferation and accumulation of immunoglobulin-producing plasma cells. Multiple myeloma and monoclonal gammopathy of undetermined significance are the most common monoclonal gammopathies; the two comprise a spectrum of disorders, ranging from a relatively benign disease, monoclonal gammopathy of undetermined significance, to a malignant disease, multiple myeloma. Aberrant promoter methylation represents a primary mechanism of gene silencing during tumorigenesis. DNA repair systems act to maintain genome integrity in the presence of replication errors, environmental insults, and the cumulative effects of aging. The methylation patterns of two genes implicated in DNA repair, O6 methylguanine DNA methyl-transferase (MGMT) and human mutL homologue1 (hMLH1) have been detected in various solid tumours. With the purpose of studying the gene silencing of MGMT and hMLH1 in plasma cell disorders, we investigated the methylation status and expression of both genes in: 29 cases of multiple myeloma; one case of plasma cell leukaemia; 13 cases of monoclonal gammopathy of undetermined significance; and two cases of polyclonal plasmacytosis, using methylation-specific polymerase-chain reaction and immunohistochemical techniques. Methylation frequencies for MGMT were 23% in multiple myeloma and 8% in monoclonal gammopathy of undetermined significance. It was 10% for hMLH1 in multiple myeloma. None of the patients diagnosed with monoclonal gammopathy of undetermined significance had hMLH1 hypermethylated. In addition, 50% of myeloma cases had a loss of hMLH1 expression, whereas silencing of MGMT was observed in 43% of myeloma and 36% of samples with monoclonal gammopathy of undetermined significance. This study indicates that repair pathway defects play a role in the pathogenesis and evolution of monoclonal gammopathies, and suggests that inactivation of hMLH1 could be implicated in multiple myeloma tumorigenesis.

Microvessel density, endothelial-cell proliferation and carbonic anhydrase IX expression in haematological malignancies, bone-marrow metastases and monoclonal gammopathy of undetermined significance.

The aim of the study was to compare the angiogenic status, potential qualitative differences in microvessels and carbonic anhydrase IX expression in bone-marrow (BM) metastases and different haematological tumours at time of diagnosis. The microvessel density (MVD), endothelial-cell proliferation (ECP) and carbonic anhydrase IX (CA IX) immunoreactivity were determined on 210 trephine biopsies from 57 patients with multiple myeloma (MM), 13 with acute myeloid leukaemia (AML), 48 with chronic myeloproliferative syndrome (CMPS), 26 with chronic lymphocytic leukaemia (CLL), 25 with epithelial BM metastases, 18 with monoclonal gammopathy of undetermined significance (MGUS) and from a control group composed of 23 patients without haematological neoplasm. There was an increased MVD and ECP in epithelial BM metastases, MM, AML, CMPS and in a part of CLL. While an ECP greater than 0 was detected in 72% of MM, 75% of CMPS and 92% of AML, it was invariably observed (100%) in the BM metastases. The absence of ECP together with a MVD comparable with the control group in our MGUS cases supports the view that MGUS is a pre-angiogenic condition. Qualitative differences in microvessels were associated with growth patterns in MM and CLL and were observed between the different entities of CMPS. In one-third of the epithelial BM metastases, there was a focal CA IX immunoreactivity, which was never observed in the haematological diseases.

Telomerase activity in plasma cell dyscrasias.

Activation of telomerase is essential for in vitro cellular immortalization and tumorigenesis. In the present study, we investigated telomerase activation and its implications in plasma cell dyscrasias including monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM) and plasma cell leukaemia (PCL). All 5 patients with MGUS exhibited normal levels of telomerase activity in their plasma cells. Elevated telomerase activity was found in the samples from 21/27 patients with MM and 4/4 with PCL. In addition, 4 myeloma cell lines all expressed high levels of telomerase activity. The expression of telomerase reverse transcriptase (hTERT) and telomerase RNA template (hTER) was positively associated with the levels of telomerase activity in MM/PCL. Tankyrase expression was upregulated, concomitant with the induction of hTERT and activation of telomerase in MM/PCL. The present findings indicate that MGUS cells may not be immortalized and that activation of telomerase plays a role in the malignant transformation from MGUS to MM.

Leukocyte alkaline phosphatase score in plasma cell dyscrasias: correlation with disease severity and circulating levels of granulocyte-colony stimulating factor.

In this study the leukocyte alkaline phosphatase (LAP) score in 106 patients with multiple myeloma (MM) in various phases of the disease (66 at diagnosis, 18 in plateau phase, 22 in relapse) was examined and compared with the score of 68 patients with monoclonal gammopathy of undetermined significance (MGUS) and 53 normal volunteers. In addition, the circulating levels of granulocyte-colony stimulating factor (G-CSF) were measured to explore the possible involvement of this cytokine in the pathogenetic mechanisms that lead to increased LAP activity. The results showed that the mean LAP score in patients with MGUS was comparable to normals and significantly lower than in MM (p < 0.001). Also, it increased with increasing tumor mass, and was lower in myelomas with stable disease than in those with active disease. G-CSF concentrations closely mirrored the behaviour of LAP score (r = 0.850, p < 0.001), significantly differing between each group of individuals. Its mean levels in MGUS were comparable to those of controls, whereas they were significantly increased in MM (p < 0.001), again with escalating values from cases with low tumor mass to advanced stages, and with lower concentrations in patients in plateau phase than in those in relapse. A significant correlation was found between G-CSF and neopterin levels (r = 0.578, p < 0.001), thus indicating an origin of the cytokine from monocytes and macrophages. These findings suggest that LAP scoring may assist in distinguishing benign from malignant paraproteinemias and may be used to follow the progression of plasma cell neoplasias.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma cell proliferation in monoclonal gammopathies: measurement using BU-1 antibody in flow cytometry and microscopy: comparison with serum thymidine kinase.

AIMS: The labelling index as defined by the percentage of bone marrow plasma cells doubling their DNA in the S phase is a useful prognostic factor in multiple myeloma. The aim of this study was to examine the specificity and sensitivity of a new flow cytometric method for measuring the labelling index. METHODS: Bone marrow specimens from five patients with monoclonal gammopathy of undetermined significance and 61 patients with multiple myeloma were investigated. The labelling index (LI%) was determined by means of a microscopic and flow cytometric method using the antibromodeoxyuridine antibody BU-1. Serum thymidine kinase, another index of proliferation, was measured by radioimmunoassay. RESULTS: Good comparability (r = 0.83) and nearly equal imprecision (CV < 20%) were found with microscopic and flow cytometric methods of LI% measurement. However, 1000 or more cells had to be counted by microscopy around the cutoff value to avoid an unacceptable imprecision. Plasma cells with increased S phase (LI% > 1%) were characterised by their reduced light chain fluorescence intensity ratio between plasma cells and nonspecifically stained cells (7.9 v 14.8, p < 0.002), that is, by their generally lowered cytoplasmic immunoglobulin content. There was a moderate correlation between thymidine kinase and labelling index (r = 0.56, p < 0.001). At 100% specificity, myelomas with proliferating plasma cells were more sensitively detected by the labelling index than by serum thymidine kinase (55% v 32% sensitivity). CONCLUSIONS: The labelling index represents a more specific and sensitive proliferation marker than serum thymidine kinase. Flow cytometry does not result in greater precision.

Serum deoxythymidine kinase: no help in the diagnosis and prognosis of monoclonal gammopathy.

Serum deoxythymidine kinase activity (S-TK) was determined in the diagnostic evaluation and follow-up of patients with monoclonal gammopathy of undetermined significance (MGUS). During a 4-year period 35 patients were included in the study. Normal concentrations of S-TK were found in 33. Patients with non-progressive monoclonal gammopathy kept a stable, and for the individual, a characteristic level of S-TK during several years of follow-up. A moderately elevated level of S-TK during observation did not indicate progression. Even in four out of five patients developing symptomatic multiple myeloma S-TK remained unchanged. Determination of S-TK does not give diagnostic or prognostic information in monoclonal gammopathy.

[Amylase-producing plasma cell dyscrasia. Genomic analysis in a case of intramuscular tumor formation and a review of the literature].

We describe a 53-year-old male patient with multiple myeloma (IgA, kappa) who showed massive intramuscular tumors and hyperamylasemia of the salivary (S) type 10 months after initial diagnosis. Suspension culture of the abnormal plasma cells in the pleural fluid showed the production of S-amylase, which was confirmed by the expression of S-amylase mRNA comigrating with salivary gland mRNA. Cytogenetic analysis of the cells showed common abnormalities 1p+q-and 8q+. They expressed IL-6 mRNA, but not c-myc mRNA. Neither structural abnormality nor amplification was detected in the alleles of S amylase, and c-myc using Southern blot analysis. All of the eight patients with plasma cell dyscrasia with hyperamylasemia reported so far (including the present one) are Japanese, and showed S-type hyperamylasemia and extramedullary tumor formation at initial diagnosis or during the course of the disease. All of the four patients in whom cytogenetic analysis was performed had structural abnormalities of chromosome 1, on which the S-amylase gene is known to be located, although the break point were variable.

Use of leucocyte alkaline phosphatase (LAP) score in differentiating malignant from benign paraproteinaemias.

The leucocyte alkaline phosphatase (LAP) score of peripheral blood neutrophils was examined in 20 patients with multiple myeloma and compared with the score in 18 patients with monoclonal gammopathy of undetermined significance (MGUS). The mean (95% confidence limit) LAP score in those with multiple myeloma was 186 (169-218) compared with 92 (64-120) in the MGUS group. In the multiple myeloma group all but one patient had a high LAP score, irrespective of disease. No cause for raised LAP, such as infection, was present in any of the patients with multiple myeloma. In the MGUS group six patients had a raised LAP score; in two of them another cause for such a rise was present (autoimmune haemolytic anaemia and primary thrombocythaemia). In neither group did the LAP score correlate with duration of the disease, bone marrow plasma cell count, paraprotein concentration, haemoglobin, total white cell or neutrophil count. It is concluded that a normal LAP count in patients with paraproteinaemia suggests a benign condition, but a raised count does not indicate a malignant condition.

Sialyltransferase activity and sialic acid levels in multiple myeloma and monoclonal gammopathy.

A significant elevation of peripheral blood mononuclear cell sialyltransferase activity (STA) was observed in 14 patients with multiple myeloma (MM), and compared to 7 patients with monoclonal gammopathy of undetermined significance (MGUS) and to 10 controls. Serum sialyltransferase was significant higher in MM patients as compared to controls. It was also higher than in MGUS patients, but the difference here was not statistically significant. STA was also determined in mononuclear bone marrow cells of 5 patients with MM (with 50 to 100% plasma cells in the bone marrow aspirate) and found to be 19 times higher than that of bone marrow mononuclear cells from 6 patients with non-malignant disorders (with less than 1% plasma cells in the bone marrow aspirate). No significant differences were observed in peripheral blood mononuclear cell sialic acid levels between MM, MGUS and controls.

A lactate dehydrogenase-immunoglobulin G1 complex, not blocked by anti-idiotype antibody, in a patient with IgG1-lambda type M-proteinemia.

The serum of a patient with IgG1-lambda type M-proteinemia showed an abnormal isoenzyme pattern for lactate dehydrogenase (LDH, EC 1.1.1.27). By affinity chromatography, we showed that four isoenzymes (LDH2, LDH3, LDH4, and LDH5) were bound to the M-protein. This complex formation was not blocked by anti-idiotype antibody, even though the binding capacity of IgG was exclusively located in the Fab region of the molecule. Moreover, heavy and light chains of the patient's IgG, obtained by reduction, separately had affinities for each of the LDH isoenzymes. LDH-IgG complex was easily dissociated by affinity chromatography on 5'-AMP-Sepharose 4B or by added NADH. We propose the following hypothesis for the LDH-IgG complex formation: LDH can recognize the gamma-Fab region of IgG at the NAD+ binding site of the molecule, but the affinity of the LDH molecule for immunoglobulin is much weaker than that for NADH or 5'-AMP.

[Alpha 1-protease inhibitor: characteristics of its biochemical and biological properties and its level in various diseases (review of the literature and personal observations)]. / Alpha 1-ingibitor proteaz: kharakteristika biokhimicheskikh i biologicheskikh svoistv i opredelenie urovnia pri razlichnykh zabolevaniiakh (obzor literatury, sobstvennye nabliudeniia).

The authors review biological and biochemical properties and the clinical importance of the serum proteases alpha 1-inhibitor with broad-range antiproteolytic activity. Congenital deficiency of this protein is a frequent enough condition linked with predisposition to some diseases of the lungs and liver. Early determination of the deficiency of alpha 1-Pi is fairly urgent, since it permits the early administration of the preventive measures and substitution therapy. The immunochemical technique makes it possible to determine all the varieties of alpha 1-Pi, as they are antigenically similar. Sera from 267 patients with different diseases were examined. The content of alpha 1-Pi was found to be elevated in Waldenström's macroglobulinemia, chronic active hepatitis and liver cirrhosis and to be lowered in bronchial asthma. In multiple myeloma and pollinoses, no alterations in the alpha 1-Pi content were recorded.

Plasma cell acid phosphatase activity as prognostic factor in multiple myeloma: relationship to the thymidine-labeling index.

Plasma cell acid phosphatase (AP) activity and thymidine labeling index (LI%) were evaluated concomitantly in 52 patients with monoclonal gammopathies. AP score, percentage of AP positive plasma cells, and LI% were significantly higher in 26 patients with multiple myeloma (MM) at the time of diagnosis than in 11 monoclonal gammopathy of undetermined significance (MGUS) and eight smoldering myeloma (SM) patients. LI% had the highest statistical correlation with disease status. A 1% cutoff could clearly separate the patients with progressive MM compared to those with stable disease (SM-MGUS) (P less than .001). There was a significant overall correlation between the AP score and LI% (P less than .005). Since LI% is a recognized powerful prognostic factor, this correlation suggests that the AP score can also be a reliable test predicting patient survival duration. In addition, we identified a subgroup of IgG MM patients with very high tumor mass who had a low LI% but a high AP score. This was associated with very poor patient survival and indicated the discrete prognostic importance of AP score in this subgroup with low LI%. Thus, both the LI% and AP score can be recommended as helpful clinical tests in patients with monoclonal gammopathies.

Enzymological studies in chronic lymphocytic leukemia.

Adenosine deaminase (ADA), 5'nucleotidase (5'NT), ecto-5'NT, purine nucleoside phosphorylase (PNP), hypoxanthine-guanine phosphoribosyltransferase (HGPRT), adenine phosphoribosyltransferase (APRT), adenosine kinase (AK), AMP-deaminase (AMPD) and adenylate kinase (AdKin) activities were assayed in peripheral blood lymphoid cells from 20 patients with B-cell type chronic lymphocytic leukemia (CLL). Significantly decreased mean activities of ADA, 5'NT, ecto-5'NT, PNP and AMPD were observed when comparing B-CLL lymphoid cells with control peripheral blood lymphocytes (PBL). AK and AdKin activities however, were found to be higher in B-CLL. Relatively wide ranges of ADA and 5'NT activity were observed. In patients with paraproteinaemia, 5'NT activity was found to be relatively high and in the range of the activities in normal PBL. ADA activity seemed to be slightly higher in patients without paraproteinaemia. No correlation could be found between the enzyme activities and the number of cells rosetting with sheep erythrocytes or bearing surface immunoglobulin (sIg). A relationship was suggested between 5'NT activity and Ig production.