High-frequency expression of a conserved kappa light-chain variable-region gene in chronic lymphocytic leukemia.

Malignant B lymphocytes from several patients with chronic lymphocytic leukemia (CLL) were examined for reactivity with murine monoclonal antibody 17.109. This antibody, prepared against the rheumatoid factor (RF) paraprotein Sie, recognizes a crossreactive idiotype on 48% of human IgM RF paraproteins, but does not react with IgM paraproteins without RF activity or substantially with normal pooled immunoglobulin. The 17.109-reactive idiotype is a marker for a kappa III variable-region gene, designated V kappa RF, that is conserved in outbred human populations. In a limited study of 31 CLL patients, the leukemic cells from 5 of 20 patients with kappa light chain-expressing CLL were recognized by the 17.109 monoclonal antibody. Despite having malignant cells specifically reactive with this antibody, patients with 17.109-positive CLL did not have elevated serum levels of circulating antibody bearing 17.109-reactive determinants. Total RNAs isolated from the CLL B lymphocytes, or from hybridomas produced by fusing the CLL cells with the WI-L2-729-HF2 cell line, were fractionated electrophoretically and examined by blot hybridization. Under stringent hybridization conditions capable of discerning a single base-pair mismatch, RNA from the 17.109-idiotype-positive CLL cells hybridized to synthetic oligonucleotide probes corresponding to framework and complementary-determining regions in the V kappa RF gene. The high frequency of the 17.109-associated idiotype and the V kappa RF gene in CLL suggests that the disease may arise from B lymphocytes that express a restricted set of inherited immunoglobulin variable-region genes with little or no somatic mutation.     

Comparison of serum free light chain and urine electrophoresis for the detection of the light chain component of monoclonal immunoglobulins in light chain and intact immunoglobulin multiple myeloma

Response criteria for multiple myeloma are based upon changes in monoclonal protein levels quantified using serum and/or urine protein electrophoresis. The latter lacks sensitivity at low monoclonal protein levels and since 2001, the serum free light chain test has been available and its clinical utility proven, yet guidelines have not recommended it as a replacement for urine assessment. Herein we evaluated responses using serum free light chain measurements and serum and urine electrophoresis after 2 and 4 cycles of therapy and after stem cell transplantation in 25 light chain and 157 intact immunoglobulin myeloma patients enrolled in the IFM 2007-02 MM trial. All 25 light chain patients had measurable disease by serum free light chain and urine methods at presentation. By contrast 98 out of 157 intact immunoglobulin patients had measurable disease by serum free light chain compared to 55 out of 157 by urine electrophoresis. In all patients there was substantial agreement between predicate (serum/urine protein electrophoresis) and test (serum protein electrophoresis and serum free light chain) methods for response assessment (Weighted Kappa=0.83). Urine immunofixation became negative in 47% light chain and 43% intact immunoglobulin patients after 2 cycles of therapy. At this time the serum free light chain ratio normalised in only 11% and 27% patients, respectively. In summary we found good agreement between methods for response assessment, but the serum free light chain test provided greater sensitivity than urine electrophoresis for monitoring. To our knowledge this is the first report comparing both methods for response assignment based on the International Myeloma Working Group guidelines.     

Monoclonal Bence Jones proteinuria in chronic lymphocytic leukaemia

A series of 52 consecutive patients with newly diagnosed chronic lymphocytic leukaemia (CLL) was investigated for the presence of serum and urine monoclonal immunoglobulins. The overall incidence of monoclonal gammopathy (MG) was 69%. Serum M components belonging to the IgG and IgM classes were found in 27% of cases with a concentration ranging from 1.7 to 40.3 g/l (mean 10 g/l). A monoclonal free light chain, i.e. Bence Jones protein (BJP), was documented in the urine of 65% of cases. In 42% of the 52 patients the urinary excretion of BJP represented the sole detectable monoclonal immunoglobulin abnormality. The occurrence of serum monoclonal immunoglobulins was not found to correlate with the stage or progression of the disease. Conversely, the isolated urinary excretion of BJP showed a relationship with the tumour load, as evaluated in terms of clinical enlargement of lymphoid areas. The presence of BJP alone was also a major distinctive feature of patients with more aggressive disease. These preliminary data would suggest that the isolated urinary excretion of BJP may represent a parameter of clinical significance in evaluating patients with CLL.     

Demonstration and identification of monoclonal proteins in the urine of patients with Sj?gren's syndrome.

Fresh sera and concentrated urine from 17 patients with primary Sjögren''s syndrome (SS) were fractionated by high-resolution agarose electrophoresis to investigate the presence of monoclonal immunoglobulins or their components. Homogeneous protein bands were found in the gamma-globulin region in 47% of serum samples and 76% of urine specimens of all patients tested. These monoclonal proteins were detected more often in patients with extraglandular SS (77% in serum, 100% in the urine) than in patients with glandular SS (14% in serum, 43% in the urine). Immunofixation electrophoresis showed that the majority of these monoclonal proteins were free kappa or lambda light chains. Fractionation of unconcentrated parotid salivas from five SS patients failed to reveal the presence of monoclonal light chains or immunoglobulins. The present findings further substantiate our previous observation that a monoclonal process coexists with the polyclonal activation in SS patients.     

Cell-surface immunoglobulins in chronic lymphocytic leukemia and allied disorders

Immunoglobulin on the surface of peripheral blood lymphocytes from 57 patients with chronic lymphocytic leukemia (CLL) and allied disorders was investigated by fluorescence microscopy and correlated with circulating immunoglobulin. In 38 of 48 patients with CLL, the predominant surface immunoglobulin identified on peripheral blood lymphocytes was M (IgM) of either kappa or lambda light chain type. In five patients, the predominant surface protein was immunoglobulin G (IgG) of either kappa or lambda type. In three others, the lymphocyte surface immunoglobulin could not be definitely identified and in two, no surface immunoglobulin was detected. Circulating immunoglobulin levels, particularly IgM, were depressed in the majority of patients with CLL. In three subjects with IgM-bearing lymphocytes, the serum contained a circulating IgM M component and three of the five subjects with IgG-bearing cells, had a circulating IgG M component. In three patients with CLL, immunoglobulin disappeared from the cell surface with progression of the disorder, although neoplastic cells remained in the circulation. The amount of immunoglobulin on the surface of cells from patients with chronic lymphosarcoma cell leukemia was much greater than that on cells from patients with CLL, and the surface immunoglobulin pattern in hairy cell leukemia also appeared distinctive. Study of immunoglobulin on the surface of lymphocytes has helped to define the cellular origin and monoclonal nature of CLL, the source of circulating M components in this disease, and the relationship of CLL to other lymphoproliferative disorders. Although technically demanding, the study of surface immunoglobulin should prove useful in clinical medicine.     

Incidence and clinicobiologic characteristics of leukemic B-cell chronic lymphoproliferative disorders with more than one B-cell clone

Leukemic B-chronic lymphoproliferative disorders (B-CLPDs) are generally believed to derive from a monoclonal B cell; biclonality has only occasionally been reported. In this study, we have explored the incidence of B-CLPD cases with 2 or more B-cell clones and established both the phenotypic differences between the coexisting clones and the clinicobiologic features of these patients. In total, 53 B-CLPD cases with 2 or more B-cell clones were studied. Presence of 2 or more B-cell clones was suspected by immunophenotype and confirmed by molecular/genetic techniques in leukemic samples (n = 42) and purified B-cell subpopulations (n = 10). Overall, 4.8% of 477 consecutive B-CLPDs had 2 or more B-cell clones, their incidence being especially higher among hairy cell leukemia (3 of 13), large cell lymphoma (2 of 10), and atypical chronic lymphocytic leukemia (CLL) (4 of 29). In most cases the 2 B-cell subsets displayed either different surface immunoglobulin (sIg) light chain (n = 37 of 53) or different levels of the same sIg (n = 9 of 53), usually associated with other phenotypic differences. Compared with monoclonal cases, B-CLL patients with 2 or more clones had lower white blood cell (WBC) and lymphocyte counts, more frequently displayed splenomegaly, and required early treatment. Among these, the cases in which a CLL clone coexisted with a non-CLL clone were older and more often displayed B symptoms, a monoclonal component, and diffuse infiltration of bone marrow and required early treatment more frequently than cases with monoclonal CLL or 2 CLL clones.     

Characterization of malignant lymphomas in leukemic phase by multiple differentiation markers of mononuclear cells. Correlations with clinical features and conventional morphology.

Peripheral blood and bone marrow cells of 38 patients with malignant lymphoma in the leukemic phase were defined by multiple immunologic markers and determination of the enzyme terminal deoxynucleotidyl transferase (TdT). Despite shared B cell markers (surface immunoglobulins, binding of aggregated immunoglobulin G [IgG]) distinctions could be made between the cells of patients with chronic lymphocytic leukemia (CLL) and those of patients with other B-lymphoproliferative disorders on the basis of morphology, intensity of surface immunofluorescence and number of mouse rosette-forming cells (MRFC). In 15 patients with CLL, the mean value for MRFC was 47.5 per cent, differing significantly (p < 0.001) from the value found in 10 patients with non-CLL B-cell leukemic lymphomas (7.5 per cent) and in normal control subjects (4 per cent ± 3/mean ± 1 SD). Of 11 patients with leukemic diffuse poorly differentiated lymphocytic lymphoma (DPDL), four had cells that formed spontaneous rosettes with sheep erythrocytes (T cells), and seven had a predominance of null cells. TdT activity was present in six of six patients studied, including three patients each with the null and T cell proliferations. This group of 11 patients with leukemic DPDL was characterized clinically by prominent mediastinal involvement in 10, a median age of 29 years and a median survival of 12 months. Malignant cells of two patients with leukemic diffuse histiocytic lymphoma seemed to be of B cell origin, as they were characterized by monoclonal surface immunoglobulin M (IgM) of kappa light chain type. Leukemic cells in the remaining two patients were characterized by a prominent Fc receptor, which might be considered evidence of a monocytic disorder. These data further support the usefulness of cell marker analysis in delineating the heterogeneity of cellular types involved in leukemic and lymphomatous disorders, and suggest its eventual clinical usefulness in the diagnosis and prognosis of these disorders.     

Patients with a deficiency of natural killer cell activity lack the VEP13-positive lymphocyte subpopulation

Many patients with B-type chronic lymphocytic leukemia (CLL) exhibit a profound defect in their natural killer (NK) cell activity, the basis of which is still obscure. Hence, we analyzed the NK cells from peripheral blood samples from 11 patients with CLL for phenotype and function, after removal of the leukemic cells with a monoclonal antibody (BA-1) plus complement. Phenotypic analysis of these nonleukemic cells with monoclonal antibodies (MoAbs) against NK cells revealed that the CLL patients had higher percentages of HNK-1-positive cells (23.5% compared to controls with 14.7%). In contrast, VEP13- positive cells were absent or low in seven patients (0.8% compared to controls with 11.2%) and normal in four patients (10.5%). When testing NK cell activities against K562 or MOLT 4 target cells, patients with no or minimal numbers of VEP13-positive cells were found to be deficient, while patients with normal percentages of VEP13-positive cells had NK cell activity comparable to controls. Isolation by fluorescence-activated cell sorter of HNK-1-positive cells from patients lacking VEP13-positive cells and NK cell activity indicated that the majority of the HNK-1-positive cells in these patients had the large granular lymphocyte morphology that is characteristic of NK cells. Thus, the deficiency of NK cell activity in CLL patients appears to result from the absence of cells carrying the VEP13 marker.     

Kidney failure in a patient with chronic B-lymphocytic leukaemia (B-CLL) with underlying cast nephropathy. The value of free immunoglobulin light chain identification for early diagnosis of this complication

We describe a case of an untreated female patient monitored over 8 years for chronic B-lymphocytic leukaemia (B-CLL). Over the 8 years, the patient has gradually developed severe kidney failure, even though the criteria for B-CLL treatment had not been fulfilled. Kidney biopsy revealed renal damage due to lamda free light chains cast nephropathy as well as an infiltration of renal parenchyma with B-CLL cells. It was not before this biopsy that the presence of monoclonal immunoglobulins has been investigated. Immunofixation identified free monoclonal lamda light chains in the serum and urine. Their serum concentration, quantified by densitometry, was 2.6 g/l and urine concentration was 0.5 g/l. A specific evaluation of free light chains in the serum revealed an extremely high concentration of free X light chains, over 4500 mg/l, and normal concentration of K free light chains, 10 mg/l. The aim of this report is to emphasise that monoclonal immunoglobulin may be present in B-CLL as well as other lymphoprolipherative diseases and that it may cause damage to organs, similar to multiple myeloma or monoclonal gammopathy of undetermined significance. The described case confirms poor prognostic value of monoclonal immunoglobulin free light chains in patients with B-CLL and usefulness of an evaluation of their presence in patients with B-CLL, particularly if the patients have increased creatinine level. The described case also highlights the need for evaluation of the presence of free light chains in the serum of all patients with unclear cause of renal failure.     

Developmentally restricted immunoglobulin heavy chain variable region gene expressed at high frequency in chronic lymphocytic leukemia.

During fetal development, murine and human B-lineage cells rearrange and express a highly restricted set of immunoglobulin heavy chain variable region genes (VH genes). We noted that a VH gene of the restricted human fetal repertoire, designated 51p1, potentially could encode the VH region of two human IgM rheumatoid factor proteins. These rheumatoid factors share a cross-reactive idiotype (CRI) defined by reactivity with G6, a murine monoclonal antibody that recognizes an antibody heavy chain determinant present on many human IgM autoantibodies, particularly rheumatoid factors. Recently, we found that the G6 CRI also is expressed frequently by neoplastic CD5 (Leu1) B cells from patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma. However, neoplastic CD5-negative B cells from patients with lymphomas of follicular center cell origin rarely express this CRI. Here, we report that G6-reactive leukemic cells from two unrelated CLL patients express a VH gene that shares greater than 99% homology with a rearranged VH gene previously isolated from the leukemic cell DNA of another CLL patient and that is identical to VH 51p1. Using the polymerase chain reaction, we find that this VH gene is rearranged, and presumably expressed, in the genomic DNA of all examined cases of G6-reactive CLL or small lymphocytic lymphoma. Thus these data indicate that the autoantibody-associated G6 CRI is a serologic marker for a conserved and developmentally restricted VH1 gene that is expressed at high frequency in CD5 B-cell malignancies and early B-cell ontogeny.     

Biochemical and aggregation analysis of Bence Jones proteins from different light chain diseases

Deposition of immunoglobulin light chains is a result of clonal proliferation of monoclonal plasma cells that secrete free immunoglobulin light chains, also called Bence Jones proteins (BJP). These BJP are present in circulation in large amounts and excreted in urine in various light chain diseases such as light chain amyloidosis (AL), light chain deposition disease (LCDD) and multiple myeloma (MM). BJP from patients with AL, LCDD and MM were purified from their urine and studies were performed to determine their secondary structure, thermodynamic stability and aggregate formation kinetics. Our results show that LCDD and MM proteins have the lowest free energy of folding while all proteins show similar melting temperatures. Incubation of the BJP at their melting temperature produced morphologically different aggregates: amyloid fibrils from the AL proteins, amorphous aggregates from the LCDD proteins and large spherical species from the MM proteins. The aggregates formed under in vitro conditions suggested that the various proteins derived from patients with different light chain diseases might follow different aggregation pathways.     

Biochemical and aggregation analysis of Bence Jones proteins from different light chain diseases

Deposition of immunoglobulin light chains is a result of clonal proliferation of monoclonal plasma cells that secrete free immunoglobulin light chains, also called Bence Jones proteins (BJP). These BJP are present in circulation in large amounts and excreted in urine in various light chain diseases such as light chain amyloidosis (AL), light chain deposition disease (LCDD) and multiple myeloma (MM). BJP from patients with AL, LCDD and MM were purified from their urine and studies were performed to determine their secondary structure, thermodynamic stability and aggregate formation kinetics. Our results show that LCDD and MM proteins have the lowest free energy of folding while all proteins show similar melting temperatures. Incubation of the BJP at their melting temperature produced morphologically different aggregates: amyloid fibrils from the AL proteins, amorphous aggregates from the LCDD proteins and large spherical species from the MM proteins. The aggregates formed under in vitro conditions suggested that the various proteins derived from patients with different light chain diseases might follow different aggregation pathways.     

Free immunoglobulin light-chain serum levels in the follow-up of patients with monoclonal gammopathies: correlation with 24-hr urinary light-chain excretion

In patients with light-chain myeloma or primary AL-amyloidosis, 24-hr light-chain excretion in the urine is considered an essential marker of the tumor mass. However, 24-hr urine collection and analysis may be cumbersome and prone to inaccuracy. Recently, a sensitive immunonephelometric assay for immunoglobulin free light chains (FLC) in the serum was developed. We sought to determine whether the serum level of monoclonal FLC could be used as an indicator of urinary excretion and disease evolution. Seven patients with light-chain myeloma and AL-amyloidosis were studied, all of which had a monoclonal FLC that could be detected in the urine using standard methods. In four of these patients, follow-up revealed a remarkable correlation between FLC serum levels and daily urinary excretions. The ratio of serum level to urinary light-chain excretion, although stable in a given patient, was extremely variable between patients. In the three remaining cases featuring hardly measurable amounts of light chain in the urine, the serum FLC assay proved sensitive enough for correlation with clinical events. Thus, immunonephelometric measurement of serum FLCs is a reliable method for the follow-up of patients with light-chain secreting monoclonal gammopathies.     

Monoclonal immunoglobulin deposition disease: light chain and light and heavy chain deposition diseases and their relation to light chain amyloidosis. Clinical features, immunopathology, and molecular analysis

Monoclonal immunoglobulin deposition occurs in tissues as Congo Red binding fibrils in light chain amyloidosis, as less structured deposits in light chain deposition disease, and as similar but distinct deposits in light and heavy chain deposition disease. The nonamyloid forms were found in 13 patients who had evidence of plasmacytic dyscrasia by the immunohistochemical detection of immunoglobulin light chains of kappa or lambda class (with or without staining for a single heavy chain isotype) and by the absence of amyloid P component in tissue sections that did not show the birefringence characteristic of amyloid after Congo Red staining. All but two of the patients presented with proteinuria with or without azotemia. Clinical syndromes involving other organ systems were less common but occasionally severe. Four patients had overt multiple myeloma. Three others had hypercalcemia and mild bone marrow plasmacytosis but no lytic lesions. Analyses of immunoglobulin synthesis in bone marrow cells from seven patients showed excess light chains in all and incomplete light chains or heavy chain fragments in six, regardless of whether an intact monoclonal protein or related subunit was in the serum or urine. The fibrillar (amyloidotic) and nonfibrillar forms of monoclonal immunoglobulin deposition occur either in overt multiple myeloma or in the course of less neoplastically aggressive plasmacytic dyscrasias. Bone marrow cells from patients with either type produce immunoglobulin fragments that are related to those deposited in the affected tissues.     

Lymphocyte surface immunoglobulin density and immunoglobulin secretion in vitro in chronic lymphocytic leukemia (CLL)

Lymphocyte surface immunoglobulin (SIg) and immunoglobulin (Ig) secretion were studied in 14 patients with chronic lymphocytic leukemia (CLL) and 12 healthy subjects. The determination of SIgM-bearing (SIgM+) cells by immunofluorescent staining and the quantification of SIgM by radioimmunoassay (RIA) permitted the calculation of the SIgM density. In 12 normal subjects the percentage of SIgM+ cells averaged 8% (range 4%-12%) and the SIgM density 10.2 ng antigenic equivalent/10(6) SIgM+ cells (SD 4.3). In 12 patients with CLL the respective figures were 68% (range 35%-90%) and 0.68 ng (SD 0.57). Ig secretion from pokeweed mitogen-stimulated CLL cells was markedly diminished as compared with normal lymphocytes. In coculture experiments CLL cells had no suppressive effect on Ig secretion of normal lymphocytes and normal lymphocytes did not enhance Ig secretion leukemic lymphocytes. These results indicate that the impaired secretory activity of CLL cells results from an intrinsic anomaly of these cells.     

Differentiation of chronic lymphocytic leukemia cells after in vitro treatment with Epstein-Barr virus or phorbol ester. I. Immunologic and morphologic studies

Leukemic cells from ten patients with "nonsecretory," B-type chronic lymphocytic leukemia (CLL) were cultured alone or in the presence of Epstein-Barr virus (EBV) or a phorbol ester (12-0-tetradecanoylphorbol-13-acetate; TPA) for 7 days. At periodic intervals the cell morphology, cytoplasmic immunoglobulin content (direct immunofluorescence) and capacity for immunoglobulin secretion (hemolytic plaque assay) were assessed. A variable but significant number of the TPA-treated CLL cells from all patients expressed cytoplasmic immunoglobulin of a single light-chain type at some stage, usually within the first 3 days. EBV induced similar changes in seven of eight cases tested. Untreated cell cultures were negative or contained a few cytoplasmic immunoglobulin-positive cells. Cells from five of nine cases secreted immunoglobulin of a single light-chain type. In every instance this was identical to the surface and cytoplasmic immunoglobulin. Cytologic changes were observed in the leukemic cells after treatment with one or both agents in nine of ten cases. The major feature was an increase in cell size associated with immunoblastic or plasma-cytoid features. Mitotic figures and binucleate cells were also present. These studies indicate that EBV and TPA are effective at inducing immunoglobulin synthesis and secretion in "nonsecretory" B cell neoplasms and are useful tools for studying the maturation potential inherent in these tumors. The study also suggests that the secreted immunoglobulin is a monoclonal product.     

Monoclonal gammopathy of undetermined significance. Natural history in 241 cases

Two hundred forty-one patients with a monoclonal protein in the serum but initially no evidence of multiple myeloma, macroglobulinemia, amyloidosis or lymphoma were followed up for more than five years. At the conclusion of the studies the patients were classified as follows: Group 1, patients without significant increase in monoclonal protein, 57 per cent; group 2, patients with more than 50 per cent increase in monoclonal serum protein or development of monoclonal urine protein, 9 per cent; group 3, patients who died without five-year serum studies, 23 per cent; and group 4, patients in whom myeloma, macroglobulinemia or amyloidosis developed, 11 per cent. Initially, the hemoglobin level, size of serum monoclonal protein peak, number of plasma cells in the bone marrow and levels of normal immunoglobulins were not significantly different among the four groups. The median interval from recognition of the monoclonal protein to diagnosis of multiple myeloma was 64 months, of macroglobulinemia 103 months and of amyloidosis 92 months. A significant increase of the monoclonal protein or development of myeloma, macroglobulinemia or amyloidosis occurred in 18 per cent of the patients with monoclonal immunoglobulin G(IgG), in 28 per cent with immunoglobulin A (IgA) and in 25 per cent with immunoglobulin M (IgM). Retrospective analysis of age, sex, presence of organomegaly, hemoglobin level, size and type of serum monoclonal protein peak, presence of small amounts monoclonal light chain in the urine, serum albumin level, levels of uninvolved immunoglobulins, IgG subclass and level of plasma cells in the bone marrow did not show how to distinguish initially between stable benign disease and progressive disease. Therefore, periodic reexamination of patients with monoclonal gammopathy is essential.     

GPI-Anchored Fibromodulin as a Novel Target in Chronic Lymphocytic Leukemia: Diagnostic and Therapeutic Implications

Background: We have previously reported the aberrant expression of Fibromodulin (FMOD) in patients with chronic lymphocytic leukemia (CLL). Although FMOD has been considered as a cytoplasmic or secretory protein, we discovered the cell surface expression of FMOD in leukemic B cells via anchoring with glycosylphosphatidylinositol (GPI). Objective: To evaluate FMOD as a new biomarker in CLL patients in comparison with healthy individuals. Methods: A monoclonal antibody was generated against human FMOD. The cell surface expression of FMOD in 52 CLL patients and 45 healthy individuals were compared by flow cytometry. A bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) was used to determine the cell surface localization of FMOD using ELISA and flow cytometry techniques. Annexin V-FITC and propidium iodide (PI) was used to detect apoptosis induction in CLL PBMCs following in vitro incubation with anti-FMOD mAb. Results: The results demonstrated the widespread cell surface expression of GPI-anchored FMOD in CLL patients (median: 79.9 %), although healthy individuals had low FMOD expression (median: 6.2 %) (p≤0.0001). The cut-off value of FMOD expression was estimated with high sensitivity and specificity at 17.9%. Furthermore, in vitro apoptosis induction of leukemic cells following incubation with anti-FMOD mAb showed a direct apoptosis of CLL cells (27.9%) with very low effect on healthy PBMCs (6%). Conclusion: The membrane-anchoring of FMOD by means of a GPI moiety in leukemic cells supports FMOD as a highly potential diagnostic and therapeutic target in CLL patients.