M components-a review of 1242 cases.

Among 1242 patients referred for immunologic investigation 1255 M components were detected in the serum. Of these patients 50.9% had multiple myeloma, 18.1% had nonmyelomatous malignant diseases such as macroglobulinemia, lymphoma, leukemia or cancer, 4.3% had connective tissue diseases, 2.5% had primary generalized amyloidosis (PGA) and the rest had various "benign" conditions. Whereas IgG was the commonest M component in multiple myeloma, connective tissue diseases and the other benign conditions, IgM was the commonest M component in lymphoma and leukemia; Bence Jones proteinemia was most frequently observed in PGA. The ratio of kappa to lambda light chains varied from 1.7:1 in IgG myeloma to 1:9 in IgD myeloma, and was 1:2.1 in PGA. Bence Jones protein was detected in 422 (66%) of 640 urine samples tested, the prevalence ranging from more than 70% in multiple myeloma and PGA to as low as 36% in various benign conditions. It is evident that the class and type of M components and the presence of Bence Jones proteinuria have no definite significance with regard to the diagnosis. Therefore, thorough investigation and follow-up at regular intervals are required when M components are detected.     

IgD Plasma Cell Neoplasia: Clinical Manifestations and Characteristic Features

Three patients, one with plasma cell leukemia and clinically asymptomatic hypernephroma and meningioma, and two others with multiple myeloma, had M-components of IgD/λ type. In the first case, IgD globulin was found in the serum, ascitic and pleural fluids. Including our patients, 50 cases of IgD myeloma have been reported in the literature. A review of this group showed some significant differences from the other classes of multiple myeloma. IgD myeloma seems to involve a larger proportion of younger people, 66% being less than 59 years of age. The involvement of internal organs and renal damage were more frequent in IgD myeloma than in other classes. Serum total protein was frequently not increased, the relative concentration of M-component was often low and in 12% there was no spike in electrophoresis. The diagnosis therefore was sometimes difficult. In a quarter of the cases Bence Jones proteinemia was found and in 15% there were multiple spikes, both these manifestations being rare in IgG or IgA classes of myeloma. In 89%, IgD globulin had lambda type light chain, clearly contrasting with the figure of approximately 30% in other classes. Bence Jones protein was found in the urine in 91%. The survival time seemed to be shorter than in other myelomas.     

Analysis of urinary proteins from 50 patients with multiple myeloma by discelectrophoresis (author's transl)]

Urinary proteins from 50 patients with multiple myeloma (37 Ig G, 6 Ig A, 7 Bence Jones) were investigated by discelectrophoresis in polyacrylamidgels containing sodium dodecylsulfat. All samples were also characterized by immunelectrophoresis. Quantitatively and qualitatively normal proteinuria was found in 13 patients (26%). 22 patients (44%) had monoclonal free light chains in the urine, kappachains were eliminated mainly in the monomeric form, lambdachains in all samples in the dimeric form. In 2 patients were found to exist light chains as monomers and dimers. 11 other patients (22%) had peaks of monoclonal Ig G or Ig A in the urine, always associated with the elimination of other nonmonoclonal proteins. Non-specific proteinuria was found in the remaining 4 patients. The clinical validity of the findings is discussed.     

Clinical and laboratory findings in primary generalized and multiple-myeloma-related amyloidosis.

Thirty-four patients with primary generalized amyloidosis (PGA) and 14 with multiple-myeloma-related amyloidosis (MRA) were studied. The commonest clinical manifestations in PGA were nephrotic syndrome, hepatomegaly and congestive heart failure, and in MRA, low back pain, plasmacytoma and rheumatoid-arthritis-like syndrome. Eight patients with PGA had limited clinical expression of the disease, such as involvement of only kidneys, joints, parotid glands or gastrointestinal tract; in one patient amyloidosis was limited to lymph nodes. Low serum concentrations of total protein and albumin were common. M components were detected in the serum of 91% of patients with PGA and 92% of patients with MRA: 70% of the M components in PGA and 25% of those in MRA had lambda light chains. Bence Jones proteinemia was detected in 56% of the patients with PGA and in 77% of those with MRA. The serum concentration of immunoglobulins was decreased substantially in more than two thirds of the patients with PGA. Proteinuria (greater than 250 mg/24 h) was observed in 78% of patients with PGA and in 93% of patients with MRA. Bence Jones proteinuria was noted in 75 and 77% of patients, respectively. Plasmacytic infiltration of the bone marrow was found in 90% of the patients with PGA. The mean survival time of the patients with PGA was 28 months and of those with MRA, 29 months from the time of diagnosis.     

Younger Age of Presentation and Extraosseous Tumour in IgD Myelomatosis

A study of 14 personal patients and 16 others in the literature shows that (1) IgD myelomatosis often presents at a significantly younger age than other forms of myelomatosis, and (2) during life extraosseous tumour can be detected in about two-thirds of these patients.The IgD form represents 1·5% of myelomatosis and shows an increased incidence of osteolytic lesions, hypercalcaemia, and renal failure, together with heavy Bence Jones proteinuria (90% type L).Like only Bence Jones myelomatosis, the IgD form seems to behave clinically in a more vicious manner.     

Clinical manifestations of multiple myeloma: relation to class and type M component.

From analysis of serum samples and clinical data from 632 patients with multiple myeloma it was determined that IgG was the commonest class of myeloma and that this type seemed to be the most benign. IgD myeloma and lambda light-chain disease were the most aggressive types; patients with these types were usually younger at diagnosis and more commonly had azotemia, osteolytic lesions and Bence Jones proteinemia. The sexes were equally represented in all but IgD myeloma, in which males predominated. Prognosis was more favourable when the M component had kappa light chains.     

Clinical features of common acute lymphoblastic leukemia antigen (CALLA)-positive myeloma: report of four cases

Four patients with common acute lymphoblastic leukemia antigen (CALLA)-positive myeloma are presented. The subclasses of monoclonal protein were IgD kappa (1 case), IgA lambda (1 case), and IgA kappa (2 cases). Bence Jones proteinuria was seen in all cases. The clinical stages were determined as IIA (2 cases) and IIIA (2 cases). All patients died with a median survival time after diagnosis of 62 days due to rapid development of renal failure (3 cases), and renal insufficiency and pneumonia (1 case). According to light microscopic evaluation, these myelomas corresponded to plasmablastic (1 case), immature (2 cases), and intermediate (1 case) types. Both CALLA and a cytoplasmic immunoglobulin identical with the serum monoclonal protein were simultaneously detected in single cells from all cases using immunofluorescent double labeling. These findings suggest that CALLA-positive and plasma-blastic myelomas constitute clinically a subgroup characterized by extremely poor survival but they represent cytologically different subcategories.     

Immunogenicity and antigenicity of immunoglobulins: detection of human immunoglobulin light-chain carbohydrate, using concanavalin A

Concanavalin A binding to glycoprotein bands on nitrocellulose blots was used to detect mannose, sorbose, N-acetylgalactosamine and/or glucose residues on 100% (31/31) of human Bence Jones protein light chains, following sodium dodecyl sulphate-polyacrylamide gel electrophoresis. All (20/20) light chains form IgG myeloma proteins and light chains from a preparation of normal polyclonal human IgG were also bound by concanavalin A. The specificity of concanavalin A for glycoproteins was demonstrated by its binding to human Fc fragments and a human monoclonal anti-Rhesus D antibody (REG-A), but not to human albumin pFc' fragments and aglycosylated REG-A derived from cells grown in the presence of the glycosylation inhibitor tunicamycin. These results suggest that all Bence Jones proteins and light chains from myeloma IgG proteins contain mono- or oligosaccharides linked O-glycosidically to serine or threonine residues.     

Bence Jones proteins and light chains of immunoglobulins. XIII. Effect of elastase-like and chymotrypsin-like neutral proteases derived from human granulocytes on Bence Jones proteins.

Bence Jones proteins can be cleaved specifically by several types of endopeptidases into fragments corresponding to the amino-terminal, variant (VL) portion and to the carboxyl-terminal, constant (CL) portion of the light polypeptide chain. Two types of neutral proteases, designated elastase-like (ELP) and chymotrypsin-like (CLP), have been isolated and purified from human polymorphonuclear leukocytes. Because these proteases have defined proteolytic activity under physiologic conditions for several types of human proteins, we investigated their effect on human Bence Jones proteins. Incubation of kappa-type or lambda-type Bence Jones proteins with ELP or CLP under appropriate conditions resulted in cleavage of both types of light chains as evident by immunochemical and electrophoretic analyses. Treatment with ELP or CLP of one kappa Bence Jones protein resulted in the formation of a single component that had antigenic and electrophoretic properties similar to the VL fragment derived from pepsin digestion of the native protein. No component corresponding to the CL could be detected immunochemically or electrophoretically. Studies of isolated pepsin-labile (37 degrees C) and pepsin-stable (55 degrees C) CL fragments demonstrated the marked susceptibility of the carboxyl-terminal half of the light chain to proteolysis by the leukocyte-derived neutral proteases. Incubation with ELP of three other kappa Bence Jones proteins and three reduced-alkylated lambda Bence Jones proteins resulted, in each case, in the formation of a homogeneous component which was electrophoretically and immunochemically distinct from the pepsin-derived VL fragment. An identical component could also be formed by incubating a pepsin-derived VL fragment with ELP. In the ELP-treated samples, no CL-related material was detected electrophoretically or immunochemically with antisera possessing specificity for CL antigenic determinants present on the unfolded light polypeptide chain or on the isolated CL. The component formed by ELP or CLP treatment of certain Bence Jones proteins thus appears to be VL-related, but lacks the idiotypic antigenic determinant present on the native protein. In this respect, these neutral protease-derived light chain components are similar to the amyloid-like VL fragments generated in vitro from certain endopeptidase-treated Bence Jones proteins.     

Study of the antigenic structure of human immunoglobulin lambda-chain using monoclonal antibodies]

Nine monoclonals against human Ig lambda chains were produced, 4 antibodies react with C-domain, 5--with V-domain of the lambda chain. Anti-C lambda domain antibodies recognize not less than 3 epitopes and one of them is expressed only on the isolated chain. Anti-V lambda antibodies bind both isolated lambda chain and intact IgG, IgM, IgA. Four epitopes are expressed by few lambda Bence Jones proteins of the III subgroup, the immunogen possessing the same isotype. The 4 mentioned epitopes represent private idiotypic determinants. The epitope 3E10 is characteristic of 50% Bence Jones proteins of the II and III V lambda-subgroups thus representing a common idiotypic determinant. Using anti-V lambda antibodies germ line variability of V lambda III proteins was analysed and the similarity of antigenic structure of normal and myeloma human Ig lambda chains was demonstrated.     

Resistance of proteinuric rats to furosemide: Urinary drug protein binding as a determinant of drug effect

The effect of drug binding to urinary proteins on the diuretic response to furosemide was assessed in normal and nephrotic rats. Nephrosis was induced by treating Sprague-Dawley rats with puromycin aminonucleoside. Binding of furosemide to urinary proteins was found to range from 60 to 95% depending on the concentration of urinary protein. The diuretic response to furosemide reaching the renal tubular lumen was inversely correlated with the degree of proteinuria, a finding that was independent of serum protein concentration of glomerular filtration rate. These data suggest that the binding of furosemide to urinary protein decreases the diuretic effect of furosemide and that drug-protein interactions of this type may also be important in modulating the activity of other lumenally-active drugs or endogenous substances exhibiting a high degree of protein binding. The binding of furosemide to urinary protein may explain the refractoriness of some patients with proteinuria to this agent.     

Refolding of the immunoglobulin light chain.

The kinetics of the refolding reactions of type lambda Bence Jones proteins from 4 M GuHCl were studied by CD, ultraviolet absorption, and fluorescence spectrophotometry. The kinetics were complex and consisted of at least three phases, an undetectable fast phase, a detectable fast phase, and a slow phase. The slow phase followed first-order kinetics and the three experimental methods used gave similar rate constants for all the Bence Jones proteins (about 3 X 10(-3) s-1). The refolding reaction of VL fragment was too fast to be measured in the present experiments. The refolding process of CL fragment was very similar to those of Bence Jones proteins except that the detectable fast phase was less significant. The rate constant of the slow phase observed for the CL fragment was similar to those of the slow phase observed for Bence Jones proteins. The activation energy of the slow phase was the same for a Bence Jones protein and its CL fragment. These results indicate that the refolding kinetics of the CL domain are very similar to those of isolated CL fragment and that refolding of the VL domain precedes refolding of the CL domain, even though both domains have similar immunoglobulin folds. However, the results of refolding experiments on Bence Jones proteins, and VL and CL fragments in the presence of ANS, as well as the other lines of evidence, indicate that the refolding kinetics of the Bence Jones protein molecule cannot be expressed as simple sum of the refolding reactions of isolated VL and CL fragments.     

Urography in Myelomatosis

To investigate whether urographic contrast media might precipitate Bence Jones protein in the renal tubules and lead to renal failure in patients with myelomatosis, the reaction between the media and myeloma urine was studied in vitro. Appreciable precipitation was found only in urine at or below pH 4·5, and its occurrence did not correlate with the type or concentration of protein present. It is concluded that the risk of urography in myelomatosis is very small.     

Serum amyloid A (SAA) protein-interaction with itself and serum albumin.

Serum amyloid A (SAA) protein is a 12,000 dalton protein that exists in serum under physiologic conditions as an 85,000 dalton complex and under certain conditions, as a 170,000 dalton component. To study the reason for this finding, the behavior of 125I-SAA was studied in the presence of cold SAA and several serum proteins. SAA caused a shift of some of the radioactivity to the region of albumin. Addition of normal human serum or albumin caused a shift of a significant fraction of the radioactivity to a peak eluting slightly ahead of albumin (80.000 daltons). This interaction could be blocked by the addition of cold SAA. No shift was noted when IgG or Bence Jones proteins were added. Thus, it appears that low molecular SAA protein has a tendency to aggregate with itself and to bind to albumin but not to human IgG or Bence Jones proteins.     

Plasma cell tumours: cytomorphological features in a series of 12 cases diagnosed on fine needle aspiration cytology

U. Handa, S. Chhabra and H. Mohan
Plasma cell tumours: cytomorphological features in a series of 12 cases diagnosed on fine needle aspiration cytology Objective: Plasma cell tumours represent autonomous proliferation of plasma cells and can manifest as multiple myeloma, monoclonal gammopathy of undetermined significance, variants of plasma cell myeloma or plasmacytoma. Methods: We report 12 cases of plasma cell tumours, which were initially diagnosed as plasmacytoma on fine needle aspiration cytology (FNAC). The patients were further subjected to bone marrow examination, serum electrophoresis, urine examination for Bence–Jones proteins, and x‐ray examination of the skeleton. Results: The cytological smears from all cases were cellular and showed numerous plasma cells in varying degrees of maturity. Subsequent to investigations, five cases were labelled as multiple myeloma with secondary extramedullary plasmacytoma, three as solitary bone plasmacytoma and two as primary extramedullary plasmacytoma. In the remaining two cases, bone marrow and urine examination findings were not available, so a conclusive diagnosis of multiple myeloma or solitary plasmacytoma could not be made. Conclusion: The study highlights the role of FNAC in the diagnosis of plasma cell tumours. Subsequent work‐up and follow‐up of these patients is important to rule out the presence of multiple myeloma.     

The N-linked sugar chains of human immunoglobulin G: their unique pattern, and their functional roles

In contrast to other serum glycoproteins, the majority of the N-linked sugar chains of human serum IgG are not sialylated. In addition, extremely high micro-heterogeneity occurs in the serum IgG sugar chains. This micro-heterogeneity is mainly produced by the presence or absence of the two galactoses, the bisecting GlcNAc, and the fucose residue. Interesting evidence is that the molar ratio of each sugar chain of the serum IgG samples is quite constant in healthy individuals. By adding the information of the characteristic feature of the sugar patterns of myeloma IgG samples and glycosylated Bence Jones proteins, which are the products of monoclonal B-cells, it was proposed that B-cells in the human blood are a mixture of clones equipped with different sets and ratios of glycosyltransferases. It was also proposed that each glycoform of IgG might have a different function. This hypothesis was realized by the comparative studies of the function of IgG samples before and after removal of galactose residues, fucose residue, or sialic acid residues.     

Waldenstr?m's macroglobulinemia: review of 45 cases.

Of 168 patients with monoclonal IgM in the serum 45 (27%) had Waldenström''s macroglobulinemia. The mean age at diagnosis was 66 years. Generalized weakness, fatigue and bleeding manifestations were the usual chief complaints. Lymphadenopathy and hepatosplenomegaly were frequent. Moderate or severe anemia was noted in 29 patients, 9 had abnormal liver function, 8 had cold agglutinemia and 7 had cryoglobulinemia. Two patients had false-positive VDRL tests. The serum concentration of IgM usually exceeded 1000 mg/dl. Comparison of IgM values obtained by immunoquantitation and electrophoresis showed two types of discrepancy: readings were too high by immunoquantitation when IgM of low molecular weight was present, and readings were too low when, probably, IgM/IgG complexes were present or the serum was hyperviscous. Bence Jones protein was detected in 71% of the urine samples tested but the concentration was usually low, exceeding 200 mg/24 h in only nine instances. The mean survival time from the time of diagnosis for the 24 patients who died was 49.5 months and for the patients who are still alive, 43 months. Survival seemed to be related to the presence of azotemia, hypoalbuminemia and abnormal liver function.     

Complete amino acid sequence determinations demonstrate identity of the urinary Bence Jones protein (BJP-DIA) and the amyloid fibril protein (AL-DIA) in a case of AL-amyloidosis.

The complete primary structures of both the main amyloid fibril protein component (AL-DIA) and the soluble Bence Jones protein (BJP-DIA) obtained from the same patient with AL-amyloidosis are reported for the first time. The amino acid sequences were determined by automated Edman degradation following proteolytic digestion of the isolated proteins and HPLC separation of the resulting fragments and by amino-terminal sequencing after treatment with pyroglutamate aminopeptidase. Sequencing data were confirmed by amino acid analysis and plasma desorption mass spectrometry (PDMS). Molecular weights of the complete proteins were determined by laser desorption mass spectrometry. The amyloid fibril preparation contained a complete monoclonal lambda immunoglobulin light chain (subgroup 1.2) as well as different-sized fragments thereof which were identified by immunoblotting and amino-terminal sequencing following immobilization of electrophoretically-separated proteins on poly(vinylidene difluoride) (PVDF) membranes. The soluble urinary Bence Jones protein (BJP-DIA) was a dimer of monoclonal L-chains with a primary structure identical to that of the amyloid L-chain (AL-DIA) and thus represented the amyloid precursor protein.     

Infrared spectroscopy of human amyloid fibrils and immunoglobulin proteins

The presence of the antiparallel-β-pleated sheet coformation io isolated human amyloid protein fibrils has been confirmed by infrared spectroscopy. In most amyloid samples, this conformation was enhanced by acidic solution conditions. Infrared spectroscopy (Amide I and Amide V absorption bands) and x-ray diffraction methods were also used to examine the immunoglobulin molecule for solid state-β-structure. It was found that both heavy chains and Bence Jones proteins exhibited some β-pleated sheet content upon acid and/or heat treatment. Furthermore, pepsin digests comprising either the variable-rich region (Fd′) of the immunloglobulin heavy chain or in particular, filamentous variable segments of κ and λ Bence Jones proteins were, as isolated, very similar to amyloid in β-structure content. Data from other immunoglobulin-derived sample did not exhibit extensive β-pleated sheet content. On the other hand, most amyliod and immunoglobulin-derived samples did display some β-structure when cast from 50% HCOOH solution. Under these conditions, however, filamentous light chain-variable segments exhibited well-defined infrared patterns rich in antiparallel-β-pleated sheet structure and gave a “cross-β” x-ray diffraction pattern.     

Conformational transitions of non-helical proteins effected by dodecyl sulfate. Circular dichroism of alpha1-acid glycoprotein, Bence Jones protein, carbonic anhydrase B, deoxyribonuclease, pepsinogen, and plasminogen.

Circular dichroism (CD) of serum alpha1-acid glycoprotein, urinary Bence Jones protein, human carbonic anhydrase B, deoxyribonuclease from bovine pancreas, porcine pepsinogen, and plasminogen from human serum was tested in the absence and presence of 0.005-0.05 M sodium dodecyl sulfate. It was found that in all cases the CD spectra of these proteins were modified by the dodecyl sulfate into spectra indicating the presence of a moderate content of alpha-helix. The transitions were enhanced by addition of acid (pH 2.1-4.4) in all cases tested. Comparison of the various proteins with respect to the amount of reconstruction of the main chain conformation showed that the amount of helix formed depended on the amino acid composition of the protein. Rigidity due to cross-linking by disulfide bridges is the strongest deterrant to the conformational change of the main chain. The CD bands of the native proteins in the 250-350 nm spectral zone were extinguished by sodium dodecyl sulfate, and new weak bands were observed the positions of which corresponded approximately to those of the native proteins. In all cases, except the carbonic anhydrase B, the bands of thus denatured proteins were negative.