Myeloma proteins (M-components) with antibody-like activity

Plasma cell disorders in HIV-infected patients: epidemiology and molecular mechanisms

Highly active antiretroviral therapy (HAART) has significantly improved the outcome and survival of human immunodeficiency virus (HIV)-infected patients. Subsequently, long-term morbidities including cancer have become of major public health and clinical interest for this patient population. Plasma cell disorders occur at higher incidence in HIV-infected patients; however, the molecular mechanisms driving the plasma cell disease process and the optimal management for these patients remain to be defined. This article provides an up-to-date review of the characteristics and management of HIV-infected patients with plasma cell disorders. We first present 3 cases of plasma cell disorders in HIV-infected patients, ranging from polyclonal hypergammaglobulinemia to symptomatic multiple myeloma. We then discuss the epidemiology, clinical presentation, and management of each of these plasma cell disorders, with an emphasis on the molecular events underlying the progression of plasma cell diseases from monoclonal gammopathy to symptomatic multiple myeloma. We propose a three-step hypothesis for the development of multiple myeloma. Finally, we discuss the use of high dose chemotherapy and autologous hematopoietic stem cell transplantation in the treatment of HIV-infected patients with multiple myeloma. Our review includes the care of HIV-infected patients with plasma cell disorders in the current era of HAART and novel agents available for the treatment of multiple myeloma.

Phosphate binding by a myeloma protein

A patient with IgG kappa myeloma had markedly elevated serum phosphate concentrations but no clinical features of hyperphosphataemia. The hyperphosphataemia was due to a high phosphate per protein unit than normal IgG.

Acquired von Willebrand's disease caused by a monoclonal antibody

A 67-year-old man with malignant lymphoma and acquired von Willebrand's disease is described. His bleeding symptoms started late in life and at this time a monoclonal IgGK serum protein was found. He had a prolonged bleeding time, decreased platelet adhesiveness, low values for factor VIII clotting activity (VIII:C), factor VIII related antigen (VIIIR:Ag) and ristocetin co-factor activity (VIII:Rcof). Infusion of factor VIII concentrates (fraction I-0) did not correct the abnormalities. No inhibitory activity in vitro of the patient's plasma or IgG fraction could be demonstrated against VIII:C, VIIIR:Ag and VIII:Rcof. In order to demonstrate an antibody that binds factor VIII without inhibiting its biological activities in vitro, advantage was taken of the fact that staphylococcal protein A strongly binds the Fc part of IgG molecules. Addition of staphylococci to mixtures of patient IgG and a factor VIII preparation resulted in removal of all factor VIII activities (VIII:C, VIIIR:Ag, VIII:Rcof) from the supernatant at sedimentation of the bacteria. The active binding principle was the M-component, i.e. probably a monospecific antibody molecule. We hypothesize that the complex is formed in vivo and eliminated at an accelerated rate.

The early history of plasma cell tumors in mice, 1954-1976

Plasma cell tumors (PCTs) in mice became available at an exciting period in immunology when many scientists and laboratories were occupied with how to explain the genetic basis of antibody diversity as well as antibody structure itself. An unlimited source of PCTs in an inbred strain of mice became a useful adjunct in these efforts. A PCT was a greatly expanded monoclone and a source of a single molecular species of immunoglobulin (Ig) molecule. The PCTs provided not only the components of the Ig-producing cell but also potentially functional secreted products. Many of the monoclonal Igs produced by PCTs in the mouse and others found in humans were found to have specific antigen-binding activities. These became the prototypes of monoclonal antibodies. This chapter describes the origins of PCTs in mice and attempts to recapture some of the ambience of the day albeit from personal recollection. The great discovery of the hybridoma technology by Cesar Milstein and Georges Kohler in 1975 began a new direction in immunology.

Prevalence of vitamin B12 deficiency in patients with plasma cell dyscrasias: a retrospective review

BACKGROUND

To the authors' knowledge, the prevalence of vitamin B12 deficiency among patients with plasma cell dyscrasias (PCD) is largely unknown. Identifying this vitamin deficiency in such patients could help improve their anemia and increase their tolerance to potentially neurotoxic agents.

METHODS

The authors retrospectively reviewed the charts and laboratory results of 664 consecutive patients diagnosed with PCD who had their vitamin B12 and folate status evaluated between 1997 and 2001 at the Cleveland Clinic Multiple Myeloma Research Program. The patients were screened for vitamin B12 deficiency using serum vitamin B12 and methylmalonic acid.

RESULTS

Of the 664 patients whose medical charts were reviewed, information on vitamin B12 status was available for 522 patients (78%). Among these 522 patients, 71 (13.6%) had laboratory-defined vitamin B12 deficiency and the remaining 451 patients (86.4%) did not. On univariate analysis, vitamin B12 deficiency correlated with immunoglobulin A (IgA) PCD (P = 0.04), higher mean corpuscular volume (P = 0.008), and longer follow-up (P = 0.048). In a covariate adjusted model, only the presence of IgA PCD was associated with an increased prevalence of vitamin B12 deficiency (P = 0.003).

CONCLUSIONS

Vitamin B12 deficiency was prevalent in patients with PCD, especially in patients with the IgA subtype. Serum vitamin B12 measurements should be part of the initial evaluation and subsequent workups for anemia in patients with PCD.

Systemic reactions and fatalities associated with allergen immunotherapy

OBJECTIVE

The primary objective of this review is to discuss systemic allergic reactions and risk factors associated with the injection of allergen vaccines.

DATA SOURCES

A review of the literature on anaphylactic reaction, adverse effects, and fatalities associated with allergen immunotherapy (IT) was conducted.

STUDY SELECTION

The expert opinion of the author was used to select relevant data.

RESULTS

Systemic allergic reactions associated with the injection of allergen vaccines usually begin within 20 minutes. However, on occasion, they begin 20 to 30 minutes or longer after an injection. Such reactions can also occur after allergen skin testing. Most reactions associated with skin testing and allergen IT are mild and readily respond to appropriate treatment. However, severe and even fatal reactions have been reported with both skin testing and IT.

CONCLUSIONS

Risk factors for skin testing and allergen IT include: 1) patients, particularly asthmatic patients, suffering with seasonal exacerbation of their symptoms; 2) patients who demonstrate exquisite sensitivity to particular allergen(s); 3) patients on beta-blockers; 4) patients with asthma, especially if their asthma is unstable; 5) patients in whom rush IT is used; and 6) patients in whom high doses of potent standardized allergen vaccines are used. It is essential that strict attention be paid to the risk factors for systemic reactions, and that techniques and management be initiated both before and after skin testing or IT to minimize these risks. Done properly, the risk of skin testing and IT is minimal.

Cationic myeloma M-components frequently show cross-reacting anti-DNA, Anti-F(ab')2 and anti-nucleosome specificities

134 cationic human IgG myeloma proteins were studied for expression of anti-DNA Idiotypic markers. 64 were studied for 16/6, F4, 3I, and 8.12, and 70 for expression of F4 and 3I. 31.3% showed at least one anti-DNA Id marker and many cationic myelomas were also positive for anti-DNA ELISA reactivity as well as anti-F(ab')2. Five M-components showed anti-nucleosome reactivity and one without detectable anti-DNA Id markers showed very strong anti-nucleosome antibody which was also inhibited by DNA and Sm antigens. Anti-idiotypic antisera produced either against Id(+) anti-DNA reactive M components or F(ab')2 fragments of affinity purified SLE IgG anti-DNA showed preferential cross-reactive idiotype reactivity between Id(+) anti-DNA reactive M components. Our findings indicate that human IgG monoclonal proteins positive for several common anti-DNA Ids and possessing anti-DNA ELISA reactivity, can serve as models for SLE Id marker antigens and as a source to prepare anti-Ids from IVIG.

The detection of antithyroglobulin activity in human serum monoclonal immunoglobulins (monoclonal gammopathies)

The sera of 159 patients with monoclonal gammopathies were examined for the presence of anti-thyroglobulin (Tg) activity. An enzyme-linked immunosorbent assay was employed. Thirty-one (19.5%) sera were found to bind Tg. The activity against Tg was further confirmed by using purified immunoglobulins and employing competition assays. The anti-Tg antibodies were found in the sera of patients with IgG, IgM and IgA gammopathies. Anti-Tg antibodies were more frequent among patients with IgG gammopathy. Autoantibodies to Tg are found in patients with Hashimoto's thyroiditis, Graves' disease and occasionally in patients with thyroid carcinoma. Natural autoantibodies directed against human Tg have been detected, as well, in healthy subjects. None of the patients in the present study whose serum was found to contain high titers of anti-Tg human monoclonal antibodies had any clinical or biochemical evidence of thyroid disease. Our results of a high incidence of anti-Tg activity in the sera of patients with monoclonal gammopathies support previous reports of autoantibody properties characteristic of these immunoglobulins.

Monoclonal gammopathies in children

Over a 10-year period sera of 4000 pediatric patients were subjected to agar gel electrophoresis and immunoelectrophoresis. Retrospective examination of the electrophoresis patterns indicated that single or multiple homogeneous immunoglobulin components were present in sera of 155 children (3.9%). They were most frequently found in patients suffering from primary and secondary immunodeficiency diseases, hematological malignancies, autoimmune diseases, and severe aplastic anemia. Follow-up analysis revealed that most of these monoclonal gammopathies were transient. The monoclonal gammopathies in the serum of 79 patients were identified by immunoblotting for class and light-chain isotypes. A marked absence of IgA monoclonal gammopathies and a predominance of monoclonal gammopathies of the lambda light-chain isotype were found. Most of the B-cell mono- or oligoclonal proliferations in children can probably develop due to a disturbance in the regulatory T-cell function.

Antibody specificity of the human monoclonal immunoglobulins: the elusive target antigen

Human monoclonal immunoglobulins (HMIGs) are encountered in different clinical conditions mainly including (auto)immune disorders, immunodeficiencies and B-cell malignancies. However, in some cases no associated-disease is evidenced and they are considered as "idiopathic". Their incidence increases with age. The factors involved in the emergence and regulation of the growth and differentiation of B-cell clones secreting HMIGs are unknown but might implicate T-cell dysfunction. One approach to elucidate the origin of such B-cell clones is to identify the putative target antigen. For this reason, we have reviewed the antibody (Ab) specificity of 8439 HMIGs described in the literature, the data coming from 24 systematic screenings. Very few HMIGs present anti-hapten activity (1%) or specificity for foreign antigens (0.3%). On the other hand, the data quoted strongly document an auto-Ab (Ab1 type) activity in a large percentage of the HMIGs, mainly of the IgM type (at least greater than 30%), with properties similar to those of naturally occurring auto-Abs. Furthermore, there is some evidence that HMIGs may express anti-idiotypic activity (Ab2) to human (auto)-Abs. Finally, many of the HMIGs which are devoid of detectable auto-Ab activity (i.e., mainly IgG, IgA) share cross-reactive idiotypes with natural auto-Abs. It may be speculated that some of these HMIGs actually represent either Ab of the Ab3 type i.e., anti-anti-idiotypic Ab to auto-Abs or Ab which have varied sufficiently to loose auto-or-foreign-antigen-binding activity but maintaining idiotype. As a whole, these data demonstrate that many HMIGs are the secretory products of the auto-reactive B-cell clones which produce natural auto-Abs (including anti-idiotypic and anti-anti-idiotypic Abs) and which are characterized by a very high degree of idiotypic connection. Since HMIGs arise from such clones, it may be postulated that the emergence of HMIGs might be due to a dysfunction of the system that normally regulates such an Ab production.

Selective bone marrow involvement of lymphoplasmacytic cells secreting monoclonal IgA rheumatoid factor in a patient with Sjögren's syndrome and serum hyperviscosity

The clinical features and results of serological studies of a patient with Sjögren's syndrome, IgA kappa monoclonal gammopathy, and hyperviscosity syndrome are reported. The novel aspect of this case is the selective localisation to the bone marrow of lymphoplasmacytoid cells secreting IgA kappa morphologically identical to the cells infiltrating the salivary glands. The serum of the patient contained large amounts of immunoglobulin-anti-immunoglobulin immune complexes. By gel filtration chromatography it was shown that the immune complexes formed a peak of molecular weight 680 kilodaltons. The immune complexes were dissociable under acidic conditions. The immunoglobulin with rheumatoid activity was characterised as monoclonal IgA kappa protein. Treatment with plasmapheresis combined with immunosuppressive treatment with cyclophosphamide reduced the serum viscosity with concomitant clinical improvement.

Lupus anticoagulant associated syndrome in benign and malignant systemic disease--analysis of ten observations

The clinical and laboratory findings in seven female patients with primary autoimmune diseases, one female patient with lymphoplasmacytoid (LP) immunocytoma and IgM paraproteinemia, and two male patients with multiple myeloma are described. The common denominator in all patients was a lupus anticoagulant or a closely related coagulation disorder. Recurrent thrombosis was observed in six patients with autoimmune diseases and in two patients with malignant monoclonal gammopathies. Other clinical manifestations included cerebral disorders (four patients with autoimmune disease/two patients with monoclonal gammopathy), repeated obstetric complications (6/1), asymptomatic valvular heart disease (6/1), renal dysfunction (6/2), hepatic involvement (2/2), and arthropathy (2/0). Laboratory investigations revealed a biologic false-positive serological test for syphilis in six patients with autoimmune disease and one with monoclonal gammopathy, antinuclear antibodies (4/0), antibodies against DNA (4/1), and a positive direct Coombs test (3/1) which was accompanied by hemolytic anemia in two patients (1/1). Additionally slight leukocytopenia (2/1) and thrombocytopenia (6/2) were observed; abnormal bleeding was only seen in one patient with severe thrombocytopenia. Other complications characteristic of LP immunocytoma or multiple myeloma were missing. The obvious similarities between the patients with autoimmune diseases and the patients with malignant monoclonal gammopathies suggest analogous pathogenetic mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Search for antibodies to skeletal muscle proteins in amyotrophic lateral sclerosis

We have investigated serum from 16 patients with amyotrophic lateral sclerosis (ALS) and 15 patients with other neurological diseases (OND) for antibodies which react with skeletal muscle derived antigens. Two different preparations of skeletal muscle antigens were used: i) proteins released from rat diaphragm in organ culture and ii) proteins obtained from a muscle homogenate. We also compared antigen preparations from denervated and non-denervated muscles. A rabbit anti-serum reacted strongly with three proteins in both types of protein preparation, but none of these proteins were specific to denervated muscle. None of the 16 ALS sera could be shown to react with protein antigens from any of the muscle preparations. One of the ALS patients had an IgG lambda monoclonal protein in the setting of a multiple myeloma. This monoclonal protein did not react with protein antigen from rat muscle, human grey or white matter.

Neuropathy and motor neuron syndromes associated with plasma cell disease

Increasing numbers of patients are being recognized with neurological abnormalities associated with the immunochemical changes of plasma cell disease. To illustrate the wide spectrum of clinical disorders that can be found, I discuss in detail 5 patients: 2 with neuropathy, 3 with amyotrophic lateral sclerosis (ALS), all of whom had serum monoclonal paraproteinemia. In addition, I report in tabular form 6 patients with paraproteinemia and the following clinical presentations: 1) systemic lupus with polyneuropathy and severe cerebritis, 2) myasthenia gravis with thymoma, 3) polymyositis, 4) polymyositis, arthritis and Grave's disease, 5) relapsing polyneuritis (one of the original patients diagnosed by Austin) and 6) ALS, dystonia and parkinsonism. Major improvements in clinical condition occurred sometimes, but not always, coincident with reductions in the levels of the paraprotein using prednisone, cyclophosphamide, chlorambucil and plasma exchange treatments even in some of the patients who had the clinical appearance of ALS. Patients with neuromuscular diseases should be routinely screened with serum immunoelectrophoresis for monoclonal gammopathy. If a monoclonal gammopathy is found and if the disease is serious, then those patients should be treated as if they had an autoimmune disorder.

A human myeloma immunoglobulin G binding four moles of calcium associated with asymptomatic hypercalcemia

A calcium-binding immunoglobulin G (IgG1 lambda RUP) was identified in the serum of a patient with multiple myeloma, asymptomatic hypercalcemia, and a normal ionized serum calcium. Calcium binding by IgGRUP was confirmed by two-dimensional electrophoresis with calcium-45 and equilibrium dialysis. Amino acid analyses indicated an unusually high number of glutamic (or glutamine) residues in the L chain and Fab fragment but no detectable gamma-carboxyglutamic acid. As determined by equilibrium dialysis with 45Ca, the intact IgGRUP and its Fab fragments bound calcium at an optimum pH of 7.4. There was minimal binding of calcium to H chains and no binding by L chains or the Fc fragment. Recombination of H and L chains partially restored the binding activity. By Scatchard analysis, the binding affinity (Kd) of IgGRUP was 1.7 X 10(-3) M and the binding capacity was 4 mol of calcium/mol of IgG. The binding of 4 mol of calcium/mol of IgG is twice that reported previously for two other calcium-binding myeloma proteins and suggests unique properties of IgGRUP.

Human monoclonal antibodies to myelin-associated glycoprotein. Comparison of specificity and use for immunocytochemical localisation of the antigen

Recent reports demonstrate that a population of patients with gammopathy and demyelinating neuropathy have monoclonal antibodies to myelin-associated glycoprotein. Using the immunoblotting technique we compared the species specificity: human monoclonal antibodies to myelin-associated glycoprotein reacted with human, monkey, calf, dog, rabbit and guinea pig myelin, but not with rat or mouse. On the immunoblot myelin-associated glycoprotein consistently stained as a diffuse band with an apparent molecular weight ranging from 90-100 X 10(3) dalton. Experiments showed that when human CNS myelin had been incubated at 37 degrees C before gel electrophoresis, there was a general shift of staining towards the lower end of the molecular weight range. This low molecular weight myelin-associated glycoprotein, when released from the membrane, contains the antigenic determinant. Peptide mapping by limited proteolysis reveals that the antigenic determinants for 4 different monoclonal antibodies appear to lie very close together in the molecule. The distribution of the antigen was studied in nervous tissue with the unlabelled peroxidase-antiperoxidase method. The results obtained are in close agreement with the localization reported with polyclonal antisera to myelin-associated glycoprotein.

Human monoclonal IgM with autoantibody activity against intermediate filaments

Monoclonal IgMs from two patients with Waldenström macroglobulinemia were found to react with intermediate filaments. This was shown by (a) immunostaining of various tissues and cultured cells and (b) immunological characterization of the reactive antigen after blotting of polypeptides separated from total cell extracts by gel electrophoresis or purified intermediate filaments on nitrocellulose sheets. One monoclonal IgM had an activity directed only against vimentin, whereas the other reacted with four different classes of intermediate filaments--vimentin, desmin, glial fibrillary protein, and keratins. All of the reactivity of the latter IgM was absorbed by purified vimentin, suggesting that different classes of proteins of intermediate filaments share common antigenic determinant(s). The significance of such autoantibody activity of human monoclonal IgM is discussed in the light of the startling frequency of IgM anti-intermediate filaments antibodies in various diseases.

Plasma cell dyscrasia and peripheral neuropathy: identification of the myelin antigens that react with human paraproteins

In some cases of polyneuropathy and plasma cell dyscrasia, the monclonal antibodies react with human peripheral nerve myelin. To identify the myelin antigens involved, we separated the proteins of human central and peripheral nerve myelin by polyacrylamide gel electrophoresis, transferred the proteins onto nitrocellulose sheets, and used an immunoenzymatic technique to detect the reactive antigens. Serum IgM but not IgG from three patients with neuropathy and complement-fixing anti-human myelin IgM paraproteins immunostained a protein of approximately 100,000 daltons in human peripheral nerve myelin and a protein or closely migrating proteins of similar size in human central nervous system myelin. In a fourth patient, both IgM and IgG immunostained the antigen. Immunostaining was specific for the paraprotein light chain type, and absorption of the patients' sera with human peripheral nerve myelin eliminated the reaction with the central nervous system proteins. No reaction was seen with rabbit peripheral nerve myelin or with membranes prepared from human myotubes, human T cells, or human fibroblasts. Control sera from six patients with neuropathy and IgM paraproteins that did not react with myelin, from four patients with IgM paraproteins but no neuropathy, and from three normal subjects did not immunostain myelin.

Polyneuropathy with monoclonal gammopathy: studies of 11 patients

Among patients with chronic idiopathic nonfamilial polyneuropathy studied 3 to 21 years after onset, we identified 11 cases associated with monoclonal gammopathy (MCG) (5 with IgGk, 4 with IgMk, 2 with IgG lambda). The patients, aged 29 to 80 years, presented with sensorimotor polyneuropathy of insidious onset and slow, nonfluctuating progression, delayed motor and sensory nerve conduction, and increased cerebrospinal fluid (CSF) protein. None of the patients in the initial or follow-up study (mean, 9.2 years) had or developed signs of multiple myeloma, malignant plasma cell dyscrasia, macroglobulinemia syndrome, amyloidosis, neoplasia, or other associated illness. The CSF revealed abnormalities of protein electrophoresis or immunoelectrophoresis in 9 of the 11 patients. Three of 5 sural nerve biopsies studied by immunofluorescence demonstrated deposition in nerve fibers of the light chain characteristic of the abnormal circulating immunoglobulin. The findings suggest that these patients form a distinct subset of the dysimmune neuropathies. Although the immunoglobulin deposition and abnormal protein patterns in serum and CSF could be secondary to nerve damage, we propose that an immunopathological mechanism underlies the neuropathy. Immunosuppressants had minimal to marked beneficial effect in 4 of 5 patients, indicating that this polyneuropathy is potentially treatable.

Subpopulations of T-lymphocytes in multiple myeloma

The percentage and absolute numbers of T lymphocytes bearing Fc receptor for IgG and IgM were evaluated in 13 patients with multiple myeloma and in a group of controls of the same age range. An increase in the percentage of the TG cells was found, whereas TM cell numbers were not different from those of the controls. In order to better define the properties of the TG lymphocytes, their ability to suppress the PWM-induced B cell differentiation was tested in an in vitro experimental assay. TG cells from multiple myeloma exert a suppressor activity as the TG of the controls in this system. The possible interpretation of suppressor T cell increases in these patients is discussed.

Insulin resistance and monoclonal gammopathy

Two maturity-onset diabetic patients developed severe insulin resistance during the course of monoclonal gammopathies. One patient had Waldenström macroglobulinemia and the other had multiple myeloma with IgA gammopathy. The maximum insulin binding capacity (MIBC) was 121 U/liter and 54.7 U/liter, respectively, during insulin resistance. The clinical courses of insulin resistance paralleled the activity of the monoclonal gammopathies (MG) with the insulin resistance disappearing after the monoclonal gammopathies were controlled. Six other diabetic patients with concurrent insulin resistance and monoclonal gammopathies are reviewed.

A calcium binding IgG myeloma protein

A calcium binding IgG was isolated and purified by column chromatography from serum of a myeloma patient with asymptomatic hypercalcaemia. The myeloma IgG, characterized as an IgG kappa, revealed a normal sized heavy chain (56 000 dalton), and a light chain of 31 000 dalton. Another population of IgG separated and purified from the same patient's serum did not bind calcium and had a normal 26 000 dalton light chain. Calcium binding activity in vitro is optimal at pH 8.0, and reaches its maximum after 3 h of 45Ca myeloma IgG incubation. Cleavage of the purified IgG by trypsin yielded peptides which were further isolated by column chromatography and characterized as Fab and Fc fragments. Light and heavy chains were obtained by reacting the immunoglobulin with dithiothreitol and iodoacetamide followed by Sephadex G-100 chromatography. Calcium binding activity was proved to be associated with Fab IgG fragment. Preparates containing Fc, heavy or light chains did not bind calcium in vitro.

Myasthenia gravis with a monoclonal gammopathy--report of a case

An elderly man with relapsing myasthenia gravis was found to have hypergammaglobulinaemia, a monoclonal peak of gamma mobility and paraproteinaemia IgG, type K. Bence-Jones proteinuria, type K was present. This is the fourth report of myasthenia gravis associated with a monoclonal gammopathy. Myasthenia gravis is considered to be an autoimmune disease. Recent findings implicate a dysfunction of cellular immunity in the pathogenesis of both immunoproliferative and autoimmune disease. We suggest that the association of myasthenia gravis and monoclonal gammopathy in our patient might have stemmed from a disorder of T lymphocyte function.

A monoclonal macroglobulin with antinuclear activity

Serum containing a monoclonal IgM protein from a patient with Waldenstroms' macroglobulinaemia gave intense immunofluorescent staining of kidney nuclei. The Fab mu fragments of this immunoglobulin were obtained. The IgM and Fab fragments reacted in vitro with kidney nuclei using unfixed cryostat sections of rat or mouse kidney. After treatment of the patient with chemotherapy, the monoclonal IgM disappeared, and no more antinuclear activity could be detected in the serum. The results strongly suggest that this IgM protein had antinuclear activity.

Two cases of monoclonal immunoglobulins with antistreptolysin activity: clinical and laboratory study

In two patients with a persisting, high antistreptolysin titre the antistreptolysin activity in both cases resided exclusively in a monoclonal IgG component in the serum. This component had all the characteristics of a true antibody. A history in both patients of arthritis with or without angina suggested that the monoclonal antibodies were reactive in origin, although definite proof was lacking. In one case there was a suggestion of incipient myeloma. Whenever an extremely high antistreptolysin titre persists after antibiotic treatment the possibility of paraproteinaemia should be considered.

Myeloma with xanthoderma due to an IgG lambdamonoclonal anti-flavin antibody

When yellow skin and yellow hair developed in an elderly patient with multiple myeloma, we ruled out the usual causes of such pigmentation but identified a monoclonal IgGlambda (lgGGar) with anti-flavin antibody activity. Purified IgGGar was bright yellow, and the acid-dissociated chromophore was identified as riboflavin by chromatography and absorption spectroscopy. Native IgGGar contained 1.45 moles of flavin per mole of IgG, and increased to 2 moles with addition of riboflavin to saturation. The flavin was localized to the Fab fragment and was bound to IgGGar with high affinity. IgGGar showed strongest affinities for riboflavin, flavin mononucleotide and flavin adenine dinucleotide, and lower affinities for dinitrophenyl derivatives and naphthoquinone. The demonstration of hapten bound to the circulating monoclonal immunoglobulin in this case suggests the possibility of bound but colorless haptens on other myeloma proteins as well as on normal immunoglobulins.

An IgM Waldenström with specificity against phosphorylcholine

Anti-phosphorylcholine specificity has recently been shown to occur with relatively high incidence among IgA myeloma proteins secreted by oil-induced plasma cell tumors in the BALB/c strain of mice. A similar screening of human myeloma sera indicates that in man activity for phosphorylcholine is very rare. Among 904 human sera containing IgG, IgA, and IgM M-components only one reacted with phosphorylcholine-containing antigens. This serum was obtained from a patient with macroglobulinemia Waldenström. The active homogeneous protein could be isolated by affinity chromatography using a Sepharose-phosphorylcholine immunoadsorbent. It was an IgM immunoglobulin; the light chains were of the kappa type. The association constant for the reaction with phosphorylcholine was homogeneous and equalled 6.4 times 10-4 l. mol-1 at 25 degrees and 8.1 times 10-4 l. mol-1 at 2 degrees, indicating that the binding reaction is exothermic. The valences of the pentamer IgM, the 7S IgM subunit produced by reduction with cysteine, and the Fab fragment obtained by cleavage with papain were 10, 2, and 1, respectively. By all criteria available for antibody-like binding such as high specificity, restriction of the binding sites to the Fab part of the molecule and correct stoichiometry this IgM exhibits the fundamental characteristics associated with conventionally induced antibodies.

Immunologic Aspects of the Hematologic Neoplasms

Understanding the pathogenesis and pathophysiology of the hematologic malignancies now requires knowledge of their immunology. Many of these tumors appear to arise from the immune cells themselves (B or T cell tumors); most have associated disturbances in immune cell function. New immunodiagnostic methods may become potentially useful clinical tools for evaluating extent of disease, tumor cell kinetics, response to treatment, and prognosis.