Plasma-cell myeloma. II. Clinical aspects

Antibodies gone bad - the molecular mechanism of light chain amyloidosis

Light chain amyloidosis (AL) is a systemic disease in which abnormally proliferating plasma cells secrete large amounts of mutated antibody light chains (LCs) that eventually form fibrils. The fibrils are deposited in various organs, most often in the heart and kidney, and impair their function. The prognosis for patients diagnosed with AL is generally poor. The disease is set apart from other amyloidoses by the huge number of patient-specific mutations in the disease-causing and fibril-forming protein. The molecular mechanisms that drive the aggregation of mutated LCs into fibrils have been enigmatic, which hindered the development of efficient diagnostics and therapies. In this review, we summarize our current knowledge on AL amyloidosis and discuss open issues.

Renal manifestations of plasma cell dyscrasias: an appraisal from the patients' bedside to the research laboratory

One of the most prominent features of plasma cell dyscrasias is the frequent occurrence of renal dysfunction. Renal insufficiency is a common finding with elevated serum creatinine in more than 50% of patients with multiple myeloma at the time of diagnosis. Renal failure is the second most common cause of death in myeloma surpassed only by infections. The reasons for renal failure are multifactorial and early accurate diagnosis of the renal alterations may significantly impact morbidity and survival. Renal failure may result from selective glomerular, tubular interstitial, or vascular pathology or from a combination of pathologic events. The disorders associated with plasma cell dyscrasias include those characterized by monoclonal light chain deposition, encompassing AL-amyloidosis, in addition to the less well-characterized entities, such as heavy chain deposition disease and heavy chain amyloidosis. Therefore, it is more accurate to refer to them as monoclonal immunoglobulin deposition diseases. Staining of renal biopsy specimens for kappa and lambda light chains using immunofluorescence techniques and more sophisticated advanced diagnostic techniques such as immunoelectron microscopy permit detailed characterization of the various renal pathologic manifestations. Renal biopsies can identify monoclonal immunoglobulin deposition, and nephrologists have an opportunity to detect an underlying plasma cell dyscrasia early in its clinical course before overt hematologic alterations become manifest and irreversible renal damage has occurred. The overall spectrum of clinical and pathologic manifestations of monoclonal immunoglobulin deposition renal diseases has expanded considerably in recent years. Recent developments in the research arena promise new therapeutic interventions aimed at avoiding or ameliorating renal damage and even promoting reversal of some of the pathologic alterations. Currently, the 5-year survival rate in myeloma is 29% in white patients and 30% in African-American patients, a rather modest improvement from 24% in the 1970s. Bone marrow ablation followed by transplantation is available as an alternative mode of therapy that may be extraordinarily helpful in a subset of patients with early myeloma.

Amyloidosis of the larynx: a clinicopathologic study of 11 cases

Laryngeal amyloidosis (LA) is uncommon and poorly understood, with limited long-term clinicopathologic and immunophenotypic studies in the literature. Eleven cases of LA were retrieved from the files of the Otorhinolaryngic-Head & Neck Tumor Registry from 1953 to 1990. The histology, histochemistry, immunohistochemistry, and follow-up were reviewed. All patients (three women and eight men) presented with hoarseness at an average age of 37.8 years. The lesions, polypoid or granular, measured an average of 1.6 cm and involved the true vocal cords only (n = 4), false vocal cord only (n = 1), or were transglottic (n = 6). An acellular, amorphous, eosinophilic material was present in the stroma, often accentuated around vessels and seromucous glands, which reacted positively with Congo red. A sparse lymphoplasmacytic infiltrate was present in all cases that demonstrated light chain restriction by immunohistochemistry in three cases (kappa = 2, lambda = 1). Serum and urine electrophoreses were negative in all patients. Treatment was limited to surgical excision, including a single laryngectomy. Six patients manifested either recurrent and/or multifocal/systemic disease: two patients with light chain restriction were dead with recurrent disease (mean, 11.1 years); two patients were dead with no evidence of disease (mean, 31.7 years); and two patients were alive, one with light chain restriction and recurrent and multifocal disease (41.6 years) and one with no evidence of disease after a single recurrence (43.4 years). The remaining five patients were either alive or had died with no evidence of disease an average of 32.4 years after diagnosis. No patient developed multiple myeloma or an overt B-cell lymphoma. LA is an uncommon indolent lesion that may be associated with multifocal disease (local or systemic). The presence of an associated monoclonal lymphoplasmacytic infiltrate and recurrent/multifocal disease in the respiratory or gastrointestinal tract of a few cases and the lack of development of a systemic plasma cell dyscrasia or overt systemic B-cell malignancy suggest that some LA may be the result of an immunocyte dyscrasia or tumor of mucosa-associated lymphoid tissue.

Bence Jones proteins bind to a common peptide segment of Tamm-Horsfall glycoprotein to promote heterotypic aggregation

Bence Jones proteins (BJPs) are the major pathogenic factor causing cast nephropathy ("myeloma kidney") by coaggregation with Tamm-Horsfall glycoprotein (THP). Understanding the interaction between these proteins is therefore important in developing treatment strategies to prevent renal failure from cast formation in multiple myeloma. We developed an enzyme-linked immunoassay to examine this phenomenon. Five different human BJPs (four kappa and one lambda immunoglobulin light chains) were used in this assay that demonstrated these proteins bound THP with different affinity. BJPs competed among themselves for binding to THP. The binding site was a peptide portion of THP since these proteins also bound deglycosylated THP. Also, one monoclonal antibody directed against a peptide segment of human THP prevented binding of THP to BJPs. By altering the conformation of THP, reducing agents decreased binding between these two proteins in concentration-dependent fashion. In turbidity studies, the monoclonal antibody that prevented binding and a reducing agent, dithiothreitol, decreased coaggregation. Deglycosylated THP did not coaggregate with BJPs. We concluded that ionic interaction between BJPs and a specific peptide binding site on THP promoted heterotypic coaggregation. The carbohydrate moiety of THP was also essential for coaggregation, perhaps by facilitating homotypic aggregation of THP.

Urinary excretion of beta 2-microglobulin in myeloma patients

The levels of beta 2-microglobulin in urine and serum were determined in 39 patients with myelomatosis. In 25 patients the serum beta 2-microglobulin was elevated, and in seven of the patients with increased serum beta-microglobulin the urinary excretion of the protein was also increased. It was concluded that the increased urine beta-microglobulin indicates a renal tubular disorder.

Ultrastructure of a plasma-cell myeloma in the mandible

Tumor cells exhibited large amounts of rough endoplasmic reticulum arranged in a lamellar pattern, large numbers of mitochondria with a perinuclear distribution, and a prominent Golgi complex, but only a small number of immunoglobulin granules. No crystalline structures of immunoglobulins were observed. Nuclei exhibited patchy condensation of chromatin and large nucleoli. The ultrastructural features suggest that this case could be a "resecretory" myeloma.

Gamma A myeloma with hyperviscosity and obstructive uropathy

A patient with gamma A myeloma, hyperviscosity and an obstructive uropathy is described. Operation revealed a proteinaceous mass obstructing the right renal pelvis. Immunoprecipitin and immunofluorescent analysis of this mass and concentrated urine demonstrated the presence of gamma A myeloma protein, kappa light chains and albumin. This is the first description of an obstructive uropathy in multiple myeloma owing to a proteinaceous matrix containing paraprotein.

Renal plasmacytoma

Plasmacytoma, a localized extramedullary mass of plasma cells, is one manifestation of multiple myeloma. Renal plasmacytomas are rare lesions with neovascularity on arteriogram. This may cause confusion with the much more common renal cell carcinoma unless the clinician is aware of this entity. A case is presented, the literature reviewed, and problems in management discussed.

Two cases of plasmacytoma in the oral cavity

Two cases of plasmacytoma in the oral cavity are described. The first case was a plasmacytoma of the palate in a 64-year-old man, which be an oral manifestation of multiple myeloma, with fatal course 17 months after the first examination. The second was a plasmacytoma in a 43-year-old man, manifesting first in the mandible. A review of the recent Japanese dental literature was made: 14 cases were found in the literature exhibiting evidence of plasmacytoma in the oral region. Eight of these patients had oral manifestations of multiple myeloma (IgG myeloma, 3; IgA myeloma, 1; IgD myeloma, 1; B-J myeloma, 1; undetermined, 2). The other six cases were single lesions of plasmacytoma. The ratio of males to females was 1:1. The mandible was more frequently involved than the other oral structures. The site of predilection was the posterior portion of swelling and, less frequently, pain. Surgical treatment was favored in single lesions of plasmacytoma, while in myeloma chemotherapy and a combination of radiotherapy-chemotherapy constituted 75% of treatment.

Amyloid fibril proteins: proof of homology with immunoglobulin light chains by sequence analyses

The sequences of the 35 and 36 amino-terminal amino acids of two purified amyloid fibril proteins have been determined. Results indicate that these two proteins are derived from homogeneous immunoglobulin light chains of variable region subgroup V(kappaI). The relation between amyloidosis and immunoglobulins is thus more firmly established.