Monoclonal gammopathies in Japanese patients with Sjögren's syndrome

Analysis of autoantibodies to recombinant La (SS-B) peptides in systemic lupus erythematosus and primary Sjogren's syndrome

Autoantibodies to a polymerase III transcription factor, La (SS-B), are frequently detected in the serum of patients with Sjogren's syndrome and systemic lupus erythematosus. To define the humoral immune response to this protein, we analyzed the patterns of antibody recognition toward 13 recombinant La peptides by immunoblotting and determined the heterogeneity of antibodies reactive with the immunodominant epitopes. The smallest epitopes that were strongly antigenic and recognized by greater than 70% of sera tested (immunodominant) were encoded by the subclones BgX and XA located in the 5' and 3' halves of the La cDNA, respectively. Conformation of the immunodominant La peptides played a major role in antibody recognition. Although greater diversity in antibody binding to carboxyl-terminal La peptides was observed, the overall pattern of peptide recognition by anti-La antibodies was similar in different diseases. The antibody responses to the immunodominant peptides were strongly correlated (r = 0.68, P less than 0.001). One- and two-dimensional isoelectric focusing of affinity purified IgG anti-La peptide antibodies revealed restricted heterogeneity and oligoclonal bands (kappa light chains). These observations suggest that anti-La antibodies are induced and/or maintained by the self antigen and that their diversity is constrained either by mechanisms related to tolerance or by affinity maturation of the humoral immune response.

A high incidence of rheumatoid factor idiotypes in monoclonal proteins in the serum and in lymphoma cells in patients with Sjögren's syndrome

Patients with Sjögren's syndrome (SS) develop lymphoproliferative disorders such as monoclonal gammopathies and non-Hodgkin's lymphomas. Cross-reactive idiotypes (CRI) were studied in 22 serum monoclonal immunoglobulins (Igs) and in cytoplasmic Ig in four B-cell lymphoma cells in patients with SS. This was done by utilizing monoclonal anti-idiotypic antibodies which were produced against monoclonal rheumatoid factors (RF) derived from three patients with SS and one patient with Waldenström's macroglobulinemia. By the Western blotting or dot immunobinding technique, CRI was detected not only in monoclonal RFs but in monoclonal Igs which had different heavy- or light-chains from the original monoclonal RF used for immunization. A higher incidence of CRI was found in 22 monoclonal Igs associated with SS than in 27 monoclonal Igs in patients with Waldenström's macroglobulinemia, multiple myeloma or malignant lymphoma. In four patients with malignant lymphoma associated with SS, three showed one or three CRI in the lymphoma cells, whereas only two out of 20 patients with other malignant lymphoma showed CRI, demonstrating a significant difference between two groups. These data indicate that monoclonal proliferation of B-cell lineage in patients with SS, benign or malignant, takes place more often among RF-producing clones than other B-cell disorders.

Plasma cell dyscrasias: current status

This is a review of the current status of the monoclonal gammopathies (plasma cell dyscrasias). We begin with the recognition of a monoclonal protein in serum and urine. We briefly discuss the differential diagnosis of the monoclonal gammopathies. Clinical and laboratory findings as well as the management of multiple myeloma are addressed. Future approaches for the treatment of myeloma are provided. The variant forms of multiple myeloma, including smoldering myeloma, plasma cell leukemia, nonsecretory myeloma, IgD myeloma, osteosclerotic myeloma, solitary plasmacytoma of bone, and extramedullary plasmacytoma, are briefly reviewed. Diagnosis and treatment of Waldenström's macroglobulinemia are presented. The recognition and differential diagnosis of the heavy-chain diseases (gamma, alpha, and mu) are included. Monoclonal gammopathy of undetermined significance ("benign" monoclonal gammopathy) is presented in detail. Amyloidosis is not included in this review.

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/Sjögren's autoantibody specificities in sera with paraproteins

Antinuclear antibody and anti-RNA-protein autoantibodies were determined in 143 sera containing paraproteins and 39 control sera. Antinuclear antibodies were commonly present in the paraprotein sera by indirect immunofluorescence. 19 of 143 sera (13%) had elevated anti-Ro/SSA activity in a solid phase Ro/SSA binding assay, and 5 (3.5%) had Ro/SSA precipitating autoantibody. Eighteen sera had La/SSB binding autoantibodies (12%) but only one had an anti-La/SSB precipitin. Anti-nRNP(Sm) was not detected in any of these sera. The solid phase anti-RNA protein assays were repeated using anti-lambda and anti-kappa conjugates. Both lambda and kappa light chain autoantibodies were found in all positive sera consistent with polyclonal anti-Ro/SSA and anti-La/SSB responses. Paraprotein sera containing Ro/SSA precipitins were analyzed by isoelectric focusing followed by exposure to 125I-labeled Ro/SSA and autoradiography. All sera with anti-Ro/SSA binding paraproteins also contained polyclonal anti-Ro/SSA. Our data are consistent with the hypothesis that anti-Ro/SSA paraproteins are common and arise from a previously present polyclonal anti-Ro/SSA response.

Monoclonal gammopathy and multiple myeloma in the elderly

The term 'benign monoclonal gammopathy' indicates the presence of a monoclonal protein in persons without evidence of multiple myeloma, macroglobulinaemia, amyloidosis, lymphoproliferative disease, or other related disorders. The term 'monoclonal gammopathy of undetermined significance' (MGUS) is preferable because it is not known at diagnosis whether an M-protein will remain stable and benign or develop into symptomatic multiple myeloma or related disorders. Immunoelectrophoresis and immunofixation of the serum and urine are necessary to determine the presence and type of M-protein. At the Mayo Clinic, follow-up data have been gathered for more than 13 years on 241 patients with an initial benign monoclonal gammopathy. Nineteen per cent of these patients developed multiple myeloma, macroglobulinaemia, amyloidosis, or related diseases during the follow-up period. There is no reliable technique for differentiating a patient with a benign monoclonal gammopathy from one who will subsequently develop a serious disease. It is necessary to follow these patients indefinitely. Important in the complete understanding of the elderly patient with monoclonal gammopathy are the following: clinical manifestations, laboratory findings, and differential diagnosis of multiple myeloma; the course and prognosis and the induction therapy and treatment of multiple myeloma; newer therapeutic approaches; and the management of complications such as hypercalcaemia, hyperuricaemia, renal failure, bacterial infections, skeletal disease, and neurological problems.

A monoclonal surface immunoglobulin (IgM/D-L) with specificity for surface antigen of ox red blood cells in a patient with leukemic lymphosarcoma

A patient with B-cell leukemic lymphosarcoma, whose lymphocytes had a monoclonal (IgM/D-L) surface immunoglobulin (SmIg) and formed rosettes with ox red blood cells (ORBC), is described. The leukemic cells were documented to have a monoclonal SmIg and cytoplasmic Ig (CIg) and secreted a monoclonal immunoglobulin (MIg) whose antibody activity was directed to the surface antigen of ORBC. Pretreatment of the leukemic cells with anti-mu, anti-delta, or anti-lambda inhibited E(ox) rosette formation specifically. Pretreatment of the leukemic cells with pronase removed the SmIg and abolished E(ox) rosette formation simultaneously, and regeneration of the SmIg was parallel with recovery of the rosette formation. A small amount of serum MIg could be detected by agarose gel electrophoresis and antiidiotypic antibody against the 19 S component of the serum revealed that the monoclonal SmIg, CIg, and serum MIg shared the same idiotope. This case suggests that lymphocytes of some B-cell malignancies may bind to ORBC through SmIg.