Search

To analyse autologous lymphocyte cytolytic activities of potential importance for cell-based immunotherapy in multiple myeloma (MM), in vitro differentiated dendritic cells (DCs) loaded with patient-specific monoclonal immunoglobulin (mIg) were used as autologous target cellsin cytotoxicity assays. Effector populations consisted of purified natural killer (NK) cells (CD56+, CD3-) and T cells (CD3+). The MM patients' NK cells cultured in the presence of interleukin 2 (IL-2) showed pronounced cytotoxic activity towards autologous mature DCs. Autologous MM DC targets displayed similar susceptibility to NK cell lysis, compared with allogeneic control DC targets, despite high surface expression of self major histocompatibility complex (MHC) antigens. However, some degree of classic MHC class I-mediated negative regulation was implicated in the NK-DC interactions, as indicated by class I blocking experiments. NK-mediated lysis was also discerned towards primary autologous MM cells. The results indicated that the major effector mechanism was mediated through the perforin-granzyme exocytosis pathway. In conclusion, NK cells from MM patients displayed significant and consistent cytotoxicity towards autologous mature DCs, suggesting that innate immunity could be implicated in MM and may influence the outcome of the administration of tumour antigen-pulsed DCs in treatment trials.

Rhabdomyolysis is a rare complication in haematological malignancies, and a diverse range of factors has been implicated in the etiology of the syndrome. In the present study we analysed muscle morphology and antibody reactivities to skeletal muscle proteins in a patient diagnosed with lambda (lambda) light chain-secreting multiple myeloma (MM) and amyloidosis, who developed a progressive rhabdomyolysis. The muscle tissue analysis showed focal amyloid depositions and a low degree of atrophy and inflammation. Antibody reactivities against muscle proteins of approximately 42, 51 and 66 kD, respectively, were present in the patient's serum. The antibody specificities were revealed by lambda light chain- or IgM-specific antibodies. The results indicate a possible etiologic link between antibody reactivities towards muscle proteins and muscle tissue disorder in a patient with the unique combination of rhabdomyolysis, amyloidosis and MM of the light chain type.

Multiple myeloma (MM) is a B-cell malignancy characterized by an accumulation of malignant plasma cells in the bone marrow. It is unclear whether genetic background could have an etiological impact on MM or influence the course of the disease. Interleukin-10 (IL-10) has been implicated in the growth and differentiation of normal B cells, and has also been shown to enhance the proliferation of MM cells. To address the putative involvement of IL-10 genetic variation in MM, we analyzed previously defined loci for bi-allelic polymorphism at position -1082 and two microsatellite loci (IL10.G and IL10.R) in the IL-10 promoter region. Seventy-three patients with MM, 27 with monoclonal gammopathy of undetermined significance, and 109 ethnically matched individuals as controls were included in the study. Significantly increased frequencies of the IL10.G genotype 136/136 and the IL10.R genotype 112/114, in addition to a decreased frequency of the IL10.R genotype 114/116, were found among the MM patients. Increased production of IL-10 was detected in the supernatants of lipopolysaccharide-stimulated peripheral blood mononuclear cells from MM patients who were homozygotes (136/136) and heterozygotes (136/non-136) for the IL10.G allele 136, as compared with the other IL10.G genotype carriers (non-136/non-136). These results suggest that the genetic variation in the IL-10 promoter region may play a role in the development of MM., (Copyright 2001 Wiley-Liss, Inc.)

Activation of telomerase is essential for in vitro cellular immortalization and tumorigenesis. In the present study, we investigated telomerase activation and its implications in plasma cell dyscrasias including monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM) and plasma cell leukaemia (PCL). All 5 patients with MGUS exhibited normal levels of telomerase activity in their plasma cells. Elevated telomerase activity was found in the samples from 21/27 patients with MM and 4/4 with PCL. In addition, 4 myeloma cell lines all expressed high levels of telomerase activity. The expression of telomerase reverse transcriptase (hTERT) and telomerase RNA template (hTER) was positively associated with the levels of telomerase activity in MM/PCL. Tankyrase expression was upregulated, concomitant with the induction of hTERT and activation of telomerase in MM/PCL. The present findings indicate that MGUS cells may not be immortalized and that activation of telomerase plays a role in the malignant transformation from MGUS to MM., (Copyright 2001 Cancer Research Campaign.)

Multiple myeloma (MM) is a B-lineage malignancy with unknown aetiology. It has been considered that predisposing genetic factors might be implicated in the disease. In this study, the microsatellite polymorphism in the exon 3 of the cytotoxic T-lymphocyte antigen-4 (CTLA-4) gene was analysed in patients with MM and monoclonal gammopathy of undetermined significance (MGUS), together with ethnically matched healthy controls. The results showed that frequencies of the genotype 86/86 and of the allele 86 were significantly decreased in MM and MGUS compared with matched healthy controls, indicating that the CTLA-4 microsatellite polymorphism might represent a susceptibility locus for MM and MGUS.

Proinflammatory cytokines such as interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-alpha) and IL-1beta are considered to be involved in the pathogenesis of multiple myeloma (MM). In the present study, we examined a G/C polymorphism at position -174 in the promoter region of IL-6, a biallelic polymorphism at position -308 in the promoter region of TNF-alpha, the TaqI restriction fragment length polymorphism in exon 5 of IL-1beta and a variable number of identical tandem repeat polymorphisms in intron 2 of IL-1 receptor antagonist (IL-1Ra) genes. The alleles of these loci are known to influence the level of production of the cytokines and the IL-1Ra. Seventy-three patients with MM, 27 with monoclonal gammopathy of undetermined significance (MGUS) and 129 healthy individuals were included. No difference was found between patients and healthy controls or between MM and MGUS patients in the distributions of genotypes and frequencies of alleles of the IL-6 (-174), TNF-alpha (-308), IL-1beta TaqI and IL-1Ra gene polymorphisms. No associations between the polymorphisms at the loci under study and clinical factors such as age, sex, clinical stage at onset and M-protein type were observed. Our results indicate that the cytokine (IL-6, TNF-alpha and IL-1beta) and IL-Ra gene polymorphisms do not confer susceptibility to the development of MM.

Introduction: Multiple myeloma is accompanied by decreased polyclonal serum immunoglobulin concentrations. This suppression might be due to non-specific effects on the polyclonal lymphocyte populations as previously suggested, or it could include specific variable region-dependent mechanisms. Thus, differentiation, survival and activation to Ig secretion of B-lineage cells are dependent on the expression and signalling through the variable Ig receptor. The present study addresses the question whether such variable region-specific alterations were present in the peripheral repertoire of IgM antibodies in patients with IgG-secreting MM., Materials and Methods: IgM reactivity repertoires towards a large panel of antigens in extracts of homologous tissues (liver, brain, stomach and heart muscle) and bacteria (Bacillus macquarensis) were analysed in sera from 22 patients diagnosed with IgG1 MM. Healthy, matched volunteers served as control donors. A modified Western assay was used, and values obtained from area integration by image analyses were submitted to multiparametric statistics., Results and Conclusion: The results confirm previous observations on the depression of serum IgM concentrations in multiple myeloma, and demonstrate concentration-independent, patient- and V-region-specific alterations in the polyclonal reactivity repertoires. Since the scoring of IgM reactivities by this technique is independent of IgG and because the deviations of IgM reactivity are not coincident with reactivities of (myeloma) IgG in the individual sera, the results indicate that the immunological syndrome of MM includes significant V-region-specific alterations in the polyclonal repertoires of IgM antibodies.

In recent studies, the sequence of Kaposi's sarcoma-associated herpes virus (KSHV) or human herpes virus-8 (HHV-8) was detected in dendritic cells (DC) of patients with multiple myeloma (MM). A concern was raised whether there is an causal association between the viral infection and development of these tumors. In the present study, we have examined DC generated from blood adherent cells from 8 Swedish MM patients at different clinical stages and 2 patients with monoclonal gammopathy of undetermined significance. In addition, 6 myeloma cell lines and bone marrow cells from 2 MM patients were also studied. By polymerase chain reaction (PCR), including nested PCR, no virus DNA was demonstrable in the patients' DC or in myeloma cell lines or fresh bone marrow cells. Moreover, no antibody against KSHV was found in the serum of these 10 patients. Thus, our results indicate that blood-derived DC of MM patients in Sweden usually are not infected with KSHV/HHV-8. This study also suggests that KSHV/HHV-8 is not regularly associated with MM and consequently does not play a primary role in the pathogenesis of these tumors.

Idiotypic structures expressed on the myeloma Ig protein might be regarded as a tumor-specific antigen. Five patients with IgG myeloma were immunized with the purified serum M-component by repeated intradermal injections together with soluble granulocyte-macrophage colony-stimulating factor (GM-CSF). All patients developed an idiotype (Id)-specific T-cell immunity, defined as blood T cells predominantly secreting interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) (type I cells). Id-specific DNA synthesis was induced in one patient. Delayed-type hypersensitivity against the Id was not evoked. The specific IFN-gamma/IL-2 T-cell response was inhibited (46% to 100%) by a major histocompatibility complex (MHC) class I monoclonal antibody (MoAb) in all five patients. A 5% to 37% inhibition by an MHC class II MoAb was seen in four patients. CD4+ as well as CD8+ T cells enriched by magnetic microbeads contained Id-specific cells. The T cells recognized peptides corresponding to the complementarity-determining regions 1, 2, and 3 of the heavy chain of the Id. There was a transient rise of B cells producing IgM anti-idiotypic antibodies in all patients. The results indicate that immunization of myeloma patients using the autologous M-component and soluble GM-CSF may evoke an Id-specific predominantly MHC class I-restricted type I T-cell response.

The monoclonal immunoglobulin (Ig) (M-component) secreted by the tumour plasma cells in multiple myeloma (MM) has specific antigenic determinants (idiotypes; id) that can serve as tumour-specific antigens. The intact Ig molecule is a weak antigen, and small fragments of id protein might be more immunogenic for the induction of id-specific immunity. Dendritic cells (DC) have attracted attention as the most efficient antigen-presenting cells and promising adjuvants for immunotherapy in tumours. In this study the in vitro T-cell response against F(ab')2 and Fab fragments, heavy and light chains of the M-component was examined in five patients with MM clinical stage I. All fragments were able to stimulate T cells but F(ab')2 or Fab fragments and heavy chains induced a stronger response than light chains. DC induced a significantly stronger id-specific immune response than monocytes. Moreover, with DC as antigen-presenting cells, a predominant interferon (IFN)-gamma (type-1 T-cell) response was seen in all patients. Both IFN-gamma and interleukin (IL)-4 (type-1 and type-2 T-cell) responses were noted when monocytes were used. Our study suggests that DC pulsed with idiotypic fragments such as F(ab')2 fragment and heavy chain can be used for the induction of type-1 anti-idiotypic T-cell response for immunotherapy in MM.

Myeloma plasma cells constitute 10% to 90% of the total bone marrow cell count in patients with multiple myeloma (MM). These cells express a variety of cell surface markers, such as HLA-ABC and HLA-DR, and surface antigens that are necessary for professional antigen-presenting cells, including adhesion and costimulatory molecules. In this study, we examined the expression of major histocompatability complex (MHC) and costimulatory molecules on CD38(bright,++) plasma cells in bone marrow aspirates from eight MM patients. Small percentages of plasma cells expressed weak but detectable levels of HLA-DR, HLA-DQ, CD40, CD80, and CD86, which could be upregulated by interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha. CD38++ plasma cell and CD38(dim,+) cells were sorted from freshly isolated bone marrow mononuclear cells and tested for their capacity to act as antigen-presenting cells. Indeed, both CD38++ plasma cells and CD38+ cells were able to stimulate allogeneic T cells and present the soluble antigens purified protein derivative and tetanus toxoid to autologous T cells. Recognition of the antigens led to T-cell proliferation and secretion of IFN-gamma and was MHC class-I and -II restricted. Antigen processing and presentation by CD38++ and CD38+ cells were abolished by treatment of the cells with chloroquine. Hence, our study provides for the first time evidence that myeloma plasma cells may act as antigen-presenting cells. Further studies are warranted to examine in detail the molecules required for inducing T-cell stimulation.

Multiple myeloma is characterized by a proliferation of clonal B lymphocytes and plasma cells. The idiotypic structure of clonal immunoglobulin (Ig) expressed on the tumour B-cell surface can be regarded as a tumour-specific antigen and, as such, a potential target for anti-idiotypic T and B-cells in an immune regulation of the tumour-cell clone. Active immunization using the autologous mono-clonal Ig as a 'vaccine' was shown to induce tumour-specific immunity in murine B-cell tumours and in human B-cell lymphoma. With the aim to induce or amplify an anti-idiotypic response in multiple myeloma, five stage I-III patients were repeatedly immunized with the autologous monoclonal IgG. Induction of idiotype-specific cellular immunity was analysed in vitro by an enzyme-linked immunospot assay (interferon-gamma and interleukin-4 secreting cells). B cells secreting anti-idiotypic IgM antibodies were also analysed. An anti-idiotypic T-cell response was amplified 1.9-5-fold in three of the five patients during immunization. The number of B cells secreting anti-idiotypic antibodies also increased in these three patients. In two of the patients induction of idiotype-specific immunity was associated with a gradual decrease of blood CD19+ B cells. The induced T-cell response was eliminated during repeated immunization. Further studies are warranted to optimize the immunization schedule in order to achieve a long-lasting T-cell immunity against idiotypic determinants on the tumour clone. A role for immunity in controlling the tumour clone remains to be established.

The presence of idiotype-reactive T-cell subsets and their relation to the tumor load were analyzed in 9 patients with monoclonal gammopathy of undetermined significance (MGUS), in 12 patients with multiple myeloma (MM) clinical stage I, and in 9 patients with MM stage II/III. An enzyme-linked immunospot assay was used to identify interferon-gamma (IFN-gamma)-, interleukin-2 (IL-2)-, or IL-4-secreting T cells after stimulation by F(ab')2 fragments of monoclonal IgG. The response to autologous IgG was significantly higher than that induced by isotypic monoclonal IgG. Comparable results were obtained in a proliferation assay (3H-thymidine incorporation). A total of 8 of 9 patients with MGUS, 7 of 12 patients with MM stage I, and 3 of 9 with MM stage II/III had T cells secreting IFN-gamma and/or IL-2 (T helper [Th1] type-1 cells), whereas cells secreting both Th1 and Th2 or Th0 types of cytokines were more frequent in patients with MM, particularly in those with MM stage II/III. The number and frequency of Th1-type cells were significantly higher in MGUS patients as compared with those of MM stage II/III. The results indicate that idiotype-reactive T cells of the Th1 and Th2 or Th0 subsets were present in MGs and might provide indirect evidence that idiotype-reactive Th1-type cells may have a regulatory impact on the human tumor B cells.

Idiotype-specific T cells were characterized in patients with multiple myeloma stage I by analysing idiotype-induced DNA synthesis (3H-thymidine incorporation), IL-2 and IFN-gamma production at the single cell level (ELISPOT) (in vitro tests) and delayed type hypersensitivity (DTH) skin reaction (in vivo test). In seven out of eight patients at least one of the four tests was positive. In five patients three or more tests were positive. One patient was negative in all four tests. Six patients had both IL-2 and IFN-gamma-secreting cells and three of them also a DTH response. Furthermore, those three patients with a proliferative response also had IL-2 and IFN-gamma-secreting cells induced by the idiotype. The data indicate that part of the idiotype-specific T cell fraction belongs to the CD4 Th1 cell population. Whether CD8-specific T cells also were present could not be ruled out. The present study provides further support for the existence of idiotype-specific T cells in multiple myeloma. Such cells might be an important target for an immune-mediated therapeutic approach.

In this paper some recent and partly preliminary results on anti-idiotypic immunity against clonal B cells in human monoclonal gammopathies are summarized. B cell lines producing antibodies to idiotypic determinants on autologous monoclonal immunoglobulin could be propagated after activation with Epstein-Barr virus of peripheral blood lymphocytes from patients with MGUS and MM clinical stage I but not from untreated persons with advanced MM. Blood T lymphocytes from patients with MGUS and Waldenström's macroglobulinemia were activated to DNA synthesis and production of interleukins by the autologous M protein. In another series of experiments T cell clones raised from patients with MM clinical stage I and MGUS bound F(ab')2 fragments of the autologous M protein and were stimulated to DNA synthesis by the idiotope-bearing protein. Control experiments demonstrated the specificity for idiotypic determinants. Ten of eleven clones were CD4-/CD8+. Finally, using a panel of 8 mAbs to alpha/beta V region epitopes, we noted a clonal expansion of CD4+ and CD8+ T cells in MGUS and MM patients.

Natural killer (NK) activity and NK-related cell surface markers (CD16, CD56, CD57) of peripheral blood lymphocytes were studied in patients with multiple myeloma and MGUS (monoclonal gammopathy of undetermined significance). A strong correlation (p less than 0.0001) was found between the numbers of cells positive for the different NK cell surface markers. The proportion of CD16+ cells correlated highly to the lytic capability (lytic units/10(6) cells) of K562 cells (p less than 0.0001). High NK activity and high numbers of cells with NK-related cell surface markers were found in patients with a low tumor burden compared to controls, whereas low values were seen in patients with an advanced disease. The results indicate that NK cells might be involved in the disease process in monoclonal gammopathies, perhaps by exerting a regulatory function on the proliferating B-cell clone.

Patients with newly diagnosed multiple myeloma were randomly allotted to an intermittent high-dose melphalan/prednisone (MP) treatment (120 patients) or a continuous low-dose melphalan (M) regimen (99 patients). The median observation time was 59 months (range 33-84). Response to therapy was obtained in 45% of the MP group and 31% of the M group (P less than 0.05). No significant difference in response with regard to clinical stage was noted. Median survival was 36 months in the MP group and 29 months in the M group. Survival was longer in stage I and II myeloma than in the stage III cases, at least in the MP group. The median and 5-yr survival rates in stages I and II were significantly better in the MP than in the M group. Response to therapy was associated with length of survival, median survival being 62 months in responding patients and 20 months in non-responders. The MP and M groups did not differ in this respect.

The autopsy findings of a woman with myelomatosis diagnosed half a year before her death are described. She had an IgG-lambda myeloma which initially responded to treatment. However, subsequently she developed a condition characterized by massive soft tissue involvement with increased number of plasma cells in peripheral blood. Rounded hard myeloma infiltrates were disseminated through the body, only sparing the adrenal glands and intracranial structures.

Individual specific antisera were raised against the monoclonal serum component from six IgG myeloma patients. Idiotypic (Id) determinants were identified in direct or indirect immunofluorescence (IFL) on 0.5-44% B lymphocytes from five patients with active disease. Id determinants were not detected on B lymphocytes from one IgG-k myeloma patient with an imbalance in the expression of upsilon heavy chains and kappa light chains. Nor were Id determinants detected on E-rosetting cells. Id structures were usually present together with upsilon chains on monoclonal B lymphocytes, some of which also carried mu and/or delta chains. Blood cells with lymphoplasmacytoid appearance were abundant in two patients. These cells carried IgG with Id determinants both in the cytoplasm and on the surface. Fc receptors were present on most cells carrying surface Id structures but were rare on cells with cytoplasmic monoclonal characteristics. The results further support the hypothesis of multiple myeloma as a differentiating B-lymphocyte tumour.

20 patients with benign monoclonal gammopathy (BMG) have been studied for blood lymphocyte and subpopulations. 4 patients had slightly decreased T-lymphocyte values. Total B-lymphocytes were within the normal range. In 3 BMG patients an abnormal ratio between kappa- and lambda-bearing lymphocytes was detected indicating circulating monoclonal cells. 41 lymphoid cells using the kappa: lambda-ratio. 54% of the patients had monoclonal blood cells at diagnosis. the incidence and numbers of such cells increased with advanced clinical stage. Thus, it seems as if tumor volume is the main factor responsible for the appearance of monoclonal blood cells in multiple myeloma.

The in vitro monoclonal and polyclonal immunoglobulin (Ig) production of peripheral blood mononuclear cells was studied in human multiple myeloma (four IgG myelomas, one IgA myeloma) and in one patient with benign monoclonal gammopathy. Using an enzyme-linked immunosorbent assay with anti-class-specific antisera and antisera against idiotypic structures on the myeloma protein, it was possible to quantitate separately monoclonal and polyclonal Ig of the same class in cell culture supernatants. After stimulation with pokeweed mitogen (PWM) patients' cells produced lower amounts of polyclonal Ig than cells from healthy adults. In contrast, production of monoclonal Ig could not be enhanced by PWM. Moreover, the kinetics of monoclonal Ig production was different from that of polyclonal Ig. Myeloma cells contained large amounts of monoclonal Ig while their content of polyclonal Ig was low. A rapid release of preformed monoclonal Ig during the first day of culture was not inhibited by puromycin. A later phase of release was partly suppressed by puromycin and was probably caused by active protein synthesis.

In a randomized clinical trial intermittent high-dose melphalan/prednisone (MP) treatment has been compared with human leukocyte interferon (IFN) administration. Three to 6 X 10(6) IU of IFN was given im daily. Therapy was continued to progression of the disease. Fifty-five patients were randomized to receive MP and 75 were randomized to receive IFN. Forty-four percent of the patients receiving MP responded to therapy as opposed to only 14% of the patients receiving IFN (P less than 0.001). This difference was mainly due to a low response rate in IFN-treated IgG myelomas, while the response rate for IgA and Bence Jones myelomas did not differ significantly between the two treatment groups. Median duration of response was shorter for IFN-responding patients (23 months) as compared to patients in the MP group (35 months). During follow-up, second-line therapy was given more frequently in the IFN group (91%) than in the MP group (59%). Time on initial treatment was significantly shorter in the IFN group (3 months) than in the MP group (19 months). Since more patients responded to second-line therapy in the IFN group than in the MP group, total survival did not differ significantly between the two groups.

alpha-interferon (alpha-IFN) is a biological response modifier with a dose-dependent activity. The present study on the treatment of patients with multiple myeloma with high doses of natural alpha-IFN was designed to meet this dose-dependent concept. 50 previously untreated patients with IgA and BJ myelomas and a s-Creatinine less than or equal to 200 mumol/l entered the study. Various treatment schedules were tested. The initial plan was to give the patients 30 X 10(6) U alpha-IFN daily. This dosage, however, gave unacceptable toxicity. Step-by-step decreasing dose schedules were given to the patients, 10 X 10(6) U of alpha-IFN daily for 7 consecutive d repeated every 3rd week was found to be the maximal tolerable dose that could be given to most patients. 36% (95% confidence levels: 22%-50%) of the patients responded: 41% of the IgA myelomas and 23% of BJ myelomas. Median time to response was 1.5 months and median response duration was 20 months. Impaired general condition and central nervous system and gastrointestinal-related toxicity were the main adverse reactions. Hematological side-effects were mild.

112 patients with multiple myeloma have been studied at diagnosis for the presence of blood clonal B-cell excess (CBE), defined as a ratio between kappa+ and lambda+ lymphocytes outside the normal range (0.9-3.5). 48 patients (43%) had CBE. The increase in light chain-bearing lymphocytes was always that of the M component light chain isotype. The proportions of patients exhibiting CBE were the same in different stages. The response frequency was not influenced by the presence of CBE. However, patients with CBE had a shorter remission duration time (p less than 0.001) and total survival (p less than 0.05) than those without CBE. This was also noticed when each clinical stage was analyzed separately. Moreover, survival was shorter in patients with a large fraction of CBE than in those with a small one. Cox regression analysis revealed that CBE was a much stronger predictor of remission duration than age, clinical stage and renal dysfunction. CBE and response to initial treatment independently were the best factors to indicate survival. It is suggested that analysis of CBE should be included in the clinical characterization of untreated patients with multiple myeloma.

Thirty-two consecutive, previously untreated patients with plasma cell myeloma were treated with 4-day courses of melphalan (0.25 mg/kg/day) and prednisolone (2 mg/kg/day) every sixth week. The observation period ranged from 26 to 75 months and the total median survival time was 29 months. 75% of the patients responded to therapy and their median survival time was 42 months. Sex did not influence either the response rate or the survival time. Most patients were treated in an out-patient clinic and required a minimum of check-ups.

Purified blood lymphocytes from 30 patients with myelomatosis were studied. B lymphocytes with sIg were identified by direct IFL after staining with F(ab')2-fragments of antibodies against heavy or light chain specificities. Forty per cent of the patients had B lymphocyte values above the normal range; the median percentage of B cells was 7.25 as compared to 4.5 for control donors (p less tha 0.01). Lymphocytes bearing the light chain isotype of the myeloma protein were selectively increased in 20 of 30 patients suggesting monoclonality. The heavy chain specificities on such lymphocytes were usually that of the serum myeloma globulin sometimes together with mu and/or delta. Tentatively, mu and/or delta carrying monoclonal lymphocytes may represent early precursors to the malignant plasma cells. In patients with IgG myelomas, gamma-bearing blood lymphocytes may be late during maturation. The presence of monoclonal lymphocytes with surface bound gamma chains in untreated patients was associated with unfavourable prognosis.

Antisera were produced in rabbits against idiotypic determinants of the myeloma protein from 3 patients with IgG-k myeloma. The antisera did neither cross-react nor react with normal immunoglobulin (Ig). Idiotypic Ig-structures were demonstrated by indirect immunofluorescence (IFL) on 70-94% of peripheral B-lymphocytes inuntreated patients. The total numbers of circulating B-lymphocytes were increased with a simultaneous decrease of T-lymphocytes. Only one of the patients had blood lymphocytes which stained for cytoplasmic Ig with idiotypic antiserum. The monoclonal lymphocyte population decreased gradually during treatment. Plasma cell counts in bone marrow, IgG concentration in serum and erythrocyte sedimentation rate decreased simultaneously, whilt the haemoglobin concentration increased. Very few monoclonal lymphocytes were present during remission. Later, the monoclonal lymphocyte population began to increase in 2 of the patients in parallel with clinical signs indicating relapse. It is concluded that presence of monoclonal B-lymphocytes indicates dissemination of the disease and that they may belong to the malignant cell clone.

The stimulation of peripheral blood mononuclear cells by purified autologous and/or allogeneic monoclonal IgG was studied in five patients with multiple myeloma (MM), nine patients with monoclonal gammopathy of undetermined significance (MGUS) and six healthy individuals. Single cells secreting IFN-γ or IL-2 were identified using an enzyme-linked immunospot assay. Patients' cells were preferentially stimulated by autologous monoclonal IgG at low concentrations (1-100 pg/ml). while 100 ng/ml or higher stimulated T cells both from patients and. to a lesser degree, healthy individuals. This biphasic dose-response of T-cell stimulation by autologous monoclonal IgG was reproduced in all patients. The numbers of cells secreting IFN-γ and IL-2 in response to allogeneic IgG were significantly lower than the numbers obtained using autologous IgG in patients with MM and MGUS. Cells from healthy individuals were stimulated by allogeneic monoclonal IgG, but to a lesser extent. The results of this study support the presence of idiotype-reactive T cells in patients with MM and MGUS and also may suggest a general but less pronounced T-cell reactivity to monoclonal IgG among these patients. [ABSTRACT FROM AUTHOR]