The Current Status and Future Prospects of Treatment for Multiple Myeloma

Higher proportion of non-classical and intermediate monocytes in newly diagnosed multiple myeloma patients in Egypt: A possible prognostic marker

Background

Interaction between multiple myeloma (MM) cells and proximal monocytes is expected during plasma cell proliferation. However, the role of monocyte subsets in the disease progression is unknown.

Objective

This study evaluated circulating monocyte populations in MM patients and their correlation with disease severity.

Methods

Peripheral monocytes from 20 patients with MM attending Assiut University Hospital in Assiut, Egypt, between October 2018 and August 2019 were processed using a flow cytometry procedure and stratified using the intensity of expression of CD14 and CD16 into classical (CD16^-CD14⁺⁺), intermediate (CD16⁺CD14⁺⁺), and non-classical (CD16⁺⁺CD14⁺) subsets. The data were compared with data from 20 healthy control participants with comparable age and sex.

Results

In patients with MM, the percentage of classical monocytes was significantly lower (mean ± standard error: 77.24 ± 0.66 vs 83.75 ± 0.5), while those of non-classical (12.44 ± 0.5 vs 8.9 ± 0.34) and intermediate (10.3 ± 0.24 vs 7.4 ± 0.29) monocytes were significantly higher when compared with those of controls (all p < 0.0001). Proportions of non-classical and intermediate monocytes correlated positively with serum levels of plasma cells, M-protein, calcium, creatinine and lactate dehydrogenase, and correlated negatively with the serum albumin level. Proportions of classical monocytes correlated positively with albumin level and negatively correlated with serum levels of M-protein, plasma cells, calcium, creatinine, and lactate dehydrogenase.

Conclusion

Circulating monocyte subpopulations are skewed towards non-classical and intermediate monocytes in MM patients, and the intensity of this skewness increases with disease severity.

Peptichemio, Vincristine, Prednisone Induction Treatment in Multiple Myeloma

Twenty-nine patients with multiple myeloma, 16 untreated and 13 relapsing after treatment with melphalan and/or cyclophosphamide, were treated with Peptichemio (PTC), vincristine (VCR) and prednisone (PRD). The treatment was well tolerated and produced rapid resolution of bone pain and improved performance status in symptomatic patients. Rapid and marked monoclonal component reduction (greater than 50 per cent) was noted in 50% of previously untreated and 31% of previously treated patients. The median survival of previously untreated patients was 27 months, 19 months for stage III patients. Four patients resistant to common alkylating agents responded to PTC-VCR-PRD treatment and achieved long remissions (from 18 to 38 months). The therapeutic results suggest that the present combination regimen may be indicated for induction treatment of multiple myeloma patients in an advanced stage of the disease, and for treatment of myeloma patients refractory or resistant to melphalan and/or cyclophosphamide.

Autologous bone marrow transplantation with immunotoxin-purged marrow for advanced multiple myeloma

A system to purge the bone marrow of myeloma cells has been developed in our laboratories with the aim of treating with myeloablative radiochemotherapy patients suffering from advanced multiple myeloma. This system is based on the ex vivo incubation of the marrow with an immunotoxin composed of the 8A monoclonal antibody--that recognizes plasma cells and B-cell precursors--and the ribosome-inactivating protein momordin. 8 patients have so far been treated. 4 are surviving from 4 to 18 months after ABMT, whereas 4 died after 1 to 6 months, 2 from infections, 1 from relapsing disease and 1 from veno-occlusive disease. A marked tumour reduction was observed in all evaluable patients; however, none has achieved complete disappearance of the disease. The haemopoietic reconstitution was significantly delayed in 3 patients. These preliminary results show the feasibility of this approach in advanced MM patients with heavily infiltrated marrow. The place of ABMT in the treatment of MM remains to be determined; the selection of patients with still responding and less advanced disease would probably produce better results.

Comparison of whole-body 64-slice multidetector computed tomography and conventional radiography in staging of multiple myeloma

This study compares the sensitivity of whole-body multidetector CT (MDCT) and conventional radiography (CR) in the staging of multiple myeloma (MM). Twenty-nine patients with MM underwent a staging examination both by MDCT and CR. CT examination was performed with a collimation of 64x0.6 mm, a tube potential of 100 kVp, an effective tube current-time product of 100 mAs and automatic dose modulation as low-dose protocol. Number, size and diagnostic confidence of osteolytic lesions were determined and compared. The effective dose of MDCT and CR was assessed. Using MDCT, the detection of osteolysis was increased seven-fold concerning the spine. Ninety-seven lesions in 18 patients were detected exclusively by MDCT. The detection rate concerning the spine, pelvic skeleton and thoracic cage was significantly higher (p< or =0.001), and diagnostic confidence was increased by MDCT (p<0.02) compared to CR. Therapy was changed after MDCT in 18.2% of the patients with a clinical suspicion of progressive disease. The estimated effective dose of MDCT (4.8 mSv) and CR (1.7 mSv) was comparable. In conclusion, MDCT has a significantly higher sensitivity and reliability in the detection of osteolysis than CR and can be recommended as standard imaging method in the staging of MM.

The major vault protein (MVP), a new multidrug resistance associated protein, is frequently expressed in multiple myeloma

The major vault protein (MVP), a ribonucleoprotein complex which mediates the transport of xenobiotic toxins, has been implicated in multidrug resistance (MDR) not mediated by p-glycoprotein (P-gp) or multidrug resistance related protein (MRP). We evaluated, via immunohistochemistry, the presence of MVP in plasma cells of myeloma patients. Among 73 patients registered with the Southwest Oncology Group (SWOG), 52 patients (74%) were positive for MVP. The presence of MVP and P-gp were significantly associated (p < 0.01). A univariate analysis of response versus MVP positivity showed borderline statistical significance (p = 0.043) with no association with OS or PFS. In particular, MVP positivity at first biopsy was associated with non-responsiveness to therapy (7/7 patients, 100%). MRP was not present in any of 23 samples tested. An increased proliferative rate (Ki-67 > 5%) was significantly associated with shorter OS (log rank p-value = 0.0002). The collective work indicates that MVP protein is common and abundant in myeloma with potential relevance to therapeutic response.

Response level and survival after conventional chemotherapy for multiple myeloma: a Finnish Leukaemia Group study

The relation between overall survival time (OS) and response level (CR, 75%R, PR, MR, SD) was analysed in 432 multiple myeloma patients from 4 prospective Finnish Leukaemia group trials, treated with conventional chemotherapy. The primary regimen was either melphalan and prednisolone or combination chemotherapy with melphalan as a main component. Both the influence of the pre-treatment factors in patients with different levels of responses and the aspects related to chemotherapy were analysed. The 324 patients aged up to 70 yr and the 10(8) older patients were dealt with as separate groups. Irrespective of the primary chemotherapy regimen, the level of response was not significantly influencing in the OS time, and this was true in both age categories. The median OS of the patients up to 70 yr of age who had any response was 57 months, compared to the 10 months of those with PD (p < 0.001). The corresponding figures for the older patients were 40 and 4 months (p <0.001), respectively. The pretreatment prognosticators for the patients with minimal responses were not more favourable than for patients with responses at higher levels. The prolonged primary chemotherapy was favourable in patients having responses less than PR. Accordingly, the primary goal of conventional chemotherapy for multiple myeloma is stabilization of disease, not the level of response.

Erythropoiesis and erythropoietin in multiple myeloma

In this review, the pathophysiology and treatment of the anemia of multiple myeloma will be examined. While the anemia of cancer has multiple causes, an important component is labeled the "anemia of chronic disease" which is characterized by the combination of a shortened erythrocyte survival with failure of the bone marrow to increase red cell production in compensation. Depressed erythropoiesis is itself related to a combination of factors, including impaired availability of storage iron, inadequate erythropoietin response to anemia, and overproduction of cytokines which are capable of inhibiting erythropoiesis. These cytokines are involved in the retention of iron in the reticuloendothelial system, gastrointestinal tract and hepatocytes, may interfere with erythropoietin production by the kidney, and may exert direct inhibitory effects on erythroid precursors. While overproduction of several such cytokines, including IL-6, IL-1 and TNF-alpha, has been definitely demonstrated in multiple myeloma patients, it is still unclear whether they are directly involved in the pathogenesis of the anemia which develops. Although several mechanisms, such as hemodilution, bleeding, and decreased red cell survival operate, the anemia is mostly caused by defective erythropoietic activity. This in turn is partly explained by inadequate erythropoietin (Epo) production even in some patients without renal impairment. Based on measurements of serum erythropoietin and transferrin receptor, the distinction between marrow unresponsiveness to normal Epo stimulation and deficient Epo production is important for the treatment of the anemia of multiple myeloma with recombinant human Epo. Higher doses would probably be necessary if adequate Epo production is present, whereas only replacement therapy with lower doses may be sufficient when Epo production has been shown to be inappropriate.

Vincristine and oral etoposide in refractory multiple myeloma

A total of 15 patients with refractory multiple myeloma (MM; 4 primary unresponsive and 11 relapsed and resistant to re-induction/salvage therapy) received i.v. vincristine on day 1 and oral etoposide daily for 4 days, the treatment being repeated at 3-weekly intervals. The patients were re-assessed after three cycles of chemotherapy, and non-responders received no further therapy. There was no complete or partial response. A minimal response was seen in two patients, and two others showed stable disease. None of the responses was sustained, and all patients eventually had progressive disease. It is concluded that combination chemotherapy with vincristine and oral etoposide given by this schedule is unlikely to be of any value in refractory myeloma.

AgNORs and myeloma prognosis

The argyrophilic nucleolar organizer regions (AgNORs) were analysed in bone marrow biopsies from 80 patients with multiple myeloma (MM) at presentation. The mean AgNOR number per MM cell (AgNOR counts) and their distribution within the nucleus (configuration) were assessed. AgNOR counts were significantly associated with several recognized prognostic factors: Durie and Salmon clinical staging system (p = 0.02), percentage of plasma cells (PCs) in aspirates (p = 0.01) and in bone marrow biopsies (p = 0.0000), pattern of bone marrow involvement (p = 0.0003), calcaemia (p = 0.0005) and creatininaemia (p = 0.0003). AgNOR counts were also associated with the degree of PC differentiation (p = 0.0000). A single central cluster of 2-3 large-sized AgNORs (configuration A) was evident in most G1 MM; one cluster of 4-5 medium-sized dots or two clusters of 2-4 dots (configuration B) were seen in most G2 MM; many small-sized, scattered dots were present in G3 MM (configuration C). AgNOR counts and configuration were related to the prognosis: in the univariate analysis, the 5 year survival rate was 7% for cases with > 4.5 AgNORs/cell and 46% for cases with < or = 4.5 AgNORs/cell (p = 0.01), 53% for configuration A, 12% for configuration B and 0% for configuration C (p = 0.0000). AgNOR counts (p = 0.02) and configuration (p = 0.000) were independent prognostic variables in the multivariate analysis. The AgNOR counts were significantly higher in "fulminant myeloma" than in less aggressive cases (p = 0.002). The plasma cell labelling index (LI%), evaluated in 44 MM patients, showed significant correlation with prognosis: the 5 year survival rate was 51% for LI% < or = 1 and 17% for LI% > 1 (p = 0.02). More than 70% of patients with low LI% had low AgNOR counts and more than 70% of patients with high LI% had high AgNOR counts (p = 0.007). AgNOR counts and configuration reflect the myeloma cell mass, the degree of differentiation and the kinetics of the myeloma cells. They offer an exact evaluation of the tumour characteristics and can be useful additional parameters for MM prognosis.

Multiple myeloma presenting as an acute abdomen

We report a case of myeloma which presented as an acute abdomen with an associated pancreatic mass. This clinical picture has not been reported previously.

Argyrophilic nucleolar organizer region counts and prognosis in multiple myeloma

The prognostic significance of argyrophilic nucleolar organizer regions (AgNORs) has been evaluated in bone marrow trephine biopsies from 64 patients with multiple myeloma (MM) prior to therapy. The univariate Kaplan-Meyer survival analysis showed a significant correlation between survivals and AgNOR counts (median of survival 51.3 months for cases with < or = 4.62 AgNORs per plasma cell (PC) versus 16 months for cases with > 4.62 AgNORs per PC; P = 0.0000) or AgNOR distribution in PC nucleus (AgNOR configuration) (median of survival 71.67 months for cases with tightly grouped AgNORs, 16.26 for partially grouped and 11.74 for dispersed AgNORs; P = 0.001). Significant prognostic correlations were also found for monoclonal immunoglobulin type (P = 0.008), platelet counts (P = 0.0078), serum creatinine level (P = 0.0001), Durie's clinical stage (P = 0.02), percentage of plasma cells in bone marrow biopsies (BMPC%) (P = 0.005), pattern of medullary involvement (P = 0.003) and PC atypia (P = 0.009). Borderline result was detected for the percentage of PCs in aspirates (P = 0.06). No significant correlation was found between prognosis and patients age, sex, haemoglobin level, serum albumin or calcium level, marrow cellularity and excess of haemosiderin. Multivariate survival analysis showed that only two variables were significantly correlated with prognosis: AgNOR counts (P = 0.003) and AgNOR configuration (P < 0.001). In addition, the analysis of variance showed significant association between AgNOR number and platelet counts, haemoglobin level, calcaemia, creatininaemia, clinical stage, percentage of PCs in aspirates, BMPC%, pattern of medullary involvement, PC atypia, marrow cellularity and configuration of AgNORs. Our results indicate that AgNOR counts and configuration have prognostic and diagnostic value and therefore they are useful independent parameters to assess the pretherapeutic aggressiveness of multiple myeloma.

Prognostic factors in multiple myeloma

The pretreatment characteristics of 265 multiple myeloma patients treated between 1977 and 1983 were evaluated as potential prognostic factors for survival. Patients whose diagnosis was based on bone marrow plasmacytosis (greater than 30%) were noticed to have poorer survival (P less than 0.001). Although classification of patients according to stage has traditionally been used to identify prognostic groups, differences in survival were noted only between Stage III and Stage I or II patients using one of two common staging systems. Multivariate analysis using Cox's proportional hazards model identified the following prognostic factors in order of importance: plasmacytosis (hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.49 to 3.27), hypercalcemia (HR = 1.68, CI = 1.22 to 2.32), hypoalbuminemia (HR = 1.51, CI = 1.15 to 1.99), alkaline phosphatase (HR = 1.62, CI = 1.18 to 2.23), hyperuricemia (HR = 1.46, CI = 1.09 to 1.96), and renal insufficiency (HR = 1.48, CI = 1.08 to 2.04). All patients were followed from 2 to 7.5 years and 130 (49%) survived over 2 years. Logistic regression analysis demonstrated that hyperuricemia, hypoalbuminemia, renal insufficiency, plasmacytosis, gender, alkaline phosphatase, and hypercalcemia were significant predictors of 2-year survival. Knowledge of these factors could be of value in predicting prognosis and planning therapy in patients with multiple myeloma.

In vitro synergistic activity of PDN-IFN alpha and NM + IFN alpha combinations on fresh bone-marrow samples from multiple myeloma patients

The differential staining cytotoxicity (DiSC) assay was used to evaluate the in vitro sensitivity of tumour and normal bone-marrow cells from 21 multiple myeloma (MM) patients to antitumour agents methylprednisolone (PDN), nitrogen mustard (NM) and recombinant interferon alpha-2b (IFN alpha) tested singly and in the combinations PDN + IFN alpha and NM + IFN alpha. Both the PDN-IFN alpha and NM-IFN alpha associations were more efficacious than any agents used singly in reducing the percentage of myeloma cell survival. However, whereas NM, alone and in combination with IFN alpha, provoked a severe reduction in normal bone-marrow population, PDN and PDN + IFN alpha induced an increase percentage survival of normal bone-marrow cells. These findings indicate that, at least in vitro, the PDN-IFN alpha combination exerts a great antitumor effect which is not associated with a relevant cytotoxic activity on normal myeloid cells.

DNA and RNA flow cytometric study in multiple myeloma. Clinical correlations

Flow cytometric studies of cellular DNA and RNA content using the acridine-orange technique were conducted in 81 patients with multiple myeloma (MM). All patients were treated with the M-2 protocol and clinical response was evaluated according to the criteria of the Chronic Leukemia-Myeloma Task Force. Aneuploid DNA stemlines were found in 38.2% of untreated patients with a median DNA index (DNA-I) of 1.15 in marrow aspirates and 1.22 in biopsy specimens. The median percentage of cells with abnormal DNA content was 31.5 (aspirates) and 35 (biopsy specimens) and a positive correlation with the percentage of bone marrow plasma cells was observed. Significantly higher proliferation (S-phase) was found in marrow biopsy specimens as compared with marrow aspirates. Significantly higher RNA content (RNA index [RNA-I]) was observed in aneuploid versus diploid patients in biopsy material. There was no difference in response to the Memorial Hospital M-2 protocol between diploid and aneuploid patients. In patients with DNA-I greater than 1.15 remission duration was shorter as compared with DNA-I less than or equal to 1.15. Furthermore, no difference in cellular RNA content was noted between responders and nonresponders. This study demonstrates no correlation between cellular RNA content and response, as previously described for patients treated with vincristine, Adriamycin, and dexamethasone (VAD), but DNA aneuploidy appears to be an adverse prognostic factor in MM patients treated with the M-2 protocol. It also demonstrates that prognostic models for MM are not universal but depend on the chemotherapeutic regimen used.

Malignant plasma cells are sensitive to LAK cell lysis: pre-clinical and clinical studies of interleukin 2 in the treatment of multiple myeloma

To assess the role of the cytokine interleukin 2 (IL2) in the treatment of patients with multiple myeloma, we examined the sensitivity of plasma cell lines and malignant plasma cells from multiple myeloma (MM) patients to cell and cytokine-mediated killing induced by IL2. Unstimulated peripheral blood mononuclear cells (PBM) from normal donors produced little killing (mean lysis 1.0 +/- 1.0%, effector:target (ET) ratio 50:1), but cytotoxicity was modestly increased when PBM were incubated with IL2 prior to assay (8.0 +/- 2.9%). Unstimulated PBM from patients with MM also failed to kill autologous malignant plasma cells (mean 0.6 +/- 0.6%), but after exposure to IL2 they induced substantial lysis of autologous malignant cells (mean 55.3 +/- 22.1%). In addition, tumour necrosis factor (TNF) and interferon-gamma (IFN-gamma), two cytokines released from mononuclear cells in response to IL2, also reduced the survival and thymidine uptake of malignant plasma cells in culture. To determine whether these potentially beneficial immunomodulatory effects could be reproduced by in vivo administration of IL2, we have administered seven courses of IL2 to four patients with MM after autologous bone marrow transplant (ABMT). No serious adverse effects were noted. Increases in natural killer (NK) and lymphokine-activated killer (LAK) activity of PBM occurred during IL2 infusion, although cells capable of killing autologous MM cells did not circulate. However, IL2 infusions also induced substantial increases in the production of the cytokines TNF and IFN-gamma from peripheral blood lymphocytes. These results suggest that the in vivo administration of IL2 in MM deserves further evaluation, particularly for its potential to control minimal residual disease.

Treatment of refractory multiple myeloma with the vincristine-adriamycin-dexamethasone (VAD) regimen

Seventeen patients with advanced refractory multiple myeloma were treated with a 4-day continuous infusion of vincristine and adriamycin in combination with 4-day intermittent high-dose dexamethasone (VAD). Ten patients entered a partial remission (59%). Complete remission was not achieved in any patients. The median response duration was 11 months and the median survival of the responding patients was 18 months versus 5 months for non-responders. Major complications during VAD treatment were infections probably due to a combination of myelosuppression and intensive corticosteroid therapy. The VAD regimen offers a useful chemotherapy that produces an overall high response rate even in intensively pretreated patients resistant to first line therapy. The treatment results in a clear tendency to longer survival in responding patients.

Erythropoietin treatment of anemia associated with multiple myeloma

Anemia is a common complication of multiple myeloma. It resolves early in the disease if chemotherapy induces a complete remission, but persists if the disease progresses, causing disabling symptoms and often requiring blood transfusions. We treated 13 patients with myeloma-associated anemia by administering recombinant human erythropoietin three times a week for six months. Eleven patients (85 percent) had steady increases in hemoglobin levels and eventual correction of the anemia. Their symptoms of anemia subsided, and they reported a heightened sense of well-being. No patient had any adverse side effects, particularly episodes of hypertension. Monitoring of the serum M component showed a predominantly stable tumor load without apparent interaction between the underlying disease and the response to erythropoietin therapy. The number of erythroid burst-forming units in the bone marrow and peripheral blood and the level of erythropoiesis in bone marrow smears increased significantly during therapy. Pretreatment serum levels of erythropoietin were higher in the patients who did not respond and in those who required more than two months of treatment before they responded. Serum iron, ferritin, and transferrin concentrations reflected responses to treatment. We conclude that recombinant human erythropoietin is a promising therapeutic tool for treating myeloma-associated anemia.

Bulky extramedullary plasmacytomata: rare mode of relapse in myelomatosis

In two cases of myelomatosis relapse was accompanied by the development of bulky extramedullary plasma cell tumours, which created serious management problems. In both cases the histology was of a poorly differentiated plasmacytoid tumour with frequent mitoses. In one case paraprotein had completely disappeared from the serum and urine after six months' treatment with melphalan alone but did not correlate with improved survival. It is concluded that extramedullary spread of myelomatosis in the form of bulky tumour deposits is a rare and ominous mode of tumour progression or relapse. Rises in serum and urinary paraprotein concentrations are not the inevitable signs of relapse.

Induction and maintenance therapy in multiple myeloma: a multicenter trial of MP versus VCMP

In a prospective multicenter trial, 320 untreated myeloma patients of stage II and III were randomized for remission induction into two groups receiving six monthly courses of either MP or VCMP treatment. Response rates were equal in both groups: 72% remission, 21% no change, 7% progress for patients evaluable by TCM changes and 56% remission, 11% no change, 33% progress for BJ- and non-secretory myelomas. The overall survival rate was 60% after 4 years. An unexpected finding was the significantly longer survival of MP treated patients compared to the VCMP group. After successful remission induction, patients were randomized into one group receiving maintenance treatment using the induction scheme q 8 weeks, and another group without further chemotherapy. Although patients in the latter group relapsed significantly earlier, differences between both groups concerning acquired resistance to first line therapy or survival have not been noticed to date.

The pharmacokinetics of melphalan during intermittent therapy of multiple myeloma

During intermittent melphalan-prednisone therapy the area under the plasma concentration-time curve of melphalan increased by an average of 45% after oral or intravenous administration of the drug in myeloma patients during the initial three courses at six-week intervals. The rise in melphalan plasma concentrations could not be referred to an alteration in melphalan elimination, metabolism, erythrocyte/plasma partition ratio, or protein binding. A possible explanation could be that covalent binding sites of melphalan were successively saturated during intermittent treatment, resulting in higher drug concentrations during successive courses of therapy.

Multiple myeloma in central Norway 1981-1982: a randomized clinical trial of 5-drug combination therapy versus standard therapy

67 previously untreated patients with multiple myeloma were entered on a randomized clinical trial to determine whether the use of combination chemotherapy including vincristine, carmustine, alkylating agents, and prednisone was more effective than conventional therapy with melphalan and prednisone. The treatment groups did not show significant differences with respect to major prognostic factors. With the 2-drug combination therapy and 5-drug combination therapy, 67 and 74% of the patients achieved remission, respectively. Moreover, no significant difference was found between the two treatment schedules in terms of median survival (30+ months). The survival curves for stage III patients treated with the two regimens did not differ significantly. After 12 months, patients who had achieved remission were randomized to have treatment discontinued or to have maintenance treatment. 7 of 15 patients on maintenance therapy relapsed, whereas 9 of 14 patients who had their therapy discontinued relapsed, and the survival of the two groups was similar.

Cytostatic drug sensitivity test for human multiple myeloma, measuring monoclonal immunoglobulin produced by bone marrow cells in vitro

An in vitro cytostatic drug sensitivity test for human multiple myeloma has been developed, predicting differences in sensitivity of the individual tumor to various anticancer drugs. Bone marrow preparations containing the tumor cells were incubated with cytostatic drugs and cultured for 10 days. Using an enzyme-linked immunosorbent assay we measured tumor products--monoclonal immunoglobulin and beta 2-microglobulin--in the culture supernatants. The reduction of these products in vitro due to the drugs administered was compared with the patients' further clinical course during treatment with different standard cytostatic drug regimens. We found a predictive value of more than 80% for this easily performed test.

Vindesine in refractory multiple myeloma

In 12 of 18 patients with multiple myeloma refractory to treatment with the combination of vincristine, melphalan, cyclophosphamide, and prednisone, favorable results were obtained by replacing vincristine in this combination with vindesine. Although only three patients showed marked reductions (greater than 50%) of myeloma protein, this treatment, which was well tolerated, was also clearly beneficial to the other responding patients, thus postponing the need for more toxic treatment programs.

Separation of malignant plasma cells from the bone marrow of patients with myelomatosis

Complement-mediated lysis of bone marrow cells from patients with myelomatosis using a rabbit antiserum raised against normal peripheral blood mononuclear cells was found to greatly enrich the abnormal plasma cells. Cellular morphology was good and the cells were able to synthesize and secrete paraprotein. This was found to be a quick and useful method of preparing myeloma plasma cells for further studies of their metabolic properties.

Hypercalcemia, renal failure, and relapse in multiple myeloma

Forty-two patients with multiple myeloma that responded to initial treatment were observed for at least 6 months during a 2-year period. Eleven deaths occurred, seven of these being associated with hypercalcemia. None of these patients developed renal insufficiency before the serum calcium level rose, although kidney function deteriorated later in five of them. In those patients who are susceptible, hypercalcemia appears to be a good early indicator of relapse in multiple myeloma.

Multiple myeloma

Multiple myeloma is a malignant neoplasm of plasma cells involving bone and bone marrow, frequently leading to extensive skeletal destruction, bone marrow failure, renal dysfunction, and problems related to the monoclonal myeloma proteins. Vigilant supportive care and effective chemotherapy can prolong survival and improve the quality of life in most patients.