Search

Smoldering multiple myeloma (SMM) carries a 50% risk of progression to multiple myeloma (MM) or related malignancy within the first 5 years following diagnosis. The goal of this study was to determine if high levels of circulating plasma cells (PCs) are predictive of SMM transformation within the first 2-3 years from diagnosis. Ninety-one patients diagnosed with SMM at Mayo Clinic from January 1994 through January 2007, who had testing for circulating PCs using an immunofluorescent assay and adequate follow-up to ascertain disease progression, were studied. High level of circulating PCs was defined as absolute peripheral blood PCs >5 × 10(6)/l and/or >5% PCs per 100 cytoplasmic immunoglobulin (Ig)-positive peripheral blood mononuclear cells. Patients with high circulating PCs (14 of 91 patients, 15%) were significantly more likely to progress to active disease within 2 years compared with patients without high circulating PCs, 71% versus 24%, respectively, P=0.001. Corresponding rates for progression within 3 years were 86% versus 34%, respectively, P<0.001. Overall survival (OS) after both SMM diagnosis and MM diagnosis was also significantly different. High levels of circulating PCs identify SMM patients with an elevated risk of progression within the first 2-3 years following diagnosis.

Multiple myeloma (MM) is characterized by accumulation of clonal plasma cells (PCs). CD45, a key regulator of antigen-mediated signaling and activation in lymphocytes, is present in early stages of PCs development. We studied CD45 expression on MM PCs by flow cytometry, correlating it to important biological disease characteristics. Additionally, we examined the expression of various adhesion molecules on PCs. A total of 75 patients with untreated MM (29), relapsed MM (17), smoldering MM (12), and monoclonal gammopathy of undetermined significance (MGUS) (17) were studied. The proportion of PCs expressing CD45 was higher among those with early disease (MGUS or smoldering MM) compared to those with advanced disease (new or relapsed MM) (43 vs 22%; P=0.005). Among those with advanced disease, patients with bone lesions had a lower percentage of CD45-positive (CD45+) PCs; 14 vs 34% (P=0.02). Patients with high-grade angiogenesis had a lower percentage of CD45+ PCs; 13 vs 31% (P=0.03). The median overall survival for the CD45+ group (>20% PCs positive) was 39 vs 18 months for the CD45-negative (CD45-) group (P=0.07). The expression of CD138, CD56 and CD54 were higher among the CD45- PCs. This study demonstrates important biological correlates of CD45 expression on myeloma cells., (Leukemia (2005) 19, 1466-1470.)

In myeloma, the bone marrow plasma cell percentage (BMPC%) is usually estimated independently on the aspirate, core biopsy, and plasma cell labeling index (PCLI) samples. This study was done to determine which of the 3 individual estimates correlates best with complete response (CR) and survival. Seventy-five consecutive patients who underwent SCT for relapsed myeloma were studied. The median BMPC% on the marrow aspirate, core biopsy, and PCLI studies were 20, 25, and 20, respectively. There was a significant correlation between the three methods, rho > 0.65, P < 0.001. However, in 8% of patients the BMPC% was different by an absolute value of 50% between methods. No individual method was predictive for CR. However, the highest estimate of the BMPC% among the three methods was a significant predictor of CR (P = 0.02). Survival following SCT was longer among patients with a low BMPC% (< or =60) by the PCLI method compared to those with higher values, median survival 23 versus 7 months, respectively, P = 0.02. PFS was also different, with survival times of 11 and 5 months, respectively, P = 0.003. Similar results were obtained when the highest estimate of the BMPC% was used in survival analysis (P = 0.02 and 0.004, respectively). Statistical significance was lower when the BMPC% on the aspirate or biopsy used in survival analysis. Compared to any individual method of estimating BMPC%, the highest estimate of the BMPC% is the best predictor of CR in myeloma. It is also prognostic for poor survival and PFS following SCT for myeloma. We recommend that all three methods of estimating BMPC% be routinely performed and that the highest value be used for prognostic purposes., (Copyright 2001 Wiley-Liss, Inc.)

The plasma cell labeling index (PCLI) is a measure of plasma cell proliferative activity and is an important prognostic factor in newly diagnosed multiple myeloma (MM). Occasionally patients have been observed with stable, plateau phase MM with minimal numbers of residual light-chain-restricted monoclonal plasma cells, but a high PCLI. No data are available on the outcomes for such patients. Data from 57 patients with plateau phase MM and a marrow PCLI of more than 1.0% were compared with 105 matched control patients with MM with a marrow PCLI of less than 1.0%. All patients had less than 10% total plasma cells on marrow aspirate and biopsy. The median time to progression and overall survival were 8 months and 20 months, respectively, in the high PCLI group versus 39 months and 56 months, respectively, in the low PCLI group (P < .0001). These findings suggest that a high PCLI in patients with apparently stable, plateau phase MM is an adverse parameter that may predict a short time to disease progression and death.

We studied the effect of complete response (CR) among 126 consecutive patients who underwent stem cell transplantation (SCT) for myeloma. The CR rate with SCT was 33%. Median overall survival (OS) from diagnosis of myeloma was 56 months. OS following SCT was 22 months. Progression-free survival (PFS) was 12 months. OS was not different between patients who achieved CR and those who did not, median survival 25 vs 24 months, P = 0.5. Corresponding median times for PFS were 15 and 11 months, P = 0.2. The plasma cell labeling index (PCLI) was high (> or = 1%) in 36% (high risk group) and was associated with poor OS and PFS (P < 0.001). Achieving CR did not influence OS or PFS in either the high or the low risk group. In contrast, OS and PFS were significantly influenced by high PCLI both in patients who achieved CR and those who did not. OS was poor (< 30 months) in high risk patients regardless of CR status and in low risk patients who did not achieve CR, compared to low risk patients achieving CR (57 months), making them candidates for novel post-transplant treatment options. Outcome following SCT is dependent more on biological variables such as the PCLI than on CR status.

Purpose: To study the prognostic value of plasmablastic morphology after autologous stem-cell transplantation for relapsed or primary refractory myeloma., Patients and Methods: Seventy-five patients were studied. Investigators blinded to the clinical details of the individual cases reviewed bone marrow aspirate slides to determine plasmablastic classification. Plasmablasts were defined using strict, well-described criteria. Plasmablastic morphology was considered to be present (plasmablastic myeloma) when 2% or more plasmablasts were present in the plasma-cell population., Results: Patients underwent transplantation 5 to 88 months (median, 20 months) after the initial diagnosis of myeloma. Twenty-eight percent of patients had plasmablostic morphology. A significantly greater proportion of patients with plasmablastic morphology had abnormal cytogenetics compared with those with nonplasmablastic classification (73% v 31%, respectively; P = .003). The overall survival rate measured from the time of transplantation was significantly worse in patients with plasmablastic morphology compared with those without (median survival time, 5 months v 24 months, respectively; P < .001). Progression-free survival time was shortened also, with a median time of 4 months compared with 12 months, respectively (P < .001). In the multivariate analysis, plasmablastic classification was the most powerful prognostic factor after transplantation for both overall (P = .001) and progression-free survival rates (P < .001). We also identified three risk groups based on plasmablastic morphology: plasma-cell labeling index, lactate dehydrogenase, and cytogenetics. The median overall survival time was 38 months when none of these factors was abnormal, 17 months with one abnormal factor, and 8 months with two or more abnormal factors (P < .001)., Conclusion: Plasmablastic morphology is a powerful independent predictor of poor survival rate after autologous stem-cell transplantation for relapsed or primary refractory myeloma.

The proliferative rate of malignant plasma cells, as measured by the plasma cell labelling index (PCLI), is an important prognostic factor in multiple myeloma (MM); however, the PCLI alone is probably Inadequate to describe tumour growth because it ignores the idea that myeloma cells may have a reduced rate of apoptosis. The aims of this study were to develop a flow cytometric method to measure the apoptosis index of fresh marrow plasma cells and develop a plasma cell growth index (PCGI) that related both proliferation and apoptosis to disease activity. Marrow aspirates were obtained from 91 patients with plasma cell disorders and the plasma cells in apoptosis were identified by either 7-amino actinomycin-D (7-AAD) or annexin V-FITC three-colour flow cytometry. The median plasma cell apoptotic index (PCAI) for patients with monoclonal gammopathy of undetermined significance (MGUS), smouldering or indolent myeloma (SMM/IMM), and new multiple myeloma (MM) was 5.2, 3.4 and 2.4, respectively (P=0.03, MGUS v MM). The median PCLI for these same patient groups was 0.0, 0.2 and 0.6, respectively (P<0.001, MGUS v MM). The paired PCLI and PCAI for each sample were used to derive the PCGI=2 + [PCLI-(O.1)(PCAI)]. The median PCGI for patients with inactive disease (MGUS, SMM/IMM or amyloidosis) was 1.8 compared to 2.4 for those with active disease (new or relapsed MM) (P<0.001). These results suggest that a decrease in the PCAI may be a factor in the progression from MGUS to SMM to overt MM.

We evaluated the blood from 150 patients with primary AL-amyloidosis for circulating monoclonal plasma cells using a sensitive slide-based immunofluorescence technique. The percentage of monoclonal blood plasma cells (BPC) that were in S-phase was determined by the bromodeoxyuridine labelling index (BLI). Monoclonal BPC were detected in 16% (24/150) of patients. The median number of monoclonal BPC was 1 x 10(6)/l and 4.6% (7/150) of patients had a high number. The BLI was zero in all but three patients. This study demonstrates that monoclonal plasma cells circulate in the peripheral blood of patients with AL-amyloidosis.

Monoclonal plasma cells (CD38+CD45-/dim) are typically present in the blood of patients with active myeloma and can contaminate stem cell harvests. This has led to strategies that select CD34+ cells for use in autologous stem cell transplantation with the goal of decreasing tumor cell contamination. The aim of this study was to learn if the CD34 antigen is expressed on monoclonal plasma cells in the blood or marrow of patients with multiple myeloma. We used three-color flow cytometry (surface CD38;CD45 and cytoplasmic kappa or lambda) to identify monoclonal plasma cells in the blood (n = 24) and marrow (n = 37) from patients with plasma cell proliferative disorders. In each case the CD38+CD45- and CD38+CD45dim+ monoclonal populations were then analyzed for CD34 expression. In all 24 blood and 37 marrow samples, the CD38+CD45-monoclonal plasma cells were negative for CD34 expression. CD38+CD45dim+ monoclonal cells were documented in the blood of 11 patients and in the marrow of 33 patients and this cell population was also CD34-negative in all cases. These results indicate that CD34 is usually not expressed on the CD38+CD45-CD45dim+ monoclonal plasma cells in the blood or marrow of patients with plasma cell proliferative disorders. CD34 selection methods should therefore decrease the chance of tumor cell contamination of the stem cell product.

We sought to determine whether circulating tumor cells in the blood stem cell harvest from patients with multiple myeloma are associated with a shortened disease-free survival. Prospective analysis was performed in 33 patients of blood obtained at leukapheresis for future transplantation. An immunofluorescence microscopy procedure identified the tumor cells by their morphology and monotypic light chain staining. Eighteen patients had increased (> or = 0.2 x 10(6)/l) monoclonal plasma cells circulating in the blood at stem cell harvest. Fifteen of the 18 have relapsed, with a median relapse-free survival of 6.2 months. Of 15 patients with < 0.2 x 10(6) cells/l, seven have relapsed, with a median relapse-free survival of 22.5 months (P = 0.008). Patients with circulating plasma cells showed a trend toward shorter overall survival (P = 0.078). In a multivariate analysis using the bone marrow plasma cell labeling index and beta 2-microglobulin, the absolute number of plasma cells in the stem cell harvest achieved borderline significance for predicting relapse-free survival (P = 0.057). In conclusion, increased monoclonal plasma cells in the blood stem cell harvest are associated with a shortened relapse-free survival. This does not necessarily indicate that the circulating plasma cells were responsible for relapse. These results, however, have implications with regard to the timing of obtaining blood stem cells for patients who are candidates for ablative chemotherapy.

The purpose of this study was to quantitate the number and labeling index of monoclonal plasma cells in the blood of patients with newly diagnosed multiple myeloma (MM) to learn if these values were independent prognostic factors for survival. Patients were candidates for this study if they had untreated myeloma requiring therapy, were evaluated at our institution between 1984 and 1993, and had a sample of blood analyzed with a sensitive immunofluorescence technique for monoclonal plasma cells and the blood B-cell labelling index (BLI). The % blood monoclonal plasma cells (%BPC) and the BLI were analyzed along with stage, marrow plasma cell LI, % marrow plasma cells, calcium, creatinine, albumin, beta-2-microglobulin, and C-reactive protein as univariate and multivariate factors for survival. Eighty percent of the 254 patients accrued to this study had monoclonal BPC detected. The median % BPC was 6% and 57% (144 of 254) of patients had a high number (> or = 4%). Patients with > or = 4% BPC had a median survival of 2.4 years vs 4.4 years for those with < 4% BPC (P < .001). The BLI was also prognostic (P = .008). In a multivariate analysis, the % BPC, age, albumin, stage, marrow plasma cell LI, and the BLI were independent factors for survival. The %BPC and the marrow plasma cell LI best separated the group into low, intermediate, and high risk myeloma with median survivals of 52, 35, and 26 months, respectively. Patients with high %BPC were less likely to have lytic bone disease from their MM (P = .002). The %BPC and the BLI are independent prognostic factors for survival and are useful in identifying patients as low, intermediate, and high risk. Clonal cells in the blood should be quantified in future clinical trials for myeloma.

This study serially quantitated monoclonal plasma cells (PC) in the peripheral blood (PB) of 33 patients with multiple myeloma (MM) at diagnosis, after therapy, and at relapse using a sensitive immunofluorescence technique. The goal was to learn which disease phase is best for harvesting PB stem cells free of monoclonal PC. In 24 chemotherapy responders, 88% (21/24) had circulating PC at diagnosis; after therapy, 63% (15/24) had none, 33% (8/24) had < 3 x 10(6)/L, and only one had > or = 3 x 10(6)/L. In nine cases who failed to respond to initial chemotherapy, 89% (8/9) had high levels (> or = 3 x 10(6)/L) of circulating PC at diagnosis that remained high after therapy. In the relapse phase, 88% (21/24) had circulating PC and 63% (15/24) had high numbers. This study demonstrates that the PB is least likely to have circulating monoclonal PC during the period after successful chemotherapy. Patients who fail to respond to initial chemotherapy or are in relapse are likely to have tumor cells in the PB.

We evaluated the harvest product from 47 patients undergoing peripheral blood (BP) stem cell collections for monoclonal plasma cells (PC) using a sensitive immunofluorescence technique. 60% (28/47) had documented tumour cells in the apheresis product. The 32 patients in plateau had a mean of 1.62 x 10(6) PC/l v 74.64 x 10(6) in 15 relapsed patients (P < 0.01). 32% (6/19) of patients without any tumour cells in the initial sample had them detected on a subsequent apheresis sample. In four cases (all treated with GM-CSF) small numbers of tumour cells were detected initially but became undetectable on a subsequent sample.

Immunofluorescent staining (immunofluorescence bone marrow aspirate) and immunoperoxidase staining (immunoperoxidase bone marrow biopsy) were compared in 26 patients with plasma cell dyscrasia and less than 10% marrow plasma cells. Their clinical diagnoses included monoclonal gammopathy of undetermined significance (13 patients), treated multiple myeloma (four patients), multiple myeloma with less than 10% marrow plasma cells (two patients), primary systemic amyloidosis (two patients), monoclonal gammopathy of undetermined significance with neuropathy (two patients), angiofollicular lymph node hyperplasia (two patients, all with the POEMS [polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes] syndrome), and primary (amyloidosis) amyloid neuropathy (one patient). The percentage of plasma cells was greater than 5% in 23% of patients and less than or equal to 5% in 77% of patients. With immunofluorescence bone marrow aspirate and immunoperoxidase bone marrow biopsy, light-chain restriction was demonstrated in 84% of all cases and accurately determined in 96% of all cases as shown by serum and urine paraprotein analysis or tissue amyloid typing. Monoclonal populations of plasma cells can be readily identified with immunofluorescence bone marrow aspirate and immunoperoxidase bone marrow biopsy in most patients with paraproteins and marrow plasmacytoses not diagnostic of multiple myeloma.

We evaluated the number and labelling index of circulating peripheral blood monoclonal plasma cells (PBPC) in 57 patients with newly diagnosed smouldering multiple myeloma (SMM) to determine if these measurements could distinguish SMM from active multiple myeloma (MM). The PBPC were detected by a sensitive slide-based immunofluorescence procedure that identified PC by their morphology and monoclonal light chain staining. The presence of abnormal PBPC (defined as an increase in number or proliferative rate of circulating monoclonal plasma cells) was correlated with patient status at 6 and 12 months after testing. 16 of the 57 patients progressed within 12 months and 63% of these had abnormal PBPC. In contrast, only 10% (4/41) of those patients who remained stable had abnormal PBPC. The median time to progression for patients with abnormal PBPC was 0.75 years, compared to 2.5 years for those patients without abnormal PBPC (P < 0.01). The detection of PBPC is important and helps to identify patients with active MM when other parameters suggest SMM. The lack of abnormal PBPC suggests SMM, and these patients may have a stable course without the need for immediate chemotherapy.

Background: The analysis of peripheral blood mononuclear cells for plasma cells and B-cell surface light chain ratios may provide additional insight on the pathogenesis of multiple myeloma and predict disease activity. The goals of this study were to correlate these parameters with clinically determined disease activity and establish a cutoff value of circulating plasma cells that could be used in future clinical trials., Methods: Peripheral blood samples from 84 patients with monoclonal gammopathies were analyzed by an immunofluorescence, slide-based, labeling index (LI) technique for detection of plasma cells, the LI, and light chain ratios. These parameters were compared with disease activity., Results: Of the 84 patients studied, 27% had inactive and 73% had active disease. The mean number of plasma cells for patients with inactive disease was 0.61 x 10(6)/l, compared with 139.6 x 10(6)/l for patients with active disease (P < 0.001). The mean ratios of involved to uninvolved light chain percentages for patients with inactive and active disease were 1.6 and 9.2, respectively (P = 0.002). The absolute number of plasma cells better predicted disease activity than the light chain ratio. By use of a cutoff value of 3 x 10(6)/l, 67% of patients with active disease were determined to have 3 x 10(6)/l or more plasma cells, and 96% of those with inactive disease had less than 3 x 10(6)/l plasma cells., Conclusions: These results suggest that detection of circulating plasma cells is a marker of disease activity in patients with plasma cell disorders and that an appropriate cutoff value is 3 x 10(6)/l or more circulating plasma cells.

The plasma cell labeling index (PCLI) and serum beta 2-microglobulin (beta 2M) are independent prognostic factors in multiple myeloma (MM). Recently, levels of thymidine kinase (TK) and C-reactive protein (CRP) have been shown to have prognostic value. We studied 107 patients with newly diagnosed myeloma to determine whether TK and CRP values added prognostic information not already available using the PCLI and beta 2M. Univariate survival analysis showed prognostic significance for the PCLI, TK, beta 2M, age, serum albumin, and CRP. Multivariate analysis showed that only PCLI and beta 2M have independent prognostic significance. The survival curves were better separated using the PCLI and beta 2M than with other combinations of variables. Among nine patients under age 65 with low PCLI and low beta 2M, eight were alive almost 6 years after starting chemotherapy. These good-risk patients could not be identified by standard clinical features. Although creatinine and calcium were normal, other features such as bone lesions, osteoporosis, fracture, and anemia were present and stage distribution was similar to other patients in the study. In conclusion, PCLI and beta 2M measured at diagnosis are independent prognostic factors. They must be considered when interpreting the results of clinical trials and should be helpful in counseling patients and in designing new trials. When the PCLI and beta 2M values are known, the TK and CRP values do not add useful additional prognostic information.

These studies indicate that monoclonal plasma cells can be detected in the peripheral blood of patients with active myeloma even when they are not detectable by routine WBC differentials performed on Wright-stained blood smears. These cells are usually not present in patients with MGUS and true SMM. They are detected in approximately 60% of patients with new, active MM and over 90% of patients with relapsed or refractory MM. If treatment is effective, they tend to decrease or disappear from the blood. When immunological, molecular, or cytogenetic studies are performed on peripheral blood cells from patients with MM, it must be realized that monoclonal plasma cells may be present and that they can influence the results of these tests. Although monoclonal plasma cells can circulate in the peripheral blood, it is not yet clear whether this cell represents the myeloma stem cell. It is possible that there are precursor cells that do not have plasma cell morphology in the blood or marrow that then differentiate into plasma cells. This question can only be answered by first depleting the plasma cells and then examining the remaining B-cells with appropriate immunological and molecular techniques.

The detection of peripheral blood plasma cells is clinically important, but difficult to perform by use of routine smears. To simplify the detection process, the peripheral blood T cells from ten patients with known active multiple myeloma were depleted using anti-CD2 coated magnetic beads. In all cases, there was enrichment of the immunoglobulin (Ig) positive cells after T cell depletion (mean enrichment factor, 3.4; median, 3.2; range, 1.2-5.1) with a mean pre-bead %Ig+ cells of 7.3 compared to 20.4 for the post-bead sample (p = 0.005). The monoclonal plasma cells were similarly enriched and more easily enumerated on the microscope slides prepared from the T cell depleted sample.

Tritiated thymidine labeling indices (LI), although useful in diagnosis and prognosis of multiple myeloma, have not found wide-spread application because autoradiographic analysis is difficult and time consuming. Using a monoclonal antibody (BU-1) reactive with 5-bromo-2-deoxyuridine (BrdUrd), we have developed an immunofluorescent procedure that allows DNA S-phase measurements to be determined in 4 hr. Plasma cells are easily identified by reactivity with a fluorescein isothiocyanate-conjugated antihuman immunoglobulin, and cells in DNA S phase are detected via BU-1 and a rhodamine-conjugated antimouse immunoglobulin. Results using this method on 12 patients with multiple myeloma compare favorably (correlation coefficient 0.84), with those obtained by tritiated thymidine. This immunofluorescent slide method will facilitate application of labeling indices as a clinical test to measure disease activity in patients with multiple myeloma and other hematologic neoplasms.

Clinical outcomes for multiple myeloma (MM) are highly heterogeneous and it is now clear that pivotal genetic events are the primary harbingers of such variation. These findings have broad implications for counseling, choice of therapy and the design and interpretation of clinical investigation. Indeed, as in acute leukemias and non-hodgkins lymphoma, we believe it is no longer acceptable to consider MM a single disease entity. As such, the accurate diagnosis of MM subtypes and the adoption of common criteria for the identification and stratification of MM patients has become critical. Herein, we provide a consensus high-risk definition and offer practical guidelines for the adoption of routine diagnostic testing. Although acknowledging that more refined classifications will continue to be developed, we propose that the definition of high-risk disease (any of the t(4;14), t(14;16), t(14;20), deletion 17q13, aneuploidy or deletion chromosome 13 by metaphase cytogenetics, or plasma cell labeling index >3.0) be adopted. This classification will identify most of the 25% of MM patients for whom current therapies are inadequate and for whom investigational regimens should be vigorously pursued. Conversely, the 75% of patients remaining have more favorable outcomes using existing – albeit non-curative – therapeutic options.Leukemia (2007) 21, 529–534. doi:10.1038/sj.leu.2404516; published online 18 January 2007 [ABSTRACT FROM AUTHOR]